Variability in transfusion practice for coronary artery bypass surgery persists despite national consensus guidelines: a 24-institution study. Institutions of the Multicenter Study of Perioperative Ischemia Research Group

Transfusion Algorithms and How They Apply to Blood Conservation: The High-risk Cardiac Surgical Patient

Considerable blood product support is administered to the cardiac surgery population. Due to the multifactorial etiology of bleeding in the cardiac bypass patient, blood products frequently and empirically are infused to correct bleeding, with varying success. Several studies have demonstrated the benefit of algorithm-guided transfusion in reducing blood loss, transfusion exposure, or rate of surgical re-exploration for bleeding. Some transfusion algorithms also incorporate laboratory-based decision points in their guidelines. Despite published success with standardized transfusion practices, generalized change in blood use has not been realized, and it is evident that current laboratory-guided hemostasis measures are inadequate to define and address the bleeding etiology in these patients.

Blood conservation strategies in cardiac surgery

Despite the continuous efforts to increase the safety of blood components, red blood cell transfusions remain associated with some risks and side effects. Therefore, numerous techniques have been developed to decrease blood use, but they also carry risks and bear costs. Most of them are frequently used in cardiac surgery, which still consumes a large part of the available blood supply. Among western countries the use of alternative techniques, but also transfusion practice, has been shown to vary markedly. 'Blood conservation' is a global concept engulfing all possible strategies aimed at reducing patients' exposure to allogeneic blood components. The development of the 'best strategy' consists of the selection of those techniques that are most appropriate to the local specific situation. It implies the establishment of a reliable system, collecting data both at the surgical team and at the medical level.

Indications for Blood Transfusion in Cardiac Surgery

In addition to its life-saving effect in hemorrhagic shock, transfusion of allogenic packed red blood cells can be beneficial in situations where a critically low hematocrit is contributing to a state of oxygen-supply dependency. These benefits are countered by the risks of transfusion-associated lung injury, transfusion-associated immunomodulation, and cellular hypoxia after RBC transfusion. The critical hematocrit is patient and organ specific, and varies intraoperatively according to the duration and temperature of bypass, as well as for a variable postoperative period. Future randomized studies must prospectively evaluate regional indicators of tissue oxygenation in transfusion algorithms.

Allogeneic blood transfusions explain increased mortality in women after coronary artery bypass graft surgery

BACKGROUND

Postoperative mortality is greater in women than men after coronary artery bypass graft surgery. Because allogeneic blood transfusions are more common in women and have been associated with immunomodulation, the impact of transfusion on sex differences in infection and mortality was examined.

METHODS

A cohort study was conducted using Michigan Medicare beneficiaries who had undergone coronary artery bypass graft surgery. Information was used regarding allogeneic blood transfusion, infection, and mortality within the 100-day period after surgery.

RESULTS

Blood transfusions were more common in women than in men (88.2%, 95% CI 87.1%-89.2% vs 66.7%, 95% CI 65.5%-67.9%). Patients who received transfused blood were more likely to have an infection than patients who did not (14.6%, 95% CI 13.8%-15.5% vs 4.9%, 95% CI 4.1%-5.9%). There was a dose-response relationship between the number of units of whole blood or packed red cells received and the prevalence of infection (P = .035). The unadjusted risk of mortality attributable to female sex was 13.9% (95% CI 8.1%-19.6%), but was no longer statistically significant when adjusted for blood transfusion (population attributable risk 0.6%, 95% CI -6.0% to 6.6%). Patients who received a transfusion were 5.6 times as likely to die within 100 days after surgery as those who did not receive a transfusion (95% CI 3.7-8.6).

CONCLUSION

The increased risk of mortality in women after bypass surgery may be explained by transfusion-related immunosuppression.

Objectives and limitations of bloodless medical care

PURPOSE OF REVIEW

To outline the rationale, limitations, and execution of bloodless medical and surgical programs, highlighting characteristics that contribute to successful outcomes.

RECENT FINDINGS

Clinical experiences with patients who refuse blood transfusions for religious reasons have provided valuable lessons and raise intriguing questions about the necessity of routine blood transfusions. Healthcare centers with bloodless medicine and surgery programs feature a novel concept of patient care aimed at improving outcomes. A one-tiered approach to minimize blood usage for all patients, regardless of religious beliefs, is being successfully adopted at an increasing number of institutions. Since most single blood-conservation techniques reduce blood usage by just 1-2 units, a series of integrated preoperative, intraoperative, and postoperative conservation approaches is required. These include preoperative autologous donation, erythropoietic support, acute normovolemic hemodilution, individualized assessment of anemia tolerance, implementation of conservative transfusion thresholds, meticulous surgical techniques, and judicious use of phlebotomy and pharmacologic agents for limiting blood loss.

SUMMARY

The objectives of bloodless medicine and surgery programs are straightforward but require staff with expertise in transfusion medicine, intensive teamwork, patient-specific customization, careful planning, and integrated use of multimodal strategies.

Population-based audit of fresh-frozen plasma transfusion practices

BACKGROUND

In contrast to decreasing red blood cell (RBC) consumption in Finland, the use of fresh-frozen plasma (FFP) has been increasing since the 1990s, suggesting that FFP use may not always be optimal. To improve transfusion practices, knowledge of current FFP use and regional, national, and international comparison is necessary.

STUDY DESIGN AND METHODS

Nine (of 21) Finnish hospital districts participated. Data concerning FFP-transfused patients in the years 2002 and 2003 were collected from existing computerized medical records into a yearly updated database as part of a Finnish benchmarking project on blood component use.

RESULTS

Data included 11,590 FFP-transfused patients and 60,240 FFP units (71.2% of Finnish FFP use) delivered to Finnish hospitals during the study period. FFP was transfused most often to surgery patients (62.8% of FFP transfusion hospital visits) with blood circulatory system problems (32.3% of surgically treated and FFP-transfused patients). In only 65.9 percent of FFP-transfused patients were coagulation variables measured at any point in the hospital episode, and FFP was usually transfused in paired doses. Mean FFP use in Finland is comparable to other countries.

