Institutional variability in red blood cell conservation practices for coronary artery bypass graft surgery. Institutions of the MultiCenter Study of Perioperative Ischemia Research Group

Institutional Red Blood Cell Transfusion Rates Are Correlated Following Endovascular and Surgical Cardiovascular Procedures: Evidence That Local Culture Influences Transfusion Decisions

Background

The relationship between local hospital culture and transfusion rates following endovascular and surgical cardiovascular procedures has not been well studied.

Methods and Results

Patients undergoing coronary revascularization, aortic valve replacement, lower extremity peripheral vascular intervention, or carotid artery revascularization from up to 852 US hospitals in the Nationwide Readmissions Database were identified. Crude and risk‐standardized red blood cell transfusion rates were determined for each procedure. Pearson correlation coefficients were calculated between respective procedural transfusion rates. Median odds ratios were estimated to reflect between‐hospital variability in red blood cell transfusion rates following the same procedure for a given patient. There was wide variation in red blood cell transfusion rates across different procedures, from 2% following carotid endarterectomy to 29% following surgical aortic valve replacement. For surgical and endovascular modalities, transfusion rates at the same hospital were highly correlated for aortic valve replacement (r=0.67; P<0.001), moderately correlated for coronary revascularization (r=0.56; P<0.001) and peripheral vascular intervention (r=0.51; P<0.001), and weakly correlated for carotid artery revascularization (r=0.19, P<0.001). Median odds ratios were all >2, highest for coronary artery bypass graft surgery and surgical aortic valve replacement, indicating substantial site variation in transfusion rates.

Conclusions

After adjustment for patient‐related factors, wide variation in red blood cell transfusion rates remained across surgical and endovascular procedures employed for the same cardiovascular condition. Transfusion rates following these procedures are highly correlated at individual hospitals and vary widely across hospitals. In aggregate, these findings suggest that local institutional culture significantly influences the decision to transfuse following invasive cardiovascular procedures and highlight the need for randomized data to inform such decisions.

Postoperative Critical Care of the Adult Cardiac Surgical Patient. Part I: Routine Postoperative Care

OBJECTIVES

Cardiac surgery, including coronary artery bypass, cardiac valve, and aortic procedures, is among the most common surgical procedures performed in the United States. Successful outcomes after cardiac surgery depend on optimum postoperative critical care. The cardiac intensivist must have a comprehensive understanding of cardiopulmonary physiology and the sequelae of cardiopulmonary bypass. In this concise review, targeted at intensivists and surgeons, we discuss the routine management of the postoperative cardiac surgical patient.

DATA SOURCE AND SYNTHESIS

Narrative review of relevant English-language peer-reviewed medical literature.

CONCLUSIONS

Critical care of the cardiac surgical patient is a complex and dynamic endeavor. Adequate fluid resuscitation, appropriate inotropic support, attention to rewarming, and ventilator management are key components. Patient safety is enhanced by experienced personnel, a structured handover between the operating room and ICU teams, and appropriate transfusion strategies.

The role of perioperative transfusion on long-term survival of veterans undergoing surgery

OBJECTIVE

To examine the influence of perioperative blood transfusions on perioperative outcomes and late survival.

BACKGROUND

Perioperative blood transfusion has been reported to have a negative impact on perioperative morbidity but its long-term effect on survival is unknown. The purpose of this study was to evaluate the effects of perioperative transfusion on perioperative outcomes and survival.

METHODS

We studied 12,345 surgical procedures from Veteran Administration Surgical Quality Improvement Program database from July 1998 through 2010. Patients with transfusion were compared with a severity-matched control group. We performed the Fisher exact test for comparison of categorical values and Wilcoxon rank sum test for continuous values. Multivariate regression was used to eliminate other confounding factors. The predictive value of multivariate risk model was tested with receiver-operator curves. Patients were matched using an optimal 1:1 digit-matching algorithm. All analyses were performed with NCSS-2007 version 1-12. P < 0.05 was considered statistically significant.

RESULTS

The 848 patients who received perioperative transfusions had higher unadjusted rates of mortality and decreased long-term survival. The odds ratio (OR) for 10 years mortality in transfused group was 2.92 and after adjusting for preoperative risk factors decreased to 1.40 (P < 0.01). However, after data were filtered for any perioperative complications, such an association was seen before, OR = 2.05 (P = 0.006), and was lost after propensity matching, OR = 1.19 (P = 0.35).

CONCLUSIONS

After filtering out perioperative complications and adjusting for preoperative morbidity, our final analysis did not reveal an increased long-term mortality. We conclude that transfusion may reduce long-term survival through its effects on perioperative complications.

