Predictive value of shock index ≥ 1 in severe trauma patients in emergency department

Abstract

Background: the shock index (SI) defined by the ratio of systolic blood pressure to heart rate was demonstrated as a simple tool in the triage and orientation of severe trauma patients to trauma centers.
Aim: To assess the prognostic value of the SI ≥ 1 in terms of mortality in severe trauma patients admitted to the emergency room.
Methods: We performed a prospective, observational and descriptive study with the inclusion of severe trauma patients over the age of 18 years admitted to the Vital Emergency Room over a 21-month period. SI was calculated at admission: SI = heart rate / systolic blood pressure, a SI threshold value ≥1 was fixed to define two groups: SI<1 and SI≥1.
Results:A total of 290 trauma patients were included, 231 (79%) had a SI<1, whereas 59 (21%) had an SI≥1. Mean age was 43.5 ± 18 years, 82% were male. There was a significant difference in hospital mortality at 7 days and at 30 days between the two groups respectively (group SI<1 vs group SI≥1): [12% vs 40%; p <0.001 and 15% vs 47%; p <0.001]. In multivariate analysis, SI≥1 appears as an independent factor of hospital mortality at 7 days [OR = 2.03; 95% CI = 1.3-3.3; p =0.001] and at 30 days [OR = 2.69; 95% CI = 1.4- 5; p =0.002].                                                                                        
Conclusion: In severe trauma patients admitted to the emergency department; a SI ≥1 represents a predictive factor of hospital mortality at 7 days and one month.