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Background: After decades of practice of pediatric cardiac surgery, postoperative bleeding due to the immaturity of hemostasis, hemodilution, and hypothermia remains a concern. Recently, a new approach for adult coagulopathy after bypass has emerged. Prothrombin complex concentrates (PCCs), designed to treat bleeding in hemophilia patients, are safely and efficiently used off label for hemorrhage after bypass. However, optimal dosing, indications and contraindications, and laboratory tests to assess the efficacy of PCC use in children have not yet been established. This literature review outlines the challenges of bypass-related coagulopathy, the pharmacology, and the experience in use of PCCs, with a focus on their potential in pediatric cardiac surgery., Methods: After a thorough literature search of MEDLINE, Scopus, and Ovid databases using the term "prothrombin complex concentrate AND pediatric," 23 relevant articles were selected., Results: The data supporting successful use of PCCs in acquired coagulopathy after cardiac surgery in adults have been increasing. Although small volume, low immunogenicity, efficiency, and speed in correcting coagulopathy are attractive qualities of PCCs for pediatric practice, current evidence is only anecdotal. The main concerns are unknown dosing regimens, the inability to closely monitor the effects of PCCs in real time, and a possibility of thrombotic complications, which can be particularly devastating in young congenital cardiac patients whose lives frequently depend upon the patency of artificial shunts., Conclusions: Extensive, high-quality research is warranted to fill in the gaps of knowledge regarding using PCCs in pediatric cardiac practice., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Excessive bleeding and allogeneic transfusion during adult post-cardiotomy venoarterial extracorporeal membrane oxygenation (ECMO) are potentially harmful and expensive. Balancing the inhibition of clotting and distinguishing surgical from non-surgical bleeding in post-operative period is difficult. The sensitivity of coagulation tests including Thromboelastography(®) (TEG) to predict chest tube drainage in the early hours of ECMO was examined with the use of receiver-operating characteristics (ROC). The results are useful to incorporate in clinical evidence-based algorithms to guide management decisions. In the eighth hour of ECMO, 26 of the 53 adult patients (49%) studied were identified as non-bleeders (less than 2.0 mL/kg/h). All had experienced various types of cardiac surgical procedures. Fifty-two percent were female and the group was 54 ± 19 (mean ± 1 SD) years old. The coagulation parameter threshold with the maximum sensitivity and specificity to predict non-bleeding at 8 hours on ECMO was the kaolin plus heparinase TEG maximum amplitude (KH-TEG MA) at a significant ROC threshold (t) > 50 mm. The activated partial thromboplastin time (aPTT) t < 49 seconds, KH-TEG alpha-angle t > 51°, and the kaolin activated clotting time (ACT) t < 148 seconds were sensitive predictors of non-bleeders. The whole-blood KH-TEG MA was superior to the plasma-based aPTT or International Normalization Ratio (INR) to predict bleeding in the eighth hour of ECMO. Using coagulation laboratory thresholds that predict non-bleeding can begin a process of identifying patients earlier that are likely to bleed. Awareness of these parameter thresholds may improve care through patient protection from unnecessary transfusion and prolonging the life of the ECMO circuit. An algorithm incorporating the ROC thresholds was created to help recognize surgical bleeding to minimize unnecessary transfusions.

Purpose of Review: Miss-transfusion of blood has become one of the leading causes of death related to blood transfusion. New technology is able to better prevent miss-transfusions than older methods., Recent Findings: New computer-based technology is available and is very effective in preventing miss-transfusion of blood., Summary: Humans make errors. New technology can prevent those errors.