CONCLUSION

Although overall FFP use in Finland is similar to that of international figures, it does not ensure best practice. Perioperative staff, being the largest FFP user, should be encouraged to dose FFP based on coagulation variables and body weight. Improvement efforts should be directed to patient groups transfused with large amounts of FFP.

Development of permanent national register of blood component use utilizing electronic hospital information systems

BACKGROUND AND OBJECTIVES

We wanted to establish a permanent national database system, which can be utilized to study transfusion recipients and blood use in Finland.

MATERIALS AND METHODS

A regularly updated register for permanent use was developed. To study the usability of the database, years 2002 and 2003 were further analysed. Database included all transfused patients in major blood-transfusing hospitals from four university and five central hospital districts managing altogether 63% of Finnish inpatient hospital episodes.

RESULTS

Audit of gathered data reveal 96.8% match in adult blood components with Finnish Red Cross, Blood Service sales figures. Model data set includes 59,535 transfused patients (44.3% men and 55.7% women) having received 529,104 blood components. Half of all blood units were transfused in connection with surgical operations. Most of the blood recipients were elderly (51.6% are over 64 years of age). Blood-component use and transfusion-related costs varied widely between hospitals.

CONCLUSION

Hospital data managing systems can be useful for creating a population-based database system to monitor and compare transfusion practices. This record provides information about transfusion epidemiology for transfusion professionals, hospital management, and hospital administration.

Development and validation of Transfusion Risk Understanding Scoring Tool (TRUST) to stratify cardiac surgery patients according to their blood transfusion needs

BACKGROUND

Allogeneic blood transfusion is associated with transfusion reactions, infection transmission, and postoperative morbidity and mortality. The objective of this study was to develop and validate an accurate and simple clinical index to stratify cardiac surgery patients according to their blood transfusion needs.

METHODS AND RESULTS

Data on consecutive adult patients who underwent cardiac surgery at Toronto General Hospital (n = 11,113) and Sunnybrook and Women's College Health Sciences Center (n = 5316) between May 1999 and June 2004 were collected for the development, validation, and external validation of the index. Primary outcome was the exposure to blood transfusion in the operative and first postoperative days. Multivariable logistic regression modeling techniques were used to determine the relationship between each independent variable and the exposure to allogeneic blood transfusion. Score assignment for each predictor variable was based on its regression coefficient. The predicted probabilities at each total score were compared to the observed proportions of patients exposed to blood transfusion. The clinical tool consists of eight preoperative variables: preoperative hemoglobin, weight, female sex, age, nonelective procedure, preoperative creatinine, previous cardiac surgical procedure, and nonisolated procedure.

CONCLUSIONS

Based on the standards of measurement in clinical research, a valid clinical tool was developed for predicting the need for blood transfusion in patients undergoing cardiac surgery. The clinical tool was internally and externally validated, and the results suggest that it should perform well at other institutions.

Präoperative Eigenblutspende in der Herzchirurgie

BACKGROUND

Preoperative autologous blood donation is an effective method to reduce allogeneic transfusion requirement. However, this method is only rarely utilized in cardiac surgery. Besides economic concerns one essential argument against predonation is the lack of sufficient time due to the short waiting lists. The aim of the present study was to investigate the efficacy of autologous predonation to reduce allogeneic blood transfusion in routine cardiac surgery on a center without longer preoperative waiting lists.

PATIENTS AND METHODS

A total of 2,626 cardiac surgery patients were included. Primary endpoint of the study was the perioperative incidence of allogeneic packed cell transfusion. If time between diagnosis and admission to the hospital was >10 days, predonation was offered to the patients. Data were stratified for preoperative risk score. Logistic and linear regression analysis tested the influence of different variables on the incidence of allogeneic blood transfusion and the total amount of allogeneic blood.

RESULTS

Of all patients 267 (11.2%) underwent predonation. The incidence of allogeneic packed cell transfusion was reduced from 53% to 19% by autologous predonation (p<0.001). The total amount of allogeneic blood transfused was significantly different between the groups (2.2+/-4.2 vs. 0.84+/-6.3 units; p<0.001).

DISCUSSION

Autologous predonation in cardiac surgery was effective in reducing blood transfusions even in the absence of longer preoperative waiting times. It is a safe and effective method to minimize blood transfusion in cardiac surgery.

The Association Between Duration of Storage of Transfused Red Blood Cells and Morbidity and Mortality After Reoperative Cardiac Surgery: Retracted

Red blood cells (RBCs) undergo numerous changes during storage; however, the clinical relevance of these storage "lesions" is unclear. We hypothesized that the duration of storage of transfused RBCs is associated with mortality after repeat sternotomy for cardiac surgery, because these patients are at high risk for both RBC transfusion and adverse outcome. We retrospectively analyzed 434 patients who underwent repeat median sternotomy for coronary artery bypass graft or valve surgery and who received allogeneic RBCs. Three-hundred-twenty-one (74%) patients met the criteria for eligibility. After adjusting for the effects of confounders and the total number of RBC transfusions, the duration of storage of the oldest RBC unit transfused was found to be associated with both in-hospital mortality (Cox proportional hazard ratio (HR) = 1.151; P < 0.0001) and out-of-hospital mortality (HR = 1.116; P < 0.0001). The mean duration of storage of transfused RBCs was also an independent predictor of in-hospital mortality (HR = 1.036; P < 0.0001). Independent associations between the duration of storage of transfused RBCs and acute renal dysfunction and intensive care unit and hospital length of stay were also observed. The duration of storage of RBCs is associated with adverse outcome after repeat sternotomy for cardiac surgery. The clinical significance of this finding should be investigated in a large, randomized, blinded clinical trial.

Morbidity and mortality risk associated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting

OBJECTIVE

Our objective was to quantify incremental risk associated with transfusion of packed red blood cells and other blood components on morbidity after coronary artery bypass grafting.