Hemoglobin Level to Facilitate Off-Pump Coronary Artery Bypass without Transfusion

BACKGROUND

Conservation of blood during cardiac surgery is important because of the shortage of donor blood, risks associated with transfusion, and the costs of allogeneic blood products. This retrospective study explored the feasibility of off-pump coronary artery bypass (OPCAB) without transfusion.

METHODS

One hundred and two consecutive patients underwent OPCAB from January 2007 to June 2012 at Hallym University Sacred Heart Hospital. Excluding 10 chronic renal failures patients, 102 patients were enrolled. Their characteristics, clinical data, and laboratory data were analyzed. We investigated the success rate of OPCAB without transfusion according to pre-operative hemoglobin (Hb), and the cutoff point of the Hb level and the risk factors for transfusion. We implemented multidisciplinary blood-saving protocols.

RESULTS

The overall operative mortality and the success rate of OPCAB without transfusion were 2.9% (3/102) and 73.5% (75/102). The success rates in patients with Hb<11, 11 <Hb<14, and 14<Hb were 35.0%, 79.2%, and 89.7% (p=0.01), respectively. The risk factors for transfusion are age>70 years, diagnosis of acute myocardial infarction, preoperative Hb and creatinine levels, and operation time. The events precipitating the need for transfusion were low Hb level in 9 patients and hypotension or excessive bleeding in 18 patients.

CONCLUSION

The preoperative Hb level of >11 facilitates OPCAB without transfusion. These results suggest that transfusion-free OPCAB can be performed by modifying the risk factors and correctable causes of transfusion and improving various blood salvage methods.

Effect of hospital culture on blood transfusion in cardiac procedures

BACKGROUND

In our effort to reduce the use of blood products in cardiac operations in a health care system, we noted variations in transfusion practices among facilities. Interestingly, surgeons practicing at the same hospital had similar transfusion rates. We sought to quantitate the contribution of hospital influence on individual surgeons' transfusion practices.

METHODS

Blood transfusion data for coronary artery bypass graft operations at 12 Providence Health & Services facilities between January 2008 and June 2011 were reviewed. Frequency of perioperative blood transfusion, amount of transfusion, components transfused, and timing of transfusions were compared. Variation among surgeons at the same institution vs between institutions was computed based on multilevel mixed-effect logistic and linear regression models. Intraclass correlation coefficients were calculated.

RESULTS

A total of 5,744 nonemergency first-time coronary artery bypass graft procedures were performed by 42 not-low volume (n>30 in 2.5 years) surgeons at 12 Providence Health & Services hospitals during the 3.5-year study period. Frequency, amount, timing, and blood component usage were different among facilities but relatively similar for surgeons within a facility. The variance of red blood cell transfusion rate among hospitals (.82) is more than two times that among surgeons practicing within the same hospital (.35). Thus, surgeons contribute 30% to the variation, and 70% of the total variation can be explained by the hospital effect.

CONCLUSIONS

In our multihospital system, the hospital that a surgeon practices at plays a larger role in determining blood utilization than the individual surgeon's preference.

Timing and incidence of postoperative infections associated with blood transfusion: analysis of 1,489 orthopedic and cardiac surgery patients

BACKGROUND

Transfusion rates remain high in cardiac and orthopedic surgery and differ widely across physician practices in spite of growing knowledge that allogeneic blood transfusion (ABT) is associated with a risk of postoperative infection.

METHODS

This prospective observational study compared the timing and incidence of ABT-associated postoperative infections (PIs) in 1,489 orthopedic or cardiac surgery patients at nine hospitals.

RESULTS

Of 455 cardiovascular and 1,034 orthopedic surgery patients, 415 (55.6% of the cardiovascular patients and 15.7% of the orthopedic patients) were given ABT. The overall rate of PI during hospitalization was 5.8%. The relative risk of PI was 3.6-fold greater after ABT (50 patients; 12.1%) than in patients not having ABT (36 patients; 3.4%; 95% confidence interval 2.4, 5.4; p = 0.001). Postoperative infections appeared both during hospitalization (n = 86) and within four weeks after discharge (n = 81).

CONCLUSIONS

Patients should be followed for as long as four weeks after discharge to determine the true incidence and risk of ABT-associated PI.

Postoperative blood loss and transfusion associated with use of Hextend in cardiac surgery patients at a blood conservation center

BACKGROUND

Hydroxyethyl starch (HES) solutions are readily available colloids, but their widespread use is shadowed by controversies surrounding their effects on bleeding. This retrospective study was conducted to evaluate the relationship between Hextend (HEX; Hospira, Inc.) doses of 1 to 20 mL/kg and allogeneic transfusion and 24-hour chest tube drainage (CTD) in cardiac surgeries at a blood conservation center.