Background: In adults with right-sided congenital heart disease, vasoplegia during and after cardiopulmonary bypass appears to be a frequent complication. The incidence of vasoplegia in the general adult and pediatric cardiac surgical population has been investigated, but the incidence in adult patients with right-sided congenital heart disease is unknown. Perioperative vasopressin levels during cardiac surgery have been studied in other cardiac surgical patients, but are not known in adults with right-sided congenital heart disease. The purpose of this study was to investigate the incidence of vasoplegia in adult patients undergoing right-sided cardiac surgical procedures requiring cardiopulmonary bypass and to determine the vasopressin response to cardiac surgery in this population., Methods: Twenty patients were enrolled and demographic, hemodynamic, cardiopulmonary bypass, and use of vasoactive medication data were collected. In addition, perioperative serum vasopressin levels were measured. Sixty adult patients undergoing left-sided cardiac surgery served as controls., Results: The incidence of vasoplegia in the control patients was 10% and the incidence in the adult patients with right-sided congenital heart disease was 20%. Vasopressin levels were low at baseline (0.5 ± 0.5 pg/mL), increased slightly after induction of anesthesia (0.6 ± 0.6 pg/mL), increased after initiation of cardiopulmonary bypass (99.7 ± 168.2 pg/mL), and decreased after surgery (31.3 ± 43.6 pg/mL)., Conclusions: This study showed that the incidence of vasoplegia (20%) in patients with right-sided congenital heart disease undergoing cardiac surgery was double that of a population of patients undergoing aortic valve surgery (10%). Serum vasopressin concentration was not associated with vasoplegia in this population of congenital cardiac surgical patients., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Patients with atriopulmonary Fontan tend to undergo conversion to total cavopulmonary connections secondary to arrhythmias or poor flow dynamics. However, the ideal candidate is unknown., Methods: Between December 1994 and May 2011, 70 patients (40 males [57%]) underwent Fontan conversion. Median age was 23 years (range, 4 to 46 years). Excluded were 1.5 ventricle conversions. The most common diagnoses included tricuspid atresia in 34 patients (49%) and double-inlet left ventricle in 16 (23%). Atrial tachyarrhythmia was present in 62 patients (89%), 41 (59%) had atrioventricular valve (AVV) regurgitation, and 32 (46%) were in New York Heart Association class III or IV. Atriopulmonary Fontan was the original connection in 58 patients (83%), whereas the Björk modification was performed in 8 (11%)., Results: Fontan was performed with an intraatrial conduit in 41 patients, an extracardiac conduit in 18, and a lateral tunnel in 11. Forty-nine patients (70%) underwent concomitant arrhythmia operations. Early death occurred in 10 patients (14%). Multivariate analysis revealed age older than 27 years (p = 0.009), AVV regurgitation (p = 0.016), lack of arrhythmia operation (p = 0.04), and male sex (p = 0.02) were predictors of perioperative death. Mean follow-up was 5 years (maximum, 17 years). Overall survival at 1, 5, and 10 years was 81%, 70%, and 67%, respectively, and 84% of patients were in New York Heart Association class I or II., Conclusions: Proper selection of Fontan conversion candidates is critical. Concomitant arrhythmia operations may be associated with improved survival. Older age and AVV regurgitation increase the risk of poor outcome, and cardiac transplantation may be a better option., (Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: We sought to evaluate whether there is variability in blood dexamethasone levels after a standard 1 mg/kg dose of dexamethasone administered before infant cardiopulmonary bypass. We hypothesized that postoperative dexamethasone drug levels are highly variable, and that the infant stress response is related inversely to the amount of dexamethasone measured in the blood., Methods: Thirty-two infants (age, ≤365 days) received 1 mg/kg of dexamethasone before cardiopulmonary bypass (CPB) initiation. Blood was analyzed for cortisol, adrenocorticotropin, and interleukin (IL)-6, IL-8, and IL-10 levels after anesthesia induction, after CPB, after intensive care unit (ICU) arrival, and 4, 8, 12, and 24 hours after surgery. Patients were grouped as high dexamethasone (≥15 μg/dL) or low dexamethasone (<15 μg/dL) based on their level at ICU arrival., Results: Dexamethasone levels varied significantly between the high (n = 22) and low (n = 10) dexamethasone groups throughout the entire postoperative course and were correlated highly with cortisol response. Patients with high dexamethasone levels had postoperative cortisol levels that were lower than their pre-CPB baseline cortisol levels. Cortisol levels remained low throughout the first 24 postoperative hours even after dexamethasone levels neared zero. There were no significant differences between groups in the duration of mechanical ventilation or ICU length of stay., Conclusions: Dexamethasone levels are highly variable at ICU arrival, despite standardized 1 mg/kg dosing before CPB initiation., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: To determine whether the use of a computerized bar code-based blood identification system resulted in a reduction in transfusion errors or near-miss transfusion episodes., Patients and Methods: Our institution instituted a computerized bar code-based blood identification system in October 2006. After institutional review board approval, we performed a retrospective study of transfusion errors from January 1, 2002, through December 31, 2005, and from January 1, 2007, through December 31, 2010., Results: A total of 388,837 U were transfused during the 2002-2005 period. There were 6 misidentification episodes of a blood product being transfused to the wrong patient during that period (incidence of 1 in 64,806 U or 1.5 per 100,000 transfusions; 95% CI, 0.6-3.3 per 100,000 transfusions). There was 1 reported near-miss transfusion episode (incidence of 0.3 per 100,000 transfusions; 95% CI, <0.1-1.4 per 100,000 transfusions). A total of 304,136 U were transfused during the 2007-2010 period. There was 1 misidentification episode of a blood product transfused to the wrong patient during that period when the blood bag and patient's armband were scanned after starting to transfuse the unit (incidence of 1 in 304,136 U or 0.3 per 100,000 transfusions; 95% CI, <0.1-1.8 per 100,000 transfusions; P=.14). There were 34 reported near-miss transfusion errors (incidence of 11.2 per 100,000 transfusions; 95% CI, 7.7-15.6 per 100,000 transfusions; P<.001)., Conclusion: Institution of a computerized bar code-based blood identification system was associated with a large increase in discovered near-miss events., (Copyright © 2013 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this prospective, randomized, double-blind, placebo controlled trial was to evaluate the safety and efficacy of continuous ropivacaine infusion of into the sternal wound., Methods: We planned to enroll 200 patients scheduled for various cardiac surgical procedures into the study. Patients, in a double-blind randomized fashion, were given either normal saline or 0.3% ropivacaine through 2 subcutaneous multiport catheters placed on either side of the sternal split at an infusion rate of 4 mL/h for 64 hours. The efficacy outcomes measured were time to extubation of the trachea, intensive care unit and hospital stay duration, pain scores, and narcotic usage. The safety outcomes measured were systemic local anesthetic toxicity, major cardiac complications, and wound infection., Measurements and Main Results: The data safety monitoring board stopped the study after enrolling 85 patients because of excessive sternal wound infections (9%, n = 44) in the ropivacaine group. This rate of infection was not statistically different from the control group (0%, n = 41, P = 0.12), but it was statistically different from our historical incidence of sternal wound infection (1.9%, no = 6381, P = 0.002). There was also a lack of evidence of efficacy for time to extubation of the trachea, narcotic usage, and pain control., Conclusions: The phase III trial did not show improvement in time to extubation of the trachea or pain control in the 0.3% ropivacaine group, but it was stopped early by the data safety monitoring board.

