Functional residual capacity (FRC) and compliance in anaesthetized paralysed children part II. clinical results

Abstract

Because anaesthesia and artificial ventilation may be associated with reduction of FRC leading to hypoxaemia, we measured changes in FRC and compliance during anaesthesia (0.5 per cent to 1 per cent methoxyflurane) and artificial ventilation in children with normal respiratory function undergoing operation on the limbs and in children with congenital cardiac anomalies undergoing surgical correction. After induction of anaesthesia in the normal children FRC fell in 35 per cent and remained at a fairly steady level throughout the operation. The lesser post-induction fall of 20 per cent observed in the children undergoing cardiac surgery was followed by a continued decrease in FRC during the surgical operation. At the end of operation the reduction in FRC was of similar magnitude in each group of children. The post-induction fall in FRC was greater than that reported for anaesthetized adults during artificial ventilation, and was inversely, proportional to the size of the child. CLs in the normal children was slightly greater at the beginning of operation than at the end, the final value being close to the reported normal figure for conscious subjects. In the children with congenital cardiac anomalies CLs was less than in the normal children both at the beginning of operation and at the end. Both normal children and those with congenital cardiac anomalies would benefit from measures designed to maintain FRC during anaesthesia and artificial ventilation. © 1973 Canadian Anesthesiologists.