Determining optimal positive end-expiratory pressure and tidal volume in children by intratidal compliance: a prospective observational study

Limited data exist regarding optimal intraoperative ventilation strategies for the paediatric population. This study aimed to determine the optimal combination of PEEP and tidal volume (VT) based on intratidal compliance profiles in healthy young children undergoing general anaesthesia.During anaesthesia, infants (1 month-1 yr), toddlers (1-3 yr), and children (3-6 yr) were assigned serially to four ventilator settings: PEEP 8 cm H2O/VT 8 ml kg-1 (PEEP8/VT8), PEEP 10 cm H2O/VT 5 ml kg-1 (PEEP10/VT5), PEEP 10 cm H2O/VT 8 ml kg-1 (PEEP10/VT8), and PEEP 12 cm H2O/VT 5 ml kg-1 (PEEP12/VT5). The primary outcome was intratidal compliance profile, classified at each ventilator setting as horizontal (indicative of optimal alveolar ventilatory conditions), increasing, decreasing, or combinations of increasing/decreasing/horizontal compliance. Secondary outcomes were peak inspiratory, plateau, and driving pressures.Intratidal compliance was measured in 15 infants, 13 toddlers, and 15 children (15/43 [35%] females). A horizontal compliance profile was most frequently observed with PEEP10/VT5 (60.5%), compared with PEEP10/VT8, PEEP8/VT8, and PEEP12/VT5 (23.3-34.9%; P<0.001). Decreasing compliance profiles were most frequent when VT increased to 8 ml kg-1, PEEP increased to 12 cm H2O, or both. Plateau airway pressures were lower at PEEP8/VT8 (16.9 cm H2O [2.2]) and PEEP10/VT5 (16.7 cm H2O [1.7]), compared with PEEP10/VT8 (19.5 cm H2O [2.1]) and PEEP12/VT5 (19.0 cm H2O [2.0]; P<0.001). Driving pressure was lowest with PEEP10/VT5 (4.6 cm H2O), compared with other combinations (7.0 cm H2O [2.0]-9.5 cm H2O [2.1]; P<0.001).VT 5 ml kg-1 combined with 10 cm H2O PEEP may reduce atelectasis and overdistension, and minimise driving pressure in the majority of mechanically ventilated children <6 yr. The effect of these PEEP and VT settings on postoperative pulmonary complications in children undergoing surgery requires further study.NCT04633720.