Delta shock index in the emergency department as a predictor of clinical outcomes in traumatic injury

Objectives

The shock index (SI) is widely used to screen for patients in shock, and the dSI is created by utilizing prehospital SI and emergency department SI to enhance predictive accuracy. However, few have compared dSI with prehospital SI and SI at ED, and even fewer have explored the directional changes in dSI. This study aims to evaluate the prediction accuracy of prehospital SI, SI at ED, and delta SI in trauma patients, proposing that the delta scoring systems provide a more precise tool for field triage.

Patients and methods

This study conducted a cohort analysis involving 48,524 patients from the trauma registry data at Tzu Chi Hospital. The three primary outcomes assessed were in-hospital mortality, intensive care unit (ICU) admission, and prolonged total length of hospital stay (≥ 30 days). The area under the receiver operating characteristic curve (AUROC) for these scores was calculated and compared using the DeLong test. The delta SI was calculated as the difference between prehospital SI and SI at the emergency department (ED). The dSI was categorized into five groups: dSI < −0.5, −0.5 ≤ dSI < −0.1, −0.1 ≤ dSI < 0.1, 0.1 ≤ dSI < 0.5, and 0.5 ≤ dSI.

Results

Prehospital SI, SI at ED, and dSI were significant predictors of in-hospital mortality, ICU admission, and prolonged length of stay (LOS) of ≥30 days. Compared to prehospital SI and SI at ED, dSI demonstrated significantly higher AUROC values in discriminating major injury, prolonged ICU stay, and in-hospital mortality. The groups with dSI < −0.5 and dSI ≥ 0.5 exhibited a significantly higher risk of in-hospital mortality compared to other dSI group with adjusted odds ratio (aOR) of 2.170 and 2.976. A J-shaped relationship in aOR values was observed across different dSI ranges for in-hospital mortality. The dSI ≥ 0.5 group had an increased risk of in-hospital mortality among elderly patients, those with major or minor injuries, and both TBI and non-TBI groups. The dSI ≥ 0.1 demonstrated accuracies of 80.94 % for predicting ISS ≥ 16, 72.91 % for ICU admission, 87.14 % for prolonged LOS ≥ 30 days, and 89.33 % for predicting mortality.

Conclusions

The dSI demonstrated significantly better discriminative ability for major injury, prolonged ICU stay, and in-hospital mortality. A potential J-shaped relationship has been identified between dSI and mortality, indicating that both the dSI < −0.5 and dSI ≥ 0.5 groups have a significantly higher risk of in-hospital mortality. It is anticipated that dSI will be integrated into clinical practice for the field triage of trauma patients in the future.