Shock index and delta-shock index are superior to existing maternal early warning criteria to identify postpartum hemorrhage and need for intervention

Abstract

Objective: To determine whether shock index (SI) is superior to traditional vital signs in predicting postpartum hemorrhage and need for intervention.

Methods: Retrospective case-control study in an academic tertiary-care county hospital. Forty-one consecutive postpartum hemorrhage (PPH) cases and 41 controls were frequency-matched by mode of delivery and maternal weight. We measured four criteria: heart rate, systolic blood pressure (SBP), SI (HR/SBP), and delta-SI (peak SI – baseline SI). Using received operating characteristic curves, we compared the discrimination performance of each criterion to predict PPH, transfusion, and surgical intervention, and identified thresholds with the strongest classification.

Results: SI ≤1.1 can be normal in peripartum. Peak SI and delta-SI were generally superior to heart rate (HR) and SBP in predicting PPH, transfusion, and surgical intervention. SI ≥1.143 and SI ≥1.412 were strong initial and “critical” thresholds. Delta-SI was the strongest classifier overall; both SI and delta-SI remain sensitive and specific when adjusted for potential confounders.

Conclusions: SI and delta-SI appear to be superior to HR and SBP in predicting PPH and need for intervention. Utility of delta-SI should be prospectively explored.

Keywords:

• Blood pressure
• heart rate
• obstetric labor
• postpartum hemorrhage
• shock index

Disclosure statement

GAD is a coinventor and patent holder of the Ebb Balloon Tamponade System (for postpartum hemorrhage) licensed to clinical innovations. JRK and CSE do not have financial, personal, political, intellectual, or religious interests.

Ethical approval

Institutional Review Board approval was granted for this work prior to any data collection (Human Protocol 37476).

Funding

There was no funding associated with this work.