Mechanical ventilation with ten versus twenty breaths per minute during cardio-pulmonary resuscitation for out-of-hospital cardiac arrest: A randomised controlled trial

Abstract

Aim of the studyThis study sought to assess the effects of increasing the ventilatory rate from 10 min−1 to 20 min−1 using a mechanical ventilator during cardio-pulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) on ventilation, acid-base-status, and outcomes. MethodsThis was a randomised, controlled, single-centre trial in adult patients receiving CPR including advanced airway management and mechanical ventilation offered by staff of a prehospital physician response unit (PRU). Ventilation was conducted using a turbine-driven ventilator (volume-controlled ventilation, tidal volume 6 ml per kg of ideal body weight, positive end-expiratory pressure (PEEP) 0 mmHg, inspiratory oxygen fraction (FiO2) 100%), frequency was pre-set at either 10 or 20 breaths per minute according to week of randomisation. If possible, an arterial line was placed and blood gas analysis was performed. ResultsThe study was terminated early due to slow recruitment. 46 patients (23 per group) were included. Patients in the 20 min−1 group received higher expiratory minute volumes [8.8 (6.8–9.9) vs. 4.9 (4.2–5.7) litres, p < 0.001] without higher mean airway pressures [11.6 (9.8–13.6) vs. 9.8 (8.5–12.0) mmHg, p = 0.496] or peak airway pressures [42.5 (36.5–45.9) vs. 41.4 (32.2–51.7) mmHg, p = 0.895]. Rates of ROSC [12 of 23 (52%) vs. 11 of 23 (48%), p = 0.768], median pH [6.83 (6.65–7.05) vs. 6.89 (6.80–6.97), p = 0.913], and median pCO2 [78 (51–105) vs. 86 (73–107) mmHg, p > 0.999] did not differ between groups. Conclusion20 instead of 10 mechanical ventilations during CPR increase ventilation volumes per minute, but do not improve CO2 washout, acidaemia, oxygenation, or rate of ROSC.ClinicalTrials.gov Identifier: NCT04657393.