Intraoperative Blood Salvage: Medical Controversies

Intraoperative Blood Salvage: Medical Controversies Walter H. Dzik and Bradford Sherburne

NTRAOPERATIVE blood salvage (IBS) and autotransfusion were first reported in 1886. Used infrequently in the early part of this century, the practice of IBS became more commonplace with the development of modem cardiovascular and trauma surgery. The last decade has witnessed an explosive increase in its application of elective and emergency surgery. During the last 20 years, there have been many publications on the topic. A number of review articles have also been published. I - 12 Despite the widespread experience with blood salvage and intraoperative autotransfusion, a number of medical controversies persist. We review the primary articles that have addressed the indications, contraindications, and complications of IBS. Our interpretations of the literature are also offered. We have not addressed costJ benefit controversies of IBS, administrative issues in running a blood salvage program, or the relative merits of different commercially available devices. We have not included a large number of articles that report on IBS but do not directly address the medical controversies surrounding its use. We hope to define for the reader the scope of controversial medical issues associated with IBS, draw conclusions from the available literature, and point toward areas where further research is needed. We have used the term intraoperative blood salvage (IBS) rather than intraoperative autotransfusion (lAT) in order to distinguish the practice of blood salvage from other forms of intraoperative autotransfusion such as hemodilution and the intraoperative infusion of autologous predeposit blood.

I

CANCER SURGERY

It is generally accepted that blood salvage and autotransfusion are contraindicated for procedures involving the resection of a primary, nonmetastatic From the Department oj Pathology and Laboratary Medicine, New England Deaconess Hospital; and the Departments oj Medicine and Pathology, Harvard Medical School, Boston, MA. Address reprint requests to Walter H. Dzik, MD, Director, Blood Bank and Tissue Typing Laboratory, New England Deaconess Hospital, 185 Pilgrim Rd, Boston, MA 02215. © 1990 W.B. Saunders Company. 0887-796319010403-0004$03.00/0

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malignancy. Concem exists that tumor cells harvested during IBS would be reinfused to the patient and promote metastatic disease. Less objection may exist to the use of IBS in the setting of palliative cancer surgery for the patient with established metastatic disease. Such patients, however, mayaiso have the least to gain from avoiding homologous blood. Three issues of controversy surround the use of IBS in oncologic surgery: reinfusion of cancer cells, irradiation of salvaged blood, and the immunosuppressive effects of transfusion in cancer patients. Does Intraoperative Blood Salvage and Autotransjusion Result in the Reilifusion oj Malignant Cells and the Subsequent Development oj Metastatic Disease?

The argument against the use of blood salvage during oncologic surgery rests on the reasonable assumption that malignant cells aspirated from the surgical field would not be removed by processing techniques commonly used in IBS. Reinfusion of these cells would presumably increase the likelihood of dissemination of the tumor. There has been no direct proof of such occurrence, however. Yaw et al l3 were the first to raise a concem that aspirated cancer cells would be reinfused to the patienł. They reported on a single case of a man with persistent hemoptysis due to an eroding bronchogenic carcinoma. During surgery, blood was aspirated from the site of the tumor into a Bentley type autotransfusion device that neither centrifuged nor washed the aspirated blood. In addition, pleural fluid was aspirated into the autotransfusion device. Sampies were taken from the autotransfusion machine before and after the blood passed through an in-line filter in the machine. When these sampies were centrifuged, tumor cells were identified cytologically. The authors noted that they had no evidence for the viability of the tumor cells observed, but wamed against the possibility of reinfusion of malignant cells. More than a decade later, the report of Dale et al 14 reexamined the issue of reinfusion of malignant cells. These authors studied a Haemonetics (Braintree, MA) Cell Saver device that both centrifuges and washes salvaged blood. Two units of blood were each "spiked" with a different tumor Transfusion Medicine Reviews. VoIIV, No 3 (July), 1990: pp 208-235

INTRAOPERATIVE BLOOD SALVAGE

celi line. In the first experiment, an Epstein-Barr transformed lymphoblastoid cell line was 5lChromium elCr) labeled and added to a unit of blood at a final concentration of approximately 100 cells per microliter. This blood was then processed through the Celi Saver, washed with approximately 1,500 roL of saline, and resuspended in saline to a final volume of 460 roL. Sampies were taken from the blood before processing, from the discard fluid, and from the blood after processing. The radioactivity of these sampies was counted in triplicate. The sampies were centrifuged so that the total radioactivity could be separated into the portion that was in the plasma or resuspension fluid and the portion that remained with the cells. The second experiment had the same experimental design but used a different tumor cellline. A human adenocarcinoma celi line, which had been passed through nude mice, excised, and disaggregated, was radiolabeled and added to a unit of blood at a final concentration of approximately 10 cells per microliter. The results of both experiments showed that approximately 85% to 90% of the radioactivity originally present in the blood remained in the blood after processing. The radioactivity was found in the cellular portion of the blood rather than in the supematant, and very little appeared in the discarded wash solution. Although the behavior of tumor celllines does not always parallei that of in vivo tumor cells, and although the possibility exists that the tumor cells "leaked" 5lCr, which was then "taken up" by the red cells, the results support the concept that malignant cells are carried through the autotransfusion device despite centrifugation and washing and would be presumably reinfused into the recipient. Since all patients undergoing resection of a malignancy are at risk for subsequent metastatic disease, the real focus of controversy in the use of IBS during oncologic surgery is the increment in risk imposed by IBS. No studies directly answer this question. In support of those who would not use IBS in cancer surgery is the recent report by Lane. 15 In this study, C57BU6 mice were infused with blood collected in citrate phosphate dextrose adenine-l (CPDA-l) that had been admixed with malignant melanoma cells (FlO) known to produce pulmonary metastases in these animals. Syngeneic animals without tumor were injected with either fresh blood and tumor cells or with błood that had

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been stored at 4°C with tumor cells for up to 21 days. The fresh blood with tumor cells was found as likely to produce metastases as tumor cells suspended in saline. One pulmonary metastasis developed for approximately every 500 tumor cells infused. Refrigerated stored blood produced fewer metastases. The clinical experience with the use of peritoneovenous shunts for the treatment of malignant ascites may be relevant to the controversy regarding reinfusion of tumor cells during IBS. Patients treated with such shunts usually have ascitic fluid known to be contaminated with malignant cells. Despite the direct vascular infusion of such fluid, reports of patients treated with peritoneovenous shunts have emphasized that widespread pulmonary metastases or miliary metastases do not develop shortly after surgery.16-l9 Nevertheless, deposits of tumor cells enmeshed in fibrin have been occasionally found at the venous tip of the catheter,20,21 and noninvasive tumor "emboli" have been noted in the pulmonary microcirculation. 22-23 Since the nature of these patients' underlying illnesses has not allowed for long-term follow-up, the real risk of eventual metastatic seeding as a resułt of venous reinfusion of autologous tumor cells is not adequately answered by these studies. In support of those who would use IBS in cancer surgery are studies that document that circulating tumor cells in cancer patients do not correlate with the likelihood of metastatic disease. 24 Moreover, occasional reports from the surgical oncołogy literature find no increased incidence of metastatic disease following surgery using IBS. 25 Klimberg et al 26 used the Haemonetics Cell Saver device in 49 patients undergoing surgical procedures for urologie malignancy including 24 radial cystectomies, 10 radical prostatectomies, 13 radical nephrectomies. Five of the 49 patients developed metastases during routine clioical follow-up from 12 to 23 months. The incidence and pattem of metastatic disease in these patients was no different from that found in other patients (nonmatched controls) who were treated with similar operations not using autotransfusion. The authors failed to find an incremental risk of clinically evident metastatic disease as a result of the use of IBS. In a recent report, Hart et al 27 provided followup information on IBS use in 49 patients undergo-

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DZIK AND SHERBURNE

ing radical cysteetamy for eareinoma af the bladder. Thirty-three patients had follaw-up after l year. Of these, 29 were alive at a median follawup time of 26 manths. Seven of the 33 had evidenee of postoperative reeurrence af tumor. The pattem of reeurrenee in most of these patients was either to loeal lymph nodes or to draining lymph nodes. One patient, however, died with multiple pulmonary metastases without evidenee of loeal reeurrence. With a median follaw-up af 26 months, no patient bad developed metastatie disease to multiple organs that eould be explained solelyon the basis of intravaseular dissemination of tumor as a result of autotransfusion. The postaperative survival of sueh patients is shown in Fig I. Dur own experienee with intraoperative salvage during reseetian af extensive rena! tumars has been equally eneouraging. 28 IBS was used in seven patients who underwent radical nephreetomy and removal of tumor extending into the renal vein, up the vena eava, and into the right atrium of the heart. Resectian af the eardiae and vena eaval portion of the tumor was performed using eardiopulmonary bypass followed by total eireulatary arrest. IBS was used throughout surgery exeept during removal of friable tumor from the right atrium and vena eava. A median af 3 U (range, O to 56 U) of blood were salvaged and reinfused in eaeh patient during the surgery. With a median follow-up of 1 year, the development of metastatic disease ap-

pears to be no more frequent than that expeeted for these patients. In faet, despite the dramatie extent of intravaseular tumor and the radical nature of the surgieal reseetion, four of the seven patients are alive with no evidenee af metastatie disease at 4, 10, 16 and 32 months postoperatively.

Would Gamma Irradiation oj Salvaged Blood Remove the Risk oj Reinjusion oj Malignant Cells? Many hospital blood banks have blood irradiators capable of delivering 50 to 100 Gy to a unit of blood in minutes. Sinee malignant eells are sensitive to high-dose radiation, this treatment would seem a logieal way to allow widespread use of IBS during oneologie surgery without risk of promating metastatic disease. Surprisingly, there are no published clinical reports using this strategy. The sensitivity of both normal and malignant eells to high-dase radiation is well known. Inereasing doses of gamma radiation delivered to mammalian tumor eells in vitro deerease the ability of these eells to propagate in eulture. At doses greater than 10 Gy, there is a logaritbmie decline in the fraetion of eells eapable of propagation in vitro. The dose ofradiation needed to "sterilize" 63% of the residual number of propagating eells is designated Do. For most eelllines tested, Do is 1.5 ± .5 Gy.29 Thus, 50 Gy translates into approximately a 15 log kill and 80 Gy into approximately a 25 log

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Ag 1. Use ot IBS during cancer surgery. Postoperative mortality due to metastatic cancer in patients after resection ot renal or bladder carcinoma. Thirtyeight patients with bladder car· cinoma received nonirradiated blood (median, 500 mLI col· lected by IBS with washing. Ali patients with renal carcinoma received blood (median, 250 mLI colleeted by IBS/washing. Data kindly supplied by Z. Wajsman, MO, Department ot Surgery. Di· vision ot Urology. University ot Florida. Gainesville. FL.

INTRAOPERATIVE BLaOO SALVAGE

reduction in cells capable of propagation. Low numbers of malignant cells in the oxygen-rich environment of salvaged blood may be even more sensitive to gamma radiation. Red cells are known to tolerate up to 200 Gy and maintain adequate posttransfusion survival. 30 Would the Use oj Intraoperative Blood Salvage in Oncologic Surgery Actually Improve Disease-Free Survival by Avoiding the Immunosuppressive Effects oj Allogeneic Transjusions? A growing controversy has developed from retrospective studies that suggest that some patients who receive transfusions at the time of resection of a primary malignancy relapse sooner than patients who are not transfusedY-33 One explanation for these observations is that allogeneic transfusions may exert a nonspecific immunosuppressive effect. Several explanations have been forwarded to explain the proposed immunosuppressive effect of blood transfusions including activation of suppressor T cells, production of antiidiotypes, reticuloendothelial blockade, suppression of natural killer cell activity and exposure of the patient to plasticizers or soluble plasma factors. 31 Many of the proposed explanations depend on an effect exerted by allogeneic cells. This suggests the possibility that autologous celIs collected by intraoperative salvage would not increase the likelihood of earlier tumor recurrence. The answer to whether IBS (with or without radiation) during oncologic surgery increases, decreases, or has no effect upon tumor recurrence and survival awaits further clinical triaIs . BACTERlAL CONTAMINATION OF THE OPERATIVE FIELD

Infection in the operative field is widely regarded as an absolute contraindication to intraoperative blood salvage. There is debate about whether the presence of a perforated viscus is a contraindication to IBS, even if the patient is in imminent danger of exsanguination. Several series of cases have been published, however, in which the need for blood was so urgent that it became necessary to transfuse salvaged blood in the presence ofgross enteric contamination. In this section, we review the bacteriology and experimental background for the use of contaminated salvaged blood in elective and trauma surgery, the efficacy of celI washing to remove microorganisms, and the

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issue of whether to use IBS in trauma cases or "clean-contaminated" surgery. Animai Studies oj Contaminated Intraoperative Blood Salvage

There are two extensively cited articles examining autotransfusion of grossly contaminated blood in dogs. Klebanoff et at3 4 used a modified Bentley device to salvage and transfuse blood to mongrel dogs under clean-contaminated conditions. Under hemodynamic monitoring, a branch of the superficial femoral artery was transected and alIowed to bleed freely into a groin cavity created by the dissection, collected into the Bentley unit, and reinfused via a venous cutdown. The animals were heparinized, and cycling through the salvage unit continued for 60 minutes, at which time the vessel was ligated and protamine administered. In 10 dogs, a mixture of solid fecal material, liver, splenic tissue, fat and bile was ground in amortar and the slurry was added to the Bentley reservoir during the 60 minute experiment. Five dogs in this group were given chloramphenicol folIowing the procedure. Although immediate postoperative blood cultures grew mixed coliforms in alI 10 animals, cultures became negative by 24 hours. All subjects recovered uneventfulIy without infectious sequelae, whether or not antibiotic was administered. Smith et a1 35 studied the combined effects of shock and bacterial contamination. In their model, 20%, 30%, or 40% of a dog's blood volume was removed and instilled into the peritoneal cavity during open laparotomy. A sigmoid colotomy was then performed, and 15 to 30 cc of stool were removed and allowed to mix freely with the blood in the open peritoneum. After 30 minutes of contact time, the blood was harvested into a heparinized Bentley unit and reinfused through a standard 125 micron filter while the colotomy, venous cutdown, and laparotomy incisions were closed. It was found that mortality related directly to the degree of hemorrhage and the presence of contamination. One of nine animals subjected to a 20% hemorrhage with contamination died; controls without contamination (same procedure except colotomy omitted) survived. With 30% hemorrhage, four of 15 (26%) experimental animals died compared with one of eight (12%) controls. The differences for these groups were not statistically significant probably due to sample size. With 40%

