Higher ventilation rate is associated with increased return of spontaneous circulation in in-hospital cardiac arrest patients with advanced airways

Abstract

BACKGROUND: Current CPR guidelines recommend 10 breaths/min in adult cardiac arrest patients with an advanced airway, though this is largely based on animal studies. We evaluated the association between ventilation rate and return of spontaneous circulation (ROSC) in in-hospital cardiac arrest (IHCA). METHODS: This was a secondary analysis of a cohort undergoing CPR for IHCA with an advanced airway and continuous ventilation and end-tidal CO(2) (ETCO(2)) monitoring. Patients were enrolled from 25 tertiary centers in the U.S. and U.K. A subset had intra-arrest arterial blood gases collected per routine care. RESULTS: Ventilation and ETCO(2) data were collected for 222 patients; blood gas data were available for 127. Of these 222 patients, 84.7 % were ventilated at >10 breaths/min. Patients ventilated >12 breaths/min had higher ROSC rates compared to those ventilated at 6-12 breaths/min (45 % vs. 24 %, p = 0.009). Ventilation rate remained independently associated with ROSC after adjustment for age, sex, cardiac rhythm, illness severity, and mechanical chest compression device use (adjusted OR 1.15 per 2 breaths/min increase; 95 % CI 1.04-1.28; p = 0.006). Regression analysis suggested diminishing benefit above 26 breaths/min. Patients ventilated >12 breaths/min had higher ETCO(2) (median 25 mm Hg vs. 17 mm Hg; p < 0.001). PaO(2) and PaCO(2) did not differ significantly, suggesting a hemodynamic mechanism. CONCLUSIONS: Ventilation rates above guideline recommendations were common. Rates between 12 and 26 breaths/min were associated with improved ROSC, potentially due to enhanced perfusion. However, these findings may equally reflect the impact of higher quality chest compressions that can sometimes lead to ETCO(2) oscillations that can be erroneously computed as breaths by ETCO(2) monitors. Thus, more studies are needed to determine the need to re-evaluate current ventilation targets during CPR in intubated patients.