DESIGN

The study design was an observational cohort study.

SETTING

This investigation took place at a large tertiary care referral center.

PATIENTS

A total of 11,963 patients who underwent isolated coronary artery bypass from January 1, 1995, through July 1, 2002.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among the 11,963 patients who underwent isolated coronary artery bypass grafting, 5,814 (48.6%) were transfused. Risk-adjusted probability of developing in-hospital mortality and morbidity as a function of red blood cell and blood-component transfusion was modeled using logistic regression. Transfusion of red blood cells was associated with a risk-adjusted increased risk for every postoperative morbid event: mortality (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.67-1.87; p<.0001), renal failure (OR, 2.06; 95% CI, 1.87-2.27; p<.0001), prolonged ventilatory support (OR, 1.79; 95% CI, 1.72-1.86; p<.0001), serious infection (OR, 1.76; 95% CI, 1.68-1.84; p<.0001), cardiac complications (OR, 1.55; 95% CI, 1.47-1.63; p<.0001), and neurologic events (OR, 1.37; 95% CI, 1.30-1.44; p<.0001).

CONCLUSIONS

Perioperative red blood cell transfusion is the single factor most reliably associated with increased risk of postoperative morbid events after isolated coronary artery bypass grafting. Each unit of red cells transfused is associated with incrementally increased risk for adverse outcome.

An audit of red cell and blood product use after the institution of thromboelastometry in a cardiac intensive care unit

Cardiac surgery is estimated to use 20% of the UK blood supply. However, there has been much interest recently in decreasing red cell and blood product use not only to ease strain on blood stocks or avoid potential transmission of infection but also to decrease post-operative transfusion-related complications. Coagulopathies are not uncommon in cardiac surgical patients, but the time lapse for reporting conventional laboratory results has been highlighted as an obstacle to the appropriate use of blood products. Accordingly, much interest has arisen in rapid near-patient testing of coagulation and, in January 2002, a thromboelastometer (ROTEM, Pentapharm, Germany) was purchased for our unit. This audit sought to assess its impact by retrospective analysis of 990 sequential patients' demographic data and transfusion details covering 6 months prior to its introduction and 6 months after. In the 6 months prior to its introduction, red cells were used in 60% of patients and fresh frozen plasma (FFP) and platelets used in 17 and 16% of patients, respectively. In the following 6 months, red cell use had fallen to 53% and FFP and platelets to 12 and 11%, respectively (P < 0.05). Introduction of thromboelastometry has significantly decreased our use of red cells and blood products.

Does the Use of Erythropoietin Reduce the Risk of Exposure to Allogeneic Blood Transfusion in Cardiac Surgery? A Systematic Review and Meta-Analysis

BACKGROUND

The use of blood conservation techniques is important in cardiac surgery as postoperative bleeding is common and allogeneic blood transfusion carries the risk of transfusion reactions and infection transmission. Erythropoietin with and without preoperative autologous blood donation is one of the modalities to avoid allogeneic blood transfusion. The objective of this review was to assess the effectiveness of erythropoietin in reducing the risk of exposure to allogeneic blood transfusion during or after cardiac surgery.

METHODS

A meta-analysis of 11 identified randomized controlled trials, reporting comparisons between erythropoietin and control, was undertaken. The primary outcome was the number of patients exposed to allogeneic blood transfusion during or after cardiac surgery.

RESULTS

Eleven studies, involving 708 patients, met the inclusion criteria for this review. In total, 471 patients were given erythropoietin, and 237 patients formed the control group. The administration of erythropoietin with and without preoperative autologous blood transfusion prior to cardiac surgery is associated with a significant risk reduction: RR = 0.28 (95% CI 0.18-0.44, P < 0.001) and RR = 0.53 (95% CI 0.32-0.88, P < 0.01), respectively.

CONCLUSION

The administration of erythropoietin before cardiac surgery is associated with a significant reduction in the risk of exposure to allogeneic blood transfusion. Further studies are warranted to define the patients' subgroups that may benefit the most from EPO administration.

A comparison of bivalirudin to heparin with protamine reversal in patients undergoing cardiac surgery with cardiopulmonary bypass: The EVOLUTION-ON study

OBJECTIVES

Unfractionated heparin and its antidote, protamine sulfate, allow for rapid and reversible anticoagulation during cardiac surgery with cardiopulmonary bypass, yet limitations exist, including a variable dose-response, dependence on a cofactor for anticoagulant effect, and antigenic potential. This trial was performed to evaluate the safety and efficacy of bivalirudin as an alternative to heparin with protamine reversal in on-pump cardiac surgery.

METHODS

We conducted a randomized, open-label, multicenter trial comparing heparin with protamine reversal to bivalirudin in patients undergoing cardiac surgery with cardiopulmonary bypass. The primary objective was to demonstrate comparable rates of in-hospital procedural success defined as freedom from death, Q-wave myocardial infarction, stroke, or repeat revascularization. Twenty-one institutions enrolled 101 patients randomized to bivalirudin and 49 patients to heparin treatment.

RESULTS

The primary end point of procedural success was not significantly different between the bivalirudin arm and the heparin/protamine arms at 7 days, 30 days, or 12 weeks' follow-up. Adequate anticoagulation was achieved in all patients. Secondary end points including mortality, 24-hour blood loss, overall incidence of transfusions, and duration of surgery were similar between the two arms.

CONCLUSIONS

Bivalirudin is a safe and effective anticoagulant for patients undergoing a wide range of cardiac surgical procedures with cardiopulmonary bypass. Procedural success rates with bivalirudin were similar to rates in patients receiving heparin anticoagulation, with no difference in mortality. Avoidance of blood stasis and attention to the intraoperative medical management of patients is critical for successful use of bivalirudin during cardiopulmonary bypass.

The kaolin-activated Thrombelastograph predicts bleeding after cardiac surgery

OBJECTIVE

The objective of this study was to determine the relationship of the kaolin-activated Thrombelastograph (TEG) with postoperative bleeding and laboratory tests of coagulation in the setting of cardiac surgery with the routine use of -aminocaproic acid.

