Predictors of packed red cell transfusion after isolated primary coronary artery bypass grafting--the experience of a single cardiac center: a prospective observational study

Evaluation of plasma fibrinogen levels before and after coronary artery bypass graft surgery and its association with the need for blood products

Background:

The present study investigated the plasma level of fibrinogen before and after removing the pump in coronary artery bypass graft (CABG) surgery and its relationship with the need for blood products.

Materials and Methods:

The present study was performed on 60 patients who were candidates for CABG surgery. The fibrinogen level of these patients was assessed and recorded before surgery and immediately after removing the pump. In addition, their hemoglobin level was recorded before the operation and 2 h after. In addition, the number and type of blood products transfusion were recorded intraoperatively and postoperatively and also at the intensive care unit.

Results:

Patients’ fibrinogen level after removing the pump with the mean of 130.53 ± 122.01 mg/dl decreased significantly compared to before surgery with the mean of mg/dl 224.95 ± 132.88 mg/dl (P < 0.001). In addition, the prognostic value of fibrinogen after removing the pump in determining the postoperative need of blood transfusion showed that the cut-off value of fibrinogen was < 196 mg/dl with a sensitivity of 16.82% and specificity of 80%, but it was not statistically significant (area under the curve [95% confidence interval]: 0.519 [0.350–0.689]; P = 0.825).

Conclusion:

According to the results of the present study, due to significant changes in fibrinogen levels after removing the pump compared to preoperation, it seems that this factor can play an important role in prognosis of the need to postoperative blood transfusion, although the prognostic value and the critical point mentioned in our study was not significant and it is required to do further studies.

Risk-Prediction Model for Transfusion of Erythrocyte Concentrate During Extracorporeal Circulation in Coronary Surgery

INTRODUCTION

Our objective was to identify preoperative risk factors and to develop and validate a risk-prediction model for the need for blood (erythrocyte concentrate [EC]) transfusion during extracorporeal circulation (ECC) in patients undergoing coronary artery bypass grafting (CABG).

METHODS

This is a retrospective observational study including 530 consecutive patients who underwent isolated on-pump CABG at our Centre over a full two-year period. The risk model was developed and validated by logistic regression and bootstrap analysis. Discrimination and calibration were assessed using the area under the receiver operating characteristic curve (AUC) and the Hosmer-Lemeshow (H-L) test, respectively.

RESULTS

EC transfusion during ECC was required in 91 patients (17.2%). Of these, the majority were transfused with one (54.9%) or two (41.8%) EC units. The final model covariates (reported as odds ratios; 95% confidence interval) were age (1.07; 1.02-1.13), glomerular filtration rate (0.98; 0.96-1.00), body surface area (0.95; 0.92-0.98), peripheral vascular disease (3.03; 1.01-9.05), cerebrovascular disease (4.58; 1.29-16.18), and hematocrit (0.55; 0.48-0.63). The risk model developed has an excellent discriminatory power (AUC: 0,963). The results of the H-L test showed that the model predicts accurately both on average and across the ranges of deciles of risk.

CONCLUSIONS

A risk-prediction model for EC transfusion during ECC was developed, which performed adequately in terms of discrimination, calibration, and stability over a wide spectrum of risk. It can be used as an instrument to provide accurate information about the need for EC transfusion during ECC, and as a valuable adjunct for local improvement of clinical practice. Key Findings: Risk factors with the greatest prediction for EC transfusion. Take-Home Message: The implementation of this model would be an important step in optimizing and improving the quality of surgery.

Frequency of Blood Transfusion in Elective Coronary Artery Bypass Grafting and Its Correlation With Acute Kidney Injury at a Tertiary Care Hospital in a Lower Middle-Income Country

Background

Blood transfusion remains a significant management aspect in various cardiac surgical procedures including coronary artery bypass grafting (CABG). These patients have a reportedly high incidence of transfusion of blood products. It varies considerably amongst different institutions; most variability being seen in the transfusion trigger. This case series enumerate the frequency of administration of blood products in patients during elective CABG and its association with acute kidney injury (AKI) and ascertain whether blood transfusion is justifiable at a tertiary care hospital.

Materials and methods

Using non-probability consecutive sampling, 172 patients were enrolled in the study. Patient’s preoperative hemoglobin and creatinine, intraoperative hemoglobin, transfusion trigger, number of transfusions (whole blood and packed RBCs-PRBCs), postoperative hemoglobin and creatinine in the ICU and number of transfusions in the first 24 hours were recorded.

