Re-evaluating treatment thresholds in patient blood management: Female patients experience more perioperative anaemia and higher transfusion rates in major elective surgery

BACKGROUND AND OBJECTIVES

By optimizing erythropoiesis, patient blood management (PBM) programmes can reduce transfusions, lower mortality and provide cost-effective care. While definitions of anaemia have historically varied by sex, for the purposes of PBM, anaemia is defined as a haemoglobin <130 g/L. Our objective was to describe whether perioperative anaemia and transfusion rates in the PBM setting vary by sex.

MATERIALS AND METHODS

We conducted a retrospective study of the Ontario Nurse Transfusion Coordinators Program (ONTraC) database from 2018 to 2022. ONTraC collects data from 25 Ontario hospitals which together account for >70% of Ontario's provincial blood use (~400,000 units per year). We collected data on patients undergoing elective isolated coronary artery bypass graft surgery (CABG), open heart valve replacement, CABG plus valve replacement, single-knee arthroplasty and single-hip arthroplasty.

RESULTS

From 2018 to 2022, 17,700 patients were included in the ONTraC program; 47% were females (N = 8376). Across almost all years and procedures, females were found to have a significantly lower pre-operative, nadir and discharge haemoglobin as compared with males, irrespective of PBM interventions. Transfusion rates were significantly higher for females; this was most pronounced in cardiac surgery.

CONCLUSION

Females experienced more perioperative anaemia and higher transfusion rates. Historic sex-specific definitions of anaemia may contribute to a greater tolerance of anaemia in females. Prioritizing females for multimodal PBM and consistently achieving a pre-operative haemoglobin >130 g/L may reduce the amount of red blood cell (RBC) transfusions that female patients receive.

Clinical prediction model for red cell blood transfusion in elective primary posterior lumbar spine fusion

Overestimated the cross-match of preoperative PRC preparation for elective primary lumbar spinal fusion needs revision for cost-effectiveness. We aimed to develop a novel preoperative predictive model for appropriate PRC preparation. This clinical prediction model in a retrospective cohort was studied between January 2015 and September 2022. Multivariate logistic regression models were used to assess predictive variables. The logistic coefficient of each predictor generated scores to establish a predictive model. The area under the receiver operating characteristic curve (AuROC) was used to evaluate the model. The predictive performance was validated using bootstrapping techniques and externally validated in 102 independent cases. Among 416 patients, 178 (43%) required transfusion. Four final predictors: preoperative hematocrit level, laminectomy level, transforaminal lumbar interbody fusion level, and sacral fusion. When categorized into two risk groups, the positive predictive values for the low-risk score (≤ 4) were 18.4 (95% Cl 13.9, 23.6) and 83.9 (95% CI 77.1, 89.3) for the high-risk score (> 4). AuROC was 0.90. Internal validation (bootstrap shrinkage = 0.993) and external validation (AuROC: 0.91). A new model demonstrated exemplary performance and discrimination in predicting the appropriate preparation for PRC. This study should be corroborated by rigorous external validation in other hospitals and by prospective assessments.

Adjusting Current Hemoglobin Thresholds: A Way to Improve Outcome in Women Undergoing Major Surgery

Background/Objective: In the perioperative setting, a suboptimal total hemoglobin (Hb) mass puts women and men at an unreasonable disadvantage. Anemia is an independent risk factor for transfusion, postoperative complications, and mortality. The Hb cut-off value for women was set at <12.0 g/dL by the World Health Organization (WHO) and has been rigorously debated for decades. The aim of this study was to elucidate the risk for postoperative complications in female patients with Hb levels < 12.0, 12.0-12.9, and ≥13.0 g/dL. Material and Methods: Single-center retrospective analysis of female patients undergoing major surgery. Results: In total, 6,516 patients ≥18 years of age had major surgery between 2018 and 2019 and 2,446 female patients were included in analysis. Mean age was 67.4 ± 16.6, 66.4 ± 15.6, and 64.5 ± 15.5 years in female patients with preoperative Hb levels <12.0, 12.0-12.9 and ≥13.0 g/dL, respectively. The transfusion rate of red blood cells (RBCs) was significantly higher in female patients with Hb <12.0 g/dL (53%) and with Hb 12.0-12.9 g/dL (31%) compared to female patients ≥13.0 g/dL (22%). Rates of pneumonia, acute kidney injury, and sepsis were significantly higher in patients with Hb <12.0 and 12.0-12.9 g/dL compared to patients with Hb ≥13.0 g/dL. Total length of hospital stay was significantly longer in female patients with Hb <12.0 g/dL than patients with Hb 12.0-12.9 g/dL and Hb ≥13.0 g/dL (10 days vs. 8 days). Conclusion: Taken together, our data show that Hb values below 12.9 g/dL are associated with increased probability of RBC transfusions and increased risk of postoperative complications. In addition, our results indicate that postoperative outcomes for women might be optimized by increasing cut-off values for anemia. The call to revise the anemia threshold for women by the WHO can no longer be disregarded.