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hemorrhage, seven of 10 (70%) animals receiving contaminated blood died compared with only one of 10 controls. This difference was statistically significant. When antibiotics were administered intramuscularly (penicillin and streptomycin), survival in the antibiotic treated group was identical to the controi group. As encouraging as these findings are, other investigators have noted that dogs possess a high tolerance to bacteremic challenge. 36 In fact, the majońty of the animals in Smith's studies 35 had positive blood cultures before autotransfusion (although none did in the Klebanoff study34). While human subjects become transiently bacteremic several times in an average day, these episodes are rapidly cleared, and random human blood cultures are normally steńle. 37 The implication is that bacteńal clearance in human beings, while efficient during minor challenges, is probably different from that in dogs and subhuman pńmates. The results of expeńments in the dog model must therefore be interpreted with caution. Does Celi Washing Remove Bacteria? Expeńmental evidence supports the notion that washing decreases, but does not eliminate, the microbial burden from enterically contaminated blood. Huth et a1 38 in Seattle explored the possibility of using IBS with washing duńng excision and grafting of bum eschars. As these wounds are extensively colonized by large numbers of bacteńa, the blood salvaged was subjected to a "double wash cycle" in a Haemonetics CelI Saver III. Pilot sampies of this double-processed blood demonstrated "a significant growth of bacteńa" when cultured, and the authors concluded that the product was unsuitable for use in bum patients. Boudreaux et a1 39 reported their expeńence using washed salvaged blood in trauma cases and noted that three patients who received IBS in the presence of intestinal perforation failed to manifest any septic complications. Based on this observation, they investigated the ability of the cell washer to remove bacteńa by performing quantitative cultures on expeńmentally contaminated blood duńng various stages of processing. Stock cultures of Escherichia coli were grown for 24 hours and inoculated into outdated whole human banked blood or therapeutic units taken from Polycythemia vera patients. Bacteńa were added to simulate light (l 3 X 10 colony-forming units [CFU] per milliliter),

DZIK AND SHERBURNE

moderate (l X 105 CFU per milliliter) and heavy (9 X 107 CFU per milliliter) contamination of the units. Processing was carńed out on a Haemonetics Model 15 CelI Saver using l L of saline for the wash cycle. Seńal dilution and quantitative culture demonstrated that the units retained 23% (light), 13% (moderate), and 5% (heavy) of the ońginal inoculum. An additional 10 L wash failed to produce any significant decrease in the quantity of recovered bacteńa. Cultures of the reservoir demonstrated that bacteńa were not being trapped in the filter matńx, and 97% of the inoculum could be accounted for in the wash effluent and red cells. They concluded that the bacteńa retained after celI washing were firmly bound to the red cells and that the Cell Saver, while removing a proportion of the bacteria, cannot produce a "steńle" red cell product. In a similar investigation, Rumisek and Weddle 36 designed a study ofthe effect ofwashing experimentally contaminated blood with antibiotic solutions. Rather than using stock cultures and known inoculae, expired bank blood was mixed with fresh human stool and washing was carńed out with either cefoxitin sodium or traditional "triple antibiotics" (ampicillin, gentamicin and clindamycin) added to the saline. The effluent after various wash increments and the final processed blood packs were cultured. Microorganisms isolated included Enterobacteriaciae, enteric Streptococcus species (enterococcus), and anaerobic bacteńa. To summarize their findings, colony counts of fecal streptococci and coliforms in the wash effluent decreased in logarithmic fashion, reaching near-maximal reduction between 750 and 1,000 mL of wash solution. The triple-antibiotic regimen was the most efficacious, and the final product demonstrated elimination of coliforms and reduction of enterococcus from greater than 105 CFU per milliliter to less than 2 x 103 CFU per milliliter. Plain saline wash (l ,500 mL), however, was nearly as effective, reducing coliforms from greater than 105 CFU per milliliter to about 3 x 103 CFU per milliliter and enterococcus from greater than 105 CFU per milliliter to about 15 x 103 CFU per milliliter. Cefoxitin wash was about as effective as saline wash. Counts of anaerobie bacteria failed to decrease below 105 CFU per milliliter in any of the final processed units, although Bacteroides species were eliminated when the tń­ ple antibiotic wash was used. Naturally, this study

INTRAOPERATIVE BLOOO SALVAGE

was difficult to control due to the nature of the inoculum-bacteria could be sequestered in microaggregates of stool, red celi micelles could have formed around stool particles, etc. However, the model is a realistic one, and the finding that counts was logarithmically reduced by washing (whether antibiotics were added or not) is encouraging. Further studies need to be conducted in the area of supplementing wash solutions with antibiotics. lntraoperative Blood Salvage in Clean-Contaminated Surgery

Before the introduction of IBS with washing, most intraoperative transfusion was undertaken with Bentley and/or Sorenson type devices. Although a good deal was written about intraoperative salvage with these techniques, key issues addressed were mainly concemed with coagulopathy and reinfusion techniques. Little or no mention was usually made of bacteriologic considerations-intentional culturing of salvaged blood or postoperative surveillance blood cultures were not regularly performed. Intraoperative transfusion was usually reserved for nonseptic cases such as major vascular surgery or "clean" trauma surgery such as those without fecal spillage or wounds over 4 hours old. Thus, no serious infectious complications were expected, and usually none were encountered. One study that did address this issue used a Bentley-like device during surgery for 38 women with ruptured eetopie pregnaneies. 40 Ali but six patients received more than 500 cc of autologous salvaged blood, and five patients had evidenee of ehronie pelvic inflammatory disease at laparotomy . Postoperative blood eultures were done, and all were negative, although no mention was made as to whether antibiotics were administered. Two patients did develop postoperative wound infeetions, but these were not the patients with pelvic inflammatory disease, and their preand postoperative blood eultures were negative as well. The authors felt that it was doubtful that IBS eontributed to the wound infeetions in these patients, and even went on to observe, "while frank pus at the operative site would seem to be a eontraindication to autotransfusion, the use of autotransfusion does not appear to inerease the morbidity of eetopie gestation even when it is eompounded by ehronic pelvie inflammatory disease. " In another large series, Keeling et a141 examined

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at least l U of autologous, salvaged red eells in eaeh of 725 eases. These were mainly clean cases, and over 90% involved cardiothoraeie surgery. The units were cultured after proeessing in the Haemoneties Cell Saver. Although exaet figures were not given, the authors noted that Staphylococcus epidermidis and/or diphtheroids (skin flora normally considered nonpathogenie) were reeovered "on oeeasion." In one ease, there was a smali bowel infarct identified at laparotomycultures of the salvaged unit, preoperative blood eultures, and peritoneal eultures all grew Propionibacterium acnes (an anaerobe also normally considered nonpathogenie). Despite these findings, "there was no evidenee of clinical sepsis ascribed to these organisms in any patient in the study.' ,41 Intraoperative salvage in the faee of frank eontamination has only been used if the patient were bleeding to death and uncrossmatched bank blood were not immediately available. Several studies have reported the experienee in sueh instanees. The first major series was reported by Griswold and Ortner in 1943. 42 IBS was used in 25 patients with perforation of a hollow viseus; eight patients, or about one third, survived. Examination of their tabulated results shows that of the 17 patients who died, only three patients demonstrated infeetious eomplications. This study demonstrates the high mortality rate of sueh eritically injured patients in the preantibiotic era. Glover et a143 used a slightly modified Bentley unit for autotransfusion in 183 emergeney surgeries. Blood was eollected in a primed, heparinized reservoir and reinfused through a standard filter without washing. Fourteen patients with extensive abdominal injuries, mainly due to gun shot wounds, were identified in which there was gross eontamination by intestinal eontents. Of six patients who succumbed within 24 hours, four had extensive injuries and intraetable shoek, one suffered aeute hypoxia in the recovery room without an obvious anatomie cause of death identified at autopsy , and one developed sepsis, disseminated intravaseular coagulation (DIC), renal failure, and fatal hypoxie cardiac arrest postoperatively. The authors eoncede that transfusion of eontaminated blood may have played a role in the patient who developed OIC. Ali patients received broad spectrum antibiotics throughout the perioperative period. Of the eight survivors, two had infeetious eomplications. One required lysis of adhesions for

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bowel obstruction-purulent intraabdominal collections were found at operation, but the patient also had extensive peritoneal soiling as the result of the initial injuries. The other patient was a victim of a close range shotgun blast with multiple puncture wounds of the liver, pancreas, duodenum, colon, smalI intestine, and kidney. She progressed to renal failure requiring hemodialysis, developed late intractable sepsis, and died 5 weeks postoperatively-multiple intraperitoneal abscesses were found at postmortem. Again, one could argue that the nature of her primary injury, and not contaminated salvaged blood, accounted for these findings. The two patients with the greatest transfusion requirements (8 and 13 L IBS) and the patient who received 5 L of IBS only (no banked blood) all recovered without infectious sequelae. Based on their experience, the authors concluded that the advantages of transfusing contaminated autologous blood in the face of profound hypovolemic shock at least equals, and may outweigh, the disadvantages. 43 Not all authors share this opinion, however. In their 1984 review article, Jacobs and Hsieh 8 stated, "in situations in which homologous blood is readily available, the inherent risk of transfusing contaminated blood is too great; indeed, in urban settings with modern blood banks and available Red Cross, this is an absolute contraindication." There is a spectrum of opinion among trauma surgeons about what degree of contamination to allow when IBS is used. Jurkovich et al44 published a series that assessed the cost-effectiveness of autotransfusion retrospectively in 85 consecutive trauma cases. In each instance, a Haemonetics Cell Saver III was set up for IBS; salvaged blood was actually returned to the patient in only 22 of these cases. Of the cases in which salvaged blood was not reinfused, 19% were due to early death of the patient, 60% were due to inadequate blood retrieval, and 21 % were due to "extensive peritoneal contamination from colon injury. " Despite the exclusion of grossly contaminated cases, IBS was performed in four patients with colon injuries and two with upper gastrointestinal wounds. Cultures were taken from the Cell Saver reservoir in these six cases. Two sampIes grew E coli, and one grew alpha-hemolytic Streptococcus. None of these six patients had positive blood cultures in their first postoperative week, but one died from "sepsisrelated multiple organ failure" 3 weeks postoper-

DZIK AND SHERBURNE

atively. These authors concluded, "Dur limited experience and that of others suggests that mild contamination, even with a positive blood culture, is usually well tolerated ... extensive fecal spillage, however, remains a relative contraindication to use of the autotransfuser. ,,44 Timberlake and McSwain45 published a retrospective review of trauma cases in which IBS was used in the presence of enteric contamination. Unlike the study by Glover, 43 these investigators used a Haemonetics Cell Saver to process the soiled salvaged blood. Eleven patients were identified who had injuries to the colon or small intestine, and the Cell Saver was used regardless of the degree of fecal spillage. All patients received broadspectrum cephalosporins through the perioperative period. Patients were men aged 22 to 45 with gunshot and stab wounds of the abdomen and a mean trauma score of 10; 2 to 6 U (average, 4) ofwashed Cell Saver blood and 2 to 8 U (average, 4.9) of banked blood were administered. Aliquots of each of the 45 processed Cell Saver units were cultured, and all grew organisms including Staphylococcus (coagulase negative and aureus) , Streptococcus (enteric and nonenteric), Enterobacteriaciae (E coli, Enterobacter) , Candida and anaerobes (Clostridia and Bacteroides). (Table 1). Remarkably, all 11 patients survived, and none had positive blood cultures on the first postoperative day. Three patients developed infectious seque1ae: two had wound infections that grew the same organisms as those isolated from the salvaged blood, one developed necrotizing fascitis of the abdominal wall due to Pseudomonas aeruginosa. The latter

rabie 1. Organisms Isolatad From Washed. Salvaged Blood Organism

Reference

Staphy/ococcus aureus Staphy/ococcus epidermidis Corynebacterium species Streptococcus species Escherichia coli Enterobacter species Propionibacterium acnes C/ostridium species Bacteroides species Candida species

45 41,45 41,45 44,45 44,45 45 41 45 45 45

NOTE. There is an absence ot Pseudomonas species or other nontermentative gram negative organisms that are trequently resistant to conventional antibiotic therapy.

INTRAOPERATIVE BLODD SALVAGE

nosa. The latter complication probably represented nosocomial infection, as none of this patient's perioperative blood cultures, ineluding salvage units, grew this organism, which was known to colonize their intensive care unit. The former two wound infections could have been due to IBS of contaminated blood or local contamination during primary elosure of the wound. No patient developed intraabdominal abscess, pneumonia, or urinary tract infection, and all were eventualIy discharged. These authors concluded that as long as adjunctive, perioperative broad-spectrum antibiotics are administered "the use of shed blood contaminated by intestinal contents after processing the blood through a cell washing recovery system is justified as a lifesaving measure. ,,45 Can lntraoperative Blood Salvage Be Used When There ls Contamination? The safety of perioperative transfusion of salvaged autologous blood in noncontaminated, elective surgery appears well established from the literature examined. From a bacteriologic viewpoint, no contraindications to its use can be recognized, whether celI washing is used or not. However, for the trauma victim faced with emergency surgical intervention and potential enteric contamination, the need to restore normovolemia and oxygen carrying capacity must be assessed with respect to the degree of bacteremic challenge that can be tolerated by the patient. Animai studies and the reported experiences with human trauma patients suggest that the ability of a subject to withstand a septie challenge is inversely related to the degree of shock and compromise of tissue perfusion imposed. Thus, whatever means that can be exploited to ensure that hemodynarnic stability is restored should probably be the immediate goal. This is generally accomplished by crystalloid or colloid infusions while awaiting banked blood. If banked blood is not available and red celIs are needed, then reinfusing the patient's blood with a salvage device would seem to be the appropriate course of action, even if enteric contamination is present. An insufficient quantity of banked blood should occur only in rare extraordinary circumstances. Administration of appropriate broad-spectrum antibiotics should be instituted without delay if autotransfusion of potentially contaminated blood is considered. Washing the salvaged produce would