Objectives: To describe the experience of a single, tertiary care institution in the care of patients with Fontan physiology undergoing anesthesia for noncardiac surgery., Background: The Fontan procedure was developed in 1971 to palliate patients with univentricular cardiac physiology leading to long-term survival of these patients, who may now present as adults for noncardiac surgery., Methods: We retrospectively reviewed the medical records of Fontan patients 16 years and older who underwent general anesthesia for noncardiac surgery at Mayo Clinic in Rochester, Minnesota. Preoperative data, perioperative course, intraoperative and postoperative hemodynamic, pulmonary, cardiovascular, and renal complications were described., Results: Thirty-nine general anesthetics were administered to 31 patients for noncardiac surgery after Fontan palliation. Perioperative complications occurred in 12 of the 39 (31%) noncardiac surgeries, and there was one postoperative death that occurred on day 13 after ventral hernia repair. The two patients who had complications that did not resolve (long-term dialysis and death) had ejection fractions well below the mean for the group (22% and 28%)., Conclusion: It may be more appropriate for Fontan patients to undergo anesthesia for noncardiac surgery in a tertiary institution, particularly patients with an ejection fraction of <30%. Intraoperative arterial blood pressure monitoring and overnight admission are likely appropriate for most cases., (© 2012 Blackwell Publishing Ltd.)

