Platelet-rich plasma reduces postoperative blood loss after cardiopulmonary bypass

J

THORAC CARDIOVASC SURG 1990;100:281-6

Platelet-rich plasma reduces postoperative blood loss after cardiopulmonary bypass To study the effect of plasma sequestration and reinfusion of platelet-rich plasma on blood loss after cardiopulmonary bypass, 18 patients undergoing heart operations were randomly selected either to have coDected or not to have coDected approximately 250 ml of platelet-rich plasma before initiating cardiopulmonary bypass with the use of the Haemonetics Plasma Saving System (Haemonetics Corporation, Braintree, Masse). All patients had standardized anesthesia and cardiopulmonary bypass. After reversal of heparin, autologons platelet-rich plasma was reinfused in nine patients. Thrombocyte counts, hemoglobin, and hematocrit were calculated before, during,and after cardiopulmonary bypass, and 24 and 48 hours postoperatively. Blood loss and total number of transfmions were recorded. Although 9 % of the total platelet volume was removed, there were no hemodynamic comp6cations related to the use of the Haemonetics Plasma Saving System. In both groups, significant low levels of thrombocytes, hemoglobin, and hematocrit were seen after cardiopulmonary bypass. Platelet-rich plasma-reinfnsed patients had a significantly higher number of platelets after heparin reversal. They also had significantly less blood loss after the operation, necessitating 65 % less banked blood products (p < 0.05). We concluded that reinfnsion of autologons platelet-rich plasma may serve as an effective and safe way to restore some of the hematologic derangements after cardiopulmonary bypass.

Anthony r. DelRossi, MD, Aurel C. Cernaianu, MD, Roger A. Vertrees, BA, CCP, Charles J. Wacker, BS, Sidney J. Fuller, BS, CCP, Jonathan H. Cilley, Jr., MD, and William A. Baldino, MD, Camden, N.J.

DesPite improvements in the surgical techniques and evolution of the equipment, patients undergoing heart operations with extracorporeal circulation are prone to serious hemorrhagic diathesis. Aside from inadequate surgical hemostasis, incomplete neutralization of anticoagulant, 1, 2 decreased plasma coagulation factors, especially factor V,3,4 and excessive fibrinolysis.t" thrombocytopenia and platelet dysfunction remain one of the major derangements produced by manipulation of blood through the bypass circuit.7 Increased adhesiveness to the inner surface of polyvinyl chloride tubing, damage and activation of platelets by the roller heads, as well as From the Departments of Surgery and Anesthesia and The School of Cardiovascular Perfusion, Cooper Hospital/University Medical Center, and University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden, Camden, N.J. Received for publication April 6, 1989. Accepted for publication Sept. I, 1989. Address for reprints: Anthony J. DelRossi, MD, Department of Surgery, Cooper Hospital/University Medical Center, Three Cooper Plaza, Suite 411, Camden, NJ 08103.

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increased agglutination resulting from systemic heparinization are some of the factors that may enhance platelet loss during extracorporeal circulation, with resultant bleeding tendency characterized by slow, diffuse oozing, petechiae, and ecchymosis. Although during recent years preparation, storage, and donor selection methods have made homologous platelet products freely available, the use of homologous platelet transfusions, either randomly or selectively matched for correction of postbypass bleeding, is not without risks. Complications ofplatelet transfusions are similar to those of red cells. In addition, refractoriness to random donor platelets occurs in many patients, most commonly associated with alloimmunization to histocompatibility antigens," Transfusion-transmitted diseasesf'" bacterial contamination, 11 nonhemolytic transfusion reactions, 12 and graft-versus-host disease':' are only some of the complications related to platelet replacement from banked sources. Beyond the potential hazards, there are also significant costs related to the donation and storage of these products. In an era wherein concerns that demand of blood products may exceed the supply, interest in finding 281

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DelRossi et al.

