Association between mortality from suicide in England and antidepressant prescribing: an ecological study.

BACKGROUND: Antidepressant prescribing has been increasing in England. Studies in other countries suggest that while this may be associated with reduced suicide rates, it may also be associated with increased fatal poisoning from antidepressant drugs. We therefore conducted an ecological study to assess the association between prescription rates for antidepressants and suicide or fatal antidepressant-related poisoning in England. METHODS: The Office for National Statistics provided information on the number of suicides, antidepressant-related poisoning deaths and populations for England between 1993 and 2002. The Department of Health supplied data on prescriptions for all antidepressants dispensed in England. Associations between prescriptions and deaths were assessed using Spearman's rank correlation coefficient. RESULTS: There were 46,747 suicides, 3,987 deaths involving tricyclic antidepressants and 430 involving selective serotonin re-uptake inhibitors and other antidepressants. Increased antidepressant prescribing was statistically associated with a fall in suicide rates (Spearman's rs = -0.73, p = 0.02) and fatal poisoning involving tricyclic antidepressants (rs = -0.64, p = 0.05). In contrast, increased prescribing of selective serotonin re-uptake inhibitors and other antidepressants was statistically associated with an increase in fatal poisoning involving these drugs (rs = 0.99, p < 0.001). CONCLUSION: Increased prescribing of antidepressants may indicate improved diagnosis and treatment of depression in primary care. Our analysis suggests that this was accompanied by lower suicide rates. A decrease in poisoning deaths involving tricyclic antidepressants may suggest a change in preference for using serotonin reuptake inhibitors and other antidepressant drugs for high-risk patients. This may also partially explain the increase in deaths involving these drugs. Due to the ecological nature of the design, we cannot say conclusively whether reduced suicide rates are a direct consequence of increased antidepressant prescribing rates. To confirm these associations, individual level data on prescribing and suicide is needed.

Risk of low birth weight near EUROHAZCON hazardous waste landfill sites in England.

Few studies have investigated the occurrence of both low birth weight (LBW) and congenital anomalies in populations living near hazardous waste landfill sites. The authors investigated the risk of LBW near 10 English hazardous waste landfill sites included in a previous European study, which reported an increased risk of congenital anomalies. Odds ratios, adjusted for sex, deprivation, year of birth, and study area (pooled ORs), were estimated for LBW (< 2500 gm) within 0-3 km compared with 3-7 km zones around the landfill sites. The authors found a small and not statistically significant increase in risk of LBW (OR = 1.03, 95% confidence interval = 0.98-1.08) within 3 km of hazardous waste landfill sites. Their findings suggest that previously reported results for congenital anomalies should not be extrapolated to a wider range of pregnancy outcomes but should be evaluated separately for each.

Biocompatibility of Trillium Biopassive Surface-coated oxygenator versus uncoated oxygenator during cardiopulmonary bypass.

OBJECTIVE: To determine if the Trillium Biopassive Surface (Medtronic Cardiopulmonary, Minneapolis, MN) coating added to the cardiopulmonary bypass oxygenator reduces inflammatory mediators, blood loss, and transfusion requirements. DESIGN: Prospective, randomized, and blinded human trial. SETTING: Tertiary care academic medical center. PARTICIPANTS: Thirty adult patients undergoing elective coronary artery bypass graft surgery. INTERVENTIONS: Patients received visually identical coated or uncoated oxygenators. MEASUREMENTS AND MAIN RESULTS: Hemoglobin, hematocrit, leukocyte count, platelet count, terminal complement complex, complement activation, myeloperoxidase, beta-thromboglobulin, prothrombin fragment 1.2, plasmin-antiplasmin, heparin concentration, activated coagulation time, and fibrinogen concentration were measured. Blood loss and blood product usage were recorded. In both groups, there were significant inflammatory alterations with the initiation of cardiopulmonary bypass. In the postprotamine samples, the coated oxygenator group had small but significant increases in hemoglobin, hematocrit, and leukocyte count. There were no differences in inflammatory mediators, blood loss, or transfusion requirements between the coated and uncoated groups. CONCLUSION: This human trial of Trillium Biopassive Surface-coated oxygenators did not show clinical benefits or clinically important biochemical results.

Efficacy of a simple intraoperative transfusion algorithm for nonerythrocyte component utilization after cardiopulmonary bypass.

