The Apnea Interval: Ventilation interruption during tracheal intubation and its association with cardiac arrest resuscitation care and outcome.

Abstract

Background: Guidelines for out-of-hospital cardiac arrest (OHCA) resuscitation recommend advanced airway management without interrupting chest compressions. However, the extent and impact of interrupting ventilation is unknown. We described the apnea interval that occurs during tracheal intubation and its association with clinical outcomes.

Methods: We conducted a cohort investigation of adult ventricular fibrillation (VF) OHCA patients who underwent attempted tracheal intubation prior to return of spontaneous circulation (ROSC) in a metropolitan EMS system (2017-2020). Apnea interval was defined as elapsed time between last breath delivered before and first breath delivered following tracheal intubation attempt. We used multivariable logistic regression to determine the relationship between apnea interval (≤60s vs >60s) and outcomes: ROSC, survival to hospital discharge, and favorable neurologic survival (CPC 1-2).

Results: Among 254 patients, median age was 65 years, 18% were female, and 98% had tracheal intubation success. Overall, 151 (59%) achieved ROSC, 71 (28%) survived to discharge, and 67 (26%) with favorable survival. The median apnea interval during attempted tracheal intubation was 84s (64-113s). Median chest compression fraction was 85% overall and 87% during the apnea interval. In unadjusted and adjusted analyses, a shorter apnea interval was associated with better outcomes: ROSC (72% vs 56%), survival (39% vs 25%), and favorable survival (39% vs 23%) (p<0.05 for each comparison).

Conclusions: In this VF-OHCA cohort, shorter apnea intervals (≤60 seconds) were associated with greater likelihood of favorable outcomes. Given its variability and relationship to outcomes, the apnea interval may be a modifiable measure to improve OHCA survival.