Table I. Demographic data for the two groups Age (yr) Perfusion time (min) Operation CABG VR

Combined procedures*

Control (n = 9)

PRP(n= 9)

58.2 ± 3.4 128.4 ± 4.5

59.0 ± 1.8 125.8 ± 6.8

5 (55.6%) 2 (22.2%) 2 (22.2%)

4 (44.5%) 3 (33.3%) 2 (22.2%)

Value expressed as mean ± standard deviation; percentage is given in parentheses. CABG, Coronary artery bypass grafting; VR, valve replacement. 'Combination of CABG and VR.

ways to counteract the disturbances of the platelets during extracorporeal circulation has increased." Used initially to collect plasma in community blood centers, the Haemonetics Plasma Saving System (Haemonetics Corporation, Braintree, Mass.) has evolved as an instrument for collection of platelet-rich plasma (PRP) before extracorporeal circulation. Reinfused after heparin neutralization, PRP may contain important coagulation elements lost during cardiopulmonary bypass (CPB) , their replacement resulting in significant reduction of blood loss. The present study was undertaken to establish the effectiveness of platelet sequestration and reinfusion of PRP and to measure the effect of the Haemonetics Plasma Saving System on the postoperative blood loss following CPB.

Clinical material and methods This randomized prospective study was done on 18 adult patients undergoing elective heart operations at Cooper Hospital/University Medical Center in Camden, New Jersey. During' the intraoperative preparation, a large-gauge Cordis catheter (Arrow International, Reading, Pa.) was inserted into the internal jugular vein for blood draw. All patients had anesthesia induced with fentanyl, etomidate, and pancuronium, maintained with oxygen and nitrous oxide, and supplemented with fentanyl. Patients with a history of ingestion of platelet-active drugs within 2 weeks before the operation were excluded from the study. Standard CPB was instituted in all patients with the use of two roller pumps (Cobe Corporation, Lakewood, Colo.) 'with polyvinyl chloride tubing. Heparin (3 mg/kg") was used to induce anticoagulation before cannulation, and activated clotting time (ACT) was frequently checked to measure the levelof heparinization. ACT was maintained over 400 seconds during CPB by supplemental heparin. Moderate total body hypothermia (28 0 C) was used. Nonpulsatile flowsbetween 2.0 L (hypothermia) and 2.4 L/min/m2 (normothermia) were employed. The extracorporeal circuit was primed with 2 L of Ringer's injection (Travenol Labs., Inc., Dearfield, Ill.) and 150 ml of 25% albumin (Travenol Labs.). One ampule of sodium bicarbonate and 5000 U of heparin were also added. A membrane oxygenator (Cobe Excel; Cobe Corporation) was used in all cases.

All patients signed a consent form to be included in the protocol. The study was approved by the Institutional Review Board. In nine randomly selected patients, Haemonetics Plasma Saving System was used to remove PRP according to the patient's weight, body build, and hematocrit. Collectionof PRP was started after induction of anesthesia, blood being drawn from the internal jugular catheter. A bolus of intravenous fluid was given before starting the collection of PRP, and sufficient volume replacement (lactated Ringer's solution) was infused during the collectionto replenish the lost volume. Bloodpressure was regulated with sodium nitroprusside. The Haemonetics Plasma Saving System is composed of a blood pump, centrifuge assembly programmable to variable rates, red cell detector, anticoagulant pump, plasma weigher, four air detectors, and a sensor to monitor the blood pressure. In accordance with the manufacturer's instructions, the actual centrifuge rate used in this study was 3400 to 3600 rpm. PRP was collected, properly labeled, placed on a "rocker," and stored at room temperature. Usually, one unit of PRP contains 5.5 to 7.7 X lOll viable platelets with a reduced number of contaminating white and red cells. After discontinuation of the extracorporeal circuit, heparin was antagonized with protamine sulfate (l mg/kg), half given as bolus and half as a continuous infusion. When ACT returned to or near baseline value, PRP collected and stored as has been described was reinfused to the patient. Blood samples for hematologic measurements were collected by venipuncture preoperatively (baseline), during the CPB at hypothermia (280 C) and normothermia (34 C), 15 minutes upon termination of CPB after PRP was reinfused, and at 24 and 48 hours postoperatively. Hematologic assessments consistingof platelet counts, hemoglobin, and hematocrit measurements were assessed by standard laboratory techniques. Postoperative blood losswas estimated by the volumeof blood present in the chest drainage reservoir beginning from the time of chest tube insertion intraoperatively through the first 48 hours. The content of the oxygenator was returned to each patient at the end of the procedure as centrifuged blood. Transfusion of banked blood products (whole blood, packed red cells [PRCs], and fresh frozen plasma [FFP]) was also recorded. To minimize the use of blood products in the postoperative period and avoid biased prescription of transfusions, specific rules for the administration of banked blood products were applied. Patients received PRCs only when the packed cell volume fell below 30% and FFP according to the activated partial thromboplastin time. All patients had an uneventful hospital course. In both groups, reoperation for bleeding was not necessary. SPSS Plus (version 2.0) was used for statistical analysis. Paired t test and analysis of variance (ANOYA) were used for comparison between variables. Values are presented as mean ± standard deviation. Statistical significance was assumed for p values of less than 0.05. 0

