Manual ventilation in pediatric anesthesia limits the anesthesiologist's ability to manage patients suffering from unexpected problems. Although modified Mapleson D systems connected to ventilators have been used for controled ventilation of anesthetized infants and children, the complexity of factors affecting rebreathing within the Mapleson D circuit has resulted in a variety of recommendations for fresh gas flow and minute ventilation. The aim of this study was to devise a formula for ventilator settings which would provide normal tidal volume, respiratory rate, and minute ventilation without rebreathing during mechanical ventilation in pediatric anesthesia and compare this method to manual ventilation.

56 infants and small children anesthetized with enflurane and nitrous oxide were studied. We have constructed a formula for ventilator settings which would generate a predictable normocapnia. PetCO2, PaCO2, SpO2, and SaO2 were measured during manual ventilation (control) and during mechanical ventilation.

Mean PaCO2 with the mechanical ventilation was within normal range. PaCO2 was significantly lower (P<0.05) with the manual ventilation than with the mechanical ventilation.

We conclude that our formula for ventilator settings can be safely and competently applied to mechanical ventilation with Jackson-Rees system in pediatric anesthesia.