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be most desirable, but if there is life-threatening hemorrhage, sufficient time may not be available for washing. Review of organisms recovered during IBS (Table l), suggests that the flora introduced when contamination occurs usually consists of bacteria that are normally treated effectively by conventional antibiotic therapy. One final issue worth considering is that of the immunologie effects of autologous versus homologous blood. Although a detailed exploration of this topic is beyond the scope of this review, it is generally accepted that homologous blood transfusion produces a degree of immune suppression. In addition to studies that suggest an association between homologous blood transfusion and early tumor recurrence, 31-33 Tartter46 has reviewed several reports implicating blood transfusion as responsible for increasing the frequency and severity of postoperative infection. Waymack et al used an animai model to study the effect of transfusion on mortality in rats subjected to a fulI thickness bum injury, which was inoculated with P aeruginosa. They found a statisticalIy significant increase in mortality when homologous blood was transfused compared to controi animals supported only with saline. 47 They had previously established that no increase in mortality was observed in this model when syngeneic (autologous) blood was transfused. Dawes et al48 used multiple regression analysis to identify which factors were significant1y associated with infectious complications after colon injury. The likelihood of postoperative infection increased with the number of homologous units of blood infused. Similar statistical analyses by Nichols et al 49 and DelIinger et al 50 also implicate transfusion requirements as a significant predictor of postoperative infection following abdominal trauma. These studies were adjusted to isolate transfusion as a separate variable, ie, so that transfusion requirement was not merely a marker for "sicker" patients. If one assumes that homologous blood transfusion compromises immune function and leads to an increased rate of postoperative infection, one could argue that some sort of "breakeven" point exists with respect to making a decision to use autotransfusion in clean-contaminated surgery. In other words, if one could identify the level of bacterial contamination that would produce infection if IBS were used and compare this with the amount of homologous

DZIK AND SHERBURNE

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transfusion that would increase the patient's ńsk of developing postoperative infection, then one could make a clinical decision as to which approach would likely be least detńmental to the patient's recovery. However, we are far from knowing these vańables. A clinical study of infectious complications in patients undergoing elective abdominal surgery who are randomized to receive IBS or homologous blood could address this issue. Dnti! the results of such a study are available, the decision to use IBS in clean-contaminated surgery is best made based on the circumstances of each case. It is difficult to justify the use of grossly contaminated blood except for life-threatening bleeding with no available banked blood. COAGULOPATHY

A long-standing controversy focuses on the coagulation ńsk to the patient who receives washed versus unwashed salvaged blood. Proponents of washing claim that multiple derangements of coagulation are present in salvaged blood, which if not removed by washing, will contribute to coagulopathy in the recipient. In contrast, others claim that washing is unnecessary and that the coagulation abnormalities in salvaged blood do not have a significant clinical impact on the patient. A few authors have stated that washing is in fact harmful since it removes viable coagulation elements. The controversy is of practical importance. Commercial devices for IBS are available in those products that incorporate washing into the processing of salvaged blood and those that do not. We review below selected animai and human studies from the last 2 decades that address the issue. Several factors influence the coagulation integńty of salvaged blood and should be kept in mind while consideńng the results of these studies. These factors include the clinical state of the patient, the presence or absence of systemie anticoagulation of the patient, the degree of contact of the blood with tissue surfaces before aspiration, the method of anticoagulation used duńng collection, the degree of contact of blood with the extracorporeal circuit, the presence or absence of a wash step in processing, and the quantity of salvaged blood that is infused.

Animai Studies oj the 1970s Several studies examined the effects of IBS on the coagulation system in dogs. These studies offer

the advantage of separating the effects of IBS on coagulation from the effects of shock, sepsis, multiple drugs, and hemodilution often encountered in the studies on human subjects. The studies suffer the disadvantage that coagulation effects observed in dogs may not be directly applicable to humans. Symbas51 deliberately produced hemothorax in adult mongrel dogs by bleeding one quarter of the dogs' estimated blood volume from the femoral artery into the pleural space through a plastic tube. The blood was left in the pleural space for 45 minutes to 6 hours, then drained through a chest tube into a nonanticoagulated bottle and retransfused through a blood administration set. The author found that prolonged contact of the blood with pleural tissue resulted in a marked depletion of fibńnogen and platelets before drainage. The pleuraI blood was unclottable and did not require further anticoagulation before reinfusion. The level of fibńnogen in the animal's blood stream after reinfusion of the salvaged blood was approximately 50% of that before bleeding the animaI. The platelet count immediately after reinfusion was approximately 70% of the baseline value. Tyras et al 52 studied the effect of systemie hepańnization on the coagulation abnormalities developing after infusion of unwashed salvaged blood. Fibńnogen levels were well preserved posttransfusion in animals who were systemically hepańn­ ized. In nonanticoagulated animals, however, some degree of clotting occurred during blood pooling, collection, and processing with resultant fibńnogen consumption. Posttransfusion circulating fibńnogen levels in these animals decreased by 50%. Bennet et al,53 Rakower et al,54 and Stillman et al55 further investigated the coagulation effects of blood after tissue contact in systemically hepańn­ ized dogs. In the srudy by Stillman et al,55 five systemically hepańnized dogs (4 mglkg hepańn) had blood suctioned from the femoral artery directly into a Bentley autotransfusion device that reinfused the blood as rapidly as possible into the femoral vein. A mean of 12 L (six blood exchanges) was salvaged. In five other hepańnized dogs, blood was directed from the femoral artery into a groin pouch to allow tissue contact with the blood, which was then aspirated without surface suctioning into a Bentley autotransfusion device, allowed to accumulate to 500 mL, and then reinfused. After three blood exchanges, there was a

INTRAOPERATIVE BLOOD SALVAGE

60% decline in the mean platelet counts in animals whose blood came in contact with tissue in the groin pouch. In contrast, control animals with three blood volume autotransfusions without tissue contact had insignificant changes in platelet counts. When autotransfusion with tissue contact was allowed to continue to six blood volumes, there was a significant decline in mean fibrinogen from 226 mg/dL (baseline) to 40 mg/dL after transfusion. These animals died within 12 hours and postmortem examination showed "intraintestinal blood, hematuria, and marked hemolysis," which the authors interpreted as clinical evidence of mc.

Human Studies oj the 1970s In the 1970s a variety of studies were published that addressed the effects of IBS on coagulation. Unlike the animal studies being done at the time, the reports in humans are uncontrolled and the results are very difficult to interpret. These studies often used autotransfusion devices no longer considered safe and no longer in use. 56 The studies, however, are important because they represent a large early experience with the use of blood salvage without washing. Despite the understandable inadequacies of experimental design, these studies are frequently referenced as supporting evidence in humans that unwashed IBS leads to me. A frequently referenced early study suggesting that autotransfusion resulted in DIC is that of Rakower et al. 57 Eleven patients were treated with the Klebanoff device. Seven were trauma victims and two other patients were exsanguinating after failed portacaval shunt surgery. Each was given 100 to 300 U/kg of heparin. Only individuals with uncontrollabIe bleeding at the time of surgery and 1,500 mL of salvageable blood were studied. The median estimated volume of autotransfused blood was 10 L (range, 2 to 30 L). In addition, the patients received a median of 5.2 L of crystalloid and 13 L of banked whole blood. The authors reported that a constant finding at the end of surgery was generalized oozing from all cut surfaces not correctable by protamine or fresh frozen plasma. Platelet transfusions were apparently not given. The authors found that autotransfusion was associated with evidence for mc characterized by decreased fibrinogen, decreased plateIets, prolongation of the thrombin time, prothrombin time, and partial thromboplastin times, and the deveIopment of increased levels of fibrin split products. Although

217

the authors stated that some of the coagulation abnormalities could be attributed to the administered heparin , they claimed that the findings provided "strong evidence for an ongoing defibrination process. ,,57 A subsequent editorial by the same group stated that massive intraoperative autotransfusion was always associated with defibrination. 58 The following year, three separate clinical reports in the surgical literature were published which drew attention to the development of hypofibrinogenemia, thrombocytopenia, and prolonged clotting times after IBS. Duncan et a1 59 presented data on 53 patients undergoing surgery for trauma, ruptured ectopic pregnancies, elective, or emergency indications. The Bentley apparatus was used, and the patients were not systemically heparinized. The median estimated volume salvaged and transfused was 1.5 L (range, 0.15 to 18). Comparisons were made between patients receiving less than 1.5 L of salvaged blood (group I) and those receiving greater than 1.5 L (group 11). Mortality was 11 % and 69%, respectively. Postoperative platelet counts were less than 100,000/ IJ.-L in 12% of group I patients and in 50% of group 11 patients. The postoperative partial thromboplastin time (PTT) was abnormal in 25% of group I and 77% of group II individuals. In a follow-up study, Duncan et al 60 reported increased mortality in patients undergoing vascular procedures using the Bentley apparatus. Among eight deaths, three patients were described who had marked hemolysis, hemoglobinuria, prolonged prothrombin time (PT) (18 to 24 seconds) and PTT (90 seconds) and reduced platelet counts (46,000 to 100,000). The coagulation abnormalities were attributed to blood contact with the autotransfusion device. Clotted blood was noted in the collecting reservoir, and the authors raised concem for the need for improved anticoagulation of collected salvaged blood. Similar words of caution were expressed in widely read editorials. 61.62 About the same time, Reul et al 63 reported hypofibrinogenemia in each of selected trauma patients treated with the Bentley device using citrate phosphate dextrose anticoagulation. Sampies were taken from the infusion line as well as from the patient on the first postoperative day. The volume of salvaged blood ranged from 0.6 to 3.7 L. Care was taken to avoid surface suctioning, to avoid suctioning of clotted blood, to avoid rapid roller pumping, and to limit autotransfusion to 10 to 30 minutes. Fibrinogen

218

levels ranged from 112 to 224 mg/dL (infusion line) and 135 to 392 mg/dL (postoperative venous sample). Subsequent reports 64 -67 in trauma patients and elective or emergency surgery documented that increasing quantities of autotransfused blood plus banked blood were associated with postoperative hypofibrinogenia, thromboeytopenia, and prolonged clotting times. These human studies stood in contrast to the animai experiments of the same era. A deterioration in eoagulation status occurred after smaller volumes of blood salvage in humans under clinical eonditions than in dogs under experimental conditions. Infusions of large volumes of unwashed blood collected by IBS routinely resulted in serious coagulopathies in human beings. However, the relative contributions of dilution and DIC eannot be determined from these studies. Abnormalities of platelet function were also investigated in the 1970s. Brener et al 68 showed that platelets recovered from the autotransfusion device would not aggregate to adenosine diphosphate (ADP) or epinephrine. Raines et al69 demonstrated that platelets from patients given systemic heparin that are recovered from the Bentley device did not aggregate in vitro to ADP or epinephrine stimulus and did not incorporate or release radioaetive serotonin. Platelets obtained from the patient, however, showed normal aggregation responses. This suggested that the salvaged platelets did not survive long in the circulation. The decade drew to a close with a series of articles on the use of autotransfusion in the postoperative eollection of shed mediastinal blood. For low volume transfusion no serious adverse effect on coagulation was noted. 70 AnimaI Studies of the 1980s

In part as a response to eoncems about reinfusion of unwashed salvaged blood raised in the 1970s, there was widespread clinical applieation in the 1980s of machines capable of washing salvaged blood. Some experimental studies addressed the effects on eoagulation of unwashed blood collected during intraoperative salvage. A deleterious effeet of unwashed salvaged blood on both coagulation and platelet function was demonstrated by Moore et al. 71 The authors examined the effeets of autotransfusion in dogs that were not first systemically anticoagulated with heparin. Ten dogs were bIed under eontrolled conditions from the inferior

DZIK AND SHERBURNE

vena cava into a peritoneal pouch fashioned from abdominal mesentery. One eighth of each dog' s blood volume was allowed to pool into the abdomen and was then aspirated into a Sorensen device with no more than 40 mm Hg of suction. The aspirated blood was anticoagulated with aeideitrate-dextrose (ACD) (7: l blood:ACD ratio) during colleetion and promptly reinfused through a 40 micron filter. The process was then repeated until twice the animals' blood volume was shed and reinfused over a 4-hour period. Swan-Ganz catheter hemodynamic monitoring was done to document that the experiments were not complieated by shock. The mean prothrombin time progressively prolonged in the animals to twice the baseline value. A similar doubling occurred in the partial thromboplastin and thrombin times. Mean fibrinogen decreased from 188 mg/dL to 133 mg/dL. Platelet counts declined from 185,000/IJ-L to 144,OOO/IJ-L at 4 hours and 77,OOO/IJ-L during recovery at 24 hours. Platelet aggregation studies were done on circulating venous blood collected during the autotransfusion experiments. Abnormalities of platelet funetion were more striking. Platelets from the animal's blood stream (not the salvage device) were studied. Platelet aggregation to ADP and eoUagen was normal at baseline but significantly impaired after one blood exchange and absent after a two blood volume autotransfusion. In six of eight dogs the bleeding times were significantly prolonged over baseline at 4 hours of autotransfusion. The authors proposed that contact with tissue surfaces, mechanical surfaces, and filters combine to alter blood so as to produce coagulopathy, thrombocytopenia, hypofibrinogenemia, and platelet dysfunetion when it is infused. The study of Silva et al 72 directly addressed the issue of washed versus unwashed salvaged blood in the dog model. In this study, shock, hemodilution, and hypothermia were avoided. Animals did not receive systemie anticoagulation. AU animals underwent controlled hemorrhage from the inferior vena eava into a peritoneal poueh to allow tissue contact with the blood before salvage. The animals were divided into three groups: In group I (n = 5), blood loss was replaced by banked whole blood (ACD, 7 days old, stored at 4°C). In Group II (n = 5), blood was salvaged and reinfused using a Sorensen device with ACD anticoagulation. In group III (n = 5), blood was salvaged in heparin and reinfused after washing using a Haemonetics Cell

INTRAOPERATIVE BLOOD SALVAGE

Saver device. The wash volume was equal to twice the collected blood volume, which is less than is routinely used in humans. Inadequate washing may have been an important flaw in this study. Animals were bIed up to atotal of two blood volumes over 4 hours. The authors first measured the coagulation characteństics of the blood to be infused. The whole blood had decreased platelets and decreased factor V and VIII:C. After 4 hours (two blood volumes) of salvage, blood co11ected with the Sorensen device was devoid of platelets, fibrinogen, factor II, factor V, and factor VIII:C. Washed blood co11ected with the Haemonetics device had minimai quantities of platelets and coagulation factors. Whereas fibrinogen degradation products (FDP) and fibrin degradation products (fdp) (Thrombo-We11cost Assay, We11come Diagnostics, Dartford, UK) measured 5.2 jJ.g/mL in banked blood, the measured values after 4 hours of blood salvage were 205 jJ.g/mL in peritoneal cavity blood, 158 jJ.g/mL in blood from the Sorensen device, and 29 jJ.g/mL in washed blood from the Haemonetics device. FDP/fdp levels in the animals' circulation were 4 jJ.g/mL (banked), 46 jJ.g/mL (unwashed), and 35 jJ.g/mL (washed). Platelet counts declined more in animals treated with blood salvage compared with banked whole blood. The decline in platelet count (185,OOO/jJ.L at baseline to 100,OOO/jJ.L at 4 hours) was the same in the unwashed (Sorensen) and washed (Haemonetics) groups. Mean bleeding times (normal, 2 to 5 minutes) were greater than 10 minutes in a11 three groups, reflecting the combined effects of platelet hemodilution and platelet dysfunction. Platelet aggregation studies showed decreased aggregation, which was more pronounced in the animals who received salvaged blood. Coagulation factor V, factor VIII: C, and fibrinogen were all decreased more significantly in animals treated with salvaged blood than with banked whole blood, but the decrease was similar in animals receiving unwashed or washed blood. After 4 hours of autotransfusion with either unwashed (or washed) blood, factor II averaged 70% (65%), factor V averaged 45% (28%), factor VII 90% (85%), factor VIII:C 45% (32%), and fibrinogen 118 mg/dL (106 mg/dL). Despite the adequate fibrinogen levels in animals treated with salvaged blood, the thrombin times were greater than 100 seconds in animals receiving salvaged blood but were normal in animals who received banked whole blood. There was a prolon-