Results

Out of the 172 patients, 96 (55.81%) patients received blood transfusion and 73 (42.69%) patients suffered from AKI. 45 (61.64%) patients with AKI received transfusion whereas 28 (38.36%) patients had no transfusion. Of these 96 patients, 45 (46.8%) received transfusion intra-operatively, 24 (25%) patients received both intra-operatively and post-operatively while 27 (28.2%) patients were transfused postoperatively. Majority of the patients, 46 (88.3%), received unjustifiable transfusion (Hb >8 g/dl) during the first 24 hours post-operatively.

Conclusion

There is marked divergence in the peri-operative use of blood products that remain on a loco-regional as well as international basis. A standardized and a multidisciplinary strategy as well as robust institutional regulation would significantly reduce inappropriate patient exposure to blood products.

Adverse Outcomes of Perioperative Red Blood Cell Transfusions in Coronary Artery Bypass Grafting in Hospital Universiti Sains Malaysia

BACKGROUND

Perioperative red blood cell (RBC) transfusion in coronary artery bypass grafting (CABG) has both benefits and harms. Our aim was to study the association between perioperative RBC transfusion and its adverse outcomes.

METHODS

This was a retrospective study of patients who underwent isolated CABG in Hospital Universiti Sains Malaysia, Kelantan, Malaysia, from 1 January 2013 until 31 December 2017. Data were collected from medical records, and comparisons were made between patients who received perioperative RBC transfusions and those who did not have adverse outcomes after CABG.

RESULTS

A total of 108 patients who underwent isolated CABG were included in our study, and 78 patients received perioperative RBC transfusions. Patients who received perioperative RBC transfusions compared to those who did not were significantly more likely to develop prolonged ventilatory support (21.8% versus 0%, P = 0.003), cardiac morbidity (14.1% versus 0%, P = 0.032), renal morbidity (28.2% versus 3.3%, P = 0.005) and serious infection (20.5% versus 3.3%, P = 0.037). With each unit of packed RBC transfusions, there was a significantly increased risk of prolonged ventilatory support (adjusted odds ratio [AOR] = 1.45; 95% confidence interval [CI] = 1.20-1.77; P < 0.001), cardiac morbidity (AOR =1.40; 95%CI = 1.01-1.79; P = 0.007), renal morbidity (AOR = 1.23; 95%CI = 1.03-1.45; P = 0.019) and serious infection (AOR = 1.31; 95%CI = 1.07-1.60; P = 0.009).

CONCLUSION

Perioperative RBC transfusion in isolated CABG patients is associated with increased risks of developing adverse events such as prolonged ventilatory support, cardiac morbidity, renal morbidity and serious infection.

Risk of massive blood product requirement in cardiac surgery: A large retrospective study from 2 heart centers

Cardiac surgery under cardiopulmonary bypass (CPB) accounts for most consumption of red blood cells (RBCs). Identifying risk factors for massive red blood cell transfusion (MRT) in cardiac surgery may help to reduce this consumption.We retrospectively analyzed 8238 patients who underwent valve surgery and/or coronary artery bypass grafting (CABG) under CPB at 2 major heart centers in China. Uni- and multivariate logistic regression was carried out to assess whether risk factors for MRT (defined as receiving at least 4 units RBCs) varied with type of cardiac surgery.A total of 1691 patients (21%) received at least 4 units RBCs (6.77 ± 4.78 units per person). This MRT group consumed 70% of the total units of allogeneic RBCs in the study. MRT incidence was 2-fold higher among patients undergoing CABG with or without valve surgery than among patients undergoing valve surgery alone. Multivariate logistic analysis identified the following MRT risk factors common to valve surgery alone, CABG alone, and their combination: female sex, older age, renal dysfunction, lower body mass index, lower preoperative hemoglobin, and longer CPB. Several independent MRT risk factors were also identified specific to valve surgery: active endocarditis, nonatrial fibrillation, smaller left atrium diameter, abnormal international normalized ratio, and repeat surgery.Different types of cardiac surgery share several, but not all, MRT risk factors. This study may help guide the prediction and management of patients at higher MRT risk.

