Impact of calcium administration on survival and neurologic outcomes in adults with in-hospital cardiac arrest.

Background: Calcium administration during cardiac arrest has historically been used for its potential inotropic effects, despite limited evidence of benefit. Prior studies in out‑of‑hospital cardiac arrest suggest harm, but data specific to in‑hospital cardiac arrest (IHCA) remain limited. Methods: We conducted a retrospective cohort study of adult IHCA events occurring at a single academic tertiary‑care medical center in the United States between 2011 and 2024, identified from a prospective registry. IHCA events lasting at least 5 min were included. The primary exposure was intravenous calcium gluconate administration during resuscitation. The primary outcome was sustained return of spontaneous circulation (ROSC ≥20 min). Secondary outcomes were survival to hospital discharge and favorable neurological outcome at discharge (Glasgow Outcome Scale score 4-5). Multivariable logistic regression analyses were performed. Results: Among 599 IHCA events, 234 patients (39.1%) received calcium. Calcium administration was associated with significantly lower rates of sustained ROSC (31.6% vs 57.8%), survival to hospital discharge (6.8% vs 18.9%), and favorable neurological outcome (3.0% vs 14.3%; Conclusion: Calcium administration during IHCA was independently associated with lower rates of sustained ROSC, survival to hospital discharge, and favorable neurological outcome. These findings support current guideline recommendations against routine calcium use during undifferentiated IHCA.