22.0 to 36.6 weeks gestational age preterm infants with respiratory distress syndrome, who remain ventilated between 7 and 14 days after birth will be randomized to one of two ventilator strategies: 1) a higher level of permissive hypercapnia or 2) a lower level of permissive hypercapnia to determine if either strategy will increase the number of alive ventilator-free days in the 28 days after randomization.~After parental consent obtained, intubated, mechanically ventilated infants will be randomized by use of sequentially numbered sealed opaque envelopes to the treatment assignment. Randomized infants will be stratified by gestational age at delivery (< 26 weeks, ≥ 26 wks but less than 29 weeks, and ≥ 29 weeks). Multiple births will be randomized to the same group. The envelope will be opened only on days 7-14 when infant meets criteria. Clinicians will follow pre-specified algorithms of extubation and reintubation criteria to wean infants from mechanical ventilation. The ventilation algorithms may be set aside until the infant is deemed stable enough to allow resumption of the study algorithm.~Infant will be extubated within 24 hours of meeting extubation criteria and documented on a single blood gas. A trial of extubation per attending physician is allowed independent of the trial protocol.All other care is per unit standard.~Reports of routine follow-up after discharge in babies < 27 weeks gestation will be obtained to determine neurodevelopmental impairment on this subset of babies.
Preterm infants, less than 37 weeks gestation with respiratory distress syndrome, who remain ventilated between 7 and 14 days after birth will be randomized to a ventilator strategy of either a higher level of permissive hypercapnia or of a lower level of permissive hypercapnia to determine if either strategy will increase the number of alive ventilator-free days in the 28 days after randomization.