- Email: [email protected]
Microbiologic Contamination of Intraoperative Blood Salvaged During Liver Transplantation
Microbiologic Contamination of Intraoperative Blood Salvaged During Liver Transplantation P. Feltracco, E. Michieletto, S. Barbieri, E. Serra, S. Rizzi, F. Salvaterra, U. Cillo, and C. Ori ABSTRACT Bacterial contamination is one of the potential risks of blood salvage and reinfusion during orthotopic liver transplantation (OLT) because cell-saver machines lack antibacterial protection devices. This study was designed to analyze the potential bacterial contamination of blood salvaged during OLT; a secondary end point was to evaluate whether reinfusion of potentially contaminated blood may have been responsible for clinically manifested infective complications in the same patient. After induction of anesthesia, a blood sample was drawn from the central venous catheter (CVC) immediately after its positioning, to exclude potential coexisting hematic contamination of the recipient. During the procedure, 2 other samples of salvaged blood were collected for bacteriological analysis. Twenty-six of 38 samples of salvaged blood were positive for microorganisms, whereas 12 did not reveal the presence of infectious agents. In 19 of 26 positive samples, Staphylococcus species (73%) were isolated with only 2 of 38 samples drawn from CVC being contaminated. Candida Albicans was cultured in 2 samples. The high percentage (73%) of coagulase-negative Staphylococci indicates that blood contamination could have been caused by microorganisms from the air or suctioned from contact surfaces and the surgical field. Although almost 70% of processed and reinfused units tested positive for microbes, none of the postoperative blood cultures (at day 1 and day 3) revealed growth of the same species, not even in the 2 patients who had positive CVC cultures after induction of anesthesia.
I
N RECENT years, increased survival rates have been observed following orthotopic liver transplantation (OLT), although the number of complications has not significantly decreased. Infectious complications after OLT still represent an important issue that seriously compromises the postoperative course of transplant recipients.1 Late-stage chronic liver disease makes patients more susceptible to infections likely caused by both intestinal transmigration of microorganisms and insufficiency of the hepatic filter.2 The intraoperative phase exposes the recipient to significant risk of infection, due to the highly invasive surgical procedure, the long duration, the crowded theatre, as well as the need for intraoperative transfusions of blood and hemoderivatives.3 This study was designed to analyze the potential bacterial contamination of blood salvaged during the intraoperative stages of OLT. A secondary end point was to evaluate whether reinfusion of potentially contaminated blood could be responsible for clinically manifested infective complications in the same patient.
PATIENTS AND METHODS After informed consent was obtained, we prospectively analyzed blood samples from 38 patients who underwent OLT from June to December 2005. We did not enroll patients younger than 15 years of age or those in whom blood salvage was not performed. After induction of anesthesia, a blood sample was drawn from the central venous catheter (CVC) immediately after its positioning to exclude coexisting hematic bacterial contamination in the recipient. This sample was submitted for analysis in aerobic and anaerobic culture bottles. Patients then underwent OLT. The blood salvaging cell-saver system used during the procedures was the Continuous Auto Transfusion System C.A.T.S. (Fresenius, Schweinfurt, Germany). Blood coming from the abdominal wall incision and ascitic fluid was not processed. Only the From the Department of Pharmacology and Anesthesiology University Hospital of Padova, and Department of Surgical Science University Hospital of Padova, Padova, Italy. Address reprint requests to Paolo Feltracco, Department of Pharmacology and Anesthesiology, Via Giustiniani 1 35128 Padova, Italy. E-mail: [email protected]
© 2007 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/07/$–see front matter doi:10.1016/j.transproceed.2007.05.005
Transplantation Proceedings, 39, 1889 –1891 (2007)
1889
1890 blood aspirated during hepatic dissection, hepatectomy, implantation of the graft, and biliary tract reconstruction was processed and reinfused. During OLT, 2 samples were collected (20-mL each) from the first bag of blood salvaged using a sterile technique. Blood was immediately put into both aerobic and anaerobic culture bottles for bacteriological analysis. In the postoperative period, as a surveillance protocol, 20 ⫹ 20 mL (postoperative day 1 and day 3) of peripheral venous blood was cultured for bacteria in aerobic and anaerobic fluids to identify potential postoperative blood contamination.
