LUNG FUNCTION IN THE SUPINE AND LATERAL DECUBITUS POSITIONS IN ANAESTHETIZED INFANTS AND CHILDREN

We have measured dynamic lung compliance or static lung thorax compliance, functional residual capacity (FRC), and two indices of pulmonary gas mixing (pulmonary clearance delay (PCD) and single breath alveolar mixing efficiency (SBAME)) in 25 children in the supine and lateral decubitus position during nitrous oxidehalothane anaesthesia. Fifteen children (5 month-8 yr) breathed spontaneously and 10 (4 month-9 yr) underwent mechanical ventilation. Tidal volume and rate of ventilation were, respectively. 3.5–6.6 ml kg −1 and 22–46 b.p.m. in spontaneously breathing supine children, and 8.3–15 ml kg −1 and 20–30 b.p.m. in mechanically ventilated supine children, and did not differ significantly in the lateral position. There was no significant change in compliance when the child was turned to the lateral position, but FRC increased from 22 (SD 7) to 25 (8) ml kg −1 ( P −1 ( P P