DESIGN

Prospective observational study.

SETTING

An adult heart center at a tertiary referral, university hospital.

PARTICIPANTS

Thirty adult cardiac surgical patients.

INTERVENTIONS

The kaolin-activated TEG, platelet counts, prothrombin times, activated partial thromboplastin times, and fibrinogen levels were measured before induction of anesthesia, during cardiopulmonary bypass, and on arrival in the intensive care unit. Mediastinal and thoracostomy drainage were measured every hour for 4 hours after arrival in the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

Correlation and multivariate linear regression modeling were used to describe relationships among coagulation tests, TEG parameters, and early postoperative bleeding. The TEG maximum amplitude (MA) parameter correlated well with postoperative bleeding (r = -0.6, p = 0.0018), more so than platelet count (r = -0.45, p = 0.02), fibrinogen level (r = -0.40, p = 0.06), or prothrombin time (r = 0.43, p = 0.02). The receiver operating characteristic curve c-index describing MA as a predictor for postoperative bleeding is 0.78. Abnormalities in all the laboratory test results were associated with an abnormal MA.

CONCLUSIONS

In conclusion, the kaolin-activated TEG is associated with early coagulopathic bleeding. It may reflect the severity of a global coagulopathy affecting both platelets and coagulation factors and be a guide to incremental prohemostatic therapy in this setting.

Effect of selective serotonin reuptake inhibitors on requirement for allogeneic red blood cell transfusion following coronary artery bypass surgery

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) inhibit platelet function, and use of these drugs has been associated with bleeding events. The objective of this study was to examine whether the requirement for red blood cell transfusion was increased following preoperative use of SSRIs among patients undergoing coronary artery bypass grafting (CABG).

METHODS

A population-based cohort study of transfusion requirements (red blood cells, fresh frozen plasma, and/or platelets) was conducted among patients undergoing CABG at either Aalborg or Skejby Hospitals between 1 January 1998 and 31 December 2003. All prescriptions for antidepressants, including SSRIs, filled before the date of admission for CABG were identified using prescription databases. Patients were categorized according to use of antidepressants (never users, current users [<90 days before admission for CABG], and former users). Antidepressants were classified according to their action on serotonin and norepinephrine reuptake mechanisms. Relative risk (RR) for transfusion were adjusted for: age; sex; preoperative use of platelet inhibitors (low-dose aspirin [acetylsalicylic acid], clopidogrel, and dipyridamole), NSAIDs and oral anticoagulants; place of surgery; extracorporeal circulation; concomitant valve surgery; and Charlson comorbidity index score.

RESULTS

There were 124 (3.5%) current users of SSRIs among 3454 patients. Adjusted RRs for transfusion among current users of SSRIs, users of nonselective serotonin reuptake inhibitor antidepressants, and users of other antidepressants were 1.1 (95% CI 0.9, 1.3), 0.9 (95% CI 0.6, 1.3), and 1.0 (95% CI 0.7, 1.5), respectively, when compared with never users of any type of antidepressant. The adjusted RR among former SSRI users was 1.0 (95% CI 0.7, 1.4). Risk of re-exploration for bleeding and mortality within 30 days did not differ according to the examined drug-exposure categories.

CONCLUSION

Preoperative use of SSRIs was not associated with any substantially increased requirement for allogeneic red blood cell transfusion among patients undergoing CABG. The main strengths of this study are its relatively large size, the use of prospectively collected data obtained from population-based databases with complete follow-up, and the ability to examine specific types of antidepressants. The limitations include a lack of detailed clinical data regarding other factors that may influence transfusion requirements.

Autologous Blood Donation in Cardiac Surgery: Reduction of Allogeneic Blood Transfusion and Cost-Effectiveness

OBJECTIVE

The purpose of this study was to assess transfusion requirements in patients undergoing cardiac surgery with and without autologous blood donation and to calculate the costs of predonation from the hospital perspective.

DESIGN

Observational study.

SETTING

Single university hospital.

PARTICIPANTS

Four thousand three hundred twenty-five patients undergoing elective cardiac surgery with and without autologous blood donation.

INTERVENTIONS

Eight hundred forty-nine patients (20%) underwent autologous blood donation, whereas 3,476 (80%) did not. Perioperative allogeneic blood transfusion was recorded as the primary endpoint. To avoid selection bias, patients were stratified according to their preoperative risk score. A decision model was derived from acquired data for the optimization of autologous blood donation.

MEASUREMENTS AND MAIN RESULTS

Allogeneic blood transfusion rate was 13% in patients with predonation versus 48% without predonation (p < 0.05). This difference remained statistically significant even after risk stratification. The predonation of 1, 2, or 3 units reduced the probability of receiving allogeneic blood to 24%, 14%, and 9%, respectively. An efficient program of predonation within the department of anesthesiology allowed keeping the costs of predonation low. Decision-tree analysis revealed that predonation of 2 autologous units of blood saved the most allogeneic blood for the smallest increase in costs. Incremental cost for male patients predonating 2 units was dollars 33 (US), whereas for females predonation could be done at no extra cost in comparison to patients without predonation.

CONCLUSION

Autologous blood donation significantly reduces allogeneic blood requirement in cardiac surgery. If adjusted for diagnosis and gender, autologous blood donation is a cost-effective alternative to reduce allogeneic blood consumption.

Blood conservation in the critically ill patient

This review focuses on transfusion practice in the critically ill.

Bleeding in Cardiac Surgery: Its Prevention and Treatment—an Evidence-Based Review

Expected and unexpected bleeding occur frequently in patients undergoing cardiac surgery. Bleeding after cardiac surgery can be broadly divided into two groups: surgical (unrecognized bleeding vessel, anastomosis, or other suture line) or nonsurgical bleeding (caused by coagulopathy). Factors influencing both surgical and nonsurgical bleeding can be further broken down into those occurring preoperatively and those that occur intraoperatively and postoperatively. A thorough understanding of these factors is necessary to reduce bleeding. This is a desirable clinical goal, because excessive bleeding is associated with adverse outcomes.