RESULTS
Twenty-four patients were men and 14 women with mean age of candidates being 51.9 years (range, 15– 65). Thirtythree recipients received their first transplants and 5 underwent retransplantation. The mean intraoperative blood loss was 2954.6 mL ⫾ 2079 (range, 1000 –9900 mL). The mean amount of blood reinfused during the procedure with the Rapid Infusion System (RIS) was 1035 mL ⫾ 983 (range, 362– 4845 mL). Thirty of 38 patients required homologous blood transfusion, averaging 1428 mL ⫾ 1040 (range, 500 – 4500 mL). Twenty-six samples of salvaged blood were positive for microorganisms; 12 did not reveal the presence of infectious agents. In 19 of 26 positive samples, we isolated Staphylococcus species (73%). In particular, Staphylococcus epidermidis was isolated in 10 samples, S. hominis in 5, S. haemolyticus in 3, S. saprophyticus in 1, and S. warneri in 1. One sample was positive for Escherichia coli; 1 was positive for Propionibacter acnes. Candida albicans was cultured from 2 samples, whereas 2 blood cultures were concomitantly positive both for C. albicans and S. haemolyticus. Only 2 of 38 samples drawn from the CVC at the beginning of the transplantation procedure were contaminated, whereas sterile blood was aspirated from the other 36. In the first case it was S. hominis, in the second it was S. haemolyticus. In both recipients the same microorganisms were later isolated from the salvaged blood. Regarding the postoperative course, none of the surveillance samples obtained from the recipients tested positive for bacterial contamination, nor did these patients manifest clinical signs of blood infection. DISCUSSION
Autologous salvaged blood transfusion is widely used in OLT, mainly to save banked blood and to reduce the risk of infection transmitted with homologous blood transfusions. Liver transplantation is not a programmable procedure, therefore, blood-saving systems, other than intraoperative blood salvaging, are not applicable. Bacterial contamination of the blood processed and reinfused is, however, one of the potential risks of this method because these machines lack antibacterial protection devices.4 In the many studies that have evaluated the incidence of contamination in this setting, the frequency of positive blood cultures ranged from 3% to 97%.5,6
FELTRACCO, MICHIELETTO, BARBIERI ET AL
Many factors are responsible for contamination of aspirated blood during OLT, such as long exposure of the abdominal cavity to environmental air, complex and multiple instrumentation, many hands in the operative field, substitution of operating team members, crowded operating room, as well as multiple manipulations of vascular access and fluid administration.7,8 In our study, 26 of 38 (68.4%) cell-saver samples collected during liver transplantation were positive for microorganisms. From our protocol we could not differentiate whether the cultures grew from airbone contamination or normal skin flora contamination. The high percentage (73%) of coagulase-negative Staphylococci encountered confirms the previous observations by Kang et al. who observed the same infectious agents both in the salvaged blood and on the patient’s skin, abdomen, and/or in the air.9 Even in our series, blood contamination could have been caused by microorganisms from the air or suctioned from contact surfaces and the surgical field. It is reasonable to assume that bacteria detected in the 2 CVC samples were already present in the patient’s blood because the same organisms were later cultured from the salvaged blood. It is well recognized that many patients with end-stage cirrhosis experience episodes of spontaneous infection of the abdominal cavity or undergo multiple intravenous punctures for blood tests and therapy.10 Manipulation of CVCs during insertion would not have created so great a number of colonies. The scarce number of isolations from CVCs (2 of 38) attests both to the low number of preoperative blood contaminations and the strictly aseptic CVC insertions. Oddly, 3 salvaged blood samples were contaminated with C. Albicans, which was not identified in the patient’s CVC blood. There has been no such case described in the literature. With no recognizable source, we can only speculate that the contamination might have occurred from the peritoneal cavity or from preoperative colonization of the biliary tract or possibly from the cadaveric graft. Although almost 70% of processed and reinfused units tested positive for microbes, none of the postoperative blood cultures (at day 1 and day 3) revealed growth of the same species, not even the 2 patients who had positive CVC cultures after induction of anesthesia. Plausible explanations of the absence of previous contaminants in the postoperative blood specimens could be as follows: (1) the wide spectrum antibiotic therapy usually administered in OLT, (2) the sensitivity of microorganisms to antibiotics and antifungals, (3) the low bacterial count/mL of postoperative blood compared with salvaged and reinfused blood. In conclusion, although theoretically the presence of bacteria in salvaged blood remains a reasonable cause of postoperative infections, it was not confirmed in our study. However, the high level of contamination discovered in intraoperative autotransfusions should further stimulate staff members to strictly respect the correct approach to pre-intraoperative work-up and instrumentation.
