Optimal positive end-expiratory pressure to prevent anaesthesia-induced atelectasis in infants A prospective, randomised, double-blind trial

Abstract

BACKGROUND Paediatric patients have a particularly high incidence of anaesthesia-induced atelectasis. Applying positive end-expiratory pressure (PEEP) with an alveolar recruitment manoeuvre has been substantially studied and adopted in adults; however, few studies have been conducted in children. OBJECTIVE We compared the effects of three levels of PEEP (3, 6 and 9 cmH(2)O) on anaesthesia-induced atelectasis measured by ultrasound in infants between 6 and 12 months of age who were undergoing general anaesthesia. DESIGN A prospective, randomised, double-blind trial. SETTING Department of Anaesthesia, single centre, South Korea, from May 2019 to March 2020. PATIENTS Children who were 6 to 12 months of age, whose American Society of Anesthesiologists (ASA) physical status was 1 or 2, whose height and weight were within two standard deviations of those of their peers, and who were scheduled for elective urological or general surgery were included in the study. MAIN OUTCOME MEASURES The primary outcome was the lung ultrasound score at the end of the procedure. The secondary outcomes included dynamic compliance, peak inspiratory pressure, driving pressure, cardiac index, mean arterial pressure and heart rate before and after applying PEEP. RESULTS The mean lung ultrasound score at the end of operation was 12.8 at PEEP 6 cmH(2)O and 12.1 at PEEP 9 cmH(2)O. Both were significantly lower than 18.4 at PEEP 3 cmH(2)O (P = 0.0002 and 0.00003, respectively). However, there was no significant difference between the scores of PEEP 6 cmH(2)O and PEEP 9 cmH(2)O. The Delta cardiac index (the cardiac index after PEEP - the cardiac index at 3 cmH(2)O of PEEP) was comparable among the three groups. CONCLUSION To reduce anaesthesia-induced atelectasis measured by ultrasound in healthy infants undergoing low abdominal, genitourinary or superficial regional operations, 6 cmH(2)O of PEEP was more effective than 3 cmH(2)O. PEEP of 9 cmH(2)O was comparable with 6 cmH(2)O.