Assessment of Machine Learning Methods to Predict Massive Blood Transfusion in Trauma.BACKGROUND
 Accurately predicting which patients are most likely to benefit from massive transfusion protocol (MTP) activation may help patients while saving blood products and limiting cost.  The purpose of this study is to explore the use of modern machine learning (ML) methods to develop and validate a model that can accurately predict the need for massive blood transfusion (MBT).


 The institutional trauma registry was used to identify all trauma team activation cases between June 2015 and August 2019.  We used an ML framework to explore multiple ML methods including logistic regression with forward and backward selection, logistic regression with lasso and ridge regularization, support vector machines (SVM), decision tree, random forest, naive Bayes, XGBoost, AdaBoost, and neural networks.  Each model was then assessed using sensitivity, specificity, positive predictive value, and negative predictive value.  Model performance was compared to that of existing scores including the Assessment of Blood Consumption (ABC) and the Revised Assessment of Bleeding and Transfusion (RABT).


 A total of 2438 patients were included in the study, with 4.9% receiving MBT.  All models besides decision tree and SVM attained an area under the curve (AUC) of above 0.75 (range: 0.75-0.83).  Most of the ML models have higher sensitivity (0.55-0.83) than the ABC and RABT score (0.36 and 0.55, respectively) while maintaining comparable specificity (0.75-0.81; ABC 0.80 and RABT 0.83).


 CONCLUSIONS
 Our ML models performed better than existing scores.  Implementing an ML model in mobile computing devices or electronic health record has the potential to improve the usability.
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