219

gation of the activated partial thromboplastin time (aPTT) to greater than 5 minutes and a doubling of the PT after 4 hours in both groups receiving salvaged blood. The PT and aPTT remained normal in those receiving whole blood. Whether these abnormalities of PT, aPTT, and thrombin time were due to high concentrations of FDP/fdp, depletion of coagulation factors, or residual heparin cannot be determined. Nevertheless, the results suggest a severe derangement in both groups of animals receiving salvaged blood compared with animals receiving stored whole blood. In an experimental hemothorax model in dogs Napoli et a1 73 measured the effects of reinfusion of blood that had been a110wed to sit in the pleural cavity for nearly I hour before co11ection. A reduction in systemic levels of circulating clotting factors and platelets equal to the percentage of blood volume reinfused was noted. FDP/fdp were slightly elevated posttransfusion, but the volume of salvaged blood reinfused was low (equivalent to 2 U in an adult human). In another dog study74 reinfusion of unwashed blood from the peritoneum resulted in dramatic elevation of the PT and PTT while the animaI was in the operating room. The values retumed to normal I hour postoperatively suggesting clearance of infused FDP/fdp. This latter study highlights the difficulty of assuming that coagulation results obtained during postoperative recovery apply equa11y we11 to the intraoperative peńod. Unfortunately, many of the studies done in humans do not report coagulation studies from blood sampled intraoperatively. Fina11y, an important study in primates was that by Kingsley et af5 who studied the effects of reinfusing unwashed versus washed salvaged blood in the baboon model. The baboon was selected by the investigators based on evidence that the coagulation system of the baboon was a better model for the human coagulation system than that of the dog. Twelve adult male baboons were divided into two groups. Six were treated with unwashed salvaged blood and six were treated with a washed salvaged blood. Approximately 1,200 mL of wash solution was used for each 200 mL of packed ce11s salvaged. The animals were not systemica11y anticoagulated. Blood was directed from the iliac vein into an extraperitoneal tissue pocket in the groin. Using ACD anticoagulant, 500 mL of blood was aspirated from the pocket into the autotransfusion device. It was then either washed or not depending

220

on the group and reinfused. This was repeated four times for atotal reinfusion of approximately one blood volume of the animal. Animals receiving unwashed blood experienced seizures and cardiac arrthymias not seen in animals receiving washed celIs. Sampies were taken from the animals venous circulation periodicalIy for coagulation testing. The mean prothrombin time and partial thromboplastin time became markedly elevated in both groups to the same degree. Fibrinogen decreased from 300 mg/dL to 100 mg/dL in both groups. The mean platelet count decreased to a similar degree in both groups. However, there was a marked difference in the titer of FDP/fdp between the animals receiving unwashed versus washed blood. After 2 L of blood reinfusion, the FDP/fdp titer rose to greater than 1,500 in animals receiving unwashed blood. In contrast, the FDP/fdp titer remained undetectable in animals receiving an equivalent degree of washed salvaged blood. The authors interpreted this difference as evidence for intravascular coagulation in animals treated with unwashed salvaged blood. An altemative explanation is that high concentrations of FDP/fdp present in unwashed blood (which had undergone partial to complete coagulation followed by clot lysis ex vivo) were being measured after reinfusion. Human Studies oj the 1980s Although a large number of studies from the first half of this decade report the use of intraoperative blood salvage, most used blood salvage with washing and do not address the coagulopathy controversy. Broadie et al 76 investigated the nature of blood colIected during salvage. The authors measured coagulation parameters in blood collected from the pleural and peritoneal cavities of 31 trauma patients. The blood had extremely low levels of fibrinogen, markedly prolonged PT and aPTf, and elevated fibrin(ogen) degradation products (360 /Jog/mL, normal, < 10 /Jog/mL). The results were consistent with previous reports in dogs, which had demonstrated that blood colIected from the abdominal cavity was defibrinated unless the animai was heparinized before the bleed. The clinkal impact of reinfusion of large volumes of such defibrinated blood was not welI addressed in this study. These same authors pursued the issue of unclottable blood aspirated from body cavities in a dog model in which blood admixed with iodine 125-labeled fibrinogen was alIowed to drain into

DZIK AND SHERBURNE

the peritoneum. 77 After 1 hour, the blood was aspirated and analyzed. The labeled fibrinogen was found only in fragments D and E suggesting that it had been incorporated into clot, which had undergone rapid, near-complete fibrinolysis. P1atelets, and factors II, V, and VIII were consumed. Pretreatment of dogs with heparin prevented complete clotting and lysis and permitted recovery of intact fibrinogen. Pretreatment of the animals with epsilon aminocaproic acid prevented lysis of the peritoneal blood, which remained clotting in the abdomen. The widespread use of washing during IBS in the 1980s provided little information about the impact of salvage on coagulation except for the effects of hemodilution during large volume celI salvage. Recently, the increased demand for autologous blood services has prompted the introduction by smalIer modestly-priced salvage equipment, which does not wash the colIected blood. Detailed studies of the effects of blood salvage using this newer equipment are not available. Preliminary studies suggest that in systemically heparinized patients undergoing vascular surgery, smalI volume (approximately 1,000 mL) salvage and reinfusion is well tolerated. 78,79 Throughout the last decade, unwashed salvage blood has been used postoperatively usually from mediastinal drainage following cardiothoracic surgery. Studies of postoperative salvage are often combined with those of intraoperative salvage in reviews of the topie. However, the impact on coagulation may be very different during the intraoperative period when primary hemostasis is first being established compared with the postoperative period. Nevertheless, studies suggest8 0- 82 that although mediastinal blood is defibrinated, patients can usually tolerate reinfusion of such blood (unwashed) in the postoperative period without deterioration of coagulation. More recently, this position was reexamined by Griffith et al. 83 Patients were divided (not randomly) into two groups. One group received unwashed shed mediastinal blood (405 ± 130 mL) and the other group received washed red cells collected from a comparable volume of mediastinal blood (537 ± 173 mL). Coagulation tests were performed on sampies taken from the patients' bloodstream before and after infusion of the salvaged blood. Despite the modest volumes infused, 19 of 20 patients receiving unwashed blood demonstrated an increase in titer of circulating FDP/fdp

INTRADPERATIVE BLDDD SALVAGE

after transfusion. In half of these patients the FDPt FDP/ f-lg/mL). FDPt FDP/ fdp titer was greater than 1:20 (>40 f-lgtmL). fdp elevations did not result from infusion of washed blood. lnterpretation oj the Literature on Coagulation and Washing

Several tentative conclusions can be drawn from the published animai studies: (1) There was no unequivocal evidence of ole in animals receiving unwashed salvaged blood. (2) Contact of blood with tissue, body cavities, or serosal surfaces affects the coagulation status of blood at the time of salvage. Tissue contact appears to result in partial to complete initiation of coagulation and subsequent fibrinolysis. (3) Systemie anticoagulation before contact of blood with tissue surfaces results in less activation of coagulation but does not completely prevent it. (4) Reinfusion of large volumes of salvaged blood collected from the abdomen of animals who are not systemically heparinized results in a measurable, significant coagulation disorder affecting both platelets and clotting proteins. Coagulation changes are more marked than those induced by the reinfusion of an equivalent volume of l-week-old banked whole blood. (5) Reinfusion of washed or unwashed salvaged blood resulted in abnormalities of blood clotting. Coagulation abnormalities included a greatly prolonged thrombin time in the face of adequate fibrinogen levels and prolonged PT and aPTT in the presence of adequate factor levels suggesting an effect of reinfused FDPs. FDP levels were more elevated in animals receiving unwashed than washed salvaged blood. This was particularly dramatic in the one study in higher animals (baboons). (6) Platelets collected by intraoperative salvage have likely already undergone activation and have little ar no residual ability to aggregate. Taken together the available animai and human studies suggest that blood collected during intraoperative salvage is very different depending on whether or not the patient is systemically anticoagulated. At one extreme, blood circulated through a cardiopulmonary bypass machine represents blood "harvested" from the circulation, passed through an extracorporeal device, and retumed directly to the circulation. Patients tolerate infusions of large volumes of such blood with little difficulty. Contact of heparinized blood with the extracorporeal circuit results in adsorption of fibrinogen

221

to the plastic and subsequent partial platelet consumption. 84 It should not be surprising then that blood salvaged from a heparinized patient may be directly reinfused without washing in some circumstances. At the other extreme is blood that has clotted in a body cavity of a nonanticoagulated patient and is then collected in a salvage device and reinfused. The distinction between blood salvage in systemically anticoagulated patients and nonantieoagulated patients is often not adequately emphasized. The impact of washing versus not washing a given quantity of salvaged blood is likely to be very different for patients undergoing cardiothoracic or major vascular surgery in which systemie anticoagulation occurs compared with abdominal, trauma, orthopedic, or gynecologic surgery. Moreover the degree of contact of the blood with tissue before salvage is also a major determinant of the degree of activation of coagulation and fibrinolysis in salvaged blood. Platelets

Platelets collected during intraoperative salvage do not aggregate normally. These platelets have likely undergone activation during hemorrhage and clotting before aspiration of the blood, during the turbulent flow of aspiration, or during contact with various plastic surfaces of the salvage device throughout processing. Adenosine phosphates released from celI lysis and tissue procoagulants released into the salvaged blood would also promote platelet activation. Exposure of platelets to high local concentrations of thrombin would result in granule depletion. Exposure to plasmin during cIot lysis before salvage could result in disruption of platelet membrane receptors. After receiving a significant quantity of salvaged blood, bleeding times are markedly prolonged. Coagulation

For nonanticoagulated patients, a single unifying hypothesis from the available studies is that blood collected during intraoperative salvage has undergone partial to complete clotting and subsequent lysis outside the vasculature. The accumulated evidence suggests that such blood provides no useful coagulation factors and is not more beneficial to coagulation than washed salvaged blood. Although blood that is partially clotted and not washed would be expected to contain activated clotting factors, reinfusion of such blood has not

222

DZIK AND SHERBURNE

been unequivocally shown to produce mc. This may be due to the fact that, with relatively modest volumes of infusion, activated clotting factors are sufficient1y diluted in the recipient circulation, are neutralized by natural inactivators, or are cleared from the recipient circulation. Tissue procoagulants, phospholipid membranes, and products of celllysis released into salvaged blood may, be similady tolerated in low volumes. If given in large volumes or in the presence of shock, however, protective mechanisms of the recipient may be overwhelmed. Of note is the experimental study in animals by Hardeway et al 85 who compared the effects of infusing hemolyzed autologous blood versus nonhemolyzed autologous blood in dogs who were bIed to produce shock. The combined effect of shock and infusion of hemolyzed autologous blood produced laboratory evidence of mc and death in animals, which was not seen in those who received nonhemolyzed autologous blood while in shock. Infusion of large volumes of salvaged blood (unwashed) produces reduced levels of coagulation factors and platelets, platelet dysfunction, and elevation of FDP/fdp interpreted as mc in studies in the 1970s. However, a more plausible explanation is that such laboratory results were produced by the combined effects of dilution and infusion of FDP/ fdp. Since washed blood also contributes no useful coagulation proteins or platelets to the recipient, it is also capable of resulting in hemodilution of the recipient after large volume reinfusion. Thus, the major identified difference from the available literature in the coagulation status of nonanticoagulated patients receiving washed versus unwashed salvaged blood has been the presence of FDP/fdp measured in the circulation after transfusion with unwashed products. That the coagulation abnormalities resulting from infusion of unwashed salvaged blood can be explained simply on the basis of reinfusion of blood that has clotted and undergone lysis outside the circulation has been previously proposed. Carty et al reported on IBS in patients with ectopic pregnancy: The findings in peńtoneal blood were due to the effects cłotting and subsequent lysis. There was depletion of fibńnogen and factors V, VIII and X, and the platelet count was reduced. Jf such blood is autotransfused, it will confer no haemostatic benefit . . . The very high levels of FDP (the result of lysis of intrapeńtoneal ciot) were of considerable interest. They suggest the theoretical danger of

to the patient transfused with peńtoneal blood because of their inhibitory effect on the thrombin-fibńnogen reaction, fibńn polymeńzation, and platelet aggregation. 86

Effect oj High Concentrations oj Fibrin Degradation Products/Fibrinogen Degradation Products on Coagulation

Fibrin degradation products (fdp) and fibrinogen degradation products (FDP) are produced by the action of plasmin digestion (Figs 2 and 3). The structure of fdp differs from that of FDP. Fibrin degradation products contain crosslinked Ddimers, a greater variety of molecular species and fragments with a greater average molecular weight. Salvaged blood that has undergone extravascular clotting and subsequent lysis is presumably very rich in fdp. Lysis of fibrinogen and production of FDP occurs as weB. FDP/fdp impair both normal coagulation as well as normal platelet aggregation. The adverse effects of FDP on clotting of fibrinogen have been extensively studied. 87 ,88 The large molecular weight fragment, fragment X, is formed early in plasmin digestion of fibrinogen and can compete with fibrinogen as a substrate for thrombin. Fragment Y is a large unclottable FDP, which like the smaller fragment D, is capable of forming

Fibrinogen

ł

®-®--® Fragment X

I

®--®Fragment y

Fragment D

I

®Fragment D

Fragment E

Fig 2. Formation of fibrinogen degradation products (FDP). Reprinted with permission. 888

INTRAOPERATlVE BLOOO SALVAGE

223

~

F'b"""9"

i:J

Thrombin

~

~ FibrinOimer ~

D

Plasmin ~

-00-®DOlE

Plasmin

~

~

~ YD/OY

Plasmin

2Stranded Protolibril

~

~

Oegradation ~comPlexes YYIOXO

Fig 3. Formation of fibrin degradation products (fdp). Reprinted with permission....

complexes with fibrin monomers. These complexes interrupt the growing fibril protofibril and impair formation of a cIot with normal tensile strength. Fragment Y is particularly effective at interfering with the normal action of thrombin on fibrinogen as measured by the thrombin time. On a molar basis fragment Y prolongs the thrombin time with 20 times more potency than fragment D and 100 times more potency than fragment E. 89 The even larger fdp fragments such as DD/E, YD/DY, YY/DXD and others should be very efficient at disrupting normal conversion of fibrinogen to long fibrin protofibrils. Such large fdp fragments would be expected to be present in unwashed salvaged blood. Normal platelet aggregation is also deranged by FDP/fdp.90 Normal aggregation is dependent upon platelet crosslinking by fibrinogen. A peptide domain on each gamma chain of fibrinogen binds to the activated platelet surface receptor, GPIIb-III a . FDP/fdp can also bind to GPIIb-III a in a similar fashion. 91 Degradation products thereby compete with fibrinogen and interfere with normai crosslinking and platelet aggregation. Is the concentration of FDP/fdp, which develops in patients infused with unwashed salvaged blood, sufficient to impair platelet aggregation and fibrin

formulation? The final concentration of FDP/fdp present in the circulation of recipients of unwashed salvaged blood results from the quantity infused, the blood volume of the recipient, and the elearance of FDP/fdp. Clearance is felt to be dependent on reticuloendothelial function. Patients with hypotension and/or liver disease are more likely to have impaired elearance of circulating degradation products. Fibrinogen in transfused patients may be reduced as a result of hemodilution to the range of 100 mg/dL (l mg/mL). FDP/fdp have been measured in the circulation of recipients at di1utions greater than 1: 150 corresponding to concentration greater than 300 ILg/mL (0.3 mg/mL). Since FDP have a molecular weight one-third to two-thirds less than fibrinogen, the molar ratio of fibrinogen to its degradation products can approach one. In concentrations equimolar to fibrinogen, degradation products have been shown to effectively compete with fibrinogen and interfere with coagulation and platelet aggregation. These considerations suggest that patients with decreased ability to elear FDP/fdp who receive a large quantity of FDP/fdp over a short time and who have some derangement of normal hemostasis are particularly prone to further impairment of coagulation resulting from infusion of unwashed salvaged blood.