Results The demographic and preoperative hematologic profiles were similar among the patients in the two groups (Tables I and II). The intraoperative conditions and the surgical procedures were comparable (Table I). At all times during CPB, hypertension was well controlled with

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Platelet-rich plasma

283

Table II. Characteristics ofplasma-sequestratedgroup versus control Postoperative

Bypass Base Characteristics

line

Platelet count (X103) Control 253.7 ± 65.9 PRP 235.2 ± 64.1 Significance NS Hematocrit (%) Control 33.2 ± 4.3 34.3 ± 4.2 PRP Significance NS Hemoglobin (gmjdl) Control I\.4 ± \.5 PRP I \.5 ± 1.5 Significance NS

Cold (28" C)

Warm (32" C)

Post-bypass (15 min)

Day 1

Day 2

Significance (ANOVA)

118.3 ± 38.1 93.1 ± 27.9

139.3 ± 46.2 129.9 ± 36.5

122.8 ± 70.9 127.8 ± 3\.5

128.4 ± 36.8 13\.6 ± 30.2

p<0.05 p<0.05

NS

95.4± 15.6 135.7 ± 28.1 p<0.05

NS

NS

NS

19.0.± 2.8 19.7 ± 2.5

20.1 ± 2.6 21.7 ± 2.5

22.5 ± 4.4 22.3 ± 1.9

25.8 ± 3.2 26.4 ± 1.2

27.8 ± 3.3 26.6 ± 3.0

NS

NS

NS

NS

NS

6.5 ± 0.8 6.7 ± 0.8

6.8 ± 0.9 7.3 ± 0.7

7.5 ± 1.3 7.3 ± 0.6

8.8 ± 1.0 8.9 ± 0.6

9.5 ± 0.8 9.1 ± 0.9

NS

NS

NS

NS

NS

p<0.05 p<0.05

p<0.05 p<0.05

PRP. Platelet-rich plasma group; all values are mean ± standard deviation; NS, not significant.

sodiumnitroprusside or phenylephrine, and mean arterial pressuremaintained between60 and 85 mm Hg. There were no major hemodynamic reactions to jeopardize or interrupt the collection of PRP. As expected, in both groups, CPB resulted in a statistically significant reduction of platelet number, hematocrit, and hemoglobin levels (Table II). Significantly low hematologicvalues were observed up to 48 hours postoperatively. In the control group, the platelet number decreased further after reversal of heparin with protamine sulfate (postbypass); this was not seen in the PRP-reinfused group (p < 0.05). The statistical significant difference between the platelet counts was reduced over the next 48 hourspostoperatively. Patients in the two groups received comparableamounts of centrifuged bloodretrievedfrom the oxygenator circuit (p > 0.05). The plasma-sequestrated group received a mean of 220.8 ± 61 ml PRP (range, 121 to 300 ml), representing 9% of the total platelet volume. The control group receivednone. However, a striking difference was found in the amount of blood loss between the control and the PRP-reinfused group over the first 24 hours (630.0 ± 78.5 versus 407.8 ± 87.7 ml,p < 0.05). During the secondpostoperative day, the differences in blood loss between the two groups did not reach statistical significance. However, PRP-reinfused patients had 25% less total blood loss at the end of the 48-hour postoperative period (963.3 ± 80.5 versus 718.9 ± 99.0, p < 0.05). The needfor transfusionof banked bloodproducts was significantly different (Table III). Patients in the control group received 65% more blood products given as FFP and PRC than those receiving autologousPRP (total 24 unitsof FFP plus 15 units of PRC versus 4 units of FFP

plus 15 unitsofPRC). When translated to volumes, 9750 ml of blood products were used in the control group and only 3500 ml in the PRP-reinfused group (p < 0.05). Discussion CPB remains a technique resulting in major derangement of homeostasis, with special emphasis on blood components and plasma denaturation. The alterations observed after CPB ate explainedin part by the effect of real consumption of thrombocytes triggered by the contact of blood elements with the extracorporeal circuit'!5-18 Thrombocytopenia that persists several days after bypass19, 20 with lossof platelet function,4.19,21-22 reduction in aggregability,3,23,24 and adhesiveness.P with resulting increased bleedingtime," have been extensively related to extracorporeal circulation. Also, neutralization of heparin with protamine sulfate at the completion of CPB produces a dose-dependent damaging effect on platelets.26-28 To reverse some of the derangements seen following CPB, and to attempt to restore clotting factors to levels required for normal hemostatic response, homologous banked blood products have been used extensively and routinely in cases in which bleeding tendencies were observed. 19,29-32 However, potential complications related to errors of crossmatching, allergic reactions, isoimmunization and contamination, and the threat of transfusion-induced diseases are still present. Since predonation of autologous blood.P intraoperative whole blood autotransfusion." or pharmacologic manipulation35-39 for blood conservation after cardiac surgery are still under much debate, we would like to present a sim-