Objective: The aim of this study was to evaluate cardiac risk as a consideration for selecting postoperative sedation and analgesia regimens used for cardiac surgical patients requiring cardiopulmonary bypass and early extubation., Design: An observer-blind, randomized, controlled trial., Setting: A tertiary referral medical center involving an intensive care unit., Participants: One hundred forty-five adults requiring elective cardiac surgery., Interventions: Patients were stratified preoperatively as low, moderate, or high cardiac risk based on established criteria and then assigned to 1 of 3 postoperative regimens: propofol infusion beginning at 25 μg/kg/min and morphine boluses (P), fentanyl infusion beginning at 2 μg/kg/h and midazolam boluses (F), or propofol and fentanyl infusions beginning at 25 μg/kg/min and 0.5 μg/kg/h (PF), respectively., Measurements and Main Results: Postoperative regimen P was associated with a significantly reduced time to extubation (median value, 264 minutes; p = 0.05) compared with F (295 minutes) but not PF (278 minutes) in patients characterized as low cardiac risk. The time to extubation did not differ among regimens in patients of moderate/high cardiac risk., Conclusion: Patients with low cardiac risk undergoing cardiac surgery had statistically significantly shorter times to extubation with propofol infusion and intermittent morphine than a fentanyl infusion and intermittent midazolam. These differences were not sustained in patients considered at higher cardiac risk. The time to extubation after cardiac surgery may further improve if postoperative sedation and analgesia are not administered uniformly to all patients but selected based on individual characteristics., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: Adequate hemostasis is extremely important in neurosurgery, commonly requiring the use of topical hemostatic agents. Apart from variable efficacy, the residual presence of these agents may cause foreign body reaction, infection, and delayed bone growth. This study compares the safety and efficacy of commonly used agents with a newly approved agent, Arista (microporous polysaccharide hemospheres; Medafor, Inc., Minneapolis, MN)., Methods: A brain tissue defect was created in 228 Wistar outbred rats, and either no agent (negative control), Arista, Surgicel (oxidized cellulose; Ethicon, Inc., Somerville, NJ), Avitene (microfibrillar collagen; Alcon, Inc., Humacao, PR), FloSeal (gelatin matrix thrombin sealant; Baxter Healthcare Corp., Deerfield, IL), or kaolin (positive control) was implanted. Time to hemostasis was documented. The animals were sacrificed at different intervals up to 28 days, and presence of residual material and foreign body reaction was determined., Results: Arista, Avitene, FloSeal, and Surgicel performed better (defined as complete hemostasis within 1 minute) than control (no treatment). Residual material was not present at any time with Arista, markedly contrasting with the presence of residual material in 100% of lesions in the Avitene, FloSeal, and Surgicel groups on Day 14. Avitene and FloSeal also demonstrated a propensity for causing granuloma formation, whereas Arista and Surgicel showed no such evidence., Conclusion: Each of these hemostatic agents was effective in controlling bleeding in the majority of standardized neurosurgical lesions. Arista degrades more rapidly than Surgicel, Avitene, and FloSeal and does not result in any foreign body reaction.

Objective(s): The authors have developed an alternative dosing schedule for tranexamic acid that incorporates the effects of renal function on tranexamic acid concentrations. The objectives of this study were to determine if this new dosing schedule can achieve the desired plasma concentration of tranexamic acid and reduce intra- and interpatient variability in tranexamic acid plasma concentrations relative to the current dosing schedule., Design: A prospective randomized trial., Setting: A tertiary referral medical center hospital., Participants: Cardiac surgery patients., Interventions: Cardiac surgery patients were randomly assigned to receive the authors' standard tranexamic acid loading dosage of 10 mg/kg given over 20 minutes, followed by an infusion of 1 mg/kg/h (9 patients), or the new drug dosage schedule described later (11 patients)., Measurements and Main Results: Perioperative plasma tranexamic acid concentrations were measured using high-performance liquid chromatography. From repeated-measures analysis of variance, a significant (p < 0.001) time-by-treatment interaction effect was detected indicating that differences in mean tranexamic acid concentration between treatment groups were dependent on time period. Among patients receiving the standard dosing regimen, those with renal insufficiency had lower tranexamic acid concentration at 5 minutes on cardiopulmonary bypass (p = 0.003). For patients receiving the experimental regimen, the mean tranexamic acid concentration did not differ significantly at any time point between patients with and without renal insufficiency (p > 0.20 at all time points)., Conclusions: The new dosing protocol for tranexamic acid resulted in more consistent blood concentrations of tranexamic acid, but not stable tranexamic acid levels >20 microg/mL on cardiopulmonary bypass.