Factors influencing transfusion requirement in patients undergoing first-time, elective coronary artery bypass graft surgery

CONTEXT

Coronary artery bypass graft (CABG) operation is associated with high frequency of allogeneic blood transfusion due to the acquired hemostatic challenges in patients undergoing CABG. However, allogeneic blood transfusion carries risks of infection, adverse reaction, and mortality as well as prolonged hospital stay and increased hospital cost. It is important to identify patients who require blood transfusion to mitigate their risk factors and reduce the chance of exposure to allogeneic blood.

AIMS

This study was conducted to evaluate factors that influence the decision to transfuse red cell in first-time elective CABG patients.

SETTINGS AND DESIGN

This was a cross-sectional study based on a retrospective record review. The study was done in the National Heart Institute.

MATERIALS AND METHODS

All patients who underwent first-time elective CABG were included in this study. Variables analyzed include age, gender, body weight, preoperative hemoglobin (Hb) level, patients' comorbidities, and other clinical parameters.

STATISTICAL ANALYSIS USED

Data were analyzed using SPSS software version 20.

RESULTS

A total of 463 patients underwent first-time elective CABG during the period of the study. Three hundred and eighty-six (83.4%) patients received red cell transfusion. From multiple logistic regression analysis, only age (odds ratio [OR] = 1.040, 95% confidence interval [CI]: 1.003, 1.077, P = 0.032), body weight (OR = 0.951, 95% CI: 0.928, 0.974, P < 0.001), Hb level (OR = 0.500, 95% CI: 0.387, 0.644, P < 0.001), and cardiopulmonary bypass time (OR = 1.013, 95% CI: 1.004, 1.023, P < 0.001) were the significant independent predictors of red cell transfusion.

CONCLUSIONS

By stratifying patients according to their risk factor for red cell transfusion, the high-risk patients could be recognized and should be enrolled into effective patient blood management program to minimize their risk of exposure to allogeneic blood transfusion.

Benchmarking the use of blood products in cardiac surgery to stimulate awareness of transfusion behaviour : Results from a four-year longitudinal study

Introduction

Cardiac operations account for a large proportion of the blood transfusions given each year, leading to high costs and an increased risk to patient safety. Therefore, it is important to explore initiatives to reduce transfusion rates. This study aims to provide a benchmark for transfusion practice by inter-hospital comparison of transfusion rates, blood product use and costs related to patients undergoing coronary artery bypass grafting (CABG), valve surgery or combined CABG and valve surgery.

Methods

Between 2010 and 2013, patients from four Dutch hospitals undergoing CABG, valve surgery or combined CABG and valve surgery (n = 11,150) were included by means of a retrospective longitudinal study design.

Results

In CABG surgery the transfusion rate ranged between 43 and 54%, in valve surgery between 54 and 67%, and in combined CABG and valve surgery between 80 and 88%. With the exception of one hospital, the trend in transfusion rate showed a significant decrease over time for all procedures. Hospitals differed significantly in the units of blood products given to each patient, and in the use of specific transfused combinations of blood products, such as red blood cells (RBCs) and a combination of RBCs, fresh frozen plasma (FFP) and platelets.

Conclusion

This study indicates that benchmarking blood product usage stimulates awareness of transfusion behaviour, which may lead to better patient safety and lower costs. Further studies are warranted to improve awareness of transfusion behaviour and increase the standardisation of transfusion practice in cardiac surgery.

Predictors of red blood cell transfusion after cardiac surgery: a prospective cohort study

OBJECTIVE

To identify predictors of red blood cell transfusion (RBCT) after cardiac surgery.

METHOD

A prospective cohort study performed with 323 adults after cardiac surgery, from April to December of 2013. A data collection instrument was constructed by the researchers containing factors associated with excessive bleeding after cardiac surgery, as found in the literature, for investigation in the immediate postoperative period. The relationship between risk factors and the outcome was assessed by univariate analysis and logistic regression.

RESULTS

The factors associated with RBCT in the immediate postoperative period included lower height and weight, decreased platelet count, lower hemoglobin level, higher prevalence of platelet count <150x10(3)/mm (3), lower volume of protamine, longer duration of anesthesia, higher prevalence of intraoperative RBCT, lower body temperature, higher heart rate and higher positive end-expiratory pressure. The independent predictor was weight <66.5Kg.

CONCLUSION

Factors associated with RBCT in the immediate postoperative period of cardiac surgery were found. The independent predictor was weight.