BACKGROUND: Abnormal bleeding after cardiopulmonary bypass (CPB) is a common complication of cardiac surgery, with important health and economic consequences. Coagulation test-based algorithms may reduce transfusion of non-erythrocyte allogeneic blood in patients with abnormal bleeding. METHODS: The authors performed a randomized prospective trial comparing allogeneic transfusion practices in 92 adult patients with abnormal bleeding after CPB. Patients with abnormal bleeding were randomized to one of two groups: a control group following individual anesthesiologist's transfusion practices and a protocol group using a transfusion algorithm guided by coagulation tests. RESULTS: Among 836 eligible patients having all types of elective cardiac surgery requiring CPB, 92 patients developed abnormal bleeding after CPB (incidence, 11%). The transfusion algorithm group received less allogeneic fresh frozen plasma in the operating room after CPB (median, 0 units; range, 0-7 units) than the control group (median, 3 units; range, 0-10 units) (P = 0.0002). The median number of platelet units transfused in the operating room after CPB was 4 (range, 0-12) in the algorithm group compared with 6 (range, 0-18) in the control group (P = 0.0001). Intensive care unit (ICU) mediastinal blood loss was significantly less in the algorithm group. Multivariate analysis demonstrated that transfusion algorithm use resulted in reduced ICU blood loss. The control group also had a significantly greater incidence of surgical reoperation of the mediastinum for bleeding (11.8% vs. 0%; P = 0.032). CONCLUSIONS: Use of a coagulation test-based transfusion algorithm in cardiac surgery patients with abnormal bleeding after CPB reduced non-erythrocyte allogeneic transfusions in the operating room and ICU blood loss.

Plasma tranexamic acid concentrations during cardiopulmonary bypass.

UNLABELLED: Although tranexamic acid is used to reduce bleeding after cardiac surgery, there is large variation in the recommended dose, and few studies of plasma concentrations of the drug during cardiopulmonary bypass (CPB) have been performed. The plasma tranexamic acid concentration reported to inhibit fibrinolysis in vitro is 10 microg/mL. Twenty-one patients received an initial dose of 10 mg/kg given over 20 min followed by an infusion of 1 mg. kg(-1). h(-1) via a central venous catheter. Two patients were removed from the study secondary to protocol violation. Perioperative plasma tranexamic acid concentrations were measured with high-performance liquid chromatography. Plasma tranexamic acid concentrations (microg/mL; mean +/- SD [95% confidence interval]) were 37.4 +/- 16.9 (45.5, 29.3) after bolus, 27.6 +/- 7.9 (31.4, 23.8) after 5 min on CPB, 31.4 +/- 12.1 (37.2, 25.6) after 30 min on CPB, 29.2 +/- 9.0 (34.6, 23.8) after 60 min on CPB, 25.6 +/- 18.6 (35.1, 16.1) at discontinuation of tranexamic acid infusion, and 17.7 +/- 13.1 (24.1, 11.1) 1 h after discontinuation of tranexamic acid infusion. Four patients with renal insufficiency had increased concentrations of tranexamic acid at discontinuation of the drug. Repeated-measures analysis revealed a significant main effect of abnormal creatinine concentration (P = 0.02) and time (P < 0.001) on plasma tranexamic acid concentration and a significant time x creatinine concentration interaction (P < 0.001). IMPLICATIONS: A 10 mg/kg initial dose of tranexamic acid followed by an infusion of 1 mg.kg(-1).h(-1)produced plasma concentrations throughout the cardiopulmonary bypass period sufficient to inhibit fibrinolysis in vitro. The dosing of tranexamic acid may require adjustment for renal insufficiency.

Platelet glass bead retention predicts bleeding after cardiac surgery.

OBJECTIVE: To determine if the platelet glass bead retention assay can predict bleeding after cardiac surgery. DESIGN: Prospective, observational study. SETTING: Large, tertiary care, academic medical center. PARTICIPANTS: Forty-three adult patients scheduled to undergo elective cardiac surgery employing cardiopulmonary bypass (CPB). MEASUREMENTS AND MAIN RESULTS: Whole blood samples were observed for platelet count, prothrombin time, and platelet (glass bead) retention assay. The platelet retention and prothrombin times were independent univariant and multivariant predictors of bleeding after CPB (r = 0.554, p = 0.0002 and r = 0.655, p = 0.00001). CONCLUSION: The platelet glass bead retention assay measures dynamic platelet function and is sensitive to the CPB-induced adhesion and aggregation defect and correlates with postoperative blood loss. Modification of this platelet function assay used with the prothrombin time may provide a simple and effective diagnostic approach to bleeding after CPB.