Study Objective: To determine whether a new Sonoclot-based, aprotinin-insensitive activated clotting time (aiACT) assay yields stable results over a broad range of aprotinin concentrations., Design: Prospective trial conducted on in vitro blood samples., Setting: Tertiary-care teaching medical center., Participants: 19 healthy adult volunteers., Interventions: Whole blood samples were collected from volunteers. Heparin (2 U/mL) and escalating concentrations of aprotinin of 160 to 500 kallikrein inhibitory units (KIU)/mL were added in vitro., Measurements and Main Results: Celite ACT, kaolin ACT, and aiACT assays were completed. The aiACT showed stable activated clotting time (ACT) results on heparinized, noncitrated blood with added aprotinin (P = nonsignificant). In contrast, celite ACT and kaolin ACT were greatly prolonged when aprotinin was added to heparinized, noncitrated, and citrated blood (P < 0.05). The aiACT had consistent results at all aprotinin concentrations (P = nonsignificant)., Conclusions: Aprotinin (160, 320, and 500 KIU/mL) significantly prolongs the ACT value with celite and kaolin activators but not with the aprotinin-insensitive activator.

Fenoldopam, a selective dopamine-1-receptor agonist, decreases arterial blood pressure rapidly, with a brief duration of action similar to sodium nitroprusside (SNP), but in contrast to SNP, it increases renal blood flow. We compared the hemodynamic and renal effects of fenoldopam in patients undergoing abdominal aortic surgery requiring cross-clamping of the aorta with another therapeutic option, dopamine and SNP. Fenoldopam or 2 mcg x kg(-1) x min(-1) of dopamine and SNP was infused before incision in 60 randomly selected patients in a double-blind fashion. Hemodynamic variables were recorded before incision, immediately before clamping the aorta, 5 min after cross-clamp release and upon completion of surgery. Urine output, serum creatinine, and creatinine clearance were measured intraoperatively and postoperatively. Characteristics were compared between groups using two-sample rank sum test for continuous variables and Fisher's exact test for discrete variables. The occurrence of severe hypotension, maximum systolic blood pressure, and need for additional antihypertensive drugs were not different between the groups. Most intraoperative hemodynamic variables and all indices of renal function did not differ according to treatment. Therefore, fenoldopam has no therapeutic advantage compared with similar therapies in patients undergoing major vascular surgery involving cross-clamping of the aorta.

Objectives: Infants and children undergoing cardiopulmonary bypass for repair of congenital heart defects are at substantial risk for excessive bleeding, contributing greatly to morbidity and mortality. Aprotinin significantly reduces bleeding and transfusion requirements in adults but is of indeterminate value for pediatric patients. The aim of this study was to determine plasma aprotinin concentrations in these patients with a functional aprotinin assay., Methods: Thirty patients less than 16 years of age scheduled for cardiac surgery with aprotinin were enrolled. Aprotinin was administered as a 25,000 KIU/kg bolus, 35,000 KIU/kg cardiopulmonary bypass prime, and 12,500 KIU.kg(-1).h(-1) continuous infusion. Blood samples for aprotinin concentrations (kallikrein-inhibiting units/milliliter) were obtained before aprotinin; 5 minutes post-bolus; 5 minutes after cardiopulmonary bypass initiation; 30 and 60 minutes on cardiopulmonary bypass; on discontinuation of aprotinin; 1 hour after aprotinin discontinuation; and 4 hours after permanent separation from cardiopulmonary bypass. For analysis, patients were grouped according to weight (<10 kg, 10-20 kg, >20 kg). Differences between weight groups were assessed using an exact test for categoric variables and 1-way analysis of variance for continuous variables., Results: Aprotinin concentrations differed significantly across weight groups. Five minutes after aprotinin bolus and initiation of cardiopulmonary bypass, there was significant correlation between weight and aprotinin concentration (r =.57, P =.003; r =.69, P =.001, respectively)., Conclusion: A functional assay reveals significant variability in aprotinin concentration for pediatric patients using current weight-based aprotinin dosing. Additional investigation is necessary to determine target aprotinin concentration dosing regimens to provide better efficacy.

Objective: To determine whether there is a difference between on-pump cardiopulmonary bypass (CABG) and off-pump coronary artery bypass grafting (OPCAB) without heparin reversal with regard to bleeding, transfusion requirements, and incidence of surgical re-exploration of the mediastinum., Design: Retrospective chart review., Setting: A large academic medical center., Participants: Two hundred adult patients undergoing cardiac surgery., Interventions: None., Measurements and Main Results: One hundred CABG patients were compared with 100 OPCAB patients. Statistical significance was measured with P values of