Gender is Independently Associated With Red Blood Cell and Platelet Transfusion in Patients Undergoing Coronary Artery Bypass Grafting: Data From the Netherlands Heart Registration

OBJECTIVES

The aim of this study was to evaluate the incidence of transfusions, including red blood cells (RBC), platelets, and fresh frozen plasma (FFP) during and after coronary artery bypass grafting (CABG) in the Netherlands. Furthermore, the authors aimed to identify the impact of sex on blood product transfusion.

DESIGN

A retrospective multicenter cohort study. Data were collected from January 2013 to December 2021 from the Netherlands Heart Registration (NHR) database.

SETTING

The NHR receives its data from 16 heart centers in the Netherlands.

PARTICIPANTS

Patients older than 18 years who underwent CABG in the Netherlands.

INTERVENTIONS

Coronary artery bypass grafting with extracorporeal circulation or off-pump coronary artery bypass grafting.

MEASUREMENTS AND MAIN RESULTS

The incidence of blood transfusion, defined as transfusions intraoperatively and during the length of the hospital admission after CABG. In addition, a differentiation was made according to the type of transfusion (packed RBC, platelets, and FFP). In the overall cohort (N = 42,388), the number of patients who received a transfusion of any type was 27.0% (n = 11,428). Women received more often RBC transfusions compared with men (45.4% v 15.6%, respectively, p < 0.001). There was a significant difference between the 2 sexes regarding platelet transfusion (women 10.0% v men 11.1%, p = 0.005) but not in FFP transfusion. Female sex was independently associated with RBC transfusion, using the multivariate logistic regression analysis.

CONCLUSIONS

The incidence of any blood transfusion was 27.0%, and was higher in women than in men. The female sex was independently associated with receiving RBC during and after CABG.

Development and Validation of a Risk-Prediction Nomogram for Preoperative Blood Type and Antibody Testing in Spinal Fusion Surgery

OBJECTIVE

With advancements in minimally invasive techniques, the use of spinal fusion surgery is rapidly increasing and transfusion rates are decreasing. Routine preoperative ABO/Rh blood type and antibody screening (T&S) laboratory tests may not be appropriate for all spinal fusion patients. Herein, we constructed a nomogram to assess patient transfusion risk based on various risk factors in patients undergoing spinal fusion surgery, so that preoperative T&S testing can be selectively scheduled in appropriate patients to reduce healthcare and patient costs.

METHODS

Patients who underwent spinal fusion surgery between 01/2020 and 03/2023 were retrospectively examined and classified into the training (n = 3533, 70%) and validation (n = 1515, 30%) datasets. LASSO and multivariable logistic regression were used to analyze risk factors for blood transfusion. Nomogram predictive model was built according to the independent predictors and mode predictive power was validated using consistency index (C-index), Hosmer-Lemeshow (HL) test, calibration curve analysis and area under the curve (AUC) for receiver operating characteristic (ROC) curve. Bootstrap resampling was used for internal validation. Decision curve analysis (DCA) was applied to evaluate the model's performance in the clinic.

