Ventilatory response to inspired carbon dioxide in premature infants recovering from intraventricular hemorrhage.

We examined the ventilatory response to inhaled carbon dioxide with a computerized waveform analyzer in two groups of premature infants. Twenty-seven infants suffered from periventricular-intraventricular hemorrhage (IVH) during the first week of life and comprised the study group (birth weight 1.2 +/- 0.2 kg, gestational age 29 +/- 2 weeks). The control group consisted of 15 infants without IVH (birth weight 1.4 +/- 0.3 kg, gestational age 30 +/- 2 weeks). Study infants were evaluated at a postnatal age of 9 +/- 2 weeks and control infants at 7 +/- 3 weeks. No differences were found in the slope or position of the ventilatory response curve, baseline PACO2, increase in minute ventilation, VT/Ttot, and Ti/Ttot between the two groups. Subgroups with unresolved apnea (10 IVH and eight control infants) demonstrated a rightward shift of the ventilatory response curve compared to those infants without apnea. A previous IVH did not reduce the ventilatory response to CO2 in this group of infants.