Pressure support ventilation improves ventilation during inhalational induction of anesthesia in children: A pilot study

To evaluate the impact of positive end-expiratory pressure (PEEP) with or without pressure support ventilation (PSV) on the lung volume and the ventilation distribution during inhalational induction of anesthesia in children. Prospective observational clinical pilot-study. University Children's Hospital of Lyon, France. Children without significant comorbidity (ASA 1 or 2) undergoing planned or unplanned surgery with inhalational induction of anesthesia. After the beginning of Guedel's stage 3 of anesthesia, several settings were applied for 60 s in the following systematic order: spontaneous breathing when applying a facemask (SB-Mask), then PEEP 4 cmH2O, PSV 4 cmH2O above PEEP 4 cmH2O, and PSV 4 to 7 cmH2O above PEEP 4 cmH2O, at the anesthesiologist's discretion. Children were monitored using Electrical Impedance Tomography (EIT; Pulmovista 500, Dräger, France). Tidal volume (TV), dorsal fraction of the ventilation, and end-expiratory lung impedance (EELI) were assessed with the ventilator and EIT. Twenty-two patients were included (20 analyzed), their median [IQR] age was 21 [14–36] months. TV did not significantly differ between the settings. The increase in EELI was greater with PSV (+0.60 [0.48–0.91] arbitrary units) than with PEEP 4 cmH2O alone (+0.39 [0.20–0.06] arbitrary units, p = 0.005), and did not change with increased level of PSV (+0.66 [0.40–1.22] arbitrary units). The dorsal fraction of lung ventilation decreased using PSV, from 56 % [45–63] with SB-mask to 53 % [43–56] with PSV 4cmH2O (p = 0.002) and 47 % [40–55] with PSV 7cmH2O (p = 0.001). The ventilator settings used during inhalational induction of anesthesia in children have an impact on lung ventilation. PSV during inhalational induction of anesthesia in children may restore the end-expiratory lung volume independently from the increase in TV. •. Effect of pressure support (PS) and PEEP on ventilation distribution during inhalational induction of anesthesia is unknown•We evaluated the effects of PEEP and PSV on lung volume and ventilation distribution using electrical impedance tomography.•PS during inhalational induction of anesthesia may restore the end-expiratory lung volume independently from the increase in tidal volume.