Shock index thresholds to predict adverse outcomes in maternal hemorrhage and sepsis: A prospective cohort study

Abstract

Introduction: Shock index (SI) is a predictor of hemodynamic compromise in obstetric patients. The SI threshold for action is not well understood. We aimed to evaluate SI thresholds as predictors of outcomes in obstetric patients. Material and methods: We undertook a prospective cohort study at three South African hospitals of women with postpartum hemorrhage (n = 283) or maternal sepsis (n = 126). The “first” and “worst” SI following diagnosis were recorded. SI was compared with conventional vital signs as predictors of outcomes. The performance of SI <70 g/l; blood transfusion ≥4 IU) were evaluated. Results: “First” SI was one of two best performing vital signs for every outcome in postpartum hemorrhage and sepsis. In hemorrhage, risk of all outcomes increased with increasing “first” SI; for blood transfusion ≥4 IU odds ratio was 4.24 (95% confidence interval 1.25-14.36) for SI ≥1.7 vs SI.9-1.69. In sepsis, risk of all outcomes increased with increasing “worst” SI. Sensitivity, specificity, positive and negative predictive values of “first” SI