Effect of positive end-expiratory pressure during anaesthesia induction on nonhypoxic apnoea time in infants: A randomised controlled trial.

BACKGROUND Hypoxaemia occurs frequently in infants during anaesthetic induction. OBJECTIVE We evaluated the effect of positive end-expiratory pressure during anaesthesia induction on nonhypoxic apnoea time in infants. DESIGN Randomised controlled trial. SETTING Tertiary care children's hospital, single centre, from November 2018 to October 2019. PATIENTS We included patients under 1 year of age receiving general anaesthesia. INTERVENTION We assigned infants to a 7 cmH2O or 0 cmH2O positive end-expiratory pressure group. Anaesthesia was induced with 0.02 mg kg atropine, 5 mg kg thiopental sodium and 3 to 5% sevoflurane, and neuromuscular blockade with 0.6 mg kg rocuronium. Thereafter, 100% oxygen was provided via face mask with volume-controlled ventilation of 6 ml kg tidal volume, and either 7 cmH2O or no positive end-expiratory pressure. After 3 min of ventilation, the infants' trachea was intubated but disconnected from the breathing circuit, and ventilation resumed when pulse oximetry reached 95%. MAIN OUTCOME MEASURE The primary outcome was nonhypoxic apnoea time defined as the time from cessation of ventilation to a pulse oximeter reading of 95%, whereas the secondary outcome was the incidence of significant atelectasis (consolidation score ≥2) assessed by lung ultrasound. RESULTS Sixty patients were included in the final analysis. Apnoea time in the 7 cmH2O positive end-expiratory pressure group (105.2 s) increased compared with that in the control group (92.1 s) (P = 0.011, mean difference 13.0 s, 95% CI, 3.1 to 22.9 s). Significant atelectasis was observed in all patients without positive end-expiratory pressure and 66.7% of those with 7 cmH2O positive end-expiratory pressure (P = 0.019, 95% CI, 1.7 to 563.1, odds ratio 31.2). CONCLUSION Positive end-expiratory pressure during anaesthesia induction with face mask ventilation increased nonhypoxic apnoea time in infants. CLINICAL TRIAL REGISTRATION www.clinicaltrials.gov, NCT03540940.