Background: Infants and children undergoing cardiopulmonary bypass become substantially hemodiluted secondary to the volume used to prime the oxygenator. Fresh-frozen plasma has been included in the prime to lessen dilution of clotting factors and correspondingly minimize blood loss and transfusions., Methods: We prospectively randomized 56 patients weighing 10 kg or less who required cardiopulmonary bypass to receive either one unit of fresh-frozen plasma or 200 mL of albumin 5% in the prime. After protamine administration, samples for prothrombin time, fibrinogen, platelet count, and thromboelastogram were obtained. Mediastinal chest tube drainage and transfusion requirements were documented., Results: There were no significant differences between groups regarding demographic or surgical characteristics. Blood loss during the first 24 hours was similar in both groups, but total transfusions were significantly greater in those who received fresh-frozen plasma instead of albumin 5% in the prime (8.0 +/- 4.2 versus 6.1 +/- 4.5 U, respectively; p = 0.035). Post hoc analyses suggest that for cyanotic patients and patients undergoing complex operations, fresh-frozen plasma in the prime results in less blood loss than albumin 5%., Conclusions: Substitution of albumin 5% for fresh-frozen plasma in the prime of acyanotic patients weighing 10 kg or less who undergo noncomplex operations requiring cardiopulmonary bypass significantly reduces perioperative transfusions without increasing blood loss. Further investigation is needed to determine whether increased blood loss is associated with increased transfusions when albumin 5% is substituted for fresh-frozen plasma in the prime of infants and children who are cyanotic or undergoing complex operations.

Objective: To assess the effect of heparin-coated circuits on bleeding, transfusion, and platelet count in patients undergoing primary coronary artery bypass grafting with full heparinization., Design: Randomized, double-blind study., Setting: Tertiary-care academic medical center., Participants: Eighty-eight patients undergoing coronary artery bypass grafting requiring cardiopulmonary bypass (CPB) without previous sternotomy., Interventions: Subjects received either a heparin-coated or an uncoated extracorporeal circuit for CPB. Heparin, 300 micro/kg, was administered, and supplemental amounts were administered to maintain an activated coagulation time of greater than 480 seconds. Platelet counts were determined during CPB. Mediastinal chest tube drainage was collected in the intensive care unit for 24 hours., Measurements and Main Results: The mean platelet counts were similar between the groups during CPB. There was no significant difference in 24-hour mediastinal chest tube drainage (mean +/- standard deviation; median) between the heparin-coated (n = 44, 1096 +/- 401, 1015 mL) and uncoated group (n = 44, 1150 +/- 548, 1040 mL; p = 0.91). The heparin-coated group received less allogeneic packed red blood cells (0.9 +/- 1.6, 0.0 v 1.5 +/- 1.8, 1.0 U; p = 0.04)., Conclusions: The use of a heparin-coated or uncoated cardiopulmonary bypass circuit and full heparinization marginally reduced only red blood cell transfusion but was not associated with platelet sparing or reduced perioperative bleeding., (Copyright 2003 Elsevier Inc. All rights reserved.)

Heparin-induced thrombocytopenia with thrombosis (HITT) type II is a life-threatening complication of heparin therapy that most often occurs after 5-10 days of exposure to heparin. Anticoagulation is a significant concern for patients with HITT type II being prepared for cardiac surgery requiring cardiopulmonary bypass (CPB). We report a case series of 12 patients with a history HITT type II who underwent CPB and cardiac surgery. Six patients did not express the antibody that mediates HITT type II immediately before surgery. Heparin was used as the anticoagulant for the duration of CPB only, and all these patients did well without thrombotic complications. Six patients expressed the antibody that mediates HITT type II immediately before surgery. Hirudin was used as the anticoagulant for CPB in these patients. The ecarin clotting time was used to guide hirudin therapy during CPB. The patients receiving hirudin did well, but they had a large amount of bleeding, required transfusions of multiple allogeneic blood products, and had a frequent rate of reexploration of the mediastinum after CPB.