Antiphospholipid syndrome and perioperative hemostatic management of cardiac valvular surgery.

Hemostatic aspects of antiphospholipid syndrome (APS) present unique challenges to clinicians and laboratory personnel alike, particularly in the perioperative period. These challenges are especially evident in patients requiring cardiac valve replacement surgery. However, the literature outlining the optimal approach in such patients is limited. We present the case of a 25-year-old woman with severe aortic regurgitation as a result of APS with particular reference to the precautions necessary during perioperative care. Particularly important are the prevention of thrombotic or hemorrhagic complications, management of associated thrombocytopenia, and laboratory methods of perioperative anticoagulation monitoring in the setting of prolonged clotting times.

Plasma aprotinin concentrations during cardiac surgery: full- versus half-dose regimens.

UNLABELLED: Aprotinin is an effective but expensive drug used during cardiac surgery to reduce blood loss and transfusion requirements. Currently, aprotinin is administered to adults according to a fixed protocol regardless of the patient's weight. The purpose of this study was to determine aprotinin levels in patients receiving full- and half-dose aprotinin regimens by a simple functional aprotinin assay and to design a more individualized aprotinin dosage regimen for cardiac surgical patients. The mean plasma aprotinin concentration peaked 5 min after the initiation of cardiopulmonary bypass (full 401 +/- 92 KIU/mL, half 226 +/- 56 KIU/mL). The mean plasma aprotinin concentration after 60 min on cardiopulmonary bypass was less (full 236 +/- 81 KIU/mL, half 160 +/- 63 KIU/mL). There was large variation in the aprotinin concentration among patients. A statistically significant correlation was found between aprotinin concentration and patient weight (r(2) = 0.67, P < 0.05). IMPLICATIONS: The current dosing schedule for aprotinin results in a large variation in aprotinin plasma concentrations among patients and a large variation within each patient over time. We combined the information provided by our study with that of a previous pharmacokinetic study to develop a potentially improved, weight-based, dosing regime for aprotinin.

Blood loss from coronary angiography increases transfusion requirements for coronary artery bypass graft surgery.

OBJECTIVE: To determine the blood loss associated with coronary angiography and its impact on hemoglobin and transfusion requirements for subsequent coronary artery bypass graft (CABG) surgery. DESIGN: Retrospective chart review. SETTING: Tertiary-care, academic medical center. PARTICIPANTS: A total of 506 adult patients undergoing coronary angiography and CABG surgery. INTERVENTIONS: None (observational study). MEASUREMENTS AND MAIN RESULTS: Coronary angiography was associated with a reduction in hemoglobin of 1.8 g/dL. This reduction in hemoglobin was a significant predictor of allogeneic red blood cell transfusion. CONCLUSION: Coronary angiography contributes to a 1.8 g/dL reduction in hemoglobin concentration before CABG surgery and was associated with increased transfusion of allogeneic blood products. Measures aimed at maintaining red cell volume during coronary angiography, increasing erythropoiesis, or delaying surgery beyond 2 weeks may result in a decrease in transfusion requirements for patients undergoing CABG surgery.

Use of the surgical blood order equation in spinal instrumentation and fusion surgery.

STUDY DESIGN: A retrospective review of 182 cases of adult spine instrumentation and fusion surgery (1994-1995) from one institution. OBJECTIVES: To develop and retrospectively evaluate the use of the surgical blood ordering equation for patients undergoing spinal instrumentation and fusion surgery. SUMMARY OF BACKGROUND DATA: The provision of effective and safe blood and blood products is the primary function of the hospital transfusion service. A quantification of blood bank efficiency is the crossmatch-to-transfusion ratio. The maximal surgical blood order schedule system has been used to improve the efficiency of surgical ordering practices. The current authors have developed a theoretically more efficient system, the surgical blood ordering equation, which incorporates patient factors for ordering red blood cell units for surgical patients. METHODS: The charts of 63 patients with autologous red blood cells available and 119 adult patients with none available, who underwent multilevel spine surgery from January 1994 to July 1995, were reviewed. RESULTS: The surgical blood ordering equation was exactly correct in the ordering for 37 (20.3%) of 182 patients. The maximal surgical blood order schedule was exactly correct in ordering blood for 14 patients (7.6%). Use of the new surgical blood ordering equation to order red blood cells for surgery would result in a lower crossmatch-to-transfusion ratio than with the current system, the maximal surgical blood order schedule, for patients with autologous red blood cells available (1. 0 vs. 1.3) and patients with none available (0.9 vs. 1.2). CONCLUSION: Incorporating patient factors resulted in increased efficiency of blood ordering practices.

