Reinfusion of autologous blood after cardiac surgery

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1 Safety and Efficacy of Perioperative Cell Salvage and After Coronary Artery Bypass Grafting: A Randomized Trial Gavin J. Murphy, MD, FRCS, Simon M. Allen, FRCS, Jonathon Unsworth-White, FRCS, C. Terence Lewis, FRCS, and Malcolm J. R. Dalrymple-Hay, PhD FRCS Department of Cardiothoracic Surgery, Derriford Hospital, Plymouth, United Kingdom Background. The aim of this study was to ascertain whether cell salvage and autotransfusion after first time elective coronary artery bypass grafting is associated with a significant reduction in the use of homologous blood, a clinically significant derangement of postoperative clotting profiles, or an increased risk of postoperative bleeding. Methods. Patients were randomized to autotransfusion (n 98) receiving autotransfused washed blood from intraoperative cell salvage and postoperative mediastinal fluid cell salvage after coronary artery bypass surgery or control (n 102) receiving stored homologous blood only after coronary artery bypass surgery. Results. There was no statistical difference between the groups in terms of demographics, comorbidity, risk stratification, or operative details. Mean volume of blood autotransfused was ml. Patients in the autotransfusion group were significantly less likely to receive a homologous blood transfusion compared with controls (odds ratio 0.40, 95% confidence interval [CI] ) and received significantly fewer units of blood per patient compared with controls ( vs U, p 0.02). There was no difference between the groups in terms of postoperative blood loss, fluid requirements, blood product requirements, or in the incidence of adverse clinical events (p NS 2 ). did not produce any significant derangement of thromboelastograph values or laboratory measures of clotting pathway function (prothrombin time, activated partial thromboplastin time, fibrinogen, and fibrinogen D-dimer levels) when compared with the effect of homologous blood transfusion (p NS, repeated measures analysis of variance [MANOVA]). Conclusions. is a safe and effective method of reducing the use of homologous bank blood after routine first time coronary artery bypass grafting. (Ann Thorac Surg 2004;77:1553 9) 2004 by The Society of Thoracic Surgeons Reinfusion of autologous blood after cardiac surgery has been advocated to reduce the risk of transfusion reactions and to limit potential infectious risks associated with donor blood. Despite initial reports suggesting a significant benefit after autotransfusion of unprocessed, salvaged, intraoperative blood and shed mediastinal fluid [1 3] it became apparent that the autotransfusion of unwashed fluid was associated with fibrinolysis, coagulopathy, excessive bleeding, and a paradoxical increase in the utilization of homologous blood [3 6]. More recent randomized trials of both intraoperative [7] and postoperative cell salvage [8] with autotransfusion of washed cells have shown significant reductions in homologous blood use without increased blood loss. In spite of these findings, however, mechanical blood conservation remains underutilized in perioperative blood conservation [9, 10] in part because the issue of coagulopathy after autotransfusion has not been adequately addressed. The Accepted for publication Oct 14, Presented at the Fiftieth Annual Meeting of the Southern Thoracic Surgical Association, Bonita Springs, FL, Nov 13 15, Address reprint requests to Dr Murphy, Department of Cardiothoracic Surgery, Bristol Heart Institute, Bristol Royal Infirmary, Bristol BS2 8HW, UK; gavinmurphy@hotmail.com. aim of this study was to compare the effects of autotransfusion of washed salvaged red cells on coagulation pathway function and blood loss after cardiac surgery in a randomized controlled trial. Patients and Methods Study Population Between March 2002 and January 2003, 200 patients admitted to our institution for coronary artery bypass grafting (CABG) operations utilizing cardiopulmonary bypass (CPB) consented to enrollment in the study. Male or female patients aged 18 or over who were undergoing nonemergency first time coronary artery bypass grafting were eligible to take part. Exclusion criteria included those patients who are prevented from utilizing blood and blood products according to a system of beliefs (eg, Jehovah s Witnesses), patients on warfarin, heparin, or other systemic anticoagulant drugs preoperatively, patients with congenital or acquired platelet, red cell, or clotting disorders, patients with ongoing or recurrent Drs Murphy and Dalrymple-Hay disclose that they have a financial relationship with Medtronic by The Society of Thoracic Surgeons /04/$30.00 Published by Elsevier Inc doi: /j.athoracsur

