Neonatology Fellow Nationwide Children's Hospital Columbus, Ohio, United States
Background: As infants are resuscitated at earlier gestational ages little evidence exists to guide management. This group is at high risk for significant instability within the first week of life. The hypothalamic-pituitary-adrenal axis maintains basal and stress-related homeostasis; however, due to complex in-utero interactions, the fetus does not produce cortisol until about 28 weeks’ gestation in a normal pregnancy. Accordingly, infants born preterm have been shown to produce less cortisol than term infants. Low cortisol concentrations in extremely preterm infants have been associated with hypotension, respiratory failure, bronchopulmonary dysplasia, and death. While previous studies have examined serum cortisol concentrations in preterm infants (Scott & Watterberg Pediatr Res 1995), literature is limited for extremely preterm infants, with no published data for infants born at 22-23 weeks’ gestation. Objective: Develop an updated reference range for serum cortisol in infants < 31 weeks’ gestation during first postnatal week and characterize associations of cortisol values in first postnatal week with pre-defined clinical factors (including respiratory disease, intraventricular hemorrhage, sepsis, hypotension) on postnatal days 7 and 30 and 36 weeks’ postmenstrual age. Design/Methods: Prospective cohort study of infants born at 22-30 weeks’ gestation at three neonatal intensive care units. Enrollment is complete (100 patients). Blood was collected during routine care on day of life 0-1, 2-3, and 4-7. Samples were analyzed by liquid chromatography-tandem mass spectrometry. Demographic and clinical data were obtained from electronic medical record. Linear mixed models were used to analyze cortisol levels across time and between clinical factors. Mean and 95% confidence intervals at each time point were estimated overall and by clinical factors. Sub-group analysis estimated the difference in cortisol levels within clinical factors at each time point. Likelihood ratio tests were used to test if cortisol levels were different between clinical factors. Data analysis is ongoing.