Predictors of blood transfusions in spinal instrumentation and fusion surgery.

STUDY DESIGN: A retrospective review of 244 adult spine instrumentation and fusion surgery cases (1994-1995) from one institution. OBJECTIVES: To ascertain the predictors of blood transfusions for adult patients undergoing different types of multilevel spine surgery. SUMMARY OF BACKGROUND DATA: Blood loss and transfusion requirements during and after multilevel spine surgeries have always been perceived as great. Identifying the predictors of blood transfusion with this type of surgery may aid in reducing the amount of blood loss and the transfusion requirements. METHODS: The charts of 244 adult patients who underwent multilevel spine surgery from January 1994 to July 1995 were retrospectively reviewed. RESULTS: A large percentage of patients required blood transfusion. The significant determinants for increased amounts of allogeneic red blood cell units transfused on the day of surgery using linear multiple regression modeling were low preoperative hemoglobin concentration, tumor surgery, increased number of posterior levels surgically fused, history of pulmonary disease, decreased amount of autologous blood available, and no use of the Jackson table (R2 = 0. 63). The significant determinants for an increased amount of autologous red blood cell units transfused on the day of surgery using linear multiple regression modeling were increased autologous red blood cells available, low preoperative hemoglobin concentration, and increased number of posterior levels surgically fused (R2 = 0. 60). CONCLUSION: The need for transfusion is associated with multiple factors, suggesting that a multifaceted, integrated approach may be necessary to reduce this risk.

Comparison of blood-conservation strategies in cardiac surgery patients at high risk for bleeding.

BACKGROUND: Aprotinin and tranexamic acid are routinely used to reduce bleeding in cardiac surgery. There is a large difference in agent price and perhaps in efficacy. METHODS: In a prospective, randomized, partially blinded study, 168 cardiac surgery patients at high risk for bleeding received either a full-dose aprotinin infusion, tranexamic acid (10-mg/kg load, 1-mg x kg(-1) x h(-1) infusion), tranexamic acid with pre-cardiopulmonary bypass autologous whole-blood collection (12.5% blood volume) and reinfusion after cardiopulmonary bypass (combined therapy), or saline infusion (placebo group). RESULTS: There were complete data in 160 patients. The aprotinin (n = 40) and combined therapy (n = 32) groups (data are median [range]) had similar reductions in blood loss in the first 4 h in the intensive care unit (225 [40-761] and 163 [25-760] ml, respectively; P = 0.014), erythrocyte transfusion requirements in the first 24 h in the intensive care unit (0 [0-3] and 0 [0-3] U, respectively; P = 0.004), and durations of time from end of cardiopulmonary bypass to discharge from the operating room (92 [57-215] and 94 [37, 186] min, respectively; P = 0.01) compared with the placebo group (n = 43). Ten patients in the combined therapy group (30.3%) required transfusion of the autologous blood during cardiopulmonary bypass for anemia. CONCLUSIONS: The combination therapy of tranexamic acid and intraoperative autologous blood collection provided similar reduction in blood loss and transfusion requirements as aprotinin. Cost analyses revealed that combined therapy and tranexamic acid therapy were the least costly therapies.

Possible guidelines for autologous red blood cell donations before total hip arthroplasty based on the surgical blood order equation.

OBJECTIVES: To determine, in patients undergoing total hip arthroplasty (THA), clinical predictive criteria for preoperative autologous blood donation and to propose guidelines to increase the efficiency and reduce the cost of preoperative autologous blood donation. PATIENTS AND METHODS: In this retrospective analysis of 165 adult patients undergoing primary THA, a stepwise regression analysis was used to determine which clinical variables predict erythropoiesis in patients donating autologous blood before THA. The surgical blood order equation (SBOE), which includes values for hemoglobin lost at surgery, preoperative hemoglobin level, and minimal acceptable hemoglobin level, was used to estimate the number of units of red blood cells (RBCs) needed for each patient at surgery and thus identify which patients should have made preoperative autologous blood donations. RESULTS: The statistically significant indicators for RBC production were predonation hemoglobin concentration (P<.001) and male sex (P=.003). Combining the regression equation for erythropoiesis with the SBOE allowed development of guidelines for the use of preoperative autologous RBC donation and erythropoietic therapy. For primary THA surgery, a patient with a predonation hemoglobin level higher than 14.7 g/dL does not need preoperative autologous donation. Preoperative autologous RBC donation would be effective for men with hemoglobin concentrations of 14.7 g/dL or less and for women with predonation hemoglobin levels of 13.2 to 14.7 g/dL. In women whose hemoglobin level is less than 13.2 g/dL, erythropoietic therapy should accompany autologous donation. CONCLUSION: Incorporation of patient factors with the SBOE system may result in increased efficiency and decreased cost of autologous blood ordering practices before THA.

