Abstract 13071: Supraglottic Airway Devices Are Associated With Asphyxial Physiology Upon Arrival for ECPR in Patients With Refractory OHCA Treated With Prolonged CPR

Introduction: Multiple clinical trials have failed to show significant differences in survival between use of endotracheal intubation (ETI) and supraglottic airway devices (SGA) in patients with out-of-hospital cardiac arrest (OHCA). However, treatment in these trials was limited to standard ACLS, which favors short duration of CPR. We sought to compare the physiological effect of ETI versus SGA use in patients treated with prolonged CPR and extracorporeal pulmonary resuscitation (ECPR) for refractory ventricular fibrillation/ventricular tachycardia (VT/VF) by the Minnesota Mobile Resuscitation Consortium (MMRC). Methods: Consecutive refractory VT/VF OHCA patients transported by the MMRC to the University of Minnesota for ECPR between 2015 and 2021 were included in this retrospective analysis. Patients were considered ineligible for ECPR if they failed specific arterial blood gas metabolic criteria (lactic acid >18 mmol/L, PaO2 <50 mmHg, and ETCO2 <10 mmHg). Metabolic parameters at presentation and survival were compared between patients receiving ETI and SGA. Results: Among 260 patients (58.0±11.8 years), 46.5% received ETI and 53.5% received SGA. During the index hospitalization, 78/260 (30%) achieved neurologically favorable survival. Compared to those receiving ETI, patients receiving SGA had lower PaO2 (116.8±118.7 versus 135.8±128.3 mmHg, p=0.03), higher PaCO2 (69.7±28.9 versus 60.7±25.6 mmHg, p=0.01), and lower pH (7.00±0.19 versus 7.06±0.21, p=0.008). Significantly more patients who received SGA had PaO2 <50mmHg (29.1% versus 16.9%, respectively; p=0.02) and ≥1 ECPR exclusion criteria (33.1% versus 20.7%, respectively; p=0.03). Among patients excluded for PaO2 <50 mmHg, the presenting PaO2 was 35.5±11.0 mmHg and the presenting PaCO2 was 94.5±26.2 mmHg, suggestive of absence of effective ventilation (asphyxia) at presentation. Survival with CPC 1-2 was 34.7% versus 25.9% for ETI versus SGA, respectively (p=0.12). Conclusion: Use of SGA, during prolonged CPR in refractory VT/VF OHCA, was associated with a significant increase in the proportion of patients presenting with significant hypoxemia and asphyxial physiology, thus increasing ineligibility for ECPR.