Facemask pressure-controlled ventilation in children: what is the pressure limit?
In this study, we sought to determine the level of inspiratory pressures allowing adequate and safe ventilation without any risk of gastric insufflation (GI) in children according to age. One hundred children, aged 1 day to 16 years, ASA physical status I to II, scheduled for general anesthesia were studied prospectively. After induction of anesthesia, children's lungs were ventilated with pressure-controlled ventilation. The initial inspiratory pressure was 10 cm H(2)O and was increased by steps of 5 cm H(2)O, up to a maximum of 25 cm H(2)O. At each step, GI was detected by epigastric auscultation. The recorded data were age and weight. At each step, the inspiratory pressure, the respiratory rate, the expired tidal volume, the minute ventilation, and the occurrence of GI were also recorded. GI occurred in 78 children. GI occurred in 95% of children younger than 1 year, in 93% of children aged 1 to 5 years, and 56% of children older than 5 years (P = 0.001). The pressure threshold at which GI occurred increased with age: the younger the child, the lower the GI pressure threshold. Tidal volume increased with inspiratory pressure, but at >15 cm H(2)O, tidal volume did not change significantly. The inspiratory pressure threshold at which GI can occur depends on age. It is low in infants and increases with age. In most cases, proper ventilation without GI was obtained with an inspiratory pressure </=15 cm H(2)O. Increasing inspiratory pressure above this threshold results in an increase in GI and no change in tidal volume.