Does perinatal hypocarbia play a role in the pathogenesis of cerebral palsy?

This study aimed to evaluate the role of hypocarbia as a risk factor for mortality and for cerebral palsy in extremely low birthweight infants. The records for 215 extremely low birthweight children were analysed, grouping the infants into those who died (n=72), those who had a confirmed diagnosis of cerebral palsy (n=27) and those without major neurological symptoms at the age of 2 y (n=116). The analysed risk factors were: birthweight, gestational age, maternal diseases and toxaemia, multiple pregnancy, male gender, respiratory distress syndrome, abnormal neonatal cerebral ultrasound, occurrence of septic infection, and/or at least one episode of systemic hypotension and/or at least two episodes of hypocarbia (<3 kPa) during the neonatal period. The mortality rate was 31% and the rate of cerebral palsy was 17% in the survivors. Hypocarbia was found in 33% of children with cerebral palsy, in 10% of infants who died and in 19% of the healthy controls; the differences were statistically insignificant. Birthweight and gestational age, episodes of systemic hypotension and abnormal ultrasound emerged as risk factors for mortality. Abnormal cerebral ultrasound was the only significant risk factor for cerebral palsy. The role of hypocarbia in the pathogenesis of CP remained indistinct but the distribution of risk factors was different in infants with a mortal outcome and in infants with cerebral palsy.