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NEPHROTOXICITY AND INTRAOPERATIVE BlOOD SALVAGE

Some degree of hemolysis is common in IBS. Surface suctioning (skimming), excessive vacuum force, and mechanieal trauma to red blood celIs produced by rolIer pumps and turbuIence have been shown to increase hemolysis. 92 Fear that the products of hemolysis, ie, red celI stroma and free hemoglobin, could incite or promote renal failure during IBS has led many investigators to argue that salvaged blood should be washed before reinfusion. Others contend that washing is not needed. Randomized, prospective triais to assess renal function after infusion of salvaged blood with or without washing have not been performed, in human or in animai subjects. We review experimental and c1inieal studies on the renal effects of infusion of hemolyzed blood or stroma free hemoglobin in order to address this issue. Hemolysis and Renal Failure

An association between intravascular hemolysis and renal failure is welI established. Standard nephrology text books inc1ude entire chapters devoted to pigment nephropathies. 93 Intravascular hemolysis has been associated with acute renal failure in numerous c1inieal settings: following viraI infection or antimalarial use in glucose6-phosphate-dehydrogenase deficient patients,94 folIowing administration of glycerol to neurosurgical patients,95 during hemolytic episodes of falciparum malaria,96 and folIowing snakebite and stings by several venomous invertebrates, inc1uding jelIyfish,97 homets,98 and scorpions. 99 In such reports, hemolysis is usualIy accompanied by varying degrees of hypotension and c1inieal shock, and it is hard to ascribe renal failure sole1y to intravascular hemolysis and hemoglobinuria. Acute tubular necrosis and renal shutdown are notorious sequelae of systemie hypoperfusion; however, such c1inieal cases suggest that ischemia and hemolysis have additive, synergistic de1eterious effects on the kidneys. This notion is supported in reviews that describe the pathogenesis of renal failure folIowing transfusion of incompatible blood. 1OO ,101 The immune mechanisms activated when incompatible blood is administered cause systemie release of inflammatory mediators, such as histamine, catecholamines, kinins, and eicosanoids, which derange end-organ microperfu-

sion and promote generalized shock. To the extent that the products of hemolysis are nephrotoxie, their toxicity appears to be enhanced by shock and renal hypoperfusion. Is Red Celi Stroma Nephrotoxic?

Previous studies have suggested that incompatible red celI stroma-not hemoglobin-is the principIe nephrotoxin of acute hemolytie reactions. Schmidt and Holland demonstrated that incompatible red celI stroma, washed free of hemoglobin, was sufficient to produce acute renal failure. 102 In an effort to adsorb antibody in two patients who required transfusion but were difficult to crossmatch, washed incompatible red celI stroma was infused. Within 2 hours, both patients deve10ped signs and symptoms of hemolytic transfusion reaction (diaphoresis, apprehension, fever, hypotension, tachycardia), became transient1y anuric, but never manifested hemoglobinuria. They also noted that they and others had observed no untoward effects when compatible red celI stroma was administered to other patients. In 1976, Sandler et al reported on a case in which a crossmatch compatible unit of blood was administered after it had been inadvertent1y hemolyzed by freezing. 103 The patient developed profound hemoglobinuria, but was otherwise without any signs or symptoms of transfusion reaction; there was no evidence of DIe and renal function remained normai (he was treated with mannitol and hydration). Although few cases such as this have found their way into the literature, anecdotal reports of incidental, apparent1y benign hemoglobinuria folIowing nonimmune hemolysis can be obtained from most hospitals with an active transfusion service. For example, we recent1y observed dramatic hemoglobinuria and hemoglobinemia in a patient who received an improperly deglycerolized compatible unit of frozen red celIs. Our investigation showed that the infused produet had an osmolality of 1,800 mOsm/dL. Despite complete hemolysis of the unit, the patient manifested no symptoms and her creatinine never increased from baseline (0.7 mgl dL). Proponents of infusing unwashed salvaged blood during intraoperative salvage cite such c1inieal examples as evidence that hemolyzed blood is not nephrotoxie, so long as there is no serologie incompatibility. While it appears that infusion of smalI volumes of compatible, hemolyzed blood to the conscious, hemodynamicalIy stabIe patient is

INTRAOPERATIVE BLOOO SALVAGE

not nephrotoxic, these observations may not extrapolate to the anesthetized, hemodynamically labile patient with decreased renal perfusion. Does Hemolyzed Blood Promote Nephrotoxicity as a Result oj Disseminated l ntravascular Coagulation?

The combined effects of shock and hemolysis on the production of mc and renal failure were studied in dogs by Hardaway et al. 85 The animals were anesthetized, were transfused 2 mLlkg of autologous blood that had been either stored intact with heparin or previously hemolyzed by freeze and thaw, and were then subjected to hemorrhagic shock to maintain a mean arterial pressure of 40 mm Hg for approximately 2 hours before returning the animals' blood volume. After 24 hours, all seven animals who received the hemolyzed autologous blood died, whereas all seven who received the nonhemolyzed stored autologous blood survived. All animals who received the hemolyzed blood developed laboratory evidence of mc. Histologie study of the renal pathology was not done. To explain the different outcome in the seven pairs of animals, the authors postulated that the hemolysate acts as a thromboplastic agent and that during shock, stasis and acidosis in the microcirculation promote procoagulant activity. Such an explanation seems plausible; Quiek et al demonstrated a procoagulant activity of hemolyzed red cells in a prothrombin consumption assay with platelet-poor plasma. I04 To address the question of whether hemorrhagic shock promotes DIC in the presence of procoagulant activity, Hardaway et al performed a follow-up study in which rabbits were bIed 20% to 25% of their blood volume folIowed by intravenous injection of bovine thrombin. 105 Animals subjected to hemorrhage alone or to thrombin administration alone failed to demonstrate a statistically significant difference of coagulation parameters before and after manipulation, while animals subjected to both hemorrhage and thrombin all manifested significant changes consistent with mc, and three of these five animals died. Although the application of these studies to human beings is uncertain, the reports suggest that infusion of blood, which has been hemolyzed during collection and salvage, enhances the impact of shock on mc. CHnical studies are needed that foeus on the effeets of washed versus unwashed sal-

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vage blood on with shoek.

mc and nephrotoxicity in patients

ls Hemoglobin Nephrotoxic?

This question is best addressed by examining the evolution of stroma-free hemoglobin (SFH) solutions. As a plasma expander with oxygen-carrying eapaeity, not requiring erossmateh, SFH would be an ideal replaeement solution for acute hemorrhage and trauma, and several talented investigators have devoted their efforts toward the production of such a product. Rabiner et al claimed that the hypereoagulable state and mc, whieh folIowed administration offirst-generation SFH, was due to the stromai lipid particles, and they reported produetion of highly purified SFH virtually devoid of lipid and stroma. 106 Replacement of 20 to 47 mL of blood by the SFH in anesthetized dogs was earried out and maintained for 4 hours, at whieh time the animals were saerifieed. No signifieant ehanges were observed in urine output, ereatinine clearanee, c1earanee, or eoagulation tests; histologie examination of the kidneys showed only rare distal tubular pigment easts, and no thrombi or tubular pathology was noted. Thus, hemoglobinemia/hemoglobinuria itself did not appear to induee adverse renal effects. This promising result was folIowed by several additional reports in different animals under varying conditions in which similarly highly purified SFH was administered without observed nephrotoxicity. Bimdorf and Lopas administered human SFH similar to Rabiner' s material to cynomolgus monkeys.l07 Animals were divided into three groups. SFH equal to 25% of the animal blood volume was administered to one group, given to replace a 25% phlebotomy in another group, and used to replace a 25% bleed in a third group that had been subjected to prior dehydration. The only significant change in renal function noted was a 50% decrease in mean renal plasma flow in the nondehydrated, phlebotomized animals. Clearance of creatinine or inulin reflecting glomerular filtration rate (GFR) and paraaminohippurate (PAH) reflecting renal plasma flow (RPF) remained unchanged in each group. Renal architecture was normal histologieally. Relihan et al published a series of reports on the administration of SFH solution to dogs. They first established that a 250 mL load of SFH given to 16 to 18 kg dogs produced no change in serum blood urea nitrogen, phenolsul-

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fonphthalein excretion (which approximates RPF), or renal histology in the 5 days folIowing administration. 108 They went on to demonstrate that the solution failed to have a negative effect on these measured parameters folIowing transient renal ischemia 109 or in animals rendered acidotic by oral administration of ammonium chloride. 110 Based on these animai studies, Goldfinger coneluded in his 1977 review artiele, "that these solutions were completely nontoxic to the kidney, even though they resulted in massive hemoglobinuria . . . These studies make it elear that hemoglobin itself has no direct toxic effect on the renal tubular epithelium. ,,100 Concern over the nephrotoxicity of free hemoglobin remains, however, Savitsky et al reported their findings of a elinical trial in which highly purified (1.2% stromallipid) "second generation" SFH was administered to eight healthy male volunteers. 111 Subjects were oralIy hydrated and administered 250 mL of SFH at up to 4 mL/min while vital signs and urine output were monitored. In the six men who received the hemoglobin at 4 mL/min, mean urine output decreased 81 % in the hour following SFH administration compared with the previous hour. Similarly, mean creatinine elearance declined 51 % at 1 hour post-SFH infusion. Transient bradycardia and hypertension were also noted. Although all physiologic and laboratory values retumed to normal shortly after the experiment, the deeline in renal function was undeniable. Of interest, the investigators found that their results were virtualIy identical to triais of reł­ atively "dirty" (5% to 10% stromal lipid) SFH administered to normai subjects in the early 1950s. 112,113 Of special interest is the study report by Miller and McDonald from 1951. 112 They found that decreases of urine output, GFR (as inulin clearance), and RPF (as PAH clearance) occurred not only in patients who were given commercialIy available "first-generation" SFH solutions, but surprisingly also in normal subjects given approximately 100 cc of their own blood hemolyzed in 200 cc of heparinized distilled water injected intravenously over 15 minutes. That relatively smalI volumes of autologous hemolysate infused intravenously could result in a statistically significant decline in urine output, GFR and RPF has obvious implications for reinfusion of unwashed salvage blood during IBS. Given the similarity of their findings using "elean" second-

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generation SFH to those done in the 1950s, Savitsky et al suggested, "it was the hemoglobin itself rather than the stroma which triggered this temporary interference with renal function, since 99% removal of stroma in this study apparentły did not prevent it. ,,111 Certain heme pigments have long been known to be toxic to the kidney, as welI as other body tissues. Ferrihemate (acid hematin), a breakdown product of myoglobin and hemoglobin at low pH,93 was shown in 1960 by Litwin et al 114 to induce isosthenuria and proteinuria with tubular necrosis when administered intravenously folIowing a period of ischemia. Acid hematin alone or ischemia alone did not produce these effects. The damage brought about by oxidation and reduction of iron containing compounds in aerobic tissues is known as the Haber-Weiss cycle, whereby superoxide and peroxide metabolites are catalyzed to form extremely reactive molecules of hydroxyl free radical, which is injurious to tissue celIs (Fig 4).115 Sadrzadeh et al demonstrated that hemoglobin prornotes the generation of hydroxyl radical in an in vitro assay. 116 In this assay, hemoglobin also increased hypoxanthine-xanthine oxidase driven peroxidation of red celI membrane lipids and arachidonic acid. Both these effects could be blocked by adding haptoglobin, an acute phase reactant that binds hemoglobin with very high affinity. PalIer ll7 postulated that free-radical injury in ischemic kidneys would be exacerbated in the presence of free hemoglobin during re-perfusion. In six rats, the infusion of purified SFH during re-perfusion lowered the mean (±SD) GFR from 0.843 ± 0.05 mL/min to 0.543 ± .08 mL/min (P < .Ol) in animals that had had renal ischemia induced by ligation of the renal artery. At the same time, the mean content of malondialdehyde (MDA), which serves as an index of lipid peroxidation by free hydroxyl radicals, increased from e

/ ~

L

OH-

---------..:::::....--"""----<:::: 'OH Fig 4. Iron-catllyzed Hlber Weiss relction. Superoxide ion {.Oz-I is oxidized by ferric ion IFe3 +1 or dismutlted to peroxide {HzOzl. Peroxide relets with ferrous ion {Fe2 +1 to form hydroxyl Inion {OH-I Ind free hydroxyl rldicll {,OHI.

