Abstract Body: Background: While early vasopressor administration (epinephrine, vasopressin) and early advanced airway management (laryngeal tube [LT], endotracheal intubation [ETI]) have been associated with improved outcomes after out-of-hospital cardiac arrest (OHCA), their optimal sequence during resuscitation remains unclear.

Aims: To determine the associations between vasopressor-airway resuscitation sequence and OHCA outcomes and quality of cardiopulmonary resuscitation (CPR) in the Pragmatic Airway Resuscitation Trial (PART).

Methods: Secondary analysis of the PART trial, which compared initial airway strategies of LT vs. ETI in adults with OHCA. For each patient we determined times of advanced life support (ALS) rescuer arrival, first vasopressor administration, and first successful airway insertion. We defined resuscitation sequence as: 1) vasopressor-first or 2) airway-first. We excluded cases with either vasopressor or airway given before ALS arrival and those that received neither. We used Generalized Estimating Equations to determine associations between resuscitation sequence and outcomes (72-hour survival, ROSC, survival to hospital discharge, survival with favorable neurologic status) and CPR quality (chest compression rate 100-120 per min, chest compression fraction (CCF) ≥0.8, ventilation rate 8-12 per min), adjusting for known confounders. Secondary analyses stratified by initial rhythm (shockable vs. non-shockable) and time to first intervention (vasopressor or airway, ≤10 vs. >10 mins).

Results: Of 3,004 patients in the parent trial, we included 2,404, including 1,821 vasopressor-first and 583 airway-first. Median intervention times were: ALS arrival-to-vasopressor 8 mins (IQR 6-11) and ALS arrival-to-airway 11 mins (8-15). Compared with airway-first, vasopressor-first sequence was not associated with 72-hour survival (aOR 0.89; 95% CI: 0.66-1.20), ROSC (0.79; 0.62-1.001), hospital survival (0.98; 0.63-1.53), or hospital survival with favorable neurologic status (0.84; 0.47-1.51). Associations were similar when stratified by initial rhythm or time to first intervention. In those with available chest compression (n=1,699) and ventilation (n=892) data, vasopressor-first sequence was not associated with chest compression rate (aOR 0.90; 95% CI: 0.73-1.11), CCF ≥0.8 (0.94; 0.72-1.21) or ventilation rate 8-12 per min (0.79; 0.57-1.08).

Conclusions: Vasopressor-airway resuscitation sequence is not associated with OHCA outcomes or CPR quality.