CONTAMINATION OF INTRAOPERATIVE BLOOD
REFERENCES 1. Mora NP, Husberg BS, Gonwa TA, et al: The impact of the different severe infections on the outcome of liver transplantation. A study of 150 patients. Transpl Int 5(suppl):S209, 1992 2. Balan V, Marsh JW, Rakela J: Liver transplantation. In: Bricher J, (ed): Clinical Hepatology. Oxford: Oxford Medical Publications; 1999, p 2039 3. Steffen R, Reinhartz O, Blumhardt G, et al: Bacterial and fungal colonization and infection using oral selective bowel the contamination in orthotopic liver transplantation. Transpl Int 7:101, 1994 4. Sugai Y, Sugai K, Fuse A: Current status of bacterial contamination of autologous blood for transfusion. Transf Apher Sci 24:255, 2001 5. Williamson KR, Anhalt JP, Koehler LC, et al: Cultures of intraoperatively salvaged blood in light of FDA guidelines. Transfusion 29:235, 1989
1891 6. Bland LA, Villarino ME, Arduino MJ, et al: Ms Bacteriologic and endotoxin analysis of salvaged blood used in autologous transfusion during cardiac surgery. J Thorac Cardiovasc Surg 103:582, 1992 7. Ishida T, Nakaho S, Nakatani H, et al: Bacterial contamination of salvaged blood in open heart surgery: is that an airborne contamination or a normal skin flora contamination? Kyogu Geka 54:753(abstract), 2001 8. Nosanchuk JS: Quantitative microbiologic study of blood salvaged by intraoperative membrane filtration. Arch Pathol Lab Med 125:1204, 2001 9. Kang Y, Aggarwal S, Virji M, et al: Clinical evaluation of autotransfusion during liver transplantation. Anesth Analg 72:94, 1991 10. Corti A, Sabadin D, Pannacciulli E, et al: Early severe infections after orthotopic liver transplantation. Transpl Proc 23: 1964, 1991
I
N RECENT years, increased survival rates have been observed following orthotopic liver transplantation (OLT), although the number of complications has not significantly decreased. Infectious complications after OLT still represent an important issue that seriously compromises the postoperative course of transplant recipients.1 Late-stage chronic liver disease makes patients more susceptible to infections likely caused by both intestinal transmigration of microorganisms and insufficiency of the hepatic filter.2 The intraoperative phase exposes the recipient to significant risk of infection, due to the highly invasive surgical procedure, the long duration, the crowded theatre, as well as the need for intraoperative transfusions of blood and hemoderivatives.3 This study was designed to analyze the potential bacterial contamination of blood salvaged during the intraoperative stages of OLT. A secondary end point was to evaluate whether reinfusion of potentially contaminated blood could be responsible for clinically manifested infective complications in the same patient.
