Niguarda calculator: A new tool to early predict the real need for a massive transfusion after major trauma

Introduction: Massive Transfusion Protocol (MTP) is a fundamental part of the Damage Control Resuscitation (DCR) strategy but no standardized guidelines among trauma centers for the management of transfusions are nowadays available. Aim: To find an early and easy-to-use prediction model to evaluate the real need for the prosecution of an MTP. Materials & methods: We prospectively included all young adult trauma patients (≥ 16 years old) with an Injury Severity Score ≥ 16 for whom an MTP was activated at Niguarda Hospital (Milan, Italy) from December 1, 2010, to December 31, 2019 (training dataset). Another population was designated for validating the calculator from May 2020 to December 2021 (validation dataset). Eight variables were selected for the construction of the prediction model: Age, pH, Base Excess (BE), Lactate (LAC), Hemoglobin (Hb), INR, PTT, and Shock Index (SI). Multiple Imputation (MI) by chained equations was utilized to create 5 imputed data sets. Model performance was evaluated using Harrell"s c-statistic (C-Index) and calibration measures. Results: The cohort comprised 552 subjects in the training dataset and 70 subjects in the validation dataset. In the univariable analysis, all 8 selected variables were related to the MTP continuation (p<0.001). The Apparent C-index of the multivariable model was 0.736. On the external validation dataset, the C-index was 0.790. Univariate and multivariable regression analyses performed after the MI show that Hemoglobin (OR -3.07 (SE±0.051) p=0.003), INR (OR 2.18 (SE±1.44) p=0.049) and BE (OR 1.99 (SE±0.039) p=0.05) were the variable strongly related with the outcome. Conclusion: Our study elaborates an early and easy-to-use prediction model that could help trauma surgeons in shock room to better identify patients who will really need an MTP prosecution during the management.

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