Genetic factors contribute to bleeding after cardiac surgery

BACKGROUND

Postoperative bleeding remains a common, serious problem for cardiac surgery patients, with striking inter-patient variability poorly explained by clinical, procedural, and biological markers.

OBJECTIVE

We tested the hypothesis that genetic polymorphisms of coagulation proteins and platelet glycoproteins are associated with bleeding after cardiac surgery.

PATIENTS/METHODS

Seven hundred and eighty patients undergoing aortocoronary surgery with cardiopulmonary bypass were studied. Clinical covariates previously associated with bleeding were recorded and DNA isolated from preoperative blood. Matrix Assisted Laser Desorption/Ionization, Time-Of-Flight (MALDI-TOF) mass spectroscopy or polymerase chain reaction were used for genotype analysis. Multivariable linear regression modeling, including all genetic main effects and two-way gene-gene interactions, related clinical and genetic predictors to bleeding from the thorax and mediastinum.

RESULTS

Nineteen candidate polymorphisms were assessed; seven [GPIaIIa-52C>T and 807C>T, GPIb alpha 524C>T, tissue factor-603A>G, prothrombin 20210G>A, tissue factor pathway inhibitor-399C>T, and angiotensin converting enzyme (ACE) deletion/insertion] demonstrate significant association with bleeding (P < 0.01). Adding genetic to clinical predictors results improves the model, doubling overall ability to predict bleeding (P < 0.01).

CONCLUSIONS

We identified seven genetic polymorphisms associated with bleeding after cardiac surgery. Genetic factors appear primarily independent of, and explain at least as much variation in bleeding as clinical covariates; combining genetic and clinical factors double our ability to predict bleeding after cardiac surgery. Accounting for genotype may be necessary when stratifying risk of bleeding after cardiac surgery.

Clinical Outcomes in Cardiac Surgery: Conventional Surgery versus Bloodless Surgery

Bleeding during and after cardiac operations and the effects of cardiopulmonary bypass hemodilution commonly result in blood transfusions. Excessive microvascular bleeding can result in re-exploration and prolonged hospitalization. Nearly 20% of all blood transfusions in the United States are associated with cardiac surgery. The risks associated with the use of allogeneic blood product transfusion include mistransfusion, immunologic complications, and transmission of infectious diseases. The large demand for blood products places significant pressure on the national blood supply, resulting in frequent shortages. The variability in transfusion practice of cardiac surgery patients suggests that sound blood management and a conservative approach to this population can result in reduced transfusions without increasing morbidity or mortality and avoiding complications associated with allogeneic blood transfusion.

Blood component transfusion in primary coronary artery bypass surgery in Kuwait

OBJECTIVE

The aims of this study were to determine the rate of blood product transfusion, associated perioperative factors and cost of such blood product transfusion in primary coronary artery bypass surgery (CABG).

SUBJECTS AND METHODS

The medical records of 159 consecutive primary CABG patients (142 male, 17 female) from January 1, 2003 to June 30, 2003 at Chest Diseases Hospital, Kuwait, were reviewed. Urgent and emergency cases were included.

RESULTS

The mean age of the patients was 57.2 (range 36-77 years). Overall, 128 (80.5%) patients received blood product transfusion during primary CABG: 113 (70.5%) packed red blood cells (RBC), 54 (33.9%) fresh frozen plasma, and 13 (8%) platelets. Overall, 23 patients (12.6%) received more than two RBC transfusions intraoperatively. Significant factors for intraoperative RBC transfusion were: age >60 years, female gender, preoperative hemoglobin <12 g/dl, and 3 or more coronary bypass grafts constructed. One hundred and fifty-nine patients consumed 342 units of RBC at an average of 2.1 RBC units per patient. The cost per patient was 80 Kuwaiti dinar (KD; USD 240).

CONCLUSION

The findings indicate a high rate of blood component transfusion in primary CABG patients in Kuwait that could expose the patients to the possible adverse effects, and such transfusions have high economic impact.

Adjusted transfusion triggers improve transfusion practice in orthopaedic surgery

Although blood transfusion has never been safer, there remains concern about adverse effects. We designed guidelines, the 6-8-10-Flexinorm, based on the conditions which are relevant to the decision to transfuse. To evaluate these new guidelines, we performed a case-control study in patients undergoing elective primary total hip replacement. The study consisted of two parts. In the first part, physicians were strongly encouraged to use the new guidelines; in the second part, only registration took place. During the first and second part of the study, the use of packed red cells (PRC) in Hospital A (study hospital) decreased from 1.1 +/- 1.5 to 0.6 +/- 1.2 and 0.3 +/- 0.9 units, whereas in Hospital B (control), the use of PRC remained unchanged (1 +/- 1.5, 1 +/- 1.7 and 1 +/- 2 units). In the prestudy groups, 43% of the patients in Hospital A were transfused compared to 45% in Hospital B. In the first and second part of the study, 27%, respectively, 14% of the patients in Hospital A were transfused compared to 40% in both periods in Hospital B. The new guidelines lead to a reduction in the use of allogeneic blood and a decrease in the number of patients transfused.

Blood Conservation Strategies in Cardiovascular Surgery

Blood conservation is a measurable intervention in which clinical and financial outcomes may be tracked. This article describes a systems approach to blood conservation for a cardiac surgery population. Four key areas are discussed: needs assessment, committee construction, blood conservation strategies, and outcome measurement. Specific evidenced-based blood conservation strategies include, but are not limited to, transfusion risk index, phlebotomy techniques, management of hemostasis and hemoglobin levels which includes blood testing, pharmacologic agents, and blood transfusion prescription guidelines.

