COBRA: COde Blue Retrospective Audit in a metropolitan hospital

Inhospital cardiac arrest (IHCA) is an uncommon but challenging problem.

To investigate the management and outcomes of IHCA, and to investigate the effect of introducing a medical emergency team (MET) on IHCA prevalence.

Retrospective medical record review of 176 adult IHCA episodes at Box Hill Hospital, a university-affiliated public hospital in metropolitan Melbourne, from July 2012 to June 2017. Inpatients receiving cardiopulmonary resuscitation for IHCA, in inpatient wards, intensive care unit, cardiac catheterisation laboratory and operating theatres were included. Data collected included demographics, resuscitation management and outcomes. Average treatment effect (ATE) was derived from margins estimates and linear regression fitted to hospital outcome, adjusted for IHCA factors. An exponentially weighed moving average control chart was used to explore IHCA prevalence over time.

There were 65.3% of IHCA patients who died in hospital. IHCA prevalence was unchanged after the introduction of a dedicated MET service. Factors associated with higher likelihood of survival to discharge were initial cardiac of rhythm ventricular tachycardia (VT) (ATE 0.10 (95% CI = -0.03 to 0.25)) or ventricular fibrillation (VF) (ATE 0.28 (95% CI = 0.11-0.46)), cardiac monitoring at the time of arrest (ATE 0.06 (95%CI = -0.04 to 0.16)) and time to return of spontaneous circulation (ATE 0.023 (95% CI = 0.015-0.031)).

IHCA is uncommon and is associated with high mortality. IHCA prevalence was unchanged after the introduction of a dedicated MET service. Factors associated with improved survival to hospital discharge were initial rhythm VT or VF, cardiac monitoring and shorter resuscitation times.