Abstract 11488: Ventilation Rate and Sustained Return of Spontaneous Circulation in In-Hospital Cardiac Arrest: Is More Better?

Abstract

Introduction: Current consensus holds that CPR must balance chest compressions and ventilation rate (VR), with a low VR being essential for venous return and cardiac output. AHA guidelines recommend a VR of 10 ventilations per minute (vpm) after advanced airway placement. We sought to examine VR adherence and its impact on end-tidal CO 2 (ETCO 2 ) and ROSC >20 minutes. Methods: This is a retrospective analysis of data from AWARE II, a multicenter prospective observational study of adult in-hospital cardiac arrest (IHCA) outcomes at 14 US and UK sites. Inclusion criteria were: 1) adult patient in CA, 2) advanced airway already in place or placed during the CA, and 3) at least one minute of VR and ETCO 2 data available after removal of the last minute of CPR in subjects achieving ROSC (due to the rise of ETCO 2 just prior to ROSC). Results: A total of 563 subjects were enrolled in the parent study. Of these, 225 had ETCO 2 and VR tracings available, and 201 had sufficient data for inclusion. Mean age was 69.3 (range 18-100), patients were 63.7% male, and 16.4% had a shockable initial rhythm. A total of 116 subjects (57.7%) achieved ROSC, which was sustained in 76 (37.8%), leading to survival to hospital discharge with favorable neurological outcomes in 9 (4.5%). Mean VR was 16.3 vpm, with 171 (85.1%) subjects being ventilated in excess of guidelines; only 16 (8.0%) subjects received 8-10 vpm. Higher VR had a weak but significant association with increased mean ETCO 2 (linear R 2 = 0.11, p < 1x10 -6 ) and sustained ROSC (OR 1.05; 95% CI: 1.01-1.11; p = 0.02). Patients with sustained ROSC had a significantly higher VR at 17.7 vpm than those without sustained ROSC at 15.6 vpm (p = 0.007). Patients receiving a VR close to AHA guidelines (6-12 vpm) had a significantly lower rate of sustained ROSC (26.1%, n = 46) than patients receiving >12 vpm (42.0%, n = 148) (OR 2.30; 95% CI: 1.08-4.89; p = 0.031 using a multivariate model including patient age, shockable initial rhythm, known cardiac disease, witnessed IHCA, and use of mechanical compressions). Conclusions: VR within AHA guidelines is rare during IHCA. However, ventilation in excess of current guidelines may increase rates of sustained ROSC, an essential predicate to survival. AHA guidelines on VR in CPR with an advanced airway may not yet be optimized.