The Journal of Thoracic and Cardiovascular Surgery

2 8 4 DelRossi et al.

Table III. Chest drainage and bank blood transfusions Control

PRP

(n= 9)

(n= 9)

630.0 ± 78.5 344.4 ± 72.3 963.3 ± 80.5

407.8 ± 87.7 311.1 ± 37.6 718.9 ± 99.0

525.0 ± 50.0

542.0 ± 35.0 220.8 ± 6.1 4 FFP+ 15 PRC 3.500

Significance

Bloodloss (ml) Postop. day 1 (0-24 hr) Postop. day 2 (24-48 hr) Totals

Blood received Centrifuged blood (ml) Autologous PRP (m1)

Bank blood (units) Total bank blood (ml)

o

24 FFP+ 15 PRC 9.750

p<0.05

NS

p<0.05

NS p<0.05 p<0.05

Values are presented as mean ± standard deviation. NS, Not significant; PRP, platelet-rich plasma; FFP, fresh-frozen plasma; PRe, packed red cells.

ple alternative method for reducing postoperative bleeding and transfusion requirements through mechanical preservation of the platelets. This study was initiated to assessthe efficacy and the safety of a commerciallyavailable Haemonetics Plasma Saving System that has the capability to sequestrate a certain amount of PRP before the initiation of CPB and reinfuseit after completionof heparin neutralizationand to return it back into the circulationas nonaltered,viable thrombocytesdispersedinto physiologically normal plasma. Our study demonstrated that sequestrationof 9% of the total platelet volumedoes not produceany significant alterations of the hematologiccourse during CPB. Reinfusion of autologous PRP significantly increased the number of thrombocytes after bypass, a time when further alteration in the coagulationprofileinducedby heparin neutralizationwith protaminesulfateeventuallymay produce diffuse bleeding. There are several possible explanations for better platelet function after administration of autologousPRP. First, PRP contains thrombocytes that are not damaged by storage as are those in banked platelet concentrates.40-42 Second,plasma coagulation factors such as fibrinogen, factors V and VIII (von Willebrand), which are decreased during CPB and are inactive or destroyed in banked blood products." and fullyactivein freshcollectedPRP, may be responsible for the better hemostatic effect of reinfused-PRP. Improvement in the number of postbypass platelets with normal functional quality made a significant reduction in post-CPB bleedingpossible at the end of 24 or 48 hours,or both. In our study, patients receiving autologous PRP needed 65% less bloodproducts to control bleeding and the adjacent hematologicdisturbances,therebybeing exposed to considerablylessrisk of transfusion-transmitted diseases. Although a cost analysis was beyondthe scopeof this study, it is conceivable that important savings related to

the cost of bloodproductscould be achieved. Our observationsdemonstrated that reinfusion of autologous PRP may significantly reduce the need for homologous blood requirement after CPB in a safe and tolerable manner. This approach of mechanical preservation of platelets may be a valuabletoolfor bloodconservation, particularly in those patients in whom increasedbleeding tendency is expected. We thank Ms. Lorraine Robinson and Ms. Karen Finn for their assistance in preparing this manuscript. REFERENCES 1. Soloway HB, Cornett BM, Donahoo rv, Cox SP. Differentiation of bleeding diatheses which occur following protamine correction of heparin anticoagulation. Am 1 Clin Pathol 1973;59:188-91. 2. Lambert Cl, Marengo-Row Al, Leveson r, et al. The tri-F titer: a rapid test for estimation of plasma fibrinogen and detection of fibrinolysis, fibrin(ogen) split products, and heparin. Ann Thorac Surg 1974;18:357-63. 3. Mammen EF, Koets MH, Washington BC, et al. Hemostasis changes during cardiopulmonary bypass surgery. Semin Thromb Hemost 1985;11:281-92. 4. Mezzano D, Aranda E, Urzua J, et al. Changes in platelet beta-thromboglobulin, fibrinogen, albumin, 5-hydroxytryptamine, ATP, and ADP during and after surgery with extracorporeal circulation in man. Am 1 Hematol 1986;22:133-42. 5. Muller N, Popov-Cenic S, Buttner W, Kladetzky RG, Egli H. Studies of fibrinolytic and coagulation factors during open heart surgery. II. Postoperative bleeding tendency and changes in the coagulation system. Thromb Res 1975;7: 589-98. 6. Lambert Cl, Marengo-Row Al, Leveson lE, et al. The Treatment of postperfusion bleeding using epsilon-aminocaproic acid, cryoprecipitate, fresh-frozen plasma, and protamine sulfate. Ann Thorac Surg 1978;28:440-4.

