The Shock Index as a Predictor of Vasopressor Use in Emergency Department Patients with Severe Sepsis

INTRODUCTION Severe sepsis is a leading cause of non-coronary death in hospitals across the United States. Early identification and risk stratification in the emergency department (ED) is difficult because there is limited ability to predict escalation of care. In this study we evaluated if a sustained shock index (SI) elevation in the ED was a predictor of short-term cardiovascular collapse, defined as vasopressor dependence within 72 hours of initial presentation. METHODS Retrospective dual-centered cross-sectional study using patients identified in the Yale-New Haven Hospital Emergency Medicine sepsis registry. RESULTS We included 295 patients in the study with 47.5% (n=140) having a sustained SI elevation in the ED. Among patients with a sustained SI elevation, 38.6% (54 of 140) required vasopressors within 72 hours of ED admission contrasted to 11.6% (18 of 155) without a sustained SI elevation (p=0.0001; multivariate modeling OR 4.42 with 95% confidence intervals 2.28-8.55) . In the SI elevation group the mean number of organ failures was 4.0 ± 2.1 contrasted to 3.2 ± 1.6 in the non-SI elevation group (p=0.0001). CONCLUSION ED patients with severe sepsis and a sustained SI elevation appear to have higher rates of short-term vasopressor use, and a greater number of organ failures contrasted to patients without a sustained SI elevation. An elevated SI may be a useful modality to identify patients with severe sepsis at risk for disease escalation and cardiovascular collapse.