Desmopressin does not reduce bleeding and transfusion requirements in congenital heart operations.

BACKGROUND: Desmopressin (DDAVP) has been evaluated in many randomized clinical trials as a means to reduce blood loss and transfusion of allogeneic blood in cardiac operation requiring cardiopulmonary bypass. Desmopressin reduces blood loss in adult patients with excessive bleeding after cardiac operation. Its usefulness in patients undergoing complex congenital heart repair with cardiopulmonary bypass is unproved. METHODS: Sixty patients younger than 40 years of age scheduled for complex congenital heart operation (44 redo, 16 primary) were enrolled in this prospective, randomized, double-blind trial. Desmopressin 0.3 microg/kg or placebo was administered 10 minutes after protamine administration. Transfusion requirements and postoperative blood loss were recorded. Differences were analyzed using analysis of variance with a p value of 0.05 or less used to denote statistical significance. RESULTS: There were no differences in demographic or surgical characteristics between the DDAVP or placebo groups. There was no difference in blood loss and transfusion requirements between the DDAVP and placebo groups. During the intraoperative postinfusion time period, the median blood loss for redo patients was 343 versus 357 mL/m2 for placebo versus DDAVP, respectively, and for primary patients, the median blood loss was 277 versus 228 mL/m2. CONCLUSIONS: The prophylactic use of DDAVP to reduce excessive bleeding or transfusion requirements in patients undergoing complex congenital heart operations is not warranted.

A prospective, randomized study of cardiopulmonary bypass temperature and blood transfusion.

BACKGROUND: We hypothesized that normothermic cardiopulmonary bypass (CPB) would be associated with decreased blood loss and allogeneic transfusion requirements relative to hypothermic CPB. METHODS: After obtaining institutional review board approval and informed patient consent, we conducted a prospective, randomized study of 79 patients undergoing CPB for a primary cardiac operation at normothermic (37 degrees C) (n = 44) or hypothermic temperature (25 degrees C) (n = 35). Blood loss and transfusion requirements in the operating room and for the first 24 hours in the intensive care unit were determined. A paired t test and rank sum tests were used. A p value of less than 0.05 was considered significant. RESULTS: The normothermic and hypothermic CPB groups did not differ in demographic variables, CPB or cross-clamp duration, heparin sodium or protamine sulfate dose, prothrombin time, or thromboelastogram results. There were no differences between the two CPB groups in blood loss or transfusion requirements. CONCLUSIONS: We found that when there was no difference in duration of CPB, normothermic and hypothermic CPB groups demonstrated similar blood loss and transfusion requirements even though other studies have shown hypothermia induces platelet dysfunction and alters the activity of the coagulation cascade.

Temperature and duration of cardiopulmonary bypass influence transfusion requirements.

STUDY OBJECTIVE: To determine the influence of temperature and duration of cardiopulmonary bypass (CPB) on blood loss and transfusion requirements. DESIGN: Retrospective chart review. SETTING: Tertiary care, academic medical institution. MEASUREMENTS AND MAIN RESULTS: The charts of 378 patients who had undergone primary elective coronary artery bypass graft surgery were studied. Systemic perfusion of CPB had been conducted between 20 degrees C and 37 degrees C in all patients. Patient demographic, temperature during CPB, duration of CPB, blood loss, and transfusion requirements were all recorded. Hypothermic CPB patients had minor increases in requirements for transfusion of red blood cells (RBC; p = 0.01), fresh frozen plasma (FFP; p = 0.01), platelets (PLT; p = 0.003), and total (allogeneic and autologous) blood products (p < 0.001). Multivariate analysis revealed that decreased temperature after adjusting for duration was predictive of allogeneic (RBC, FFP, PLT, and cryoprecipitate) and total (allogeneic and autologous) transfusion requirements. The duration of CPB correlated with decreased temperature (r = -0.455; p < 0.0001). After adjusting for temperature, duration was only predictive of total (allogeneic and autologous) transfusion requirements. CONCLUSIONS: The institution of warm CPB has many ramifications for clinical practice. The hypothermic induced platelet dysfunction and increased duration associated with cold CPB may contribute to the minor increases in transfusion requirements. However, temperature appears to be a weak factor, neither supporting nor refuting the use of warm or cold CPB.