INTRAOPERATIVE BLOOD SALVAGE

0.453 ± .08 nmol/mg protein to 0.742 ± .09 nmol/mg protein (P < .05). In another experiment, administration of glycerol to provoke both hemolysis and rhabdomyolysis in the absence of ischemia increased mean MDA content from 0.336 nmol/mg to 0.842 nmol/mg protein (P < .05). This increase could be prevented by infusion of deferoxamine, an iron chelator. Deferoxamine also protected against a decline in GFR induced by ischemia and hemoglobin infusion. Paller ll7 postulated that free iron was ultimately released from the heme moiety, which then catalyzed the HaberWeiss reaction and promoted free radical formation and tissue injury; he feH that heme was rendered more toxic by acidosis and ischemia as these conditions would favor iron release. Hemoglobin can be seen microscopically within the renal tubular cells 5 hours after infusion of SFH. 118 Could renal damage be prevented if hemoglobin were prevented from entering tubular epitheliaI cells? Tam and Wong examined this by administering either 6% SFH or 6% Dextran-SFH to anesthetized, cannulated, catheterized rats. 1I9 While the former molecule freely permeates from the glomerulus into Bowman's space to produce hemoglobinuria, the latter does not, owing to its molecular weight. Compared with baseline values, the animals receiving plain SFH demonstrated a 30% decrease in GFR and a lO-fold increase in urinary levels of a lysosomal enzyme found mainly in the proximal tubules. These features are consistent with proximal tubular injury. In contrast, the animals receiving 6% dextran-SFH showed no statistically significant change in GFR or urinary lysozyme excretion. Moss and Gould are preparing a polymerized SFH that does not cross from the glomerulus into the urinary space, which in reported pilot studies with human volunteers, had no effect on urine output, urinalysis, or GFR. 120 Clinical Studies oj Intraoperative Blood Salvage and Renal Function As stated above, the critical study of IBS and renal function under washed or unwashed conditions has yet to be performed, not that anyone lacks opinions about the subject. Dr. Klebanoff,121 writing about his experience with the Bentley ATS-lOO (unwashed), stated, "the incidence of renal failure as a consequence of autotransfusion is practically nil." This investigator, however, also used a regimen of mannitol diuresis to maintain a

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high urine output throughout IBS. Reul et al,63 who transfused 25 trauma patients with the Bentley, measured plasma free hemoglobins of 22 to 218 mg/dL (mean, 63) in the immediate postoperative period, and stated, "there was no evidence of acute tubular necrosis from the autotransfusion." However, they excluded patients with underlying renal failure from entering their protocol. Brener et al,122 who used unwashed salvaged blood for major aortic surgery and generated plasma hemoglobins as high as 600 mg/dL (mean 175), noted transient increase of serum creatinine in eight of 20 patients in both their salvage and control groups. Again, they excluded any patient with an initial creatinine greater than 2.0 mg/dL from entering the study. Rakower et al,57 who used massive IBS for trauma patients, noted OIC-like bleeding (even in those patients who survived), but made no mention of any renat complications. Brewster et al 123 used IBS (155 Bentley, 20 Cell Saver) in 175 major vascular surgeries with a mean postoperative plasma hemoglobin of 187 mg/dL (range, 29 to 600). Ofthese 175 patients, 75% had normal renal function pre- and postoperatively; 20% had slightly abnormal renal function preoperatively, which did not deteriorate after IBS. Five percent (nine patients) developed abnormal renal function after IBS. Eight of these nine, however, also experienced hypotension, renal ischemia, or severe multisystem injuries. There are even fewer studies specifically addressing renal function following IBS with the washed technique. In a large retrospective series, Cali et al 124 found no difference in the incidence of renal failure (defined as serum creatinine > 1.0 mg/dL) between IBS and controI groups. Stanton et al l25 compared 50 patients undergoing IBS with the Cell Saver with a historical controI group of 50 patients in whom no salvage was used. They found a statistically significant difference between the two groups in the incidence of "renal insufficiency" defined as an increase in creatinine to twice the preoperative level. While none of the 50 patients receiving IBS with cell washing developed renat insufficiency, four of 50 controI patients did. Sharp et al. 126 reported their experience as they switched from the Bentley to the Haemonetics system. Although they did not state how they defined it, 20% of 100 patients on whom the Bentley was used went on to develop "renaI failure," while only 11.8% of 136 (16 patients) for whom the Cell

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Saver was used went on to this complication. This difference is significant (P < .01). Unfortunately, this study compares one group retrospectively (Bentley) and one prospectively (Cen Saver). In summary, the products of hemolysis can derange renal function. The combined effects of hemolysis and shock may promote mc and thrombosis in the renal microvasculature. Free hemoglobin may be directly nephrotoxic by generating free hydroxyl radicals injurious to renal tubular cells. There is no definitive study that resolves the controversy conceming hemolysis and renal failure. Presumably, the renal parenchyma is most vulnerable during periods of acidosis, shock, and circulatory compromise. Given the available clinical and experimental data, we suggest that the following clinical situations are at least a relative indication to wash salvaged blood: (1) when the patient has underlying renal insufficiency, (2) when there is shock, acidosis, hypotension or other renal vascular compromise, (3) when a significant volume of hemolyzed salvaged blood is to be infused, and (4) when there is concurrent administration of drugs that impair renal blood flow or are otherwise known to be nephrotoxic. SURGICAL DEBRIS AND DRUGS

A frequently cited concem in the autotransfusion literature has been the possible detrimental effects of reinfusion of surgical "debris" during IBS. Suture material, bone or tissue fragments, cellular enzymes, fat, and topically applied irrigants or clotting agents are obvious examples of such debris. Proponents of washing point to the benefits of removing such material from the blood. However, there is no conclusive evidence to support a greater detrimental cardiopulmonary effect from transfusion of unwashed blood compared with washed blood collected by intraoperative salvage. Nevertheless, a few reports have suggested the need for more thorough investigation of the controversy. An early study by Dorang et a1!27 in dogs investigated the effects of reinfusion during spinal surgery. Blood which had been deliberately contaminated with excessive bone, cartilage particles, and marrow fat was salvaged and reinfused. Autopsy examination of 10 dogs showed evidence in one animai of a 1 cm peripherallung infarct due to a fat embolus. Bennett et al!28 and Moore et al!29 studied the cardiopulmonary effects of reinfusion of unwashed blood in a dog model. In the

study by Moore, each dog was bIed over a 4-hour period twice its blood volume in one-eighth increments into a peritoneal pouch. The animals were not systemically anticoagulated. The blood was allowed to pool and then was suctioned under low vacuum into a Sorensen device using ACD anticoagulation at the suction tipo The salvaged blood was not washed but was reinfused through a 40 fJ.m filter. Twenty animals were studied. All received an additional 50 mLlkg of Ringer's lactate solution. Ten animals were treated with 30 mg/kg of methylprednisolone and 10 were not. The dogs who did not receive steroids had a fall in cardiac output from 3.6 Llmin to 2.6 Llmin with a rise in pulmonary artery wedge pressure from 5 to 10 mm Hg. Oxygen delivery fell as a result of decreased cardiac outpuL In both steroid treated and nontreated animals pulmonary vascular resistance rose, but blood gas results did not change during autotransfusion. Two pathologists unaware of which animals were steroid treated independently examined lung specimens. "Alveolar congestion, perivascular hemorrhage or fibrin thrombi" were noted in five of 10 steroid treated dogs and in nine of 10 dogs who did not receive steroids. The observed decline in cardiac output and rise in pulmonary artery wedge pressure suggest a depressant effect on cardiac function of salvaged blood that is partia1ly clotted, unwashed, and collected in ACD. An impairment of left ventricular function in animals (pigs) receiving inadequately heparinized salvaged blood was also suggested in the study by Lehr et al. BO However, Menkis et alB! studied the effects of unwashed salvaged blood collected from systemically heparinized humans on the contractility of isolated human heart muscle. The isometric resting force, developed force, and mean rate of developed force were not different for atrial appendages batched in heparinized unwashed salvaged blood versus heparinized arterial blood. A recent study by BulI et al!32 in dogs attempted to address possible deleterious cardiopulmonary effects of washed salvaged blood colIected in heparin. The authors collected blood in low-dose heparin from animals who were not systemically anticoagulated. The blood was kept for 90 minutes at 37°C and then diluted in saline before processing in a Haemonetics Cell Saver using a 12 minute spin time. With this protocol, the investigators found that platelets and leukocytes adhered to the sides of the plastic bowl of the salvage device and

229

INTRAOPERATIVE BLOOD SALVAGE

were not completely removed by washing. These plateletJleukocyte aggregates demonstrated procoagulant activity in vitro using a modified prothrombin time. After reinfusion with this blood through a 40 !-Lm filter, the animals were killed and studied. Pulmonary histology showed occlusive thrombi composed of platelets, fibrin, and leukocytes in pulmonary arterioles that were reported as qualitatively more extensive in study animals compared with control animals who had received either no salvaged blood or who had received banked blood. A comparison group treated with unwashed salvaged blood was not studied. The observed thrombi did not develop to an equivalent degree in blood collected in citrate (rather than heparin) nor in blood collected without platelet activation, suggesting a procoagulant effect of calcium dependent platelet activation. This study suggests a possible link between the controversies of coagulopathy and pulmonary toxicity from salvaged blood. It also suggests that salvage in citrate anticoagulant may be preferred to heparin. However, the experimental design used does not replicate the standard cell salvage situation used in human patients; it was not stated whether the histologic review was blinded; and the clinicalor physiologic consequences of the observed histology are unknown. Nevertheless, this study draws attention to the need for more investigation into the possible detrimental effects of heparin as an anticoagulant for IBS. The consequences of intravenous infusion of iodine irrigants, topical antibiotics, Gelfoam (absorbable gelatin; Upjohn Corp, Kalamazoo, MI), methylmethacralate, bile, urine, ascites, and other fluids or chemicals have not been carefully studied, but presumably are uncommon risks of cell salvage without washing. One study showed that topically applied neomycin-bacitracin used during IBS with washing resulted in inconsequential antibiotic infusion. 133 One case described reinfusion of blood presumably contaminated with pancreatic enzymes. 38 Another suggested possible reinfusion of high levels of catecholamines in blood salvaged during resection of a pheochromocytoma. 134 Before washing the salvaged blood, catechoIamine leveIs were greater than 1,000 times normal. LeveIs were not measured after washing, but would be expected to have still been markedly elevated. Nevertheless, the blood pressure effect upon reinfusion of the washed blood was no greater than that

which occurred by manipulating the tumor during surgery. Another controversial adverse effect of blood saIvage is the "washout" oftherapeutically important levels of drugs administered during surgery. Hanowell et al 135 studied the removal of the narcotic, Fentanyl (fentanyl citrate; Elkins-Sinn, Inc, Cherry Hill, NJ), from six patients undergoing surgery. A median of 750 mL of saIvaged blood was processed by centrifugation and l L washing. Although the cell saIvage device removed 74% of the Fentanyl present in the bIood collection reservoir, the overall impact on the patient was considered clinically insignificant. Tissue Ievels of Fentanyl were not expected to be appreciably affected by intraoperative blood salvage due to the Iarge voIume of distribution of the drug and due to its high lipid solubility. In a similar fashion, Shanks et al 136 studied the effects of intraoperative salvage on the pharmocokinetics of d-tubocurarine. Ten orthopedic patients had 0.5 to 2.4 L of blood processed through a Haemonetics Cell Saver. Salvage with washing accounted for a loss of only 1.4% of the administered dose of the drug, whereas 15.3% of the initial dose was lost in the urine. The experience of plasmapheresis in seriously ill patients receiving critical concentrations of drugs also does not support a concem over washout through intraoperative blood salvage. In summary, there is still insufficient knowledge, particularly in humans, to describe the cardiopulmonary effects of infusions of blood collected during intraoperative saIvage and reinfused without washing. Animai studies suggest that blood that has undergone partial hemolysis and partial-to-compIete coaguIation ex vivo may promote cardiopulmonary dysfunction of uncertain magnitude. The studies raise concem that possible adverse cardiopulmonary effects could result from infusions of large volumes of unwashed salvaged blood. On the other hand there is little to suggest that washout of therapeutic drug levels is an important adverse consequence of intraoperative salvage with washing. COLLECTION AND STORAGE OF SALVAGED BLOOD

Concem has been expressed regarding the quality of the red cells harvested during IBS. The forces required to retrieve blood from the body produces mechanical trauma that can damage the

230

red cells. As collection is carried out in an open system, the risk of bacterial contamination may limit the permissible storage time of the product. Are Red Cells lnjured by lntraoperative Blood Salvage?

Surface skimming produces a turbulent atmosphere at the blood-air interface of the suction tip, which causes hemolysis. In addition, the vacuum force applied and resistance encountered as blood traverses tubing to the reservoir stresses and deforms the red cells. Orr,137 who noted that the Bentley system could produce up to 10% hemolysis, reported studies of red cells harvested using the Haemonetics Cell Saver (washed product). Levels of 2,3-diphosphoglycerate (2,3-DPG) were 3.40 ± 0.70 mmoVmL in washed autologous cells compared to 2.47 ± 1.20 mmol/mL in homologous cells stored an average of 4.2 days (P < .OS). He also reported that washed autologous cells were more resistant to osmotic stress with Iysis starting at 0.41 ± 0.03% sodium chloride (NaCI) and complete at 0.33 ± 0.22% NaCI in autologous cells compared to 0.49 ± 0.02% NaCI and 0.39 ± 0.02% NaCI for stored homologous cells (P < .Ol). He postulated that the stress of harvesting and washing preferentially selects out younger cells, while older fragile cells are destroyed by the processing. Do Red Cells Collected by lntraoperative Blood Salvage Survive Normally?