Risk factors related to transfusion requirements in patients undergoing implantation of ventricular assist devices

OBJECTIVE

The identification of transfusion risk factors in patients receiving left ventricular assist devices to allow for targeted use of blood conservation strategies and improved blood utilization.

DESIGN

This is a retrospective analysis of prospectively collected data between April 2009 and June 2012. Linear regression was used to determine factors associated with increased transfusion. Logistic regression was used to determine factors that were associated with more than the median number of units transfused.

SETTING

Single center, university hospital.

PARTICIPANTS

Patients (n=144) who underwent left ventricular assist device implantation.

INTERVENTION

Transfused blood product data for the day of surgery and for 3 days after were obtained from the blood bank.

MEASUREMENTS AND MAIN RESULTS

Beta-blockers were associated with 1.7±0.65 fewer red blood cell (RBC) units and 2.2±0.7 fewer fresh frozen plasma units transfused. Each year of older age was associated with 0.113±0.023 units of RBC, 0.543±0.101 platelet, and 0.098±0.017 plasma units transfused. International normalized ratio was associated with more platelet transfusion (20.813±5.757 units per 1.0 increase), but not with plasma or RBC transfusion. Lower platelet counts were associated with both platelet (-0.045±0.019 units per 10,000 μL(-1)) and plasma transfusions (-0.011±0.004). Myocardial infarction was associated with increased RBC and plasma transfusion, and cardiogenic shock was associated with increased platelet transfusions, but nitrate use was associated with reduced platelet transfusion.

CONCLUSION

Beta-blockers may be a modifiable factor to decrease transfusions. The association between international normalized ratio and platelet transfusions suggests that better determination of the type of coagulopathy may promote more appropriate transfusions.

Predicting red blood cell transfusion in hospitalized patients: role of hemoglobin level, comorbidities, and illness severity

Background

Randomized controlled trial evidence supports a restrictive strategy of red blood cell (RBC) transfusion, but significant variation in clinical transfusion practice persists. Patient characteristics other than hemoglobin levels may influence the decision to transfuse RBCs and explain some of this variation. Our objective was to evaluate the role of patient comorbidities and severity of illness in predicting inpatient red blood cell transfusion events.

Methods

We developed a predictive model of inpatient RBC transfusion using comprehensive electronic medical record (EMR) data from 21 hospitals over a four year period (2008-2011). Using a retrospective cohort study design, we modeled predictors of transfusion events within 24 hours of hospital admission and throughout the entire hospitalization. Model predictors included administrative data (age, sex, comorbid conditions, admission type, and admission diagnosis), admission hemoglobin, severity of illness, prior inpatient RBC transfusion, admission ward, and hospital.

Results

The study cohort included 275,874 patients who experienced 444,969 hospitalizations. The 24 hour and overall inpatient RBC transfusion rates were 7.2% and 13.9%, respectively. A predictive model for transfusion within 24 hours of hospital admission had a C-statistic of 0.928 and pseudo-R2 of 0.542; corresponding values for the model examining transfusion through the entire hospitalization were 0.872 and 0.437. Inclusion of the admission hemoglobin resulted in the greatest improvement in model performance relative to patient comorbidities and severity of illness.

Conclusions

Data from electronic medical records at the time of admission predicts with very high likelihood the incidence of red blood transfusion events in the first 24 hours and throughout hospitalization. Patient comorbidities and severity of illness on admission play a small role in predicting the likelihood of RBC transfusion relative to the admission hemoglobin.

BMI Is an Independent Preoperative Predictor of Intraoperative Transfusion and Postoperative Chest-Tube Output

Background An increasing obese population in the United States focuses attention on perioperative management of obese and overweight patients. Objective We sought to determine if obesity, determined by body mass index (BMI), was a preoperative indicator of bleeding in coronary artery bypass graft (CABG) surgery as measured by intraoperative packed red blood cell transfusion frequency and 24-hour chest-tube output amount. Methods A retrospective chart review examined 290 consecutive patients undergoing single-surgeon off-pump or on-pump CABG surgery between November 2003 and April 2009. Preoperative variables of age, gender, hematocrit, platelet count, and BMI, chest tube output during the immediate 24-hour postoperative period, and the type of procedure (on-pump vs. off-pump) were analyzed. Logistic regression analysis was used to evaluate the likelihood of intraoperative transfusion. Linear regression analysis was used to evaluate 24-hour chest-tube output. Results Preoperative variables that significantly increased the likelihood of intraoperative transfusions were older age and low hematocrit; a significant decrease in likelihood was found with male gender, overweight BMI, and off-pump procedures. Preoperative variables that significantly increased 24-hour chest-tube output were low hematocrit, high hematocrit, and low platelets while a significant decrease in output was seen with overweight BMI and obese BMI. Conclusion Overweight and obese BMI are significant independent predictors of decreased intraoperative transfusion and decreased postoperative blood loss.