Unlabelled: Aprotinin is effective during cardiac surgery for reducing blood loss and transfusion requirements, but it is expensive. Aprotinin is usually administered to adults according to a fixed protocol regardless of the patient's weight. We previously developed a weight-based dosing protocol for aprotinin. The purpose of this prospective observational study was to determine aprotinin levels in four patient groups (n = 10 each) using the new weight-based aprotinin dosing schedule that should achieve concentrations over 100, 150, 200, and 250 kallikrein inhibitory units/mL compared with full-dose aprotinin regimen (n = 10) by a simple functional aprotinin assay. There was no difference in patient demographic or surgical variables among groups. There was less within patient variation in plasma aprotinin concentrations over time in the new weight-based aprotinin dosing schedule groups compared with the full-dose aprotinin regimen group (P < 0.02 for all comparisons). The mean plasma aprotinin concentration achieved with the new weight-based aprotinin dosing schedule was similar to the desired concentrations, but we were unable to reduce between-patient variability in aprotinin concentrations., Implications: The current dosing schedule for aprotinin results in a large variation in aprotinin plasma concentrations between patients and a large variation within each patient over time. A new weight-based dosing schedule reduced variation of aprotinin concentration over time, but was unable to reduce between-patient variability in aprotinin concentration.

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., (Copyright 2001 by W.B. Saunders Company)

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Background: Cannulation of the central circulation is essential for management of patients who require major surgery, and for patients who are critically ill. Arterial puncture is the most frequent complication associated with central venous cannulation, and is potentially fatal. Detection of arterial puncture can be problematic, especially in patients with cyanotic congenital heart disease., Methods: One thousand eleven consecutive cardiothoracic and vascular surgical patients who required central venous cannulation were studied using a new technique for detection of arterial puncture and prevention of arterial cannulation. This technique involves continuous pressure transduction of the steel introducer needle. Central venous cannulation was attempted in all patients. The sites of attempted catheterizations, number of arterial punctures and cannulations, and the number of successful catheterizations were noted. All patients were treated in accordance with standard anesthetic and surgical techniques in the institution., Results: One thousand one hundred seventy-two central venous catheters were placed. The overall success rate was 99.6%. The incidence of arterial puncture was 9.3% for central venous cannulation attempts of the internal jugular, subclavian, and femoral veins. No arterial cannulation occurred, and none of the patients had significant complications. Congenital heart disease patients had a higher incidence of arterial puncture (14.1%) and a lower rate (96.8%) of successful cannulation., Conclusion: Pressure transduction of the steel needle is a useful technique for detecting arterial puncture and preventing arterial cannulation during attempts to achieve central venous cannulation.

Platelet dysfunction is a major cause of bleeding after cardiopulmonary bypass (CPB). No timely, simple, point-of-care determinant of platelet function is available for clinical use. Adding platelet-activating factor to conventional activated clotting time methods (platelet-activated clotting test [PACT]) (HemoSTATUS; Medtronic, Inc., Parker, CO) produces rapid results (<3 min) and may yield a measure of platelet responsiveness and whole blood procoagulant activity. Blood samples were drawn for PACT, platelet count, prothrombin time, activated partial thromboplastin time, and thromboelastogram (TEG) from 200 patients undergoing cardiac surgery. The PACT significantly decreased from the baseline to postprotamine time interval (P < 0.001). The PACT correlated with 4-h mediastinal blood loss (r = -0.30, P = 0.014). The TEG maximum amplitude also correlated with 4-h mediastinal blood loss (r = -0.32, P = 0.003). The PACT had a sensitivity and specificity comparable to routine laboratory coagulation tests in predicting blood loss. The TEG maximum amplitude, however, was more predictive than both the PACT and routine coagulation tests in this respect. The PACT may be a useful indicator of platelet responsiveness or whole blood procoagulant activity, but we did not find it superior to other tests of coagulation function for predicting excessive blood loss after CPB.

Objective: The purpose of this study was to examine the effect of cardiopulmonary bypass flow rate on cerebral blood flow and cerebral metabolic rate for oxygen during hypothermic (27 degrees C) cardiopulmonary bypass., Design, Setting, and Participants: The investigation was a prospective, randomized study in a tertiary care hospital setting. The 30 participants were volunteer adult cardiac surgical patients at a single institution., Interventions: The N2O saturation method of Kety and Schmidt was used to determine global cerebral blood flow and metabolic rate during four periods: prebypass, cardiopulmonary bypass (CPB) (27 degrees C) flow rates of 2.3 and 1.2 L/min/m2, and 30 minutes post-CPB. Anesthesia consisted of fentanyl and midazolam; pH management was alpha-stat, and mean arterial pressure was maintained at 50 to 70 mmHg throughout CPB., Measurements and Main Results: In the context of an unchanged mean arterial pressure, the pump flow did not affect cerebral blood flow or metabolic rate during hypothermic CPB. Systemic venous oxygen saturation was also maintained during reduced flow at 27 degrees C. Hemodilution during hypothermic CPB maintained cerebral blood flow at prebypass levels. In the postbypass period, persistent hemodilution resulted in an elevated cerebral blood flow., Conclusions: Brain oxygenation is well maintained at lower than conventional pump flow levels during CPB. There may be practical advantages to reduced flows during hypothermia, and flow reductions do not appear to adversely affect cerebral blood flow or metabolism.

