ACID-BASE STATUS AT BIRTH AND SUBSEQUENT NEUROSENSORY IMPAIRMENT IN SURVIVING 500 TO 1000 GM INFANTS

OBJECTIVE: The purpose of this study was to assess, in infants horn we ighing less than or equal to 1000 gm, if umbilical cord blood acid-bas e measures at birth are associated with an additional increase in neur osensory impairment. STUDY DESIGN: Of 289 surviving infants with a bir th weight of 500 to 1000 gm born from 1979 to 1989, 219 had umbilical cord acid-base status measured at birth and were followed prospectivel y for greater than or equal to 1 year. Measures of neurologic impairme nt used in this study included mental retardation, cerebral palsy, and major neurosensory impairment. RESULTS: Gestational age was inversely associated with all neurosensory impairments and was a better predict or of subsequent impairment in this population than was birth weight. Very low umbilical cord pH values were also significantly related to a dverse outcomes. There was also an inverse relationship between cord b lood bicarbonate levels and major neurosensory impairment. The highly significant relationship between cord blood bicarbonate and pH values and the development of neurosensory impairments persisted in spite of adjustment for gestational age, birth weight, plurality, use of genera l anesthesia, maternal race, and presence of hypertension. CONCLUSION: An adverse acid-base status at birth is additive to the effect of ges tational age in predicting neurosensory impairment in infants weighing less than or equal to 1000 gm.