RESULTS

Being female, age, BMI, admission route, critical patient, operative time, heart failure, end-stage renal disease or chronic kidney disease (ESRD or CKD), anemia, and coagulation defect were predictors of blood transfusion for spinal fusion. A prediction nomogram was developed according to a multivariate model with good discriminatory power (C-index = 0.887); Bootstrap resampling internal validation C-index was 0.883. Calibration curves showed strong matching between the predicted and actual probabilities of the training and validation sets. HL tests for the training and validation sets had p-values of 0.327 and 0.179, respectively, indicating good calibration. When applied to the training set, the following parameters were found: AUC: 0.895, 95% CI: 0.871-0.919, sensitivity 78.2%, specificity 86.7%, positive predictive value 29.4% and negative predictive value 98.2%. If the model were applied in the training set, 2911 T&S tests (82.4%) would be eliminated, equaling a RMB349,320 cost reduction. The AUC in the internal validation was: 0.879, 95% CI: 0.839-0.927, sensitivity 75.2%, specificity 88.8%, positive predictive value 34.3%, negative predictive value 97.9%, would eliminate 1276 T&S tests (84.2%), saving RMB 153,120. The DCA curve indicated good clinical application value.

CONCLUSION

The nomogram based on 10 independent factors can help healthcare professionals predict the risk of transfusion for patients undergoing spinal fusion surgery to target preoperative T&S testing to appropriate patients and reduce healthcare costs.

Sex Differences in Red Blood Cell Transfusions and 30-Day Mortality in Cardiac Surgery: A Single Center Observational Study

In cardiac surgery, women have higher short-term mortality and a higher risk of receiving red blood cell (RBC) transfusions than men. This study's aim was to evaluate possible sex differences in RBC transfusions in cardiac surgery and their association with preoperative hemoglobin levels, body mass index, and 30-day mortality. A single-center retrospective study was conducted with 1583 patients (1181 men and 402 women) undergoing cardiac surgery. A total of 64.4% of the women and 33.0% of the men received an RBC transfusion. In a multivariable analysis, female sex was an independent predictor of RBC transfusion (OR 3.88, 95% CI 2.95-5.11, p < 0.001). Other independent predictors of RBC transfusion were age, preoperative hemoglobin level, and body mass index. The women were more likely to receive RBC transfusions than the men, regardless of the type of cardiac surgery. Decreased transfusion risk was found in all higher-than-normal weight categories in the women, but only in the severe obesity category in the men. Preoperative hemoglobin was similarly associated with RBC transfusion in the men and women. The crude 30-day mortality rate was higher in the women than in the men (2.5% vs. 0.9%, p = 0.018). In both sexes, RBC transfusion was associated with an increased probability of death within 30 days.

Preoperative Anemia and Female Gender are Risk Factors for Transfusion in Patients Undergoing Coronary Artery Bypass Grafting with a Restrictive Transfusion Strategy

Objective

Red blood cell (RBC) transfusion in cardiac surgery is associated with increased morbidity and mortality. Even when using patient blood management methods, blood transfusions may still be needed in cardiac surgery. This study examined the risk factors for blood transfusion in isolated coronary artery bypass graft (CABG) surgery with a restrictive transfusion strategy, along with individualized patient blood management.

Methods

We enrolled 198 patients (age, 61.8 ± 9.9 years; 28 females and 170 males) who underwent isolated CABG surgery in a single private hospital using a restrictive transfusion strategy between April 2015 and October 2020. Pre-, intra-, and postoperative parameters were compared between patients with and without RBC transfusions. The risk factors for transfusion and transfusion probability were analyzed.

Results

Patients who received RBC transfusions had higher European System for Cardiac Operative Risk Evaluation values (13.60 ± 18.27%). Preoperative hematocrit (Hct) [odds ratio (OR)=0.752; 95% confidence interval (CI) 0.639-0.884; P=0.001] and female gender (OR=7.874; 95% CI 1.678-36.950; P=0.009) were significant independent risk factors for RBC transfusion in logistic regression analysis. When the preoperative Hct was 30%, the RBC transfusion probability was 61.08% in females and 16.6% in males. Patients who received RBC transfusions had longer intensive care unit (31.40 ± 25.42 hours) and hospital (11.18 ± 6.75 days) stays.

Conclusion

Risk factors for RBC transfusion in isolated CABG surgery with a restrictive blood transfusion strategy were preoperative anemia and female gender.

