The effect of ventilation rate on outcome in adults receiving cardiopulmonary resuscitation.

Aim: To investigate whether a ventilation rate ≤10 breaths min in adult cardiac arrest patients treated with tracheal intubation and chest compressions in a prehospital setting is associated with improved Return of Spontaneous Circulation (ROSC), survival to hospital discharge and one-year survival with favourable neurological outcome, compared to a ventilation rate >10 breaths min.

Methods: In this retrospective study, prospectively acquired data were analysed. Ventilation rates were measured with end-tidal CO and ventilation pressures. Analyses were corrected for age, sex, compression rate, compression depth, initial heart rhythm and cause of cardiac arrest.

Results: 337 of 652 patients met the inclusion criteria. Hyperventilation was common, with 85% of the patients ventilated >10 breaths min. The mean ventilation rate was 15.3 breaths min. The corrected odds ratio (OR) of ventilating >10 breaths min for achieving ROSC was 0.91 (95% CI: 0.49 - 1.71, p = 0.78), the uncorrected OR of ventilating >10 breaths min for survival to hospital discharge was 0.91 (95% CI: 0.30 - 2.77, p = 0.78), and the uncorrected OR of ventilating >10 breaths min for one-year survival with a favourable neurological outcome was 0.59 (95% CI: 0.19 - 1.87, p = 0.32). A logistic regression with continuous ventilation rate showed no significant relation with ROSC, and a ROC curve for ROSC showed a poor predictive performance (AUC: 0.52, 95% CI: 0.46 - 0.58), suggesting no other adequate cut-off value for ventilation rate.

Conclusion: A ventilation rate ≤10 breaths min was not associated with significantly improved outcomes compared to a ventilation rate >10 breaths min. No other adequate cut-off value could be proposed.