Effect of body mass index on postoperative transfusions and 24-hour chest-tube output

An increasing obese population in the United States focuses attention on the effect of obesity on surgical outcomes. Our objective was to see if obesity, determined by body mass index (BMI), contributed to bleeding in coronary artery bypass graft (CABG) surgery as measured by intraoperative and postoperative packed red blood cell transfusion frequency and amount and 24-hour chest-tube output. A retrospective chart review examined 150 subjects undergoing single-surgeon off-pump or on-pump CABG surgery between September 2006 and April 2009. BMI groups included normal-weight (BMI <25), overweight (BMI 25 to 29), and obese (BMI ≥30). Analyses used a chi-square test to determine variances in number of transfusions, and ANOVA for transfusion amount and 24-hour chest-tube amount. The percentage of subjects receiving intraoperative transfusions varied significantly by BMI group (p = 0.022). The percentage of subjects receiving transfusions in the 72-hour postoperative period showed a decreasing linear trend based on BMI group (p = 0.054). The percentage of subjects receiving transfusions in the combined intraoperative or 72-hour postoperative period showed a decreasing linear trend based on BMI group (p = 0.054). The transfusion amount during the 72-hour postoperative period varied significantly between BMI groups (p = 0.021), and the test for a linear decrease across groups was significant (p = 0.020). Twenty-four hour chest-tube output showed variation across all three BMI categories (p = 0.018) with chest-tube output decreasing with increasing obesity in a linear fashion (p = 0.006). Transfusion rate and amount indicate total blood loss is decreased in the obese, and chest-tube output findings give a direct measurable indicator of blood loss from the surgical site indicating increasing BMI is linearly correlated with decreasing postoperative bleeding.

Predictors of transfusion of packed red blood cells in coronary artery bypass grafting surgery

OBJECTIVES

Finding predictors of blood transfusion may facilitate the most efficient approach for the use of blood bank services in coronary artery bypass grafting procedures. The aim of this retrospective study is to identify preoperative and intraoperative patient characteristics predicting the need for blood transfusion during or after CABG in our local cardiac surgical service.

METHODS

435 patients undergoing isolated first-time CABG were reviewed for their preoperative and intraoperative variables and analyzed postoperative data. Patients were 255 males and 180 females, with mean age 62.01 ± 10.13 years. Regression logistic analysis was used for identifying the strongest perioperative predictors of blood transfusion.

RESULTS

Blood transfusion was used in 263 patients (60.5%). The mean number of transfused blood products units per patient was 2.27 ± 3.07 (0-23) units. The total number of transfused units of blood products was 983. Univariate analysis identified age >65 years, weight <70 Kg, body mass index <25 Kg/m2, hemoglobin <13mg/dL, hematocrit < 40% and ejection fraction <50%, use of cardiopulmonary bypass (CPB), not using an internal thoracic artery as a bypass, and multiple bypasses as significant predictors. The strongest predictors using multivariate analysis were hematocrit < 40% (OR 2.58; CI 1.62-4.15; P<0.001), CPB use (OR 2.00; CI 1.27-3.17; P=0.003) and multiple bypasses (OR 2.31; CI 1.31-4.08; P=0.036).

CONCLUSIONS

The identification of these risk factors leads to better identification of patients with a greater probability of using blood, allocation blood bank resources and cost-effectiveness use of blood products.

[Transfusion requirements, morbidity and mortality in cardiac surgery and the use of antifibrinolytic agents: a comparison of aprotinin and tranexamic acid]

OBJECTIVE

To evaluate transfusion requirements, morbidity and mortality when 2 antifibrinolytic agents (aprotinin and tranexamic acid) were used in patients undergoing cardiac surgery.

PATIENTS AND METHODS

Comparison of the effects of 2 antifibrinolytic agents in 243 patients undergoing cardiac surgery between December 2006 and June 2008. We recorded the surgical procedures used, blood product transfusions required, complications (particularly renal), mortality, and length of hospital stay.

