We compared the ventilation and pulmonary mechanics produced by a new anesthesia ventilator (NAD 6000) using a circle system with that produced by a critical care ventilator (Servo 900C) using a nonrebreathing circuit in infants with congenital heart disease. Twenty patients, aged 1 day to 7 mo, weighing 2.1 to 4.6 kg, were studied. The NAD 6000 had improved alveolar ventilation: PaCO(2) 43 +/- 8 vs 47 +/- 5 mm Hg (P = 0.005), end-tidal CO(2) 34 +/- 7 vs 37 +/- 5 mm Hg (P = 0.042); larger inspired tidal volumes 12.9 +/- 2.8 vs 11.3 +/- 2.2 mL/kg (P < 0.001), but with higher mean airway pressures 9.7 +/- 1.6 vs 8.6 +/- 1.3 cm H(2)O (P < 0.001). These differences in ventilation and airway pressures were not clinically significant. Although there were differences in observed ventilatory variables, both machines provided adequate ventilation when set in the volume control mode.
Implications: We compared two ventilators for use in infants. Twenty infants undergoing surgery for congenital heart defects were randomized to receive ventilation first with one ventilator, then with the other. Although there were differences in observed ventilatory variables, both machines provided adequate ventilation when set in the volume control mode.