Prehospital and hospital shock indices as predictors of massive blood transfusion during the initial treatment of polytrauma patients

Objectives. To explore a possible association between the shock index and a need for massive blood transfusion, duration of hospital stay in the critical care unit, and mortality. Methods. Observational study of data for all patients over the age of 18 years with multiple high-energy injuries included in the TraumCat Registry who were treated in Hospital Universitario de Bellvitge between 2012 and 2016. We calculated shock index values before hospital emergency department arrival, on arrival at the hospital, and on admission to the critical care unit for resuscitation. The amount of blood transfused in the first 24 hours was also obtained from the registry. Results. Of 184 polytrauma patients, 75(41%) received blood transfusions. Median (interquartile range) shock indices were as follows: prehospital, 0.77 (0.61-1.01); on hospital arrival, 0.78 (0.64-1); and on critical care admission, 0.92 (0.76-1.13). Forty-six patients (25%) died. A prehospital shock index of 0.9 was significant, differentiating the amount of blood transfused. The specificity and sensitivity of the cutoff were 73% and 66%, respectively, at the prehospital recording and 74% and 80% on hospital arrival. The areas under the receiver operating characteristic curve and 95% Cls were as follows for prehospital and on-arrival shock indices: 68% (61%75%) and 72% (65%-79%). Mortality and hospital stay were not significantly associated with shock indices. Conclusions: The shock index is a useful, easy-to-obtain predictor to identify polytrauma patients who need early blood transfusion for optimal treatment. Hospital stay and mortality might be better predicted by other indicators.