There are reports that examine the survival of radionucleide labeled red cells harvested by IBS. However, most of these studies have used cells washed and processed by the Cell Saver. One study measured survival of unwashed saIvaged blood. Buth et al 138 labeled cells with 5lCr in patients undergoing aortic resection. Fourteen patients received 5lCr-tagged blood postoperatively; in six controls, the aliquot was obtained preoperatively, and in eight experimental patients the aliquot was taken from the infusion line of the autotransfuser. The half life of the cells was not statistically different between the two groups. In a prospective study of SO patients undergoing abdominal aortic surgery with IBS performed using the Cell Saver, O'Hara et al l39 compared the washed, salvaged product with bank blood with respect to several parameters, including red cell survival. Twenty-six patients received 51Cr_

DZIK AND SHERBURNE

labeled red cells taken after processing in the Cell Saver, 10 control patients received labeled cells taken from a vein after induction of anesthesia. Labeled aliquots were injected shortly after surgery. Survival of red cells in the two groups was comparable, with a mean of 6S% of the labeled cells present at postoperative days 4 through 7. Both experimental and controi groups displayed nearly identical logarithmic decay curves, although actual half-lives were not measured. The authors also reported significantly higher mean 2,3-DPG levels in salvaged blood (1.66 mmoVmL) than in bank blood (0.81 mmollmL, P = .002). Mean, free hemoglobin was significantly higher in washed salvaged blood (499 mg/dL) than in bank blood (136 mg/dL, P = .0018). Ansell et al l40 published a study of red cell survival with a double-label technique, whereby each patient could serve as his own contro!. Processed blood obtained from the Cell Saver was labeled with 51Cr, and blood obtained by venipuncture was labeled with Indium 111 (III In). Gamma ray spectra of each isotope are separable, so each population could be counted individually. Patients underwent coronary artery bypass grafting or a major vascular procedure. The ratio of Indium-labeled RBCs to Chromium-labeled RBCs was not significantly increased 30 minutes after injection. The authors argued that if the cells collected by IBS (51 Cr-labeled) were damaged or nonviable, they would have been sequestered by the reticuloendothelial system rapidly after infusion and the ratio of II lIn to 5lCr labeled red cells at 30 minutes would have been greatly increased. As this was not observed, they concluded that the in vivo survival of processed blood was not significantly different from that of nonprocessed blood. Similar experiments are reported in the orthopedic surgery literature. Ray et al 141 found that mean survival of 5lCr-labeled red cells at 24 days postinfusion was not significantly different between homologous bank blood (43% survival), autologous predeposited blood (4S% survival), and processed Cell Saver blood (S2% survival) in 33 randornly selected patients undergoing spinal surgery. Jones et al,142 however, found that the mean half-life of 5lCr-labeled cells processed by the Cell Saver was 22.4 ± 4.S days in 10 patients who underwent major orthopedic procedures, and that this represented a 20% reduction from their laboratory's normal historical controi value of 28 days.

INTRAOPERATIVE BLOOD SALVAGE

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Does Bacterial Growth Preclude Storage oj Salvaged Blood?

Williamson et al 143 at the Mayo Clinic reported their results of cultures of salvaged blood that were stored at 4°C after processing. This was in response to an FDA guideline issued in 1989 that called for a maximum 6-hour storage period of salvaged blood due to an "increased risk of bacterial contamination." Results of surveillance cultures of 220 IBS units stored at 4°C for up to 24 hours (which were transfused) and 10 U stored 25 to 44 hours (and therefore not transfused) were reported. The Dupont Isolator system (Dupont Corp, Wilmington, DE), which employs lysiscentrifugation of blood before culture, was used. Of the 220 transfused units, 137 showed no growth, 75 grew one or less colony forming units per milliliter of coagulase negative Staphylococcus or another nonpathogenic organism, and eight grew either 3 to 4 CFU per milliliter of coagulase negative Staphylococcus or Corynebacterium species or 1 to 2 CFU per milliliter of S aureus. Ofthe 10 older, untransfused units, nine had no growth and one had less than l CFU per milliliter of coagulase negative Staphylococcus. No evidence of infectious complications due to IBS was found, and the authors concluded that the risk of infection from intraoperatively salvaged blood stored at 4°C appeared to be low. How Long Should Salvaged Blood Be Stored? If washed salvaged blood is superior to homologous blood, it may be desirable to retain unused collected units for the postoperative period. The blood has been collected in any open system, however, and is suspended not in preservative solution, but in saline. From a bacteriologic point of view, studies such as Williamson's suggest that microbial contamination is negligible. However, these results were obtained from clean surgery where IBS is routinely used, often in the presence of prophylactic antibiotics. The same minimai growth pattems may not prevail in hepatobiliary surgery or other potentially contaminated cases where IBS is being increasingly used. Further studies need to be

done to define settings in which the potential for microbial inoculation would render salvaged blood suitable or unsuitable for storage. The literature cited supports the notion that red celIs that survive the rigors of harvest and washing are viable and robust. However, it is not known how long the salvaged celIs retain these favorable qualities once they are suspended in saline. There are no reported survival studies of salvaged red celIs collected intraoperatively and stored in saline at 4°C for any length of time. Neither the osmotic fragility nor the 2,3-DPG levels of salvaged red cells stored in saline for 24 hours has been determined. Should future studies show that the storage of salvaged blood in saline is suboptimal, a special storage solution with preservative and antimicrobial properties for the processing and storage of intraoperatively salvaged blood may need to be developed. SUMMARY

Although a great deal has been learned about the medical aspects of intraoperative blood salvage, several fundamental medical issues remain controversial. As pressure increases to maximize the use of IBS, more research will be needed on the application of salvage techniques in cancer surgery and in the presence of bacterial contamination. The reintroduction of the use of devices that do not wash salvaged blood have reopened investigations into the effects of reinfusion of partially hemolyzed and partially clotted salvaged blood on coagulation, renal function, and cardiopulmonary performance. More studies are also needed so that empirically based standards of practice for the collection and storage of salvaged blood can be established. No longer confined to a few pioneering surgical departments, IBS is now widely practiced and likely to continue to grow rapidly. Knowledge and research of the medical issues surrounding its use will become increasingly valuable in transfusion medicine. ACKNOWLEDGMENT The authors wish to express their appreciation to Esabella Chin for her expert preparation of the manuscript.

REFERENCES l. Watson CM, Watson JR: Autotransfusion-Review of American literature with report of two additional cases. Am J Surg 33:232-237, 1936

2. Wilson JD, Taswell HF: Autotransfusion: Historical re-

view and preliminary report on a new method. Mayo Clin Proc 43:26-35, 1968 3. Stehling LC, Zauder HL, Rogers W: Intraoperative autotransfusion. Anesthesiol 43:337-345, 1975

232 4. Brzica SM, Pineda AA, Taswell HF: Subject review: Autologous blood transfusion. Mayo Clin Proc 51:723-737, 1976 5. Brzica SM, Pineda AA, Taswell HF: Autologous blood transfusion. CRC Crit Rev Clin Lab Sci 10:31-56, 1979 6. Thurer RL, Hauer JM: Autotransfusion and blood conservation-Current problems in surgery 19:98-156, 1982 7. Young GP, PurcelI TB: Emergency autotransfusion. Ann Emerg Med 12:180-186, 1983 8. Jacobs LM, Hsieh IW: A clinical review of autotransfusion and its role in trauma. JAMA 251:3283-3287, 1984 9. Popovsky MA, Devine PA, Taswell HF: Intraoperative auto10gous transfusion. Mayo Clin Proc 60:125-134, 1985 10. G10ver IL, Broadie TA: lntraoperative autotransfusion. World l Surg 11:60-64, 1987 11. Glover IL, Broadie TA: lntraoperative autotransfusion, in Collins JA, Murawski K, Shafer AW (eds): Massive Transfusion in Surgery and Trauma, Progress in Clinical and Biological Research, vo1 108, New York, NY, Liss, 1982, pp 151-171 12. Yawn DH, Bull BS: lntraoperative salvage: Quality of products, in Maffei LM, Thurer RL (eds): Autologous Blood Transfusion: Current Issues. Arlington, VA, American Association of B100d Banks, 1988, pp 43-57 13. Yaw PB, Sentany M, Link WJ, et al: Tumor cells carried through autotransfusion-Contraindication to intraoperative blood recovery? lAMA 231:490-491, 1975 14. Dale RF, Kipling RM, Smith MF, et al: Separation of malignant cells during autotransfusion. Br J Surg 75:581, 1988 15. Lane TA: The effect of storage on the metastatic potential of tumor cells collected in autologous blood-An animai model. Transfusion 29:418-420, 1989 16. Straus AK, Roseman DL, Shapiro TM: Peritoneovenous shunting in the management of malignant ascites. Arch Surg 114:489-491, 1979 17. Oosterlee J: Peritoneovenous shunting for ascites in cancer patients. Br l Surg 67:663-666, 1980 18. Raaf JG, Phil D, Stroehlein JR, et al: Palliation of malignant ascites by the LeVeen peritoneovenous shunt. Cancer 45:1019-1024, 1980 19. Reinhold RB, Lokich JC, Tomashefski J, et al: Management of malignant ascites with peritoneovenous shunting. Am J Surg 145:455-457, 1983 20. LeVeen HH, Wapnick S, Grosberg S, et al: Further experience with peritoneovenous shunt for ascites. Ann Surg 184:574-81, 1976 21. Souter RG, Tarin D, Kettlewell MGW: Peritoneovenous shunts in the management of malignant ascites. Br J Surg 70:478-481, 1983 22. Lokich l, Reinhold R, Silverman M, et al: Complications of peritoneovenous shunt for malignant ascites. Cancer Treat Rep 64:305-309, 1980 23. Smith RRL, Stemberg SS, Paglia MA: Fatal pulmonary tumor embolization following peritoneovenous shunting for malignant ascites. J Surg Oncol 16:27-35, 1981 24. Cole WH: The mechanisms of spread of cancer. Surg GynecolObstet 137:853-871, 1973 25. Herzon FS: Autotransfusion in otolaryngology. Arch Otolaryngol 104:608-609, 1978 26. Klimberg l, Sirois R, Wajsman Z, et al: Intraoperative autotransfusion in urologic oncology. Arch Surg 121: 13261329, 1986

DZIK AND SHERBURNE

27. Hart OJ, Klimberg IW, Wajsman Z, et al: Intraoperative autotransfusion in radical cystectomy for carcinoma of the blad. der. Surg Gynecol Obstet 168:302-306, 1989 28. Shahian DM, Libertino lA, Zinman LN, et al: Cavoatrial hypemephroma: Radical resection employing total circulatory arrest. Arch Surg (in press) 29. Hall EJ: Radiobiology for the Radiologist. New York, NY, Harper and Row, 1986, pp 31-62 30. Button LN, DeWolf WC, Newburger PE, et al: The effects of irradiation on blood components. Transfusion 21:419-429, 1981 31. Petz LD, Swisher SN: lmmunology and its relation to blood transfusion, in Petz LO, Swisher SN (eds): Clinical Practice of Transfusion Medicine (ed 2). New York, NY, Churchill Livingstone, 1989, pp 31-58 32. Blumberg N, Heal JM: Perioperative blood transfusion and solid tumor recurrence-A review. Cancer Invest 5:615625, 1987 33. VanAken WG: Does perioperative b100d transfusion promote tumor growth: Transfus Med Rev 111:243-252,1989 34. K1ebanoff G, Phillips J, Evans W: Use of a disposable autotransfusion unit under varying conditions of contamination. Am J Surg 120:351-354, 1970 35. Smith RN, Yaw PB, Glover JL: Autotransfusion of contaminated intraperitoneal blood: An experimenta1 study. J Trauma 18:341-344, 1978 36. Rumisek JD, Weddle RL: Autotransfusion in penetraIing abdomina1 trauma, in RM Hauer, RL Thurer, RB Dawson (eds): Autotransfusion. New York, NY, E1sevier/North Holland, 1981, pp 105-113 37. Ness PM, Perkins HA: Transient bacteremia after dental procedures and other minor manipulations. Transfusion 20:82· 85, 1980 38. Huth JF, Maier RV, Pavlin EG, et al: Utilization of blood recycling in nonelective surgery. Arch Surg 118:626630, 1983 39. Boudreaux JP, Bomside GH, Cohn I: Emergency autotransfusion: Partial cleansing of bacteria-Iaden blood by cell washing. J Trauma 23:31-35, 1983 40. Merrill BS, Mitts DL, Rogers W, et al: Autotransfusion. lntraoperative use in ruptured ectopic pregnancy. J Reproduc Med 24:14-16, 1980 41. Keeling MM, Gray LA, Brink MA, et al: Intraoperative autotransfusion. Experience in 725 consecutive cases. Ann Surg 197:536-541, 1983 42. Griswold RA, Ortner AB: The use of autotransfusion in surgery of the serious cavities. Surg Gyn Obstet 77:167-177, 1943 43. Glover JL, Smith R, Yaw PB, et al: Autotransfusion of b100d contaminated by intestina1 contents. J Am Coll Emer Phys 7:142-144, 1978 44. Jurkovich Gl, Moore EE, Medina G: Autotransfusion in trauma. A pragmatic analysis. Am J Surg 184:782-785, 1984 45. Timberlake GA, McSwain NE: Autotransfusion of blood contaminated by enteric contents: A potentially 1ifesaving measure in the massive1y hemorrhaging trauma patient? J Trauma 28:855-857, 1988 46. Tartter PI: B100d transfusion and postoperative infeclion. Transfusion 29:456-459, 1989 47. Waymack JP, Warden GO, Miskell P, et al: Effect of varying number and volume of transfusions on mortality rate

INTRAOPERATIVE BLOOD SALVAGE

following septic challenge in an animai model. World J Surg 11:387-391, 1987 48. Dawes LG, Aprahamian C, Condon RE, et al: The risk of infection after colon injury. Surgery 100:796-803, 1986 49. Nichols RL, Smith JW, Klein OB, et al: Risk of infeetion after penetrating abdominal trauma. N Engl J Med 311:1065-1070, 1984 50. Dellinger OP, Oreskovich MR, Wertz MJ, et al: Risk of infection following laparotomy for penetrating abdominal injury. Arch Surg 119:20-27, 1984 51. Symbas PN: Autotransfusion from hemothorax: Experimental and clinical studies. J Trauma 12:689-695, 1972 52. Tyras OH, DiOrio DA, Stone HH, et al: Autotransfusion of intraperitoneal blood: An experimental study. Am Surg 39:652-656, 1973 53. Bennett SH, Geelhoed GW, Gralnick HR, et al: Effects of autotransfusion on blood elements. Am J Surg 125:273-279, 1973 54. Rakower SR, Worth MH, Berman I, et al: Hemostatic and homeostatic changes following massive autotransfusion in the dog. l Trauma 14:594-604, 1974 55. Stillman RM, Wrezlewicz WW, Stanczewski B, et al: The haematological hazards of autotransfusion. Br J Surg 63:651-654, 1976 56. Klebanoff LCG: Early clinical experience with a disposable unit for the intraoperative salvage and reinfusion of blood loss (intraoperative autotransfusion). Am J Surg 120:718-722, 1970 57. Rakower SR, Worth MH, Laekner H: Massive intraoperative autotransfusion of blood. Surg Gynecol Obstet 137:633636, 1973 58. Rakower SR, Worth MH: Autotransfusion: Perspective and critical problems. 1 Trauma 13:573-574, 1973 59. Duncan SE, Klebanoff G, Rogers W: A clinieal experience with intraoperative autotransfusion. Ann Surg 180:296304,1974 60. Duncan SE, Edwards WH, Dale WA: Caution regarding autotransfusion. Surgery 76:1024-1030, 1974 61. Mati lKG: Current concepts: Autotransfusion-A reappraisal. East African Med l 51:560-563, 1974 62. Brener Bl: Autotransfusion-Safe at any speed? Arch Surg 108:761, 1974 (editorial) 63. Reul GJ, Solis T, Greenberg SD, et al: Experience with autotransfusion in the surgical management of trauma. Surgery 76:546-555, 1974 64. Bregman D, Parodi EN, Hutehinson lE, et al: Intraoperative autotransfusion during emergency thoracic and elective open-heart surgery. Ann Thorac Surg 18:590-596, 1974 65. Due TL, lohnson JM, Wood W, et al: Intraoperative autotransfusion in the management of massive hemorrhage. Am 1 Surg 130:652-658, 1975 66. Mattox KL, Walker LE, Beall AC, et al: Blood availability for the trauma patient-Autotransfusion. l Trauma 15:663-669, 1975 67. Bonfils-Roberts EA, Stutrnan L, Nealon TF: Autologous blood in the treatrnent of intraoperative hemorrhage. Ann Surg 185:321-325, 1977 68. Brener BJ, Raines JK, Chesney C, et al: Intraoperative autotransfusion. Surg Forum 24:255-257, 1973 69. Raines l, Buth l, Brewster DC, et al: Intraoperative