PATIENTS AND METHODS After informed consent was obtained, we prospectively analyzed blood samples from 38 patients who underwent OLT from June to December 2005. We did not enroll patients younger than 15 years of age or those in whom blood salvage was not performed. After induction of anesthesia, a blood sample was drawn from the central venous catheter (CVC) immediately after its positioning to exclude coexisting hematic bacterial contamination in the recipient. This sample was submitted for analysis in aerobic and anaerobic culture bottles. Patients then underwent OLT. The blood salvaging cell-saver system used during the procedures was the Continuous Auto Transfusion System C.A.T.S. (Fresenius, Schweinfurt, Germany). Blood coming from the abdominal wall incision and ascitic fluid was not processed. Only the From the Department of Pharmacology and Anesthesiology University Hospital of Padova, and Department of Surgical Science University Hospital of Padova, Padova, Italy. Address reprint requests to Paolo Feltracco, Department of Pharmacology and Anesthesiology, Via Giustiniani 1 35128 Padova, Italy. E-mail: [email protected]
© 2007 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/07/$–see front matter doi:10.1016/j.transproceed.2007.05.005
Transplantation Proceedings, 39, 1889 –1891 (2007)
1889
1890 blood aspirated during hepatic dissection, hepatectomy, implantation of the graft, and biliary tract reconstruction was processed and reinfused. During OLT, 2 samples were collected (20-mL each) from the first bag of blood salvaged using a sterile technique. Blood was immediately put into both aerobic and anaerobic culture bottles for bacteriological analysis. In the postoperative period, as a surveillance protocol, 20 ⫹ 20 mL (postoperative day 1 and day 3) of peripheral venous blood was cultured for bacteria in aerobic and anaerobic fluids to identify potential postoperative blood contamination.
RESULTS
Twenty-four patients were men and 14 women with mean age of candidates being 51.9 years (range, 15– 65). Thirtythree recipients received their first transplants and 5 underwent retransplantation. The mean intraoperative blood loss was 2954.6 mL ⫾ 2079 (range, 1000 –9900 mL). The mean amount of blood reinfused during the procedure with the Rapid Infusion System (RIS) was 1035 mL ⫾ 983 (range, 362– 4845 mL). Thirty of 38 patients required homologous blood transfusion, averaging 1428 mL ⫾ 1040 (range, 500 – 4500 mL). Twenty-six samples of salvaged blood were positive for microorganisms; 12 did not reveal the presence of infectious agents. In 19 of 26 positive samples, we isolated Staphylococcus species (73%). In particular, Staphylococcus epidermidis was isolated in 10 samples, S. hominis in 5, S. haemolyticus in 3, S. saprophyticus in 1, and S. warneri in 1. One sample was positive for Escherichia coli; 1 was positive for Propionibacter acnes. Candida albicans was cultured from 2 samples, whereas 2 blood cultures were concomitantly positive both for C. albicans and S. haemolyticus. Only 2 of 38 samples drawn from the CVC at the beginning of the transplantation procedure were contaminated, whereas sterile blood was aspirated from the other 36. In the first case it was S. hominis, in the second it was S. haemolyticus. In both recipients the same microorganisms were later isolated from the salvaged blood. Regarding the postoperative course, none of the surveillance samples obtained from the recipients tested positive for bacterial contamination, nor did these patients manifest clinical signs of blood infection. DISCUSSION
Autologous salvaged blood transfusion is widely used in OLT, mainly to save banked blood and to reduce the risk of infection transmitted with homologous blood transfusions. Liver transplantation is not a programmable procedure, therefore, blood-saving systems, other than intraoperative blood salvaging, are not applicable. Bacterial contamination of the blood processed and reinfused is, however, one of the potential risks of this method because these machines lack antibacterial protection devices.4 In the many studies that have evaluated the incidence of contamination in this setting, the frequency of positive blood cultures ranged from 3% to 97%.5,6
FELTRACCO, MICHIELETTO, BARBIERI ET AL
