Abstract 243: Out-of-hospital Cardiac Arrest in the Outpatient Clinical Environment

Abstract

Background: Out-of-hospital cardiac arrest (OHCA) remains a leading cause of death in the US, affecting over 400,000 annually. Although outcomes have improved, rates of return of spontaneous circulation (ROSC) and survival are lower from OHCA than from in-hospital cardiac arrest. Clinical emergencies, including OHCA, in outpatient clinical settings are often first attended by rapid response teams (RRT), but the causes and outcomes from OHCA in these environments has not been characterized. An understanding of this population is critical both for RRT quality improvement and resource allocation. Objectives: We aimed to describe OHCA that occurred in outpatient clinical environments. We hypothesized that OHCA in ambulatory settings would be uncommon and would be concentrated in a limited number of higher-risk outpatient areas. Methods: Retrospective analysis of all RRT calls for non-hospitalized adult outpatients occurring between 2012- 2020 at the Hospital of the University of Pennsylvania. Results: There were 7336 RRT calls;25 were for OHCA. Information was available for 24 of these. Mean age was 64 +/- 16.7 y, and 38% were female. Initial rhythm was pulseless electrical activity in 79%, ventricular fibrillation in 13%, asystole in 4%, and was not recorded in 4%. CPR was initiated in all cases prior to the arrival of the RRT. ROSC was obtained in 84%, extracorporeal membrane oxygenation (ECMO) was initiated in 8%, and 8% did not survive. ROSC was obtained within 5 min in 58% of cases. Of those that attained ROSC, 75% survived to discharge, 80% with good neurological status (CPC 1-2). Most events (54%) were judged to be iatrogenic. Of these, 54% were due to anaphylaxis, 15% were during cardiac stress testing, and 31% were peri-procedural. The most common causes of anaphylaxis were chemotherapeutics and radiographic contrast agents. Conclusions: OHCA events are uncommon in the outpatient clinical setting and are frequently iatrogenic. These events are associated with high rates of ROSC and neurologically intact survival. Iatrogenic OHCA occurred during a limited number of clinical settings, including outpatient procedural, , infusion, and stress test locations.. This finding suggests the need to focus resuscitation training in these specific environments.