Duration of exposure to a prehospital advanced airway and neurological outcome for out-of-hospital cardiac arrest: A retrospective cohort study

Background: Out-of-hospital cardiac arrest (OHCA) studies have focused on the benefits and harms of placing an intra-arrest advanced airway, but few studies have evaluated the benefits and harms after successful placement. We hypothesize that increased time in the tumultuous prehospital environment after intra-arrest advanced airway placement results in reduced patient survival. Methods: This was a secondary analysis of adult, non-traumatic, OHCA patients with an advanced airway placed in the PRIMED trial. The exposure variable was the time interval between successful advanced airway placement and Emergency Department (ED) arrival. The outcome was cerebral performance category (CPC) 1 or 2 at hospital discharge. Multivariable logistic regression, adjusted for Utstein variables and resuscitation-associated time intervals, was used to estimate adjusted odds ratios (aOR). Results: The cohort of complete cases included 4779 patients. The median time exposed to a prehospital advanced airway was 27 min (IQR 20–35). The total prehospital time was 39.4 min (IQR 32.3−48.1). An advanced airway was placed intra-arrest in 3830 cases (80.1%) and post-return of spontaneous circulation (post-ROSC) in 949 cases (19.9%). Overall, 486 (10.2%) of the cohort achieved the CPC outcome, but this was higher in the post-ROSC (21.7%) versus intra-arrest (7.5%) cohort. CPC was not associated with the time interval from advanced airway placement to ED arrival in the intra-arrest airway cohort (aOR 0.98, 95%CI 0.94−1.01). Conclusions: In OHCA patients who receive an intra-arrest advanced airway, longer time intervals exposed to a prehospital advanced airway are not associated with reduced patient survival.