STUDY DESIGN AND METHODS

After institutional review board approval, data on 748 patients undergoing coronary artery bypass grafting (CABG), valve, or combined CABG and valve surgeries were collected. Cases not receiving HEX (due to contraindications, e.g., renal failure, bleeding diathesis) or receiving more than 20 mL per kg HEX, not accepting transfusions, or requiring more extensive surgery were excluded, and the remaining 621 cases were analyzed.

RESULTS

Overall transfusion rate and mean CTD were 12.7 percent and 460.4 mL, respectively. Patients who received transfusions received more HEX (10.8 mL/kg vs. 9.8 mL/kg; p = 0.043) but HEX per kg was not associated with higher transfusion rates in multivariate analysis (p = 0.077). HEX per kg was associated with CTD in both uni- and multivariate analyzes (p < 0.001) with 1.66 percent increase in CTD for every 1 mL per kg increase in HEX.

CONCLUSIONS

Although HEX was associated with transfusion in univariate analysis and with CTD in uni- and multivariate analysis, the former was no longer significant when adjusted for other predictors of transfusion in our selected patient population at a blood conservation center. The clinical significance of the observed increase in CTD remains undetermined. To minimize transfusion and bleeding in these patients, it is recommended that HEX be used in amounts of not more than 20 mL per kg together with point-of-care coagulation tests and other blood conservation strategies.

Blood management: a primer for clinicians

Blood transfusions are common in the hospital setting. Despite the large commitment of resources to the delivery of blood components, many clinicians have only a vague understanding of the complexities associated with blood management and transfusion therapy. The purpose of this primer is to broaden the awareness of health care practitioners in terms of the risks versus benefits of blood transfusions, their economics, and alternative treatments. By developing and implementing comprehensive blood management programs, hospitals can promote safe and clinically effective blood utilization practices. The cornerstones of blood management programs are the implementation of evidence-based transfusion guidelines to reduce variability in transfusion practice, and the employment of multidisciplinary teams to study, implement, and monitor local blood management strategies. Pharmacists can play a key role in blood management programs by providing technical expertise as well as oversight and monitoring of pharmaceutical agents used to reduce the need for allogeneic blood.

Erythropoietic therapy: Cost efficiency and reimbursement

PURPOSE

The practice of blood conservation is aimed at improving patient outcomes by avoiding allogeneic transfusions via a coordinated multidisciplinary, multipronged approach. The numerous blood conservation techniques and transfusion alternatives now available are described.

SUMMARY

Ongoing concerns exist regarding the availability of the nation's and the world's blood supply. In addition, the number of measures required to ensure blood safety has led to increases in the price of blood and blood products over the past 10-15 years. Moreover, blood transfusion carries inherent risks even under the most favorable circumstances. Investigations have established that injudicious transfusion is associated with development of ventilator-associated pneumonia, nosocomial infection, and organ dysfunction. Because most single blood-conservation techniques reduce blood usage by a mere 1-2 units, a series of integrated conservation approaches are required. These include preoperative autologous donation, use of erythropoietic agents, blood conservation techniques such as 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. Erythropoietic agents such as epoetin alfa have been used successfully to increase hemoglobin and decrease transfusion requirements, and are appropriate when used in advance of elective surgical procedures. Acquisition costs of erythropoietic stimulating agents versus costs of blood justify economic evaluation by hospitals to make the most cost-effective choice under current economic constraints.

CONCLUSION

Initiating a blood management program requires planning and support from those who are concerned about blood usage reduction and outcomes improvement. Launching a vigorous and ongoing educational program to raise awareness about the risks and hazards associated with blood transfusion is an important step in helping to reshape the medical staffs' attitudes about transfusion and the most cost-effective way to achieve clinical goals.

Klinische Aspekte der Therapie mit Erythrozyten

With the decreased risk of homologous blood transfusions, the costs of blood products have become increasingly important for hospitals with major surgical procedures and oncologic treatment. It is well established from clinical physiology that a hemoglobin concentration (cHb) lower than 6.21 mmol/l (10 g/dl) is enough to serve the oxygen demand of the tissues, but transfusion of erythrocytes is still liberally carried out. Data obtained from Jehovah's Witnesses, who categorically refuse blood transfusions, demonstrate that they have an outcome similar to patients who are transfused. The lessons we have learned from Jehovah's Witnesses should result in an emotionless discussion, and a reduction in transfusion requirements.