Many factors are responsible for contamination of aspirated blood during OLT, such as long exposure of the abdominal cavity to environmental air, complex and multiple instrumentation, many hands in the operative field, substitution of operating team members, crowded operating room, as well as multiple manipulations of vascular access and fluid administration.7,8 In our study, 26 of 38 (68.4%) cell-saver samples collected during liver transplantation were positive for microorganisms. From our protocol we could not differentiate whether the cultures grew from airbone contamination or normal skin flora contamination. The high percentage (73%) of coagulase-negative Staphylococci encountered confirms the previous observations by Kang et al. who observed the same infectious agents both in the salvaged blood and on the patient’s skin, abdomen, and/or in the air.9 Even in our series, blood contamination could have been caused by microorganisms from the air or suctioned from contact surfaces and the surgical field. It is reasonable to assume that bacteria detected in the 2 CVC samples were already present in the patient’s blood because the same organisms were later cultured from the salvaged blood. It is well recognized that many patients with end-stage cirrhosis experience episodes of spontaneous infection of the abdominal cavity or undergo multiple intravenous punctures for blood tests and therapy.10 Manipulation of CVCs during insertion would not have created so great a number of colonies. The scarce number of isolations from CVCs (2 of 38) attests both to the low number of preoperative blood contaminations and the strictly aseptic CVC insertions. Oddly, 3 salvaged blood samples were contaminated with C. Albicans, which was not identified in the patient’s CVC blood. There has been no such case described in the literature. With no recognizable source, we can only speculate that the contamination might have occurred from the peritoneal cavity or from preoperative colonization of the biliary tract or possibly from the cadaveric graft. Although almost 70% of processed and reinfused units tested positive for microbes, none of the postoperative blood cultures (at day 1 and day 3) revealed growth of the same species, not even the 2 patients who had positive CVC cultures after induction of anesthesia. Plausible explanations of the absence of previous contaminants in the postoperative blood specimens could be as follows: (1) the wide spectrum antibiotic therapy usually administered in OLT, (2) the sensitivity of microorganisms to antibiotics and antifungals, (3) the low bacterial count/mL of postoperative blood compared with salvaged and reinfused blood. In conclusion, although theoretically the presence of bacteria in salvaged blood remains a reasonable cause of postoperative infections, it was not confirmed in our study. However, the high level of contamination discovered in intraoperative autotransfusions should further stimulate staff members to strictly respect the correct approach to pre-intraoperative work-up and instrumentation.
CONTAMINATION OF INTRAOPERATIVE BLOOD
REFERENCES 1. Mora NP, Husberg BS, Gonwa TA, et al: The impact of the different severe infections on the outcome of liver transplantation. A study of 150 patients. Transpl Int 5(suppl):S209, 1992 2. Balan V, Marsh JW, Rakela J: Liver transplantation. In: Bricher J, (ed): Clinical Hepatology. Oxford: Oxford Medical Publications; 1999, p 2039 3. Steffen R, Reinhartz O, Blumhardt G, et al: Bacterial and fungal colonization and infection using oral selective bowel the contamination in orthotopic liver transplantation. Transpl Int 7:101, 1994 4. Sugai Y, Sugai K, Fuse A: Current status of bacterial contamination of autologous blood for transfusion. Transf Apher Sci 24:255, 2001 5. Williamson KR, Anhalt JP, Koehler LC, et al: Cultures of intraoperatively salvaged blood in light of FDA guidelines. Transfusion 29:235, 1989
1891 6. Bland LA, Villarino ME, Arduino MJ, et al: Ms Bacteriologic and endotoxin analysis of salvaged blood used in autologous transfusion during cardiac surgery. J Thorac Cardiovasc Surg 103:582, 1992 7. Ishida T, Nakaho S, Nakatani H, et al: Bacterial contamination of salvaged blood in open heart surgery: is that an airborne contamination or a normal skin flora contamination? Kyogu Geka 54:753(abstract), 2001 8. Nosanchuk JS: Quantitative microbiologic study of blood salvaged by intraoperative membrane filtration. Arch Pathol Lab Med 125:1204, 2001 9. Kang Y, Aggarwal S, Virji M, et al: Clinical evaluation of autotransfusion during liver transplantation. Anesth Analg 72:94, 1991 10. Corti A, Sabadin D, Pannacciulli E, et al: Early severe infections after orthotopic liver transplantation. Transpl Proc 23: 1964, 1991