RESULTS

The patients were distributed into 2 groups to receive tranexamic acid (n = 144) or aprotinin (n = 99). The incidence of transfusion in the tranexamic acid group (31.94%) was nonsignificantly lower than in the aprotinin group (38.38%) (PF = .31). The mean (SD) number of units of packed red blood cells transfused was 0.67 (1.18) in the tranexamic acid group and 1.01 (1.54) in the aprotinin group (P = .07). The mean preoperative hemoglobin concentration in the tranexamic acid group (11.79 [1.71] mg/dL) was significantly lower than in the aprotinin group (12.35 [1.70] mg/dL) (P < .01). Incipient postoperative renal failure tended to occur more frequently in the aprotinin group (19.6% compared to 16%; P = .47). Mortality at 1 year was 9.02% in the tranexamic acid group (compared to 14.14% in the aprotinin group; PF-.21); the trend for mortality related to postoperative renal failure was similar (7.6% in the tranexamic acid group compared to 12.4% in the aprotinin group; P = .22). No significant differences were observed in postoperative complications or length of hospital stay. However, the lack of randomization and the small sample size do not allow for definitive conclusions.

CONCLUSIONS

This study, subject to the aforementioned limitations, shows that tranexamic acid is as effective as aprotinin for reducing transfusion requirements in cardiac surgery in Spain.

Postoperative complications associated with transfusion of platelets and plasma in cardiac surgery

BACKGROUND

Studies in cardiac surgery have reported increased postoperative morbidity and mortality after allogeneic red blood cell (RBC) transfusions. Whether platelet (PLT) and/or plasma transfusions are a marker for more concomitant RBC transfusions or are independently associated with complications after cardiac surgery is unknown.

STUDY DESIGN AND METHODS

Data from two randomized controlled studies were combined to analyze the effects of PLT and/or plasma transfusions on postoperative infections, length of stay in the intensive care unit (ICU), all-cause mortality, and mortality in the presence or absence of infections in the postoperative period.

RESULTS

After adjusting for confounding factors, plasma units and not RBC transfusions were associated with all-cause mortality. White blood cell (WBC)-containing RBC transfusions and PLT transfusions were associated with mortality occurring in the presence of or after infections. The number of (WBC-containing) RBC transfusions was also significantly associated with postoperative infections and with ICU stay for 4 or more days.

CONCLUSION

Although it is difficult to separate the effects of blood components, we found that in cardiac surgery, perioperative plasma transfusions are independently associated with all-cause mortality. WBC-containing RBC transfusions and PLT transfusions are independently associated with mortality in the presence of infections in the postoperative period. Future transfusion studies in cardiac surgery should concomitantly consider the possible adverse effects of all the various transfused blood components.

Transfusion requirements in 811 patients during and after cardiac surgery: a prospective observational study

OBJECTIVE

To identify patients at risk for intra- and postoperative blood product transfusion in a mixed adult cardiac surgical patient population.

DESIGN

A prospective, observational study.

SETTING

A single-center university hospital.

PARTICIPANTS

Patients (n = 811) undergoing cardiac surgery from January 1, 2008, to November 30, 2008.

INTERVENTIONS

The outcome in terms of transfusion of red blood cells (RBCs), fresh frozen plasma (FFP), and/or pooled platelets within the first 24 hours after surgery was studied. Pre- and perioperative risk factors for bleeding and transfusion of blood products were studied.

MEASUREMENTS AND MAIN RESULTS

The majority of RBCs and FFP (>70%) were given to a minority of patients (<12%). The type of surgical procedure, previous cardiac surgery, and emergency operations were all significantly associated with the transfusion of RBCs, FFP, and platelets. Antithrombotic therapy was not significantly associated with the transfusion requirement in the mixed group of cardiac patients. However, in the low-risk procedures such as coronary artery bypass graft surgery, ongoing antithrombotic therapy at the time of the operation significantly increased the risk of transfusion in this otherwise low-risk category of surgery.

CONCLUSIONS

The identification of high-risk patients is necessary to optimize the perioperative management of bleeding complications. Because of the high variability in transfusion requirements, a specifically tailored patient intervention based on the individual's risk profile appears more likely to improve patient outcome compared with general interventions given to the entire patient group.