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.

Factors predicting loss and gain of red cell volume in cardiac surgery patients

Haemoglobin may be a poor indicator of changes in red cell volume (RCV) because of factors such as haemodilution. This study has been designed to analyse what peri-operative variables may be associated with loss or gain in RCV due to bleeding or transfusion. Prospective observational study. Single centre study based in a regional cardiac surgery centre. Twenty-nine elective adult cardiac surgery patients. Loss and gain of RCV were measured in theatre and for the first 24 h post-operatively. Patient and operative factors analysed were age, sex, height, weight, body surface area (BSA), induction haematocrit (Hct), estimated pre-operative RCV and antiplatelet therapy taken less than 7 days before operation, cardiopulmonary bypass (CPB) time, aortic occlusion time, minimum and maximum CPB temperatures and fluid administered. Age, sex, height, weight, BSA and induction Hct were found to predict red cell transfusion but not RCV loss. The total number of red cells transfused was significantly associated with RCV lost when expressed as a percentage reduction in the estimated pre-operative RCV but not the absolute RCV lost. Pre-operative RCV, as predicted by the variables outlined above, is more important than RCV lost in triggering red cell transfusion.

The risk associated with aprotinin in cardiac surgery

BACKGROUND

The majority of patients undergoing surgical treatment for ST-elevation myocardial infarction receive antifibrinolytic therapy to limit blood loss. This approach appears counterintuitive to the accepted medical treatment of the same condition--namely, fibrinolysis to limit thrombosis. Despite this concern, no independent, large-scale safety assessment has been undertaken.

METHODS

In this observational study involving 4374 patients undergoing revascularization, we prospectively assessed three agents (aprotinin [1295 patients], aminocaproic acid [883], and tranexamic acid [822]) as compared with no agent (1374 patients) with regard to serious outcomes by propensity and multivariable methods. (Although aprotinin is a serine protease inhibitor, here we use the term antifibrinolytic therapy to include all three agents.)

RESULTS

In propensity-adjusted, multivariable logistic regression (C-index, 0.72), use of aprotinin was associated with a doubling in the risk of renal failure requiring dialysis among patients undergoing complex coronary-artery surgery (odds ratio, 2.59; 95 percent confidence interval, 1.36 to 4.95) or primary surgery (odds ratio, 2.34; 95 percent confidence interval, 1.27 to 4.31). Similarly, use of aprotinin in the latter group was associated with a 55 percent increase in the risk of myocardial infarction or heart failure (P<0.001) and a 181 percent increase in the risk of stroke or encephalopathy (P=0.001). Neither aminocaproic acid nor tranexamic acid was associated with an increased risk of renal, cardiac, or cerebral events. Adjustment according to propensity score for the use of any one of the three agents as compared with no agent yielded nearly identical findings. All the agents reduced blood loss.

CONCLUSIONS

The association between aprotinin and serious end-organ damage indicates that continued use is not prudent. In contrast, the less expensive generic medications aminocaproic acid and tranexamic acid are safe alternatives.

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.

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.

Safety and efficacy of perioperative cell salvage and autotransfusion after coronary artery bypass grafting: a randomized trial

BACKGROUND

The aim of this study was to ascertain whether cell salvage and autotransfusion after first time elective coronary artery bypass grafting is associated with a significant reduction in the use of homologous blood, a clinically significant derangement of postoperative clotting profiles, or an increased risk of postoperative bleeding.

METHODS

Patients were randomized to autotransfusion (n = 98) receiving autotransfused washed blood from intraoperative cell salvage and postoperative mediastinal fluid cell salvage after coronary artery bypass surgery or control (n = 102) receiving stored homologous blood only after coronary artery bypass surgery.

RESULTS

There was no statistical difference between the groups in terms of demographics, comorbidity, risk stratification, or operative details. Mean volume of blood autotransfused was 367 +/- 113 mL. Patients in the autotransfusion group were significantly less likely to receive a homologous blood transfusion compared with controls (odds ratio 0.40, 95% confidence interval [CI] 0.22-0.71) and received significantly fewer units of blood per patient compared with controls (0.43 +/- 1.5 vs 0.90 +/- 2.0 U, p = 0.02). There was no difference between the groups in terms of postoperative blood loss, fluid requirements, blood product requirements, or in the incidence of adverse clinical events (p = NS chi(2)). Autotransfusion did not produce any significant derangement of thromboelastograph values or laboratory measures of clotting pathway function (prothrombin time, activated partial thromboplastin time, fibrinogen, and fibrinogen D-dimer levels) when compared with the effect of homologous blood transfusion (p = NS, repeated measures analysis of variance [MANOVA]).