2 1554 MURPHY ET AL Ann Thorac Surg PERIOPERATIVE CELL SALVAGE AND AUTOTRANSFUSION 2004;77: systemic sepsis and patients who were unable to give full informed consent for the study (eg, learning or language difficulties). The study received local ethical committee approval. Technical Procedure Patients were assigned to one of two randomized groups: one (autotransfusion group) had autotransfusion of washed intraoperative salvaged or postoperative shed mediastinal fluid as first line blood replacement therapy, postsurgery, in the intensive care unit. The other group (control group) was administered banked, homologous, leucodepleted packed red cells only as blood replacement therapy. The threshold for transfusion of homologous blood in controls was hemoglobin (Hb) less than 7 g/dl, a packed cell volume (PCV) less than 0.2, or, if clinically indicated in patients with excessive blood loss and cardiovascular instability at the discretion of intensive care (ITU) staff. Patients were randomized to the two treatment arms in a 1:1 ratio by using a block randomization procedure. Allocations were generated by a card system and concealed in sealed opaque envelopes. Patients that had given consent were randomized immediately before surgery. In the autotransfusion group all blood loss from skin incision to commencement of CPB and then after administration of protamine to skin closure was salvaged via a single lumen suction tube flushed with heparinized 0.9% normal saline (10 u/ml infused at 83 ml/h) connected to the closed rigid collection chamber of the Autolog autotransfuser device (Medtronic, Watford, UK) at high pressure suction. During CPB all spilt blood was aspirated by the CPB machine cardiotomy suckers and returned to the venous reservoir. All blood remaining in the CPB circuit after discontinuation of bypass was retransfused via the aortic cannula before decannulation and was never transferred to the autotransfuser. After closure of the sternum 28Fr soft sump drains (1 3 in number) were then connected via a Y connector to the same heparinized suction tubing and the suction reduced to 20 cm H 2 O, identical to that used for the control group. All subsequent shed mediastinal fluid for the first 12 hours postoperatively was then collected into the same collection chamber. After 12 hours hospital health and safety policy stated that all autotransfuser disposables must be discarded, at which point the drains were connected to drainage bottles identical to controls. In the control group all blood spilt before commencement of CPB and after administration of protamine was aspirated using a high pressure sucker and discarded. Postoperative mediastinal drainage was achieved by 28F single lumen rigid sump drains to a 1000 ml sterile collection chamber connected to 20 cm H 2 O wall suction via an underwater seal from which collected blood was discarded. Before autotransfusion the heparinized salvaged intraoperative blood and shed mediastinal drainage fluid underwent a washing process with resuspension of the red cells in saline at a hematocrit of 0.6. This red cell suspension was then transferred to a sterile collecting bag that was disconnected from the autotransfuser and administered via a standard blood giving set. Salvaged washed red cells were autotransfused at any time postoperatively if clinically indicated as determined by ITU staff. Otherwise salvaged blood/fluid was processed and the red cells autotransfused automatically every 4 hours before discarding of disposables at 12 hours. The low yield of intraoperative cell salvage meant that intraoperative processing and autotransfusion was not performed. Patients requiring further blood transfusion after autotransfusion (Hb 7 g/dl, PCV 0.2, or where clinically indicated) received homologous bank blood. Clotting products