A derivation and validation study of an early blood transfusion needs score for severe trauma patients.

In this study, Wang et al. investigated the validity of a simple and pragmatic prehospital blood transfusion needs scoring system to be used by emergency medical services personnel. In a retrospective review of local trauma registry data from 2004 through 2013, 24 303 patients were randomly assigned to a derivation (n=12 151) and a validation (n=12 152) cohort. A total of 784 patients received blood product transfusion either in the prehospital period or within 4 hours after arrival to the emergency department.

Transfused patients were predominately male, arrived via ambulance/helicopter, sustained more penetrating injuries, had more severe injuries and were noted to have less stable vital signs. By multivariate logistic regression, independent risks factors (excluding variables not applicable during the prehospital phase) associated with early blood transfusion were identified in the derivation cohort to derive a scoring system. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated and compared using both the derivation and validation data.

In the derivation cohort, age, penetrating injury, heart rate (HR), systolic blood pressure (SBP) and Glasgow coma scale (GCS) score were risks predictive of early blood transfusion. An early blood transfusion needs score was derived from this information. A score >5 indicated risk of early blood transfusion with a sensitivity of 83% and a specificity of 80%. The same sensitivity and specificity were found in the validation cohort, with no difference in AUC between the two cohorts (AUC of the derivation = 0.87 vs. AUC of the validation = 0.86). Based on these results, the authors conclude that an early blood transfusion scoring system has been derived and internally validated to predict blood transfusion needs in trauma patients during prehospital or initial emergency department resuscitation.

The score derived here has the advantage that it is based on variables accessible in the prehospital setting (age, penetrating injury, HR, SBP and GCS) with prediction strength similar to that obtained from comparable simple, unweighted scores like the ABC score (penetrating injury, HR, SBP, positive FAST) or the McLaughlin Score (HR, SBP, pH and haematocrit) and the more complex (weighted) TASH score (BP, gender, haemoglobin, FAST, HR, base excess and extremity or pelvic fractures). Given the retrospective nature of the study, validation of this new prehospital blood transfusion score in prospective studies is highly warranted.

– Sisse Rye Ostrowski