Hypocarbia and cystic periventricular leukomalacia in premature infants.

One hundred sixty seven survivors among very low birthweight infants with a gestational age of less than 35 weeks have been studied prospectively. The purpose of this study was to clarify the relationship of severe prenatal and perinatal complications and hypocarbic alkalosis, defined as a carbon dioxide tension (PaCO2) of less than or equal to 2.67 kPa and a pH of 7.50 or greater during the first 24 hours of life, to cystic periventricular leukomalacia (PVL) depicted by serial cranial ultrasonographic examinations. Complications occurred in 16 infants, five of whom presented with PVL, while eight of 151 infants without complications had PVL. Twenty six of the infants had hypocarbic alkalosis, six with evidence of PVL, and seven of the 136 infants without hypocarbic alkalosis had PVL. These results suggest a significant relationship of complications and hypocarbic alkalosis to PVL. Mechanical ventilation should be managed carefully in premature infants to avoid PaCO2 of lower than 2.67 kPa.