and platelets were administered at the discretion of the cardiac intensive care unit (CITU) staff in response to bleeding in the presence of coagulopathy or diminished platelet count. Operative Procedure All patients received standard fentanyl/propofol anesthesia. All patients received anticoagulation with 300 u/kg heparin, with supplemental doses if required, to achieve an activated clotting time (ACT) greater to 400 seconds before the commencement of CPB. Anticoagulation was reversed with protamine in a 1:1 ratio until the ACT had returned to within 10% of control values. CPB was established using a standard circuit with one of two membrane oxygenators (Jostra AG, Germany; Sorin Biomedica, Gloucester, UK) and a standard volume of prime (l L Hartmans, 800 ml Gelofusin, 100 ml 20% Mannitol, 5000 u Heparin). CPB flows were kept to approximately 2.4 L/min with moderate hypothermia (32 34 C) and mean arterial pressures maintained between mm Hg. The use of antifibrinolytic agents and myocardial preservation technique were at the discretion of the operating surgeon. Indications for intraoperative homologous blood transfusion were Hb less than 7 g/dl or hematocrit less than 0.21 during CPB. All patients had pedicled left internal thoracic artery grafts. No patient had predonated autologous blood for use perioperatively. Laboratory and Bedside Measurements of Clotting Pathway and Platelet Function Hb concentration and hematocrit measurements were performed preoperatively on arrival in the CITU and then at 2 hourly intervals or as clinically indicated via the indwelling arterial cannula. Hb, platelet count, prothrombin time (expressed as international normalized ratio [PT ratio], a measure of the extrinsic and common clotting pathways), activated partial thromboplastin time (APTT, expressed as APTT ratio to a normalized control value, a measure of the intrinsic and common clotting pathways), fibrinogen concentration, D-dimer concentration, and thromboelastography (TEG, Thromboelsatograph; Hemoscope, Skokie, IL) measurements were performed at the start and end of the operation and immediately before and 20 minutes after the infusion of the first autologous or homologous transfusions postoperatively. TEG was performed on celite-activated whole blood drawn from the arterial line.

3 Ann Thorac Surg MURPHY ET AL 2004;77: PERIOPERATIVE CELL SALVAGE AND AUTOTRANSFUSION Statistical Analysis Overall, blood utilization after cardiac surgery at Derriford Hospital was 63% over the period April June In order to detect an overall difference in blood utilization of 20% with a power of 0.8 and an alpha value of 0.05, 96 patients were required for each arm of the study (total 192 patients). Analysis was by intention to treat. All data were assessed for normality of distribution and equality of variance. The Student t test and ANOVA were used to compare normally distributed data and Mann Whitney was used to compare non-normally distributed data. Categorical data were compared using the Pearson 2 test. Data distribution is presented throughout as mean standard deviation (SD). Multivariate logistic regression was used to determine the independent effect of autotransfusion on the risk of receiving an allogeneic blood transfusion. General linear model repeated measures analysis (MANOVA) was used for analysis of variance when the same measurement was made several times on each subject. All data analysis was performed using the SPSS (Statistical Program for the Social Sciences) for Windows, Version 9.0 (SPSS UK Ltd., Chertsey, UK) software package. Results Baseline Characteristics A total of 16 patients failed to complete the study. In 4 patients (control n 3, autotransfusion n 1) it was decided intraoperatively to perform the grafts off pump. These patients were excluded from further analysis. In the autotransfusion group, two cases were withdrawn because of deviation from protocol and two were withdrawn intraoperatively because of an apparent post-cpb coagulopathy. The remaining patients, all in the autotransfusion group (n 8), had the autotransfuser withdrawn because of excessive bleeding or cardiovascular instability in the immediate postoperative period. All these patients (n 12) were transferred to the type of drainage used in the control group but were