Effectiveness of a patient blood management protocol on reduction of allogeneic red blood cell transfusions in orthopedic surgery

Development and validation of machine learning models to predict perioperative transfusion risk for hip fractures in the elderly

BACKGROUND

Patients with hip fractures frequently need to receive perioperative transfusions of concentrated red blood cells due to preoperative anemia or surgical blood loss. However, the use of perioperative blood products increases the risk of adverse events, and the shortage of blood products is prompting us to minimize blood transfusion. Our study aimed to construct a machine learning algorithm predictive model to identify patients at high risk for perioperative transfusion early in hospital admission and to manage their patient blood to reduce transfusion requirements.

METHODS

This study collected patients hospitalized for hip fractures at a university hospital from May 2016 to November 2022. All patients included in the analysis were randomly divided into a training set and validation set according to 70:30. Eight machine learning algorithms, CART, GBM, KNN, LR, NNet, RF, SVM, and XGBoost, were used to construct the prediction models. The models were evaluated for discrimination, calibration, and clinical utility, and the best prediction model was selected.

RESULTS

A total of 805 patients were included in the study, of whom 306 received transfusions during the perioperative period. We screened eight features used to construct the prediction model: age, fracture time, fracture type, hemoglobin, albumin, creatinine, calcium ion, and activated partial thromboplastin time. After evaluating and comparing the performance of each of the eight models, the model constructed by the XGBoost algorithm had the best performance, with MCC values of 0.828 and 0.939 in the training and validation sets, respectively. In addition, it had good calibration and clinical utility in both the training and validation sets.

CONCLUSION

The model constructed by the XGBoost algorithm has the best performance, using this model to identify patients at high risk for transfusion early in their admission and promptly incorporating them into a patient blood management plan can help reduce the risk of transfusion.

Effect of recombinant human erythropoietin combined with iron sucrose on postoperative hemoglobin in patients undergoing artificial joint replacement

With the aging of the population, an increasing number of elderly patients are opting for artificial joint replacement, leading to the exploration of various rapid rehabilitation programs in the perioperative period. In this study, we aimed to investigate the effectiveness of combining recombinant human erythropoietin and iron sucrose in altering the range and trend of postoperative hemoglobin in patients undergoing arthroplasty. Specifically, we will examine whether this combination can effectively alter the rise and fall of postoperative haemoglobin, identify the inflection point of haemoglobin change or recovery after arthroplasty, and assess the effect of treatment on serum iron in postoperative blood. We conducted a retrospective study of 138 patients who underwent unilateral total joint arthroplasty by the same surgeon in the same hospital before July 2022. The results of this study may provide valuable insights for the development of effective rehabilitation programs for patients undergoing arthroplasty.

Bone Density May Be a Promising Predictor for Blood Loss during Total Hip Arthroplasty

Background: Total hip arthroplasty (THA), which is performed mostly in elderly individuals, can result in substantial blood loss and thereby imposes a significant physical burden and risk of blood transfusion. The femoral neck cut and reamed acetabulum are the main sites of intraoperative bleeding. Whether the bone density in that region can be used to predict the amount of blood loss in THA is unknown. Methods: We retrospectively analyzed adult patients undergoing primary THA in the Department of Orthopedics, Peking Union Medical College Hospital, from January 2018 to January 2020. All these patients underwent primary unilateral THA. Patients had their bone mineral density (BMD) recorded within the week before surgery and were stratified and analyzed for perioperative blood loss. Multivariable regressions were utilized to adjust for differences in demographics and comorbidities among groups. Results: A total of 176 patients were included in the study. Intraoperative blood loss was 280.1 ± 119.56 mL. Pearson correlation analysis showed a significant correlation between blood loss and preoperative bone density of both the femoral greater trochanter (R = 0.245, p = 0.001) and the Ward’s triangle (R = 0.181, p = 0.016). Stepwise multiple linear regression showed that preoperative bone density of the greater trochanter (p = 0.015, 95% CI: 0.004–0.049) and sex (p = 0.002) were independent risk factors for THA bleeding. The area under the receiver operating characteristic curve (AUROC) of the greater trochanter and Ward’s triangle was 0.593 (95% CI: 0.507–0.678, p = 0.035) and 0.603 (95% CI: 0.519–0.688, p = 0.018), respectively. The cutoff T value on the femoral greater trochanter for predicting higher bleeding was −1.75. Conclusions: In THA patients, preoperative bone density values of the femoral greater trochanter and sex could be promising independent predictors for bleeding during surgery. Osteoporosis and female patients might have lower blood loss in the THA operation.