Less (Transfusion) Is More-Enhancing Recovery through Implementation of Patient Blood Management in Cardiac Surgery: A Retrospective, Single-Centre Study of 1174 Patients

Introduction: The implementation of Patient Blood Management (PBM) in cardiac surgery has been shown to be effective in reducing blood transfusions and associated complications, as well as improving patient outcomes. Despite the potential benefits of PBM in cardiac surgery, there are several barriers to its successful implementation. Objectives: The main objectives of this study were to ascertain the impact of the national Romanian PBM recommendations on allogeneic blood product transfusion in cardiac surgery and identify predictors of perioperative packed red blood cell transfusion. Methods: As part of the Romanian national pilot programme of PBM, we performed a single-centre, retrospective study in a tertiary centre of cardiovascular surgery, including patients from two time periods, before and after the implementation of the national recommendations. Using coarsened exact matching, from a total of 1174 patients, 157 patients from the before group were matched to 169 patients in the after group. Finally, we built a multivariate regression model from the entire cohort to analyse independent predictors of PRBC transfusion in the perioperative period. Results: Although there was a trend towards a lower proportion of patients requiring PRBC transfusion in the "after" group compared to the "before" group (44.9%vs. 50.3%), it was not statistically significant. There was a significant difference between the "after" group and the "before" group in terms of fresh-frozen plasma (FFP) transfusion rates, with a lower percentage of patients requiring FFP transfusion in the "after" group compared to "before" (14.2%, vs. 22.9%, p = 0.04). This difference was also seen in the total perioperative FFP transfusion (mean transfusion 0.7 units in the "before" group, SD 1.73 vs. 0.38 units in the "after" group, SD 1.05, p = 0.04). In the multivariate regression analysis, age > 64 years (OR 1.652, 95% CI 1.17-2.331, p = 0.004), female sex (OR 2.404, 95% CI 1.655-3.492, p < 0.001), surgery time (OR 1.295, 95% CI 1.126-1.488, p < 0.001), Hb < 13 g/dl (OR 3.611, 95% CI 2.528-5.158, p < 0.001), re-exploration for bleeding (OR 3.988, 95% CI 1.248-12.738, p = 0.020), viscoelastic test use (OR 2.18, 95% CI 1.34-3.544, p < 0.001), FFP transfusion (OR 4.023, 95% CI 2.426-6.671, p < 0.001), and use of a standardized pretransfusion checklist (OR 8.875, 95% CI 5.496-14.332, p < 0.001) remained significantly associated with PRBC transfusion. The use of a preoperative standardized haemostasis questionnaire was independently associated with a decreased risk of perioperative PRBC transfusion (0.565, 95% CI 0.371-0.861, p = 0.008). Conclusions: Implementation of national PBM recommendations led to a reduction in FFP transfusion in a cardiac surgery centre. The use of a preoperative standardized haemostasis questionnaire is an independent predictor of a lower risk for PRBC transfusion in this setting.

Efficacy of autologous plateletpheresis in adult aortic surgery: study protocol for a randomised controlled trial

INTRODUCTION

Perioperative coagulopathy is common in patients undergoing aortic surgery, increasing the risk of excessive blood loss and subsequent allogeneic transfusion. Blood conservation has become a vital part of cardiovascular surgery, but measures to protect platelets from destruction by cardiopulmonary bypass (CPB) are still lacking. Autologous platelet concentrate (APC) may have potential benefits for intraoperative blood preservation, but its efficacy has not been studied extensively. This study aims to evaluate the efficacy of APC as a blood conservation technique to reduce blood transfusion in adult aortic surgery.

METHODS AND ANALYSIS

This is a prospective, single-centre, single-blind randomised controlled trial. A total of 344 adult patients undergoing aortic surgery with CPB will be enrolled and randomised to either the APC group or the control group with a 1:1 randomisation ratio. Patients in the APC group will receive autologous plateletpheresis before heparinisation, while those in the control group will not. The primary outcome is the perioperative packed red blood cell (pRBC) transfusion rate. Secondary endpoints include the volume of perioperative pRBC transfusion; drainage volume within 72 hours post-surgery; postoperative coagulation and platelet function; and the incidence of adverse events. Data will be analysed according to the intention-to-treat principle.

ETHICS AND DISSEMINATION

This study was approved by the institutional review board of Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (no. 2022-1806). All procedures included in this study will be performed in adherence to the Helsinki Declaration. The results of the trial will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Register (ChiCTR2200065834).

Clinical presentation and in-hospital outcomes of intraoperative red blood cell transfusion in non-anemic patients undergoing elective valve replacement

Background

Intraoperative transfusion is associated with adverse clinical outcomes in cardiac surgery. However, few studies have shown the impact of intraoperative red blood cell (RBC) transfusion on non-anemic patients undergoing cardiac surgery. We assessed the in-hospital clinical outcomes of non-anemic patients undergoing isolated valve replacements and investigated the predictors associated with intraoperative RBC transfusion.