included in analysis on the basis of intention to treat. There was no difference between the groups in terms of comorbidity (Table 1), severity of coronary artery disease, left ventricular function and EUROscore (European System for Cardiac Operative Risk Evaluation) (Table 2), intraoperative factors, or the use of pharmacological blood conservation agents (Table 3). There was no difference in the effect of operation time and CPB when paired analysis (repeated measures, MANOVA) was used to compare immediately preoperative and postoperative laboratory and TEG (data not shown) measurements of clotting pathway function, Hb, and platelet count (Table 4). Efficacy of Cell Salvage and Versus Patients in the autotransfusion group received a mean of ml of autotransfused red cells postoperatively. This represented a mean extraction ratio of for shed fluid retransfused to the patient. Patients in the Table 1. Clinicopathological Data for Each Age Group N Male Age (years)* 62.3 (18.73) (9.23) Diabetic (Diet/Oral/Ins) 4/6/7 4/2/10 Hyperlipidaemic Hypertensive Current Smoker Renal Impairment 0 0 BMI a 29.0 (9.0) 27.6 (3.9) COPD p value derived from Pearsons chi square test except for a where values in parentheses represent SD and p values derived from ANOVA for normally distributed data with inequality of variance. All p NS. BMI body mass index; COPD chronic obstructive pulmonary disease. autotransfusion group were significantly less likely to receive a homologous blood transfusion compared with controls (odds ratio 0.40, 95% confidence interval [CI] ) (Fig 1) and received significantly fewer units of blood per patient compared with controls (Fig 2). Multivariate analysis was performed to exclude the possibility that confounding factors such as gender or the use of pharmacological agents may have influenced this result. On multivariate logistic regression analysis the odds ratio for patients randomized to autotransfusion to receive a transfusion of bank blood was 0.19 (95% CI ). There was no difference in the mean Hb on the second postoperative day suggesting that autotransfused red cells were still viable at this time (both g/dl, Student t test p 0.95). Safety of Cell Salvage and There was no significant increase in the incidence of adverse events specifically septic or bleeding complications between the two groups (Table 5). Four deaths occurred during the study, three from multiple organ dysfunction and one from postoperative myocardial infarction respectively (Table 5). There was no significant difference between the groups in terms of mediastinal drainage, total volume of fluid replacement, or in utiliza- Table 2. Preoperative Disease Characteristics Recent MI ( 90 days) Angiovess dis (1/2/3) 2/19/75 2/17/80 LMS EF 50% Urgent (within same admission) Euroscore 3.4 (1.9) 7 (9) 1555 p value derived from Pearsons chi square test, except Euroscore where values expressed as mean (SD) and p value derived from ANOVA. EF ejection fraction; Euroscore European system for cardiac operative risk evaluation; LMS left main stem disease; MI myocardial infarction.

4 1556 MURPHY ET AL Ann Thorac Surg PERIOPERATIVE CELL SALVAGE AND AUTOTRANSFUSION 2004;77: Table 3. Operative Details for Each Age Group Number of Grafts 3.2 (0.7) 3.2 (0.8) Int Ante Cold Blood Plegia a XC Fibrilllation a CPB Time (mins) 68.6 (27.1) 68.2 (23.7) XC Time (mins) 38.5 (17.3) 39.3 (16.4) Tranexamic Acid a Aprotinin a 9 6 Values expressed as mean (SD) and p value derived from ANOVA except a where values represent number of patients and p value derived from Pearsons chi square test. All p NS. CPB cardiopulmonary bypass; XC cross clamp. tion of pooled platelets or clotting products (Table 6). The risk of receiving an allogeneic blood product of any kind was significantly less in the autotransfusion group (odds ratio 0.44, 95% CI ). Effect of on Measures of Coagulation Pathway and Platelet Function The first postoperative autotransfusion was used to assess effects on coagulation pathway and platelet function as this was, as expected, the largest volume autotransfusion (mean volume ml). Paired t tests of indices of pretransfusion and posttransfusion clotting pathway and platelet function for both the first autologous transfusion in the autotransfusion group and the first postoperative unit of