Randomized trial of permissive hypercapnia in preterm infants

Objective. To determine whether a ventilatory strategy of permissive hyperc apnia (PHC) reduces the duration of assisted ventilation in surfactant-trea ted neonates weighing 601 to 1250 g at birth. Design. Forty-nine surfactant-treated preterm infants (birth weight: 854 +/ - 163 g; gestational age: 26 +/- 1.4 weeks) receiving assisted ventilation were randomized during the first 24 hours of age to a PHC group (PaCO2 : 45 -55 mm Hg) or to a normocapnia group (NC; PaCO2 : 35-45 mm Hg). The primary outcome measure was the total number of days on assisted ventilation. Unif orm extubation and reintubation criteria were used for both groups. All pat ients received aminophylline before extubation. Results. The total number of days on assisted ventilation expressed as medi an (25th-75th percentiles) was 2.5 (1.5-11.5) in the PHC group and 9.5 (2.0 -22.5) in the NC group (Mann-Whitney U test). The number of patients on ass isted ventilation throughout the first 96 hours after randomization was low er in the PHC group (log rank test). During that period, the ventilated pat ients in the PHC group had a higher PaCO2 and lower peak inspiratory pressu re, mean airway pressure, and ventilator rate than did those in the NC grou p. The percentage of patients requiring reintubation within 24 hours postex tubation (PHC 17% vs NC 28%) and supplemental oxygen at 28 days of life (PH C 43% vs NC 64%) and the total days of oxygen supplementation (PHC 15 [4-53 ] vs NC 32 [17-50]) did not differ between the groups. There were no differ ences in mortality, air leaks, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, or patent ductus arteriosus. Conclusion. A ventilatory strategy of PHC in preterm infants who receive as sisted ventilation is feasible, seems safe, and may reduce the duration of assisted ventilation.