(387) Cumulative Blood Loss and Maternal Early Warning System triggers

We analyzed all birth hospitalizations at a southeastern quaternary care hospital during a 2.5-year period between January 2018 and June 2021. Maternal vital sign flowsheet data within 12 hours of birth and blood loss within 24 hours of birth were extracted from the electronic health record. We used vital sign flowsheet data to determine whether MEWS criteria were met for systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), respiratory rate (RR) or oxygen saturation (SaO2), or whether the patient experienced a shock index (HR/SBP) >= 1 within 12 hours of birth (Table). Data were stratified by blood loss categories. 


Results: CBL exceeded 1,000ml for 2,024 (15.1%) of 13,433 deliveries in the study period. A total of 531,242 vital sign observations were extracted and analyzed; 5,816 birthing people (43.3%) had at least one MEWS indicator, and 3,862 (28.8%) had a shock index >=1 within 12 hours of birth. Blood loss category was strongly associated with MEWS indicators and shock index (Table 1, chi square p < .0001 for each indicator); however, among deliveries with a cumulative blood loss of >=1,000ml, 1119 (55.3%) never had a shock index >=1, and 789 (39.0%) had no vital signs that met MEWS criteria.

Conclusion: In a series of 2,024 deliveries with cumulative loss >=1,000ml, more than a third did not meet MEWS criteria for urgent bedside evaluation. Reliance on vital signs to detect significant blood loss may result in delayed diagnosis and treatment of obstetric hemorrhage.