homologous blood (approximately 300 ml) in the control group (Table 7) demonstrated that transfusion of any kind was associated with a reduction in PT ratio and an increase in APTT ratio and fibrinogen concentrations. On repeated MANOVA the effect on PT ratio and APTT ratios were more marked in the autotransfusion group however the differences in numerical terms were extremely small. TEG parameters were not significantly altered by either homologous or autologous blood transfusion (Paired t test p NS, data not shown). The pretransfusion Hb and change in Hb after transfusion was also significantly different between the two groups (Table 7). MANOVA demonstrated no difference between the groups for any of the other laboratory or TEG parameters measured. Fig 1. Homologous blood usage: number of patients requiring homologous blood transfusion. There was a significant reduction in the number of patients requiring homologous banked blood in the autotransfusion group. Pearson 2 p Comment The principal finding of this randomized prospective trial is that intraoperative and postoperative cell salvage and autotransfusion of processed red cells is associated with a significant reduction in exposure to allogeneic bank blood after nonemergency CABG. There was a reduction in the number of patients exposed to allogeneic blood as well as a significant reduction in the volume of allogeneic blood transfused per patient compared with controls. of washed red cells was not associated with any clinically significant derangement of clotting pathway or platelet function, increased postoperative bleeding, or fluid requirements. When compared the effect of autotransfusion was, in respect to most parameters measured, no different from the effect of homologous blood transfusion. The major limitation of this study was the high withdrawal rate in the autotransfusion group. In patients with excessive postoperative bleeding or in those with postoperative cardiovascular instability it was considered unethical to proceed with a treatment that had not, at that time, been demonstrated clearly to be safe in terms of generating a coagulopathy. It is possible that had these Table 4. Paired Comparison of the Effects of Surgery and Cardiopulmonary Bypass on Hemoglobin Concentration and Measures of Clotting Pathway Function Preop Postop Preop Postop p Hb 13.9 (1.3) 8.5 (1.2) 14.1 (1.3) 8.6 (1.2) PT Ratio 1.0 (0.26) 1.3 (0.23) 1.0 (0.1) 1.2 (0.15)) APTT Ratio 1.0 (0.15) 1.4 (0.45) 1.0 (0.13) 1.3 (0.22) Platelets 258 (62) 154 (86) 264 (76) 159 (55) Values represent mean (SD). p values derived from repeated measures analysis of variance (MANOVA). There was no significant difference between autotransfusion and controls for any of the parameters measured. APTT activated partial thromboplastin time; PT prothrombin time.

5 Ann Thorac Surg MURPHY ET AL 2004;77: PERIOPERATIVE CELL SALVAGE AND AUTOTRANSFUSION Table 6. Mediastinal Drainage, Fluid Requirements, and Utilization of Homologous Red Cells, Clotting Factors, and Pooled Platelet Transfusions 1557 Autotransfuse Drainage 12 hrs (mls) 774 (478) 762 (467) Total drainage (mls) 1369 (907) 1359 (842) Vol infused in 12 hrs (mls) 2655 (812) 2828 (954) Homologous red cells transfused a,b Platelets transfused a FFP transfused a Any Blood product a,c Fig 2. Homologous blood usage: number of units of blood per patient. There was a significant reduction in the mean number of units per patient in the autotransfused group compared with controls. Mann Whitney p patients been included and higher volumes of autotransfused blood been administered. There may have been a significant clinical effect or differences between the groups in terms of measures of clotting pathway function. The justification for our cautious approach is evident in the apparent lack of any increase in adverse events associated with autotransfusion. Furthermore, there was still a highly significant reduction in homologous blood usage despite the withdrawal of the autotransfuser in such a large number of patients. The second limitation of this study was the low number of patients in each group that had been administered aprotinin or antifibrinolytic agents. Modern attitudes to blood conservation stress the importance of a multimodality approach with both pharmacological and