Methods

We enrolled 345 non-anemic patients undergoing isolated valve replacements in our department from January 2015 to December 2019. The patients were stratified by the receipt of intraoperative RBC transfusion. Baseline characteristics were compared between groups and multiple logistic regression was used to identify the predictors for intraoperative RBC transfusion. The association between intraoperative RBC transfusion and in-hospital outcomes was also evaluated.

Results

Intraoperative RBC transfusion developed in 84 of the 345 enrolled patients (24.3%). Three independent predictors for intraoperative RBC transfusion of non-anemic patients undergoing isolated valve replacements were identified by multivariate logistic analysis, including female, iron deficiency and hemoglobin level. When the two groups were compared, a significant tendency of higher in-hospital mortality (6.0% vs. 1.1%, P = 0.033) and higher incidence of postoperative hypoxemia (9.5% vs. 2.7%, P = 0.007) were observed in the intraoperative RBC transfusion group. After adjustment, the presence of intraoperative RBC transfusion was associated with an increase in postoperative hypoxemia (OR = 3.36, 95% CI: 1.16–9.71, P = 0.026).

Conclusion

Intraoperative RBC transfusion was associated with poorer clinical outcomes in non-anemic adults undergoing isolated valve replacements, which significantly increased the risk of postoperative hypoxemia. The independent predictors of intraoperative RBC transfusion, such as iron deficiency and female, were identified, which may be helpful for risk assessment and perioperative management.

Non-White Race/Ethnicity and Female Sex Are Associated with Increased Allogeneic Red Blood Cell Transfusion in Cardiac Surgery Patients: 2007-2018

OBJECTIVE

To evaluate racial and/or ethnic and sex disparities in allogeneic and autologous red blood cell (RBC) transfusions in cardiac surgery.

DESIGN

A retrospective observational study.

SETTING

2007 to 2018 data from FL, MD, KY, WA, NY, and CA from the State Inpatient Databases (SID), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

PARTICIPANTS

A total of 710,296 inpatients who underwent elective or emergency coronary artery bypass grafting (CABG), cardiac valve surgery,or combination CABG and/or valve surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were cohorted by race and/or ethnicity and sex, as defined by SID-HCUP. Demographic characteristics and comorbidities were compared. Rates and risk-adjusted odds ratios (aOR) were calculated for allogeneic and autologous RBC transfusion (primary outcomes). Additional secondary analyses were conducted for in-hospital mortality, 30-day readmission, 90-day readmission, hospital length of stay, and total charges to examine the effect of RBC transfusion status. Effect modification between race and sex was assessed. When controlling for patient demographics, comorbidities, and hospital characteristics, non-White patients were more likely to receive an allogeneic RBC transfusion during cardiac surgery than White patients (Black: aOR 1.17, 99% CI 1.13-1.20, p < 0.001, Hispanic: aOR 1.22, 99% CI 1.19-1.22, p < 0.001). Women were more likely to receive allogeneic RBC than men (aOR 1.69, 99% CI 1.66-1.72, p < 0.001). In interaction models, non-White women had the highest odds of allogeneic blood transfusion as compared to White men (reference category; Black women: aOR 2.04, 99% CI 1.91-2.17, p < 0.001, Hispanic women: aOR 2.03, 99% CI 1.90-2.16, p < 0.001).

CONCLUSION

These findings highlighted the differences in the rates of allogeneic RBC transfusion for non-White and female patients undergoing cardiac surgery, which is a well-established marker of poorer outcomes.

Blood transfusion risk prediction in spinal tuberculosis surgery: development and assessment of a novel predictive nomogram

Objective

The present study attempted to predict blood transfusion risk in spinal tuberculosis surgery by using a novel predictive nomogram.

Methods

The study was conducted on the clinical data of 495 patients (167 patients in the transfusion group and 328 patients in the non-transfusion group) who underwent spinal tuberculosis surgery in our hospital from June 2012 to June 2021. The least absolute shrinkage and selection operator (LASSO) and multivariable logistic regression analyses were used to screen out statistically significant parameters, which were included to establish a novel predictive nomogram model. The receiver operating characteristic (ROC) curve, calibration curves, C-index, and decision curve analysis (DCA) were used to evaluate the model. Finally, the nomogram was further assessed through internal validation.

