Adrenocortical function in the very low birth weight infant: improved testing sensitivity and association with neonatal outcome.
OBJECTIVE
To evaluate adrenocortical function in ill preterm infants and investigate potential relationships between plasma cortisol concentrations and major neonatal outcomes.


METHODS
Randomized trial of adrenocorticotropic hormone (1-24ACTH) stimulation testing, followed by a chart review.


METHODS
Two level III neonatal intensive care units, Sacramento, Calif.


METHODS
Sixty-seven very low birth weight infants, born at 32 weeks of gestation or earlier weighing 1500 gm