Effects of transfusion load and suction pressure on renal function in intraoperative salvage autotransfusion

Although some investigations have been performed to determine the effects of transfusion load and suction pressure on renal function during intraoperative salvage autotransfusion, the precise threshold is still undetermined. A total of 625 patients undergoing surgery with the Continuous AutoTransfusion System (CATS^plus) were enrolled and divided into groups according to the utilized suction pressure and transfusion volume. Plasma free hemoglobin (FHB) and creatinine clearance (CCr) were assayed to indicate the renal function. Both 0.03 MPa suction (≥4-unit load) and >5 units transfusion changed the levels of FHB and CCr significantly when measured 24 h post-operation compared to pre-operation. Under 0.02 MPa suction (≥4-unit load), the alteration of FHB and CCr returned to normal after 24 h. Under 3 units transfusion, the levels of FHB and CCr at 6 and 12 h post-operation changed significantly compared to pre-operation (P<0.05 or P<0.01, respectively), and this alteration could be restored to normal at 72 h post-operation. After an exhaustive investigation, less than 4 units transfusion and less than 0.03 MPa suction pressure are recommended for intraoperative salvage autotransfusion.

Functional Testing for Tranexamic Acid Duration of Action Using Modified Viscoelastometry

Introduction

Tranexamic acid (TXA) is the standard medication to prevent or treat hyperfibrinolysis. However, prolonged inhibition of lysis (so-called "fibrinolytic shutdown") correlates with increased mortality. A new viscoelastometric test enables bedside quantification of the antifibrinolytic activity of TXA using tissue plasminogen activator (TPA).

Materials and Methods

Twenty-five cardiac surgery patients were included in this prospective observational study. In vivo, the viscoelastometric TPA test was used to determine lysis time (LT) and maximum lysis (ML) over 96 h after TXA bolus. Additionally, plasma concentrations of TXA and plasminogen activator inhibitor 1 (PAI-1) were measured. Moreover, dose effect curves from the blood of healthy volunteers were performed in vitro. Data are presented as median (25-75th percentile).

Results

In vivo TXA plasma concentration correlated with LT (r = 0.55; p < 0.0001) and ML (r = 0.62; p < 0.0001) at all time points. Lysis was inhibited up to 96 h (LT_TPA-test: baseline: 398 s [229-421 s] vs. at 96 h: 886 s [626-2,175 s]; p = 0.0013). After 24 h, some patients (n = 8) had normalized lysis, but others (n = 17) had strong lysis inhibition (ML <30%; p < 0.001). The high- and low-lysis groups differed regarding kidney function (cystatin C: 1.64 [1.42-2.02] vs. 1.28 [1.01-1.52] mg/L; p = 0.002) in a post hoc analysis. Of note, TXA plasma concentration after 24 h was significantly higher in patients with impaired renal function (9.70 [2.89-13.45] vs.1.41 [1.30-2.34] µg/mL; p < 0.0001). In vitro, TXA concentrations of 10 µg/mL effectively inhibited fibrinolysis in all blood samples.

Conclusions

Determination of antifibrinolytic activity using the TPA test is feasible, and individual fibrinolytic capacity, e.g., in critically ill patients, can potentially be measured. This is of interest since TXA-induced lysis inhibition varies depending on kidney function.

Effect of the application of the "Patient blood management" programme on the approach to elective hip and knee arthroplasties

BACKGROUND AND OBJECTIVES

The "Patient Blood Management" (PBM) programmes have demonstrated their value in the continuous improvement of care practice, due to continuous systematic reviewing of results and their dynamic and multidisciplinary updating in accordance with new clinical evidence. Our goal is to demonstrate the effectiveness of simple protocols, applicable in second level hospitals.

PATIENTS AND METHODS

702 patients undergoing scheduled arthroplasty from 2011 to 2018 were retrospectively analysed. During this period, the evolution of transfusion rates and anaemia and bleeding management were recorded in the patients' computerised clinical histories.

RESULTS

Stages and transfusion rates were: Year 2011-2012, "Universal self-donation programme": 62.4%; year 2013, "Optimization of preoperative haemoglobin and universal self-donation withdrawal", 22.5%; year 2015, "Stopping the use of cell-savers and drains", 13.2%; and year 2017, "Introduction of routine tranexamic acid", 3.6%. A significant reduction in the transfusion rate and volume (P<.001) and the average hospital stay (8 to 6 days) (P<.001) was achieved. In multivariate models, transfused patients have a .5-day stay and there is a trend towards a reduction in complications, being fewer in patients receiving tranexamic acid (OR .44).

CONCLUSION

A simple progressive and multidisciplinary PBM programme, with continued re-evaluation, has allowed a reduction in transfusion rates and average hospital stay.