Keeping it simple: the value of mortality prediction after trauma with basic indices like the Reverse Shock Index multiplied by Glasgow Coma Scale

Abstract

BackgroundIdentification of trauma patients at significant risk of death in the prehospital setting is challenging. The prediction probability of basic indices like vital signs, Shock Index (SI), SI multiplied by age (SIA) or the GCS is limited and more complex scores are not feasible on-scene. The Reverse SI multiplied by GCS score (rSIG) has been proposed as a triage tool to identify trauma patients with an increased risk of dying at EDs. Age adjustment (rSIG/A) displayed no advantage.We aim to (1) validate the accuracy of the rSIG in predicting death or early transfusion in a large trauma registry population, and (2) determine if the rSIG is valid for evaluation of trauma patients in the prehospital setting.Methods70 829 trauma patients were retrieved from the TraumaRegister DGU database (time period between 2008 and 2017). The area under the receiver operating characteristic curve (AUROC) was calculated to measure the ability of SI, SIA, rSIG and rSIG divided by age (rSIG/A) to predict in-hospital mortality from data at the time of hospital arrival and solely from prehospital data.ResultsThe rSIG at time of hospital admission was not sufficiently predictive for clinical decision-making. However, rSIG calculated solely from prehospital data accurately predicted risk of death. Using prehospital data, the AUROC for mortality of rSIG/A was the highest (0.85; CI: 0.85 to 0.86), followed by rSIG (0.76; CI: 0.75 to 0.77), SIA (0.71; CI: 0.70 to 0.71) and SI (0.48; CI: 0.47 to 0.49).ConclusionThe prehospital rSIG/A can be a useful adjunct for the prehospital evaluation of trauma patients and their allocation to trauma centres or trauma team activation. However, we could not confirm that the rSIG at hospital admission is a reliable tool for risk stratification.

Response to: The rSIG for trauma: one size fits all?

“…While we agree with Shi and Mao that considering site of trauma in general is an important contributor in advanced prediction model, we feel the need to emphasise that the aim was not to determine the best possible prediction model, but to find a reasonable compromise between fast and easy applicability in combination with a high prediction accuracy 2. Well-established tools for risk adjustment like the Injury Severity Score, the Trauma and Injury Severity Score (TRISS) or the Revised Injury Severity Classification V.2 (RISC2) consider the site of trauma but can only be applied knowing all relevant injuries or blood results.…”

“…We thank Shi and Mao for their interest1 in our recently published article on The age-adjusted Reverse Shock Index multiplied by the Glasgow Coma Scale (rSIG/A) in prehospital assessment of trauma patients and their allocation to trauma centres or trauma team activation 2. The authors point out some shortcomings in our manuscript.…”

“…With regard to calibration, we would like to refer to figure 3, where rSIG based on prehospital data is plotted against observed mortality 2. It shows that the prediction fits both high and low values, indicating that the projected probabilities are indeed consistent with the observed frequencies of the events under consideration, even though calibration models based on calculation were not performed.…”

“…Finally, rSIG/A was not designed as a ‘one-size-fits-all strategy’ but proposed as a useful adjunct for the prehospital evaluation of trauma patients 2…”

The rSIG for trauma: one size fits all？

“…We read with great interest the article by Frieler et al 1. The authors validated the accuracy of the rSIG (SBP/HR×GCS) in predicting the risk of mortality in trauma patients.…”