mechanical blood conservation [11]. Had the proportion of patients receiving, for example, aprotinin been greater, then the overall proportion of controls receiving allogeneic blood may have been smaller [12] and the yield of autotransfused blood may also have been lower [13]. Pharmacological agents are Table 5. Postoperative Morbidity and Mortality (SD) (SD) Ventilation time (hours) 12.7 (40.0) 6.5 (8.9) ITU Stay (days) 1.1 (1.7) 1.0 (1.2) Resternotomy 2 0 Sepsis 2 2 Leg Wound 4 4 MODS 2 1 Hospital Stay 6.8 (4.0) 9.6 (24.6) Death 3 1 Values represent number of patients or mean (SD). Pearsons chi-square test, students t-test and Mann Whitney U test all p NS. ITU intensive therapy unit; MODS multiple organ dysfunction syndrome. Values represent number of patients or mean (SD). p values derived from Mann Whitney, except for a where p value derived from Pearsons chi-square. All p NS except b p and c p chi square. FFP fresh frozen plasma. often considered unnecessary in nonemergency first time CABG, however, and this study will have direct reference to the practice of some surgeons who restrict the use of pharmacological agents to emergency, redo, or more complex surgery [10]. Several recent trials have demonstrated a significant reduction in exposure to allogeneic blood with the use of washed autotransfused cells from both intraoperative [7] and postoperative cell salvage [14]. These studies had higher postoperative transfusion thresholds (9 10 g/dl) that are associated with higher homologous transfusion rates [15] than in the current study. For example, a previous study [8] with a transfusion threshold of 10 g/dl, reported a reduction of homologous transfusion rates reported from 90% 60%. This compares unfavorably with the allogeneic transfusion rate in the control group of 60% with a transfusion threshold of 7 g/dl. Neither of these previous studies addressed the issue of potential coagulopathic changes in patients after cell salvage and autotransfusion. This study demonstrates that autotransfusion was associated with a more significant derangement of APTT ratio than homologous blood however this was not associated with any clinical sequelae. It is likely that these findings reflect the power of paired analysis to detect very small differences in large sample sizes. Given that all other measures (with the exception of a greater reduction in PT ratio) were not altered in any way suggests that whereas autotransfusion does alter some indices of clotting pathway function at the volumes transfused using this methodology the effect is virtually identical to that of homologous blood. Indeed homologous blood itself has anticoagulant properties and can, in large volumes, induce a coagulopathy. This data would suggest that autotransfused, washed, shed mediastinal, and intraoperative cells are as effective and as safe as bank blood in this respect. This study is also significant in that cell salvage and autotransfusion has been shown to be efficacious and safe in nonemergency bypass graft excluding patients that were systemically anticoagulated with heparin preoperatively. The benefit may therefore be more marked in more complex or

6 1558 MURPHY ET AL Ann Thorac Surg PERIOPERATIVE CELL SALVAGE AND AUTOTRANSFUSION 2004;77: Table 7. Paired Comparison of the Effects of Transfusion (Homologous and Autologous) on Hemoglobin Concentration and Measures of Clotting Pathway Function Pre Tx Post Tx Paired t Pre ATx Post ATx Paired t MANOVA Hb 7.3 (0.6) 8.3 (0.7) (1.2) 8.8 (1.2) PT ratio 1.4 (0.2) 1.3 (0.2) (0.2) 1.2 (0.2) APTT ratio 1.5 (0.7) 1.6 (0.8) (0.2) 1.4 (0.5) Fibrinogen 1.4 (0.7) 1.6 (0.7) (0.4) 1.6 (0.5) D dimer 1.1 (1.2) 1.2 (1.0) (0.5) 0.8 (0.6) Platelets 144 (46) 145 (36) (55) 166 (54) Values represent mean (SD). p values derived from paired t-test and repeated measures analysis of variance (MANOVA). APTT activated partial thromboplastin time; Hb hemoglobin; PT prothrombin time. emergency surgery where blood loss and the subsequent yield of cell salvage is greater [16]. Previous trials of autotransfusion of washed red cells have been criticized for the low yield in terms of retransfused red cells with a subsequent low efficacy [17, 18]. The extraction ratio in the present study was 0.5 and yielded the equivalent of approximately1uofhomologous