The utility of the prehospital shock index, age shock index, and modified shock index for predicting hypofibrinogenaemia in trauma patients: an observational retrospective study.

Purpose: Reduced fibrinogen levels are associated with worse outcomes in bleeding trauma patients. The purpose of this study was to evaluate the potential of the prehospital shock index (SI) and its derivatives, the age shock index (aSI) and the modified shock index (mSI), as predictors of hypofibrinogenaemia in trauma patients.

Methods: This retrospective study included 2383 patients who presented to a regional trauma center. We reviewed the plasma fibrinogen levels upon admission to the trauma center and patients were divided into two groups: the hypofibrinogenaemia group and the normal group. The predictive performances of the SI, aSI, and mSI were assessed by the area under the receiver operating characteristic curve (AUC).

Results: Of the 2383 patients, 235 (9.9%) had hypofibrinogenaemia. Patients with hypofibrinogenaemia were more likely to receive transfusions within 4 h and had significantly greater in-hospital mortality than patients with normal fibrinogen levels. The AUCs of prehospital SI, prehospital aSI, and prehospital mSI for the prediction of hypofibrinogenaemia were 0.75 (95% confidence interval [CI] 0.73-0.77), 0.70 (95% CI 0.68-0.72), and 0.75 (95% CI 0.73-0.77), respectively.

Conclusion: Prehospital SI and prehospital mSI demonstrated moderate performance for identifying trauma patients with hypofibrinogenaemia. The prehospital aSI had poor predictive performance. In the prehospital setting, the use of prehospital SI or prehospital mSI as the sole predictor of hypofibrinogenaemia in trauma patients is not recommended.