Results

The C-index of the nomogram was 0.787 (95% confidence interval: 74.6%–.82.8%). The C-value calculated by internal validation was 0.763. The area under the curve (AUC) of the predictive nomogram was 0.785, and the DCA was 0.01–0.79.

Conclusion

A nomogram with high accuracy, clinical validity, and reliability was established to predict blood transfusion risk in spinal tuberculosis surgery. Surgeons must prepare preoperative surgical strategies and ensure adequate availability of blood before surgery.

Predictors for Perioperative Blood Transfusion in Patients Undergoing Open Cystectomy and Urinary Diversion and Development of a Nomogram: An Observational Cohort Study

Open radical cystectomy is associated with a substantial rate of perioperative blood transfusion. Early detection of potentially modifiable perioperative factors could reduce the need for perioperative blood transfusion and thus positively impact the outcome. We conducted an observational, single-center cohort study of 1168 patients undergoing cystectomy. Perioperative blood transfusion was defined as the need for packed red blood cells and/or fresh frozen plasma units within the first 24 h after the initiation of surgery. Multiple logistic regression analysis was performed to model the association between risk factors and blood transfusion, and a nomogram was developed. Blood transfusion occurred in 370/1168 patients (31.7%). Significant predictors were age (OR: 1.678, (95% CI: 1.379–2.042); p < 0.001), blood loss ratio (6.572, (4.878–8.853); p < 0.001), preoperative hemoglobin (0.316, (0.255–0.391); p < 0.001), tumor stage (2.067, (1.317–3.244); p = 0.002), use of oral anticoagulants (2.70, (1.163–6.270), p = 0.021), and interaction between female sex and blood loss ratio (1.344, (1.011–1.787); p = 0.042). Of the major predictors found to affect perioperative blood transfusion, two can be influenced: blood loss ratio by meticulous surgery and hemoglobin by preoperative optimization. Others such as age or advanced disease are not modifiable. This emphasizes the importance of optimal management of patients prior to surgery.

The Need for Red Cell Support During Non-Cardiac Surgery Is Associated to Pre-Transfusion Levels of FXIII and the Platelet Count

Unexpected intraoperative bleeding is associated with a reduced availability of crosslinking capacity (provided through factor XIII (FXIII)) per unit of generated thrombin. Furthermore, FXIII deficiency and thrombocytopenia (but not fibrinogen deficiency) are the most prevalent modulators of clot firmness in the immediate postoperative setting. In this study, we therefore evaluated whether levels of FXIII, fibrinogen, or the platelet count influenced the probability of intraoperative red cell transfusions in patients in the operating theatre. This retrospective study was comprised of 1023 patients, which were in need of blood product support in the operating theatre and of which 443 received red cell transfusions. Due to standard operating procedures, FXIII activity, fibrinogen concentration, and platelet count were measured before transfusion took place, but without influencing the decision to transfuse. FXIII deficiency was frequent (50%), as was thrombocytopenia (49%), but not fibrinogen deficiency (9%). FXIII deficiency was associated with a significantly increased probability to receive red cell transfusions (OR 4.58, 95% CI 3.46–6.05) as was thrombocytopenia (OR 1.94, 95% CI 1.47–2.56), but not fibrinogen deficiency (OR 1.09, 95% CI 0.67–1.76). Similar results were seen for cut-off independent evaluations (receiver operating characteristics (ROC) curves, using continuously distributed variables), where the areas under the curves (AUC) of red cell transfusion for FXIII activity was 0.744 (95% CI 0.716–0.770)/0.632 (95% CI 0.601–0.661) for the platelet count, and 0.578 (95% CI 0.547–0.609) for fibrinogen concentration. All AUCs were significantly different from each other (p < 0.0001 and p = 0.0106, respectively), indicating that FXIII activity was a significantly better predictor of red blood cell (RBC) transfusion than platelet count and fibrinogen concentration. These results suggest that pre-transfusion FXIII activity and to a lesser extent the platelet count influence the probability of intraoperative red cell transfusions. Modifying FXIII activity and/or the platelet count might influence the need for downstream red cell transfusion, thus potentially reducing transfusion associated morbidity. This, however, needs confirmation in future studies.