blood per patient. This volume was significant in that it reduced the number of patients exposed to allogeneic blood. Furthermore both autotransfused and control patients had identical mean Hb concentration at two days postoperatively highlighting the viability of the autotransfused cells [19]. In conclusion intraoperative and postoperative cell salvage is efficacious and safe after CABG. This study has shown that autotransfusion of washed cells is not associated with a derangement of clotting profiles. What changes there were, were not clinically significant and were measurably no different from those produced by the transfusion of a unit of homologous leucodepleted packed red cells. Further trials in more complex surgery with or without the addition of pharmacological agents that reduce postoperative blood loss are required to evaluate this technique as part of a more comprehensive multimodality blood conservation strategy. The authors are grateful to the Cardiac Intensive Care nursing staff for their hard work and assistance during this study. Medtronic provided funding for the Autotransfuser consumables used in this study but had no input as to the design, data collection, and analysis or drafting of this report. References 1. Schmidt H, Mortensen PE, Folsgaard SL, Jensen EA. after coronary artery bypass grafting halves the number of patients needing blood transfusion. Ann Thor Surg 1996;61: de Varennes B, Nguyen D, Denis F, Ergina P, Latter D, Morin JE. Reinfusion of mediastinal blood in CABG patients: impact on homologous transfusions and rate of re-exploration. J Card Surg 1996;11: Martin J, Robitaille D, Perrault LP, et al. Reinfusion of mediastinal blood after heart surgery. J Thorac Cardiovasc Surg 2000;120: Vertrees RA, Conti VR, Lick SD, Zwischenberger JB, Mc- Daniel LB, Shulman G. Adverse effects of postoperative infusion of shed mediastinal blood. Ann Thorac Surg 1996; 62: Sandoval S, Alrawi S, Samee M, et al. A cytokine analysis of the effect of cell saver on blood in coronary bypass surgery. Heart Surg Forum 2001;4: Tawes RL Jr, Duvall TB. Is the salvaged-cell syndrome myth or reality? Am J Surg 1996;172: McGill N, O Shaughnessy D, Pickering R, Herbertson M, Gill R. Mechanical methods of reducing blood transfusion in cardiac surgery: randomised controlled trial. Br Med J 2002; 325: Dalrymple-Hay MJ, Dawkins S, Pack L, et al. decreases blood usage following cardiac surgery a prospective randomized trial. Cardiovasc Surg 2001;9: Torella F, Haynes SL, Lardi A, O Dwyer ST, McCollum CN. Unchanging attitudes to autologous transfusion in the UK. Transfusion Med 2001;11: Stover EP, Siegel LC, Body SC, et al. Institutional variability in red blood cell conservation practices for coronary artery bypass graft surgery. Institutions of the MultiCenter Study of Perioperative Ischemia Research Group. J Cardiothorac Vasc Anesth 2000;14: Helm RE, Rosengart TK, Gomez M, et al. Comprehensive multimodality blood conservation: 100 consecutive CABG operations without transfusion. Ann Thorac Surg 1998;65: Ruel MA, Rubens FD. Non-pharmacological strategies for blood conservation in cardiac surgery. Can J Anaesth 2001; 48:S Zamvar V, Payne N. Reducing blood transfusion. Some important points were missing from the study. Br Med J 2002;325: Dalrymple-Hay MJ, Pack L, Deakin CD, et al. of washed shed mediastinal fluid decreases the requirement for autologous blood transfusion following cardiac surgery: a prospective randomized trial. Eur J Cardiothorac Surg 1999;15: Bracey AW, Radovancevic R, Riggs SA, et al. Lowering the hemoglobin threshold for transfusion in coronary artery bypass procedures: effect on patient outcome. Transfusion 1999;39: Nuttal GA, Oliver WC, Ereth MH, et al. Comparison of blood-conservation strategies in cardiac surgery patients at high risk for bleeding. Anesthesiol 2000;92: Schirmer U, Hemmer W, Lindner KH, Goertz A, Schutz W, Georgieff M. Shed mediastinal blood in 500 elective cardiac surgery patients: is there enough for retransfusion routinely? J Cardiovasc Surg 1997;38: Cross MH, Munsch CM, Norfolk DR. Cell salvage reduces blood loss, but does it do so on its own? Br Med J 2002;325: Schmidt H, Lund JO, Nielsen SL. Autotransfused shed mediastinal blood has normal erythrocyte survival. Ann Thorac Surg 1996;62:105 8.