A prospective randomized trial of the surgical blood order equation for ordering red cells for total hip arthroplasty patients.

BACKGROUND: The majority of crossmatched blood is for surgical patients, and most of it is never transfused. An alternative system for ordering red cell (RBC) units, called the surgical blood order equation (SBOE), which incorporates specific patient variables for surgical patients, has been developed. STUDY DESIGN AND METHODS: A prospective double-blind randomized trial compared the SBOE with the maximal surgical blood order schedule (MSBOS) system for ordering allogeneic RBC units in 60 patients undergoing total hip arthroplasty. Autologous RBCs were available for none of the patients. RESULTS: There were no differences in patient demographic, surgical, or laboratory variables at any time. The median number (range) of allogeneic RBC units ordered was 2 (2-3) for the MSBOS and 0 (0-3) for the SBOE (p<0.0001). The SBOE ordered the correct number of RBC units for 58 percent of patients, while the MSBOS did so for 7 percent (p<0.0001). The SBOE had a lower crossmatch-to-transfusion ratio than the MSBOS (0.83 vs. 4.12). Costs were also lower with the SBOE. CONCLUSION: Incorporation of patient factors in the use of the SBOE system resulted in increased efficiency of blood-ordering practices for total hip arthroplasty.

The relation between the platelet-activated clotting test (HemoSTATUS) and blood loss after cardiopulmonary bypass.

BACKGROUND: Platelet dysfunction is one of several major causes of bleeding after cardiopulmonary bypass. A timely, simple, point-of-care determinant of platelet function recently became available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activated clotting test [PACT]) produces rapid results (<15 min) and may yield a measure of platelet responsiveness and whole-blood procoagulant activity. METHODS: Blood samples were drawn from 100 patients after cardiac surgery on their arrival in the intensive care unit for PACT, platelet count, prothrombin time (PT), and activated partial thromboplastin time (aPTT). Cumulative blood loss at 4, 8, and 12 h after arrival in the intensive care unit and perioperative transfusion requirements were quantitated. Coagulation tests and mediastinal blood loss were compared using the Spearman rank test and Pearson correlation. The sensitivity and specificity of the laboratory tests for predicting blood loss were analyzed using the receiver operating characteristic method. RESULTS: The PT was the only test that correlated with blood loss at 4, 8, and 12 h. The PACT did not correlate with blood loss at 4, 8, or 12 h, nor did the PACT correlate with the PT or the aPTT. The sensitivity and specificity of the PACT were less than those of the PT in predicting blood loss. Only the PT correlated with platelet and fresh frozen plasma transfusion. CONCLUSIONS: The PT correlated with blood loss and transfusion requirements and was superior to PACT, aPTT, and platelet count for predicting excessive blood loss after cardiopulmonary bypass.

Normothermic cardiopulmonary bypass increases heparin requirements necessary to maintain anticoagulation.

OBJECTIVE: With the practice of warm cardiopulmonary bypass (CPB) at our institution we have observed an apparent increase in heparin requirements. CPB temperature predictability affects pharmacokinetics and differences in drug metabolism can be expected. We hypothesized that heparin requirements would increase with increasing CPB temperature. METHODS: Following Institutional Review Board approval, we reviewed the charts of 354 patients undergoing primary coronary artery bypass graft surgery. We recorded patient demographic data, CPB duration, heparin requirements, and temperature during CPB. CPB was conducted between 24 degrees C and 37 degrees C. The Spearman's correlation coefficient, Pearson chi-square, and rank-sum tests were used for data analysis. RESULTS: Core temperature during CPB correlated with heparin requirements (r = 0.13, p < 0.02). However, CPB duration was shorter in warm patients than in cold patients (r = -0.455, p < 0.0001). Additional heparin requirements adjusted for duration of CPB (units/minute) were also significantly greater in the warm group (p = 0.018). CONCLUSIONS: Maintenance of adequate heparin anticoagulation during CPB is clinically important. Warm CPB patients required more heparin per minute than those undergoing cold CPB. More frequent assessment of anticoagulation and administration of additional heparin should be considered in patients undergoing warm CPB.