233 autotransfusion: Equipment, protocols, and guidelines. J Trauma 16:616-623, 1976 70. Brawley RK, Hauer 1M: Autotransfusion seminar. Surg 84:693-723, 1978 71. Moore EE, Dunn EL, Breslich DJ, et al: Platelet abnormalities associated with massive autotransfusion. J Trauma 20:1052-1056, 1980 72. Silva R, Moore EE, Bar-Or D, et al: The risk: Benefit of autotransfusion---Comparison to banked blood in a eanine model. 1 Trauma 24:557-564, 1984 73. Napoli VM, Symbas Pl, Vroon DH, et al: Autotransfusion from experimental hemothorax: Levels of coagulation factors. l Trauma 27:296-300, 1987 74. Moore KL, Bendick Pl, Broadie TA, et al: Systemic effects of intraoperative autotransfusion. Med Instrument 17:85-87, 1983 75. Kingsley JR, Valeri CR, Peters H, et al: Citrate anticoagulation and celi washing for intraoperative autotransfusion in the baboon. Am 1 Surg 131:717-721, 1976 76. Broadie TA, Glover JL, Bang N, et al: Clotting competence of intracavitary blood in trauma victims. Ann Emerg Med 10:127-130, 1981 77. Moore KL, Bang NU, Broadie TA, et al: Marks: Peritoneal fibrinolysis: Evidenee for the efficiency of the tissuetype plasminogen activator. 1 Lab Clin Med 101:921-929, 1983 78. Laschuk B, Harris KA, Carroll SE, et al: Simple method of intraoperative blood collection and reinfusion during aortic surgery. Can Soc Cardiovasc Thorac Surg 31:337-340, 1988 79. Clifford PC, Kruger AR, Smith A, et al: Salvage autotransfusion in aortic surgery: lnitial studies using a disposable reservoir. Br J Surg 74:755·757, 1987 80. Schaff HV, Haver J, Gardner TJ, et al: Routine use of autotransfusion following cardiac surgery: Experience in 700 patients. Ann Thor Surg 27:493-499,1979 81. Thurer RL, Lytle BW, Cosgrowe DM, et al: Autotransfusion following cardiac operations: A randomized, prospective study. Ann Thor Surg 27:500-507, 1979 82. Carter RF, McArdle B, Morritt GM: Autologous transfusion of mediastinal drainage blood: A report of its use following open heart surgery. Anesthesiology 36:54-59, 1981 83. Griffith LD, BiIlman GF, Daily PO, et al: Apparent coagulopathy caused by infusion of shed mediastinal blood and its prevention by washing of the infusate. Ann Thorac Surg 47:400-6, 1989 84. Edmunds HL, Addonizio VP: Extraeorporeal circulation, in Colman RW, Hirsh J, Marder VJ, et al (eds): Hemostasis and Thrombosis (ed 2). Philadelphia, PA, Lippincott, 1987, pp 901·912 85. Hardaway RM, Dumke R, Gee T, et al: The danger of hemolysis in shock. Ann Surg 189:373-376, 1979 86. Carty MI, Barr RD, Ouna N: The coagulation and fibrinolytic properties of peritoneal and venous blood in patients with ruptured ectopic pregnancy. 1 Obstet Gynaecol Br 80:701703, 1973 86a. Marder VI, Francis CW, Doolittle RF: Fibrinogen structure and physiology, in Colman RW, Hirsh J, Marder VI, et al (eds): Hemostasis and Thrombosis. Philadelphia, PA, Lippincott, 1982, pp 145-163 87. Marder VI, Matchett MO, Sherry S: Detection of serum fibrinogen and fibrin degradation products---Comparison of six

234

technics using purified products and application in clinical studies. Am l Med 51:71-82, 1971 88. Larrieu MI, Rigollot C, Marder VI: Comparative effects of fibrinogen degradation fragments D and E on coagulation. Br l Haematol 22:719-733, 1972 89. Marder VI, Shulman NR: High molecular weight derivatives of human fibrinogen produced by plasmin. l Biol Chem 244:2120-2124, 1969 90. Thorsen LI, Brosstad F, Gogstad G, et al: Competitions between fibrinogen with its degradation products for interactions with the platelet-Fibrinogen receptor. Thrombosis Res 44:611-623, 1986 91. Nachman RL, Leung LLK, Kloczewiak M, et al: Complex formation of platelet membrane glycoproteins Ub and III. with the fibrinogen D domain. l Biol Chem 259:8584-8588, 1984 92. Aaron RK, Beazley RM, Riggle GC: Haematologic integrity after intraoperative allotransfusion. Arch Surg 108:831837, 1974 93. Dubrow A, Flamenbaum W: Acute Renal Failure Associated with Myoglobinuria and Hemoglobinuria, in Brenner BM, Lazarus JM (eds): Acute Renal Failure (ed 2). New York, NY, Churchill Livingstone, 1988, pp 279-293 94. Agarwal RK, Moudgil A, Kishore et al: Acute viral hepatitis, intravascular hemolysis, severe hyperbilirubinemia and renal faiłure in glucose-6-phosphate dehydrogenase deficient patients. Postgrad Med l 61:971-975, 1985 95. Magnevik K, Gordon E, Lins LE, et al: Glycerolinduced haemolysis with haemoglobinuria and acute renal faił­ ure. Lancet 1:75-77, 1974 96. Sitprija V: Nephropathy in falciparum malaria. Kidney Int 34:867-877, 1988 97. Guess HA, Saviteer PL, Morris CR: Hemolysis and acute renal failure following a Portuguese man-of-war sting. Pediatrics 70:979-981, 1982 98. V Sakhuja, Bhalla A, Pereira BIG, et al: Acute renal failure following multiple homet stings. Nephron 49:319-321, 1988 99. Chadha lA, Leviav A: Hemolysis, renal failure and local necrosis following scorpion sting. JAMA 24:1038, 1979 100. Goldfinger D: Acute hemolytic transfusion reactionsA fresh look at pathogenesis and considerations regarding therapy. Transfusion 17:85-98, 1977 101. Greenwalt TJ: Pathogenesis and management of hemoIytic transfusion reactions. Semin Hematol 18:84-94, 1981 102. Schmidt PF, Holland PV: Pathogenesis of the acute renal failure associated with incompatible transfusion. Lancet 2:1169-1172, 1967 103. Sandler SG, Berry E, Zlotnick A: Benign hemoglobinuria following transfusion of accidentally frozen blood. lAMA 235:2850-2851, 1976 104. Quick Al, Georgatsos IG, Hussey CV: The clotting activity of human erythrocytes: Theoretical and clinical implications. Am l Med Sci 228:207-213, 1954 105. Hardaway RM, Dixon RS, Foster FF, et al: The effect of hemorrhagic shock on disseminated intravascular coagulation. Ann Surg 184:43-45, 1976 106. Rabiner SF, Helbert JR, Lopas H, et al: Evaluation of a stroma-free hemoglobin solution for use as a plasma expander. l Exp Med 126:1127-1142, 1967 107. Bimdorf NI, Lopas H: Effects of red celi stroma-free

DZIK AND SHERBURNE

hemoglobin solution on renal function in monkeys. l Appl Physiol 29:573-578, 1970 108. Relihan M, Litwin MS: Effects of stroma-free hemoglobin solution on clearance rate and renal function. Surgery 71:395-399, 1972 109. Relihan M, Olsen RE, Litwin MS: Clearance rate and effect on renal function of stroma-free hemoglobin following renal ischemia. Ann Surg 176:700-704, 1971 110. Relihan M, Litwin MS: Clearance rate and renal effects of stroma-free hemoglobin on acidotic dogs. Surg Gynecol Obstet 137:73-79, 1973 111. Savitsky IP, Doczi l, Black l, et al: A clinical safety trial of stroma-free hemoglobin. Clin Pharmacol Ther 23:7380, 1978 112. Miller IH, McDonald PK: The effect of hemoglobin on renal function in the human. l Clin Invest 30:1033-1040, 1951 113. Brandt IL, Frank NR, Lichtman HC: The effects of hemoglobin solutions on renal functions in man. Blood 6:11521158, 1951 114. Litwin MS, Walter CW, lackson N: Experimental production of acute renal tubular necrosis. III. Acid Hematin-The etiologic pigment. Ann Surg 152:1016-1025, 1960 115. Hershko C: Mechanism of iron toxicity and its possible role in red celi membrane damage. Semin HematoI26:277-285, 1989 116. Sadrzadeh SMH, Graf E, Panter SS, et al: Hemoglobin. A biological Fenton reagent. l Biol Chem 259:1435414356, 1984 117. Paller MS: Hemoglobin an myoglobin-induced acute renal failure in rats: Role of iron in nephrotoxicity. Am l PhysioI255:F539·F544, 1988 118. Friedman HI, DeVenuto F: Morphological effects of transfusions with hemoglobin solutions. Crit Care Med 10:288293, 1982 119. Tam CC, Wong JT: Impairment of renal function by stroma-free hemoglobin in rats. l Lab Clin Med 111:189-193, 1988 120. Gould S: Oxygen transport by hemoglobin solutions: A promising new therapy. Presented before the Academic Transfusion Medicine Forum, American Association of Blood Banks, 42nd annual meeting, New Orleans, LA, 1989 121. Klebanoff G: Intraoperative autotransfusion with the Bent1ey ATS-lOO. Surgery 84:708-712, 1978 122. Brener BI, Raines IK, Darling RC: Intraoperative autotransfusion in abdominal aortic resections. Arch Surg 107:7884, 1973 123. Brewster DC, Ambrosino 11, Darling RC, et al: Intraoperative autotransfusion in major vascular surgery. Am l Surg 137:507-513, 1979 124. Cali RP, O'Hara Pl, Hertzer NR, et al: The influence of autotransfusion on homologous blood requirements during aortic reconstruction. Cleveland Clin l Med Q 51:143-148, 1984 125. Stanton PE, Shannon l, Rosenthal D, et al: Intraoperative autologous transfusion during major aortic reconstructive procedures. South Med l 80:315-319, 1987 126. Sharp WV, Stark M, Donovan DL: Modem autotransfusion. Experience with a washed red celi processing technique. Am l Surg 142:522-524, 1981 127. Dorang LA, Klebanoff G, Kemmerer WT: Autotrans-

INTRAOPERATłVE BLOOD SALVAGE

fusion in long-segment spinal fusion. Am 1 Surg 123:686-688, 1972 128. Bennett SH, Geelhoed GW, Terrill RE, et al: Pulmonary effects of autotransfused blood-A comparison of fresh autologous and stored blood with blood retńeved from the pleurai cavity in an in situ lung peIfusion model. Am 1 Surg 125:696-702, 1973 129. Moore EE, Dunn EL, Bess R, et al: Amelioration of the pulmonary effects of massive autotransfusion with corticosteroids in the dog. Surg Gynecol Obstet 152:649-652, 1981 130. Lehr L, Wagner M, Kretschmer G: Left ventńcular pump failure associated with diffuse coagulation in experimental intraoperative autotransfusion. 1 Trauma 18:263-268, 1978 131. Menkis AH, Hendry Pl, Taichman GC, et al: Direct effects of autotransfused blood on myocardial muscle mechanics in man. Can 1 Surg 30:93-95, 1987 132. Buli MH, Buli BS, Arsdell GSV, et al: Clinical implications of procoagulant and leukoattractant forrnation during intraoperative blood salvage. Arch Surg 123:1073-1978, 1988 133. Paravicini D, Thys 1, Hein H: Rinsing the operative field with neomycinbacitracin solution with intraoperative autotransfusion in orthopaedic surgery. Arzheimittelforschungl Drug Res 33:242-246, 1983 134. Smith Dl, Mihm FG, Mefforo I: Hypertension after intraoperative autotransfusion in bilateraI adrenaleclomy for phenochromocytoma. Anesthesiology 58:182-184, 1983 135. Hanowell LH, Eisele lH, Erskine EV: Autotransfusor

235 removal of Fentanyl from blood. Anesth Analg 69:239-41, 1989 136. Shanks CA, Avram MI, Ronai AK, et al: The pharmacokinetics of d-tubocurarine with surgery involving salvaged autologous blood. Anesthesiology 62:161-165, 1985 137. Orr M: Autotransfusion: The use of washed red cells as an adjunct to component therapy. Surg 84:728-730, 1978 138. Buth 1, Raines lK, Kolodny GM, et al: Effect of intraoperalive autotransfusion on red celi mass and red celi survival. Surg Forum 26:276-278, 1975 139. O'Hara Pl, Hertzer NR, Santilli PH, et al: Intraoperalive aulolransfusion during abdominal aortic reconstruction. Am 1 Surg 145:215-220, 1983 140. Ansell 1, Parrilla N, King M, et al: Survival of autotransfused red blood celis recovered from the surgical field during cardiovascular operations. 1 Thorac Cardiovasc Surg 84:387-391, 1982 141. Ray 1M, Aynn le, Bierrnan AH: Erythrocyte survival following intraoperative autotransfusion in spinal surgery: An in vivo comparative study and 5-year update. Spine 11:879882, 1986 142. lones RB, Propst-Proctor SL, McDougall IR, et al: Erythrocyle survival following intraoperative autotransfusion in orthopedic surgery. Orthoped Transact 8:381, 1984 (abstr) 143. Williamson KR, Anhall lP, Koehler LC, et al: Cultures oC intraoperatively salvaged blood in light of FDA Guidelines. Transfusion 29:235, 1989 (abstr)