CONCLUSIONS

Autotransfusion is a safe and effective method of reducing the use of homologous bank blood after routine first time coronary artery bypass grafting.

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.

Post-operative course of coronary artery bypass surgery patients who pre-donate autologous blood

BACKGROUND

Pre-operative autologous blood donation is used to reduce the need of allogeneic blood in patients undergoing coronary bypass surgery operations, but it is not clear what impact the blood donation has on the post-operative course of these patients.

METHODS

We studied the post-operative course of 210 patients who pre-donated autologous blood before their coronary bypass operation (donors) and of 67 patients who were eligible to pre-donate but did not (controls).

RESULTS

The clinical variables and the technical operative parameters of the patients in the two groups were similar. There was no significant difference between the duration of assisted ventilation post-operatively (756 +/- 197 vs. 802 +/- 395 min; P=0.54) or length of stay in the intensive care unit (1.8 +/- 1.1 vs. 1.7 +/- 0.9 days; P=0.52) of the two groups. The number of autologous units of packed red cells and of fresh frozen plasma (FFP) received by the donors was significantly higher than the number of units of allogeneic packed red cells (1.5 +/- 0.9 vs. 0.3 +/- 0.9; P=0.001) and the units of homologous FFP received by the controls (2.3 +/- 0.8 vs. 0.6 +/- 1; P=0.001).

CONCLUSIONS

We found no evidence that autologous blood donation exerted a negative influence on the post-operative course of patients undergoing coronary bypass surgery. Patients who pre-donated blood received no allogeneic blood products, but the number of autologous blood products received by donors was higher than the number of blood products received by patients who did not pre-donate.

Factor V Leiden protects against blood loss and transfusion after cardiac surgery

BACKGROUND

The outcome of cardiac surgery is influenced by several factors, but the impact of specific genetic variants has not been systematically explored. Because blood conservation is a pressing issue in cardiac surgery, we tested the hypothesis that factor V Leiden (FVL), a common coagulation factor polymorphism, may protect against blood loss and transfusion in patients undergoing cardiac surgery.

METHODS AND RESULTS

We enrolled 517 patients undergoing cardiac surgery, including 26 heterozygous FVL carriers, and evaluated the impact of FVL on chest tube output and transfusion by using univariate and multivariate techniques. For patients with FVL, blood loss at 6 (238+/-131 mL) and 24 hours (522+/-302 mL) was significantly lower than that for noncarriers (358+/-259 mL and 730+/-452 mL; P<0.001 and P=0.001, respectively). In a multivariate regression analysis, controlling for ethnicity and factors known to affect blood loss, FVL was a significant independent contributor at both time points. Using a similar regression approach, FVL did not have a significant effect on the number of units transfused. However, logistic regression of the risk of receiving any transfusion during hospitalization demonstrated a significant independent protective effect of FVL on overall transfusion risk.

CONCLUSIONS

FVL represents a common genetic trait that may protect against blood loss and transfusion in this population. This study demonstrates that genetic variability can affect the outcome of cardiac surgery.

Autologous blood transfusion in the United States: clinical and nonclinical determinants of use

BACKGROUND

Preoperative donation of blood lowers the risk of allogeneic RBC transfusion. The use of autologous blood is not well quantified. This study aimed at identifying the frequency and determinants of use of autologous transfusion in the United States.

STUDY DESIGN AND METHODS

This national cross-sectional study, using the Nationwide Inpatient Sample, included all patients admitted to 900 hospitals in 19 states in 1996. Logistic regression with weighting yielded nationally representative results for the independent effects of clinical and nonclinical patient characteristics on autologous blood use.

RESULTS

Autologous transfusion was used in 19 of 1000 hospitalizations. The procedures using autologous blood most frequently were knee arthroplasty, hip replacement, prostatectomy, spinal fusion, and hysterectomy. Blacks and Hispanics were less likely to receive autologous transfusion than were whites (OR, 0. 64; 95% CI, 0.45-0.83); patients with Medicaid were less likely than the privately insured to receive autologous transfusions (OR, 0.29; 95% CI, 0.20-0.43), with racial differences greatest among the privately insured. Women received autologous blood for cardiovascular surgeries much less often than men (OR, 0.32; 95% CI, 0.20-0.49).

CONCLUSION

Ethnic minorities, women, and patients with Medicaid appear to receive fewer autologous blood transfusions than the rest of the population. Although this could reflect either better or worse quality of care, nonclinical determinants of transfusion practice warrant attention and further investigation.