Effects of positive end-expiratory pressure on pulmonary atelectasis after paediatric laparoscopic surgery as assessed by ultrasound: A randomised controlled study

Positive end-expiratory pressure (PEEP) following alveolar recruitment manoeuvre (RM) can effectively prevent anaesthesia-induced atelectasis in children. We aimed to evaluate the individual effect of PEEP following RM on atelectasis at the end of laparoscopic surgery in infants and small children.Children undergoing laparoscopic inguinal hernia repair aged 5 weeks to 2 years were randomly allocated to either the PEEP or control group. A progressive RM was performed after intubation in all cases. The PEEP group received PEEP of 5 cmH2O until the end of mechanical ventilation, while the control group did not receive any PEEP. Lung ultrasonography was performed to compare the number of atelectatic regions between the two groups after anaesthesia induction, after RM, and at the end of surgery in 12 thoracic regions.Overall, 432 ultrasonographic images were acquired from 36 children. At the end of surgery, the number of atelectatic regions (median [interquartile range]) was significantly lower in the PEEP group compared to the control group (2.0 [1.0-3.0] versus 4.0 [3.0-4.0] out of 12 regions, respectively; p = 0.02). While no difference was observed between the number of atelectatic regions after induction and at the end of surgery in the control group (p = 0.30), a decrease was observed in the PEEP group (3.0 [2.0-4.0] to 2.0 [1.0-3.0], respectively; p = 0.02).RM followed by a PEEP of 5 cmH2O can effectively reduce the regions of pulmonary atelectasis at the end of laparoscopic surgery in infants and small children.