Carbon dioxide production in cyanotic children during anaesthesia with controlled ventilation

Carbon dioxide production and ventilatory efficiency were measured during undisturbed anaesthesia with intermittent positive pressure ventilation in 34 children about to undergo closed or open cardiac surgery. Anaesthesia was provided with fentanyl or halothane and nitrous oxide. There were 15 cyanotic and 19 acyanotic children. Children with cyanotic heart disease produced approximately 20% less carbon dioxide per unit body weight than acyanotic children, but ventilation was approximately 20% less efficient. Adequate ventilation should therefore be obtained when "normal" ventilation in relation to body weight is used in cyanotic children.