Platelet transfusions during coronary artery bypass graft surgery are associated with serious adverse outcomes

BACKGROUND

Platelet (PLT) transfusions are administered in cardiac surgery to prevent or treat bleeding, despite appreciation of the risks of blood component transfusion. The current analysis investigates the hypothesis that PLT transfusion is associated with adverse outcomes associated with coronary artery bypass graft surgery (CABG).

STUDY DESIGN AND METHODS

Data originally collected during double-blind placebo-controlled phase III trials for licensure of Trasylol (aprotinin injection) were retrospectively analyzed. Adverse outcome data of patients (n = 1720) that received, and did not receive, perioperative PLT transfusion were compared. Logistic regression analysis was used to assess the association of perioperative adverse events with PLT transfusion. Propensity scoring analysis was used to verify results of the logistic regression.

RESULTS

Patients receiving PLTs were more likely to have prolonged hospital stays, longer surgeries, more bleeding, re-operation for bleeding, and more RBC transfusions, and less likely to have full-dose aprotinin administration. Adverse events were statistically more frequent in patients that received one or more PLT transfusion. Logistic regression analysis showed that PLT transfusion was associated with infection, vasopressor use, respiratory medication use, stroke, and death. Propensity scoring analysis confirmed the risk of PLT transfusion.

CONCLUSIONS

PLT transfusion in the perioperative period of CABG was associated with increased risk for serious adverse events. PLT transfusion may be a surrogate marker for sicker patients and have no causal role in the outcomes observed. However, a direct contribution to outcomes remains possible.

Factor V Leiden and perioperative risk

Factor V Leiden (FVL) is the most common known inherited cause of thrombophilia; it is present in approximately 5% of the Caucasian population. Although the risk of venous thrombosis associated with this polymorphism in various medical settings is well described, its effect on perioperative risk is only beginning to be explored. Specifically, there are few studies addressing the potential risks of FVL in the surgical population, in which both hemorrhagic and thrombotic complications convey substantial clinical and economic significance. There are speculations and unproven hypotheses regarding FVL in this population, and these therefore highlight the need to comprehensively address this issue. This review will describe the physiology of the FVL mutation, briefly clarify its risk in the nonsurgical setting, and assess current data regarding FVL in noncardiac and cardiac surgery. Finally, a summary of current clinical evidence and a plan for more detailed investigation of this potentially significant risk factor will be proposed.

The Influence of Allogeneic Red Blood Cell Transfusion Compared with 100% Oxygen Ventilation on Systemic Oxygen Transport and Skeletal Muscle Oxygen Tension After Cardiac Surgery: Retracted

In this study we investigated the effects of allogeneic red blood cell (RBC) transfusion on tissue oxygenation compared with those of 100% oxygen ventilation by using systemic oxygen transport variables and skeletal muscle oxygen tension (PtiO2). Fifty-one volume-resuscitated, mechanically ventilated patients with a nadir hemoglobin concentration in the range from 7.5 to 8.5 g/dL after elective coronary artery bypass grafting were allocated randomly to receive 1 unit (transfusion 1; n = 17) or 2 units (transfusion 2; n = 17) of allogeneic RBCs and ventilation with 40% oxygen or pure oxygen ventilation (100% oxygen; n = 17) and no allogeneic blood for 3 hours. Invasive arterial and pulmonary artery pressures and calculations of oxygen delivery (oxygen delivery index) and consumption indices (oxygen consumption index) were documented at 30-min intervals. PtiO2 was measured continuously by using implantable polarographic microprobes. Systemic oxygen transport variables and PtiO2 were similar between groups at baseline. The oxygen delivery index increased significantly with transfusion of allogeneic RBCs and 100% oxygen ventilation, whereas the oxygen consumption index remained unchanged. Oxygen 100% ventilation increased PtiO2 significantly (from 24.0 +/- 5.1 mm Hg to 34.2 +/- 6.2 mm Hg), whereas no change was found after transfusion of allogeneic RBCs. Peak PtiO2 values were 25.2 +/- 5.2 mm Hg and 26.3 +/- 6.5 mm Hg in the transfusion 1 and 2 groups, respectively. Transfusion of stored allogeneic RBCs was effective only in improving systemic oxygen delivery index, whereas 100% oxygen ventilation improved systemic oxygen transport and PtiO2. This improved oxygenation status was most likely due to an increase in convective oxygen transport with a large driving gradient for diffusion of plasma-dissolved oxygen into the tissue.

The Failure of Retrograde Autologous Priming of the Cardiopulmonary Bypass Circuit to Reduce Blood Use After Cardiac Surgical Procedures

Hemodilution during cardiopulmonary bypass (CPB) is a primary risk factor for blood transfusion in cardiac surgical patients. Priming of the CPB circuit with the patients' own blood (retrograde autologous priming, RAP) is a technique used to limit hemodilution and reduce transfusion requirements. We designed this study to examine the impact of RAP on perioperative blood product use. Using a retrospective cohort study design, the medical records of all patients undergoing CPB (excluding circulatory arrest cases) by a single surgeon were examined. Data were collected over a 24-mo period when RAP was routinely used as a blood conservation strategy (RAP group, n = 257). This group was compared with a cohort of patients during the 24 mo immediately preceding the introduction of RAP into clinical practice (no RAP group, n = 288). A small, statistically insignificant reduction in the percentage of patients receiving packed red blood cells was observed in the RAP group (44% versus 51% no RAP, P = 0.083). No differences were found between the groups in the number of units of packed red blood cells, platelets, or fresh frozen plasma transfused throughout the perioperative period. These results suggest that overall, RAP does not offer a clinically important benefit as a blood conservation technique.

IMPLICATIONS

Priming of the cardiopulmonary bypass circuit with the patients' own blood (retrograde autologous priming) resulted in insignificant reductions in blood use in a large, unselected group of patients undergoing cardiac surgical procedures.

