Characteristics and Outcomes of Rapid Response System Activations in Obstetric Patients: A Multicenter Registry-Based Study in Japan.

OBJECTIVE

Maternal clinical deterioration during the perinatal period remains a major safety concern. Rapid response systems (RRSs) facilitate early recognition and intervention for clinical deterioration; however, evidence regarding obstetric RRS activations is limited. This study examined the characteristics and outcomes of obstetric RRS activations using a multicenter registry in Japan.

METHODS

This retrospective cohort study analyzed patients with RRS activation in the In-Hospital Emergency Registry in Japan (52 hospitals; November 2017-August 2024). Obstetric patients were defined as those pregnant or within 1 week postpartum at RRS activation. We evaluated patient characteristics, activation patterns, triggers, interventions, causes of deterioration, and outcomes in obstetric patients. Obstetric and non-obstetric patients (all other patients in the cohort) were also compared to identify differences in activation patterns, triggers, and interventions.

RESULTS

Among 16,125 patients with RRS activation, 141 (0.9%) were obstetric patients (median age, 34 years). Obstetric RRS activations were more frequently physician-initiated (31.8% vs 18.1%) and occurred more often during nighttime (17:00-7:59; 47.1% vs 32.9%) than non-obstetric activations. Common triggers for obstetric RRS activations were decreased consciousness (34.0%), massive bleeding (31.2%), and hypotension (29.8%), each more frequent than in non-obstetric activations (26.0%, 2.4%, and 22.3%, respectively). Common interventions in obstetric activations were diagnostic testing (39.6%), fluid bolus (36.4%), and oxygen administration (34.5%); fluid bolus (36.4% vs 19.2%) and transfusion (20.7% vs 2.9%) were performed more frequently than in non-obstetric activations. Among obstetric patients, massive hemorrhage was the leading cause of deterioration (39.0%); 29.1% were admitted to the intensive care unit, and no deaths occurred.

CONCLUSION

Obstetric RRS activations were most often triggered by decreased consciousness, massive bleeding, and hypotension, with massive hemorrhage as the predominant cause of deterioration. These findings provide a detailed characterization of obstetric RRS activations and may inform rapid response practices and patient safety approaches in obstetric care.