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7. Holloway OS, Summaria L, Sandesara J, Vagher JP, AlexanderJC, Caprini JA. Decreasedplatelet number and function and increasedfibrinolysis contribute to postoperativebleedingin cardiopulmonarybypass patients.Thromb Haemost 1988;59:62-7. 8. Dahlke MB, Weiss KL. Platelet transfusion from donors mismatched for crossreaction HLA antigens. Transfusion 1984;24:299-302. 9. Anderson KC, Gorgone BC, Lew M. Transfusion related sepsis after prolonged plateletstorage.Blood1985;66(suppl l):273a. 10. BraineHG, KichklerRS, Charache P, et al. Bacterialsepsis secondary to platelet transfusion: an adverse effect of extended storage at room temperature. Transfusion 1986;26:391-3. 11. GorgoneBC, Lew M, AndersonKC. Bacterialcontamination of cytopheresis platelets [Abstract]. Transfusion 1986;26:584. 12. Buck SA, Kickler TS, Braine HG, et al. Elimination of allergicplatelet transfusion reactions by automated platelet washing [Abstract]. Transfusion 1985;25:459. 13. Leitman SF. Posttransfusion graft-versus-host disease. In: Smith OM, Silvergleid AJ, eds. Special considerations in transfusingthe immunocompromised patient. Washington, DC: American Association of Blood Banks, 1985:15-37. 14. Harke-H, Tanger 0, Furst-DenzerS, Papachrysanthou C, BernhardA. Effectof a preoperativeseparationof platelets on the postoperative bloodlosssubsequentto extracorporeal circulation during open heart surgery: a clinical study. Anaesthesia 1977;26:64-71. 15. Lindsay RM. Blood surface interactions [Panel Conference]. Trans Am Soc Artif Intern Organs 1980;26:603. 16. Stratta P, Canavese C, Mangiarotti G, et al. Heparin is unable to prevent contact activation by three different membranes. Proc Eur Dial Transplant Assoc 1981;18:269. 17. Kirklin JK, Westaby S, BlakstoneEH, Kirklin JW, Chenoweth DE, Pacifico A. Complement and the damaging effectof cardiopulmonary bypass. J THORAC CARDIOVASC SURG 1983;86:845-57. 18. Stratta P, Canavese C, Costa P, et al. Biological stress inducedby extracorporealcirculation: comparisonbetween cardiopulmonary bypass, hemodialysis and plasma exchange. Trans Am Soc Artif Intern Organs 1984;30:5027. 19. Harker LA, MalpassTW, BransonHE, HesselEA, Slichter SJ. Mechanismof abnormal bleedingin patientsundergoingcardiopulmonary bypass: acquired transient platelet of dysfunction associated with selective alpha-granule release. Blood 1980;56:824-34. 20. BachmannF, McKenna R, Cole ER, Najafi H. The hemostatic mechanism after open-heart surgery. I. Studies on plasmacoagulationfactors and fibrinolysis in 512 patients after extracorporeal circulation. J THORAC CARDIOVASC SURG 1975;70:76-85. 21. Addonizio VP, Smith JB, Strauss JF, Colman RW, Edmunds LH. Thromboxane synthesis and platelet secre-

