Shock Index and Modified Shock Index as Predictors of 24 Hour Mortality in Patients with Polytrauma

Abstract

Abstract Context: The failure of the vital signs to predict the severity of shock and the drawbacks of the trauma scoring systems have led to extensive research on shock index in polytrauma patients. This prospective, observational study was conducted to study the efficacy of the Shock Index (SI) and Modified Shock Index (MSI) as predictors of 24 h mortality in polytrauma patients. Aim: To validate the Shock index and Modified Shock index as predictors of 24 h mortality in polytrauma patients. Method: All patients presenting with polytrauma meeting the inclusion criteria were evaluated using the following parameters: Heart rate, Systolic blood pressure, and Diastolic blood pressure, following which SI and MSI were calculated. Abbreviated Injury Score (AIS) & Injury Severity Score (ISS) were formulated. The endpoint of the study was hospital stay, ICU stay, and 24 h mortality. Statistical Analysis: The sensitivity, specificity, positive predictive value, negative predictive value, odds ratio, positive likelihood ratio, and negative likelihood ratio of SI and MSI were evaluated using Graphpad software. ROC curves and scatter diagrams were also plotted. Results: SI >0.9 has a sensitivity of 96% and a negative predictive value (NPV) of 93.75%. Similarly, MSI >1.3 has a sensitivity of 96% and NPV of 94.12%. Statistically, a significant correlation was observed between SI & MSI with ISS, ICU stay, and hospital stay. Conclusion: SI and MSI are effective predictors of 24 h mortality but less efficient in predicting mortality that does not occur before 24 h. Higher SI & MSI values are related to higher ISS, and longer duration of ICU & hospital stays.