Rationale for withholding professional resuscitation in emergency medical system-attended out-of-hospital cardiac arrest.

Background: Half of out-of-hospital cardiac arrests (OHCA) are deemed inappropriate for resuscitation by emergency medical services (EMS). We investigated patient characteristics and reasons for non-treatment of OHCAs, and determined the proportion involving illicit drug use.

Methods: We reviewed consecutive EMS-untreated OHCA from the British Columbia Cardiac Arrest Registry (2019-2020).