A noninvasive, simple, and continuous method to assess cerebral perfusion during cardiopulmonary bypass (CPB) could help prevent cerebral ischemia. Transcranial Doppler sonography (TCD) allows a noninvasive, on-line measurement of blood flow velocity in cerebral arteries. The correlation of TCD-estimated and actual cerebral blood flow (CBF) has not been well studied during CPB. We determined the correlation of middle cerebral artery (MCA) mean velocity and CBF determined by the Kety-Schmidt method during nonbypass and two hypothermic bypass flow conditions. Sixteen patients undergoing hypothermic (27 degrees C) CPB for coronary artery bypass grafting and/or valve replacement surgery were enrolled in the study. We were able to determine MCA velocity in only 12 patients. We determined CBF and MCA velocity in each patient during four 15-min study periods: 1) prebypass after sternotomy before aortic cannulation; 2) hypothermic (27 degrees C) CPB with 1.2 L.min-1.m-2 pump flow; 3) hypothermic CPB with 2.4 L.min-1.m-2 pump flow, and 4) 30 min after weaning from CPB. There was no difference in the mean arterial pressure between the two CPB pump blood flows. The pooled change in MCA velocity and CBF as percentage of baseline (prebypass) for all patients and at all time points had a correlation of 0.33 (r). A decrease or increase in MCA velocity did not necessarily indicate a corresponding decrease or increase in CBF. This technology may be of limited usefulness during the circulatory condition of hypothermic, nonpulsatile CPB.

Background: Most blood crossmatched in a hospital blood bank is for surgical patients, and the majority is never transfused. The maximal standard blood order schedule is used to promote efficient ordering practices for surgical patients., Study Design and Methods: To ascertain the predictors of red cell transfusions for patients undergoing total hip arthroplasty, the charts of 299 adult patients undergoing primary and revision total hip arthroplasty were reviewed. A surgical blood order equation was developed for calculating the number of units of red cells that should be ordered. Stepwise regression analysis was used to determine which patient-and-case-related variables should be considered in the surgical blood order equation., Results: The significant indicators for allogeneic red cell transfusion to patients on the day of total hip arthroplasty were preoperative hemoglobin concentration, weight, age, estimated blood loss, and aspirin use. The surgical blood order equation would result in a lower crossmatch-to-transfusion ratio than would the maximal standard blood order schedule (1.23 vs. 3.14). Costs were also lower with the surgical blood order equation., Conclusion: Incorporation of patient factors resulted in increased efficiency of blood-ordering practices in total hip arthroplasty.

Background: The neurologic effects of warm heart operations is a subject of popular interest. The purpose of this study was to examine the adequacy of cerebral oxygenation during normothermic cardiopulmonary bypass and better define the relationship between hematocrit, temperature, and brain oxygen delivery., Methods: Cerebral blood flow, metabolic rate, and oxygen delivery were measured in 60 patients randomized to normothermic (37 degrees C) or hypothermic (27 degrees C) cardiopulmonary bypass. The nitrous oxide saturation technique of Kety and Schmidt was used for cerebral blood flow determinations. Both temperature groups underwent moderate (31%) hemodilution., Results: During normothermic cardiopulmonary bypass, cerebral blood flow increased secondary to hemodilution and decreased cerebral vascular resistance; a normal matching of oxygen demand and delivery was maintained. During hypothermic bypass, hemodilution and hypothermia had essentially equal, opposing effects on cerebral vascular resistance and blood flow. With hypothermia, brain oxygen demand and delivery were both reduced but not closely coupled., Conclusions: From the standpoint of global cerebral perfusion and oxygenation, our data support the practice of "warm" heart operations. It clarifies the marked influence of hematocrit on cerebral blood flow and delineates the interaction of temperature and hematocrit on cerebral oxygen delivery. It also suggests that additional investigation to better define "temperature-appropriate" hemodilution during cardiopulmonary bypass is indicated.