7 Ann Thorac Surg MURPHY ET AL 2004;77: PERIOPERATIVE CELL SALVAGE AND AUTOTRANSFUSION DISCUSSION DR LYNN H. HARRISON (New Orleans, LO): Do you have information regarding the lowest hematocrit on bypass on these patients? Some recent data have suggested that it is causally related to increased morbidity and mortality DR JOHN W. HAMMON, JR: (Winston-Salem, NC): I would like to congratulate the authors for carefully studying this group of patients. I think asking this question periodically is important. My question relates to the infusion of shed mediastinal blood after the patient reaches the intensive care unit. It appeared to me that despite the fact that there was no statistical difference between your groups of patients, there were several patients in the autotransfusion group who had very long lengths of stay and severe bleeding incidents. It was our experience in using shed mediastinal blood after the operating room that this did result in an occasional clinical disaster, probably related to the infusion of unprocessed cytokines and tissue factor from the wound that enters the mediastinal blood. Do you have any feelings about this, and did you have any similar experiences with patients receiving mediastinal shed blood? DR MURPHY: I know that the hematocrit that we transfuse on bypass is less than 0.2. I think the hemoglobin trigger is 6. I don t know from our perfusionist charts what the lowest hematocrit was in this group of patients. DR MURPHY: This has not been our experience. This was new technology in our unit when we introduced it for this trial, and we therefore had a very low threshold for removing the autotransfuser in patients who showed any signs of bleeding or cardiovascular instability, which has been demonstrated in the fact that 12 patients were withdrawn from the autotransfusion group. In actual fact, these patients who were apparently bleeding bled whether or not the autotransfuser was used or not, and in no patient was it apparent that autotransfusing blood actually exacerbated anticoagulopathy. Looking at the data that I haven t shown here because of time limitations, there was no real significant derangement in any one patient s clotting profiles after autotransfusion. I think the modern systems that we use to wash red cells are very effective and they remove much of the tissue factor and the cytokines from the shed mediastinal fluid. Requirements for Recertification/Maintenance of Certification in 2004 Diplomates of the American Board of Thoracic Surgery who plan to participate in the Recertification/Maintenance of Certification process in 2004 must hold an active medical license and must hold clinical privileges in thoracic surgery. In addition, a valid certificate is an absolute requirement for entrance into the recertification/maintenance of certification process. If your certificate has expired, the only pathway for renewal of a certificate is to take and pass the Part I (written) and the Part II (oral) certifying examinations. The American Board of Thoracic Surgery will no longer publish the names of individuals who have not recertified in the American Board of Medical Specialties directories. The Diplomate s name will be published upon successful completion of the recertification/maintenance of certification process. The CME requirements are 70 Category I credits in either cardiothoracic surgery or general surgery earned during the 2 years prior to application. SESATS and SESAPS are the only self-instructional materials allowed for credit. Category II credits are not allowed. The Physicians Recognition Award for recertifying in general surgery is not allowed in fulfillment of the CME requirements. Interested individuals should refer to the 2004 Booklet of Information for a complete description of acceptable CME credits. Diplomates should maintain a documented list of their major cases performed during the year prior to application for recertification. This practice review should consist of 1 year s consecutive major operative experiences. If more than 100 cases occur in 1 year, only 100 should be listed. Candidates for recertification/maintanance of certification will be required to complete all sections of the SESATS self-assessment examination. It is not necessary for candidates to purchase SESATS individually because it will be sent to candidates after their application has been approved. Diplomates may recertify the year their certificate expires, or if they wish to do so, they may recertify up to two years before it expires. However, the new certificate will be dated 10 years from the date of expiration of their original certificate or most recent recertification certificate. In other words, recertifying early does not alter the 10-year validation. Recertification/maintenance of certification is also open to Diplomates with an unlimited certificate and will in no way affect the validity of their original certificate. The deadline for submission of applications for the recertification/maintenance of certification process is May 10 each year. A brochure outlining the rules and requirements for recertification/maintenance of certification in thoracic surgery is available upon request from the American Board of Thoracic Surgery, One Rotary Center, Suite 803, Evanston, IL 60201; telephone number: (847) ; fax: (847) ; info@abts.org. This booklet is also published on the website: by The Society of Thoracic Surgeons Ann Thorac Surg 2004;77: /04/$30.00 Published by Elsevier Inc