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

AIM OF THE STUDY: This 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.

METHODS: This 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.

RESULTS: The 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.

CONCLUSION: 20 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.