Meeting the clinical challenge of care for Jehovah’s Witnesses1 1Editor’s Note: This article represents the current position of the Watch Tower Society on the use of blood components and fractions in the care of patients who are Jehovah’s Witnesses

Quality patient care entails more than simply biomedical interventions. Respect for the wishes, values, and preferences of patients are important elements of quality care. Unique aspects of the beliefs of Jehovah's Witnesses may present physicians with ethical and clinical conflicts. Witnesses believe that allogeneic blood transfusion (ie, whole blood, red blood cells, white cells, platelets, and plasma) and preoperative autologous blood deposit (PAD) are prohibited by several Biblical passages. This article reviews the Witness position on medical care, blood components, and fractions, placing these and related interventions into categories that may help physicians to individualize clinical management plans and meet the challenge of caring for patients who are Jehovah's Witnesses. It includes an overview of cost, safety, efficacy, and medicolegal issues related to patient care using transfusion-alternative strategies.

Use of an oxygen therapeutic as an adjunct to intraoperative autologous donation to reduce transfusion requirements in patients undergoing coronary artery bypass graft surgery1 1Members of the Hemolink Study Group are listed in Appendix

BACKGROUND

The benefits of intraoperative autologous donation (IAD) in reducing the need for allogeneic blood transfusion in surgery have been debated for several years. The purpose of this study was to determine if IAD alone or in conjunction with hemoglobin raffimer (HR) confers a reduction in red cell or blood component transfusion compared with results in standard clinical practice.

STUDY DESIGN

The Phase III clinical trial was a multicenter, randomized, double-blind study to determine the efficacy and safety of HR versus 10% pentastarch when used to facilitate IAD in 299 patients undergoing primary coronary artery bypass grafting. The patients received HR or pentastarch as an adjunct to IAD immediately before cardiopulmonary bypass. Results were compared with transfusion requirements for 150 matched patients in the reference group.

RESULTS

The frequency of allogeneic RBC transfusion in the HR, pentastarch, and reference groups was 56%, 76%, and 95%, respectively. The number of allogeneic red cell units used was 49 in the HR group, 104 in the pentastarch group, and 480 in the reference group (p < 0.001). The total number of non-RBC units administered was 150 in the HR group, 238 in the pentastarch group, and 270 in the reference group.

CONCLUSIONS

In this study, patients treated with HR in conjunction with IAD received fewer transfusions overall and a lower volume of allogeneic RBCs and non-RBC allogeneic blood products than did the two comparison groups. This confers a real benefit on the overall blood supply by decreasing use and increasing availability.

Comparison of structured use of routine laboratory tests or near-patient assessment with clinical judgement in the management of bleeding after cardiac surgery

BACKGROUND

Using algorithms based on point of care coagulation tests can decrease blood loss and blood component transfusion after cardiac surgery. We wished to test the hypothesis that a management algorithm based on near-patient tests would reduce blood loss and blood component use after routine coronary artery surgery with cardiopulmonary bypass when compared with an algorithm based on routine laboratory assays or with clinical judgement.

METHODS

Patients (n=102) undergoing elective coronary artery surgery with cardiac bypass were randomized into two groups. In the point of care group, the management algorithm was based on information provided by three devices, the Hepcon, thromboelastography and the PFA-100 platelet function analyser. Management in the laboratory test group depended on rapidly available laboratory clotting tests and transfusion of haemostatic blood components only if specific criteria were met. Blood loss and transfusion was compared between these two groups and with a retrospective case-control group (n=108), in which management of bleeding had been according to the clinician's discretion.

RESULTS

All three groups had similar median blood losses. The transfusion of packed red blood cells (PRBCs) and blood components was greater in the clinician discretion group (P<0.05) but there was no difference in the transfusion of PRBCs and blood components between the two algorithm-guided groups.

CONCLUSION

Following algorithms based on point of care tests or on structured clinical practice with standard laboratory tests does not decrease blood loss, but reduces the transfusion of PRBCs and blood components after routine cardiac surgery, when compared with clinician discretion. Cardiac surgery services should use transfusion guidelines based on laboratory-guided algorithms, and the possible benefits of point of care testing should be tested against this standard.

Predictors of transfusion requirements for cardiac surgical procedures at a blood conservation center

BACKGROUND

Previous studies defining perioperative risk factors for allogeneic transfusion requirements in cardiac surgery were limited to highly selected cardiac surgery populations or were associated with high transfusion rates. The purpose of this study was to determine perioperative risk factors and create a formula to predict transfusion requirements for major cardiac surgical procedures in a center that practices a multimodality approach to blood conservation.

METHODS

We performed an observational study on 307 consecutive patients undergoing coronary artery bypass grafting, valve, and combined (coronary artery bypass grafting and valve) procedures. An equation was derived to estimate the risk of transfusion based on preoperative risk factors using multivariate analysis. In patients with a calculated probability of transfusion of at least 5%, intraoperative predictors of transfusion were identified by multivariate analysis.

RESULTS

Thirty-five patients (11%) required intraoperative or postoperative allogeneic transfusions. Preoperative factors as independent predictors for transfusions included red blood cell mass, type of operation, urgency of operation, number of diseased vessels, serum creatinine of at least 1.3 mg/dL, and preoperative prothrombin time. Intraoperative factors included cardiopulmonary bypass time, three or fewer bypass grafts, lesser volume of acute normovolemic hemodilution removed, and total crystalloid infusion of at least 2,500 mL. The derived formula was applied to a validation cohort of 246 patients, and the observed transfusion rates conformed well to the predicted risks.

CONCLUSIONS

A multimodality approach to blood conservation in cardiac surgery resulted in a low transfusion rate. Identifying patients' risks for transfusion should alter patient management perioperatively to decrease their transfusion rate and make more efficient use of blood resources.

A phase II dose-response study of hemoglobin raffimer (Hemolink) in elective coronary artery bypass surgery

BACKGROUND

We performed this study to determine the dose-response of hemoglobin raffimer administered in conjunction with intraoperative autologous donation in patients undergoing coronary artery bypass grafting surgery. A secondary objective was to evaluate hemoglobin raffimer for reducing the incidence of allogeneic red blood cell transfusions.