Platelet-rich plasma 2 8 5

tion during cardiopulmonary bypass with bubble oxygenator. J THORAC CARDIOVASC SURG 1980;79:91-6. • 22. Davies GC, Sobel M, Salzman EW. Elevated plasma fibrinopeptide A and thromboxane B2 levels during cardiopulmonary bypass. Circulation 1980;61:808-14. 23. BoersM, Van den Dungen JJAM, KarliczekGF, Brenken D, Van der Heide JNH, WildevuurCRH. Two membrane oxygenators and a bubbler: a clinical comparison. Ann Thorac Surg 1983;35:455-62. 24. BoonstraPW, van Imhoff GW, Eysman L, et al. Reduced plateletactivationand improvedhemostasisafter controlled cardiotomy suction during clinical membrane oxygenator perfusions. J THORAC CARDIOVASC SURG 1985;89:900-6. 25. Bick RL, Arbegast N, Crawford L, Holterman M, Adams T, 'Schmalhorst W. Hemostatic defects induced by cardiopulmonary bypass. Vase Surg 1975;9:228-43. 26. Van den Dungen JJAM, Karliczek GF, Brenken D, Homan van der Heide IN, Wildevuur CHRH. Clinical studyof bloodtrauma during perfusionwith membrane and bubble oxygenators. J THoRAc CAROIOVASC SURG 1982; 83:108-16. 27. MielkeCH Jr, de Leval M, Hill JD, Macur MF, Gerbode F. Drug influence on platelet loss during extracorporeal circulation. J THORAC CAROIOVASC SURG 1973;66:84554. 28. Velders AJ, van den Dungen JJAM, Westerhof NJ, WildevuurCHRH. Platelet damage by protamine administration:protectionby reducing protamine or by prostacyclin (PGI2) treatment. Proc Eur Soc Artif Organs 1979;6:194-7. 29. WoodsJE, TaswellHF, KirklinJW, Owen CR. The transfusion of plateletconcentratesin patients undergoingheart surgery. Mayo Clinic Proc 1967;42:318-25. 30. Harding SA, Shakoor MH, Grindon AJ. Platelet support for cardiopulmonary bypass. J THORAC CARDIOVASC SURG 1975;70:350-2. 31. Pliam MB, McGoon DC, Tarhan S. Failure of transfusion of autologous wholebloodto reduce banked bloodrequirements in open-heart surgical patients. J THoRAc CAROIOVASC SURG 1975;70:338-43. 32. Mohr R, Golan M, Martinowitz D, Rosner F, Goor DA, Ramot B. Effect of cardiac operation on platelets. J THORAC CARDIOVASC SURG 1986;92:434-41. 33. Love TR, Hendren WG, O'Keefe DO, Daggett WM. Transfusion of predonated autologous blood in elective cardiac surgery. Ann Thorac Surg 1987;43:508-12. 34. Henderson AM, Maryniak JK, Simpson JC. Cardiac surgery in Jehovah's Witnesses: a reviewof 36 cases. Anaesthesia 1986;41:748-53. 35. Czer LS, BatemanTM, Gray RJ, et al. Treatment of severe platelet dysfunction and hemorrhage after cardiopulmonary bypass: reduction in blood products usage with desmopressin. J Am cen CardiolI987;9:1139-47. 36. Salzman EW; Weinstein MJ, Weintraub RM, et al. Treatment with desmopressin acetate to reduce blood loss after cardiac surgery. N Engl J Med 1986;314:1402-6.

2 8 6 DelRossi et al.

37. Teoh KH, Christakis GT, Weisel RD, et al. Blood conservation with membrane oxygenators and dipyridamole. Ann Thorac Surg 1987;44:40-7. 38. Bidstrup BP, Royston D, Sapsford RN, Taylor KM. Reduction in blood loss and blood use after cardiopulmonary bypass with high dose aprotinin (Trasylol). J THORAC CARDIOVASC SURG 1989;97:364-72. 39. DelRossi AJ, Cernaianu AC, Botros S, Lemole GM. Prophylactic treatment of post-perfusion bleeding using epsilon-aminocaproic acid. Chest 1989;96:27-30. 40. Slichter SJ, Harker LA. Preparation and storage of plate-

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let concentrates. I. Factors influencing the harvest of viable platelets from whole blood. Br J HaematoI1976;34:395-9. 41. MoroffG, Friedman A, Robkin-Klein L, GautierG, Luban NL. Reduction of volume of stored platelet concentrates for use in neonatal patients. Transfusion 1984; 24:144-6. 42. Valeri CR. Circulation and hemostatic effectiveness of platelets stored at 4 0 C or 22 0 C: studies in aspirin-treated normal volunteers. Transfusion 1976;16:20-3. 43. Osterud B, Rapaport SI, Lavine KK. Factor V activity of platelets: evidence for an activated after V molecule and for a platelet activator. Blood 1977;49:819-23.

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