Pressure‐controlled versus manual facemask ventilation for anaesthetic induction in adults: A randomised controlled non‐inferiority trial

Abstract

AbstractBackgroundPressure‐controlled face mask ventilation (PC‐FMV) with positive end‐expiratory pressure (PEEP) after apnoea following induction of general anaesthesia prolongs safe apnoea time and reduces atelectasis formation. However, depending on the set inspiratory pressure, a delayed confirmation of a patent airway might occur. We hypothesised that by lowering the peak inspiratory pressure (PIP) when using PC‐FMV with PEEP, confirmation of a patent airway would not be delayed as studied by the first return of CO2, compared with manual face mask ventilation (Manual FMV).MethodsThis was a single‐centre, randomised controlled non‐inferiority trial. Seventy adult patients scheduled for elective day‐case surgery under general anaesthesia with body mass index between 18.5 and 29.9 kg m−2, American Society of Anesthesiologists (ASA) classes I–III, and without anticipated difficult FMV, were included. Before the start of pre‐oxygenation and induction of general anaesthesia, participants were randomly allocated to receive ventilation with either PC‐FMV with PEEP, at a PIP of 11 and a PEEP of 6 cmH2O or Manual FMV, with the adjustable pressure‐limiting valve set at 11 cmH2O. The primary outcome variable was the number of ventilatory attempts needed until confirmation of a patent airway, defined as the return of at least 1.3 kPa CO2.ResultsThe return of ≥1.3 kPa CO2 on the capnography curve was observed after mean ± SD, 3.6 ± 4.2 and 2.5 ± 1.9 ventilatory attempts/breaths with PC‐FMV with PEEP and Manual FMV, respectively. The difference in means (1.1 ventilatory attempts/breaths) had a 99% CI of −1.0 to 3.1, within the accepted upper margin of four breaths for non‐inferiority.ConclusionFollowing induction of general anaesthesia, PC‐FMV with PEEP was used without delaying a patent airway as confirmed with capnography, if moderate pressures were used.