METHODS

This was a phase II, single-blind, multicenter, placebo-controlled, open-label study. Patients undergoing coronary artery bypass grafting with cardiopulmonary bypass and intraoperative autologous donation were randomized to receive a single dose of hemoglobin raffimer or control (10% pentastarch). Patients were sequentially enrolled in a dose block of 250, 500, 750, and 1000 mL.

RESULTS

Sixty patients received hemoglobin raffimer (n = 30) or control (n = 30). Hemoglobin raffimer was well tolerated. Most (98%) adverse events were mild or moderate in severity. There was an expected dose-dependent increase in the incidence of blood pressure increases and jaundice in hemoglobin raffimer-treated patients. In a dose-pooled analysis of hemoglobin raffimer versus control, increased blood pressure (43% vs 17%), nausea (37% vs 33%), and atrial fibrillation (37% vs 17%) were the most frequently reported adverse events. All serious adverse events were considered unrelated or unlikely to be related to study drug. No hemoglobin raffimer-treated patient required an intraoperative allogeneic red blood cell transfusion, compared with 5 (17%) pentastarch-treated patients (P =.052). This advantage of hemoglobin raffimer was maintained at 24 hours after surgery (7% vs 37%; P =.010) and up to 5 days after surgery (10% vs 47%; P =.0034).

CONCLUSIONS

Hemoglobin raffimer was not associated with any serious adverse events in patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass and intraoperative autologous donation in a dose-response study up to 1000 mL. Hemoglobin raffimer was effective in facilitating decreased exposure or avoidance of allogeneic red blood cell transfusions when used in conjunction with intraoperative autologous donation.

Blood Use in Patients Undergoing Coronary Artery Bypass Surgery: Impact Of Cardiopulmonary Bypass Pump, Hematocrit, Gender, Age, and Body Weight

We investigated the impact of cardiopulmonary bypass pump (CPB), hematocrit, gender, age, and body weight on blood use in patients undergoing coronary artery bypass graft surgery at a major university hospital. Participants were 1235 consecutive patients undergoing primary coronary artery surgery over a period of 2 yr (1999 and 2000); 681 patients underwent coronary surgery with use of CPB, and 554 patients underwent off-pump coronary artery bypass surgery using a median sternotomy incision. There were 881 males and 354 females. Average packed red blood cells (PRBC) transfusion for patients on CPB was 3.4 U compared with 1.6 U for the off-pump group (P = <0.001). Patients on CPB received more frequent PRBC transfusion (72.5%) compared with 45.7% of off-pump patients (P = <0.001). Average PRBC transfusion for males was 2.2 U compared with 3.6 U for females (P = <0.001). A lower percentage of males (52.6%) than females (79.4%) received transfusion (P = <0.001). The impact of CPB, off-pump status, preoperative hematocrit <35%, gender, age >or=65 yr, and weight <or=83 kilograms using median values as cut points, on blood use was examined using logistic regression models. Use of CPB, preoperative hematocrit, (<35%) female gender, increasing age, and decreased body weight were significant predictors of transfusion (P = <0.001). Preoperative hematocrit <35% and use of CPB were the strongest predictors of PRBC transfusion.

IMPLICATIONS

We examined the impact of cardiopulmonary bypass, preoperative hematocrit, gender, age, and body weight on blood use in patients undergoing primary coronary artery bypass surgery at a tertiary care institution. We found that all five of these variables are significant predictors of blood use in patients undergoing coronary artery bypass surgery.

Institutional variability in transfusion practice for liver transplantation

We prospectively evaluated the institutional variability in perioperative transfusion therapy in orthotopic liver transplantation (OLT). Adult OLTs completed during a 12-mo period were studied until the 48th postoperative hour at 8 centers. A multivariate analysis using mixed-effects logistic regression included variables predisposing to blood loss and a center random effect. In addition, the influence of the calculated perioperative hemoglobin (Hb) loss on the individual probability of receiving red blood cells (RBCs), fresh frozen plasma (FFP), and platelets in excess of the overall median were explored. The analysis was performed on 301 cases. The overall median numbers transfused were 5 RBC units, 6 FFP units, and the median platelet dose was 5.10(11), with significant intercentric differences in the proportions of cases given more than the overall median. Intercentric differences remained significant after adjustment for factors independently associated with a large blood component use. Intercentric differences in RBCs, FFP, and platelet use decreased but persisted after adjustment for the perioperative Hb loss. Intercentric differences in RBC use disappeared after adjustment for the postoperative Hb concentration. The significant heterogeneity in transfusion therapy mandates reassessment of the rational use of blood products in OLT.

Computerized quality assurance of decisions to transfuse blood components to critically ill patients

BACKGROUND

In critically ill patients optimal transfusion therapy for most clinical settings has not been determined. The objective of this study was to evaluate the impact of a computerized audit on transfusion decisions of red blood cells (RBC), fresh frozen plasma (FFP), and platelets among critically ill patients.

METHODS

Two hundred and ninety consecutive patients admitted to nine-bed medical-surgical intensive care unit at a university hospital were included in this prospective study. Prior to the study, the criteria for transfusions of RBCs, FFP and platelets were established. Phase I, the first 3-month period served as a control period. During phase II the fulfilment of these criteria was prospectively monitored by an audit software belonging to the computerized blood request program. If the predefined transfusion criteria were not met the audit software was automatically activated. The last 3-month period, phase III, was to assess if possible effects on transfusion decisions were permanent.

RESULTS

The proportion of RBC transfusions administered according to predefined trigger during the study phases I, II, and III were 55.9%, 75.1% and 67.9%, respectively (P < 0.001). The proportion of FFP and platelet transfusions according to a predefined trigger did not differ statistically significantly between the study phases. Logistic multiple regression analysis revealed an independent effect of the audit phase on the decision to transfuse RBCs and FFP.

CONCLUSIONS

The data suggests that a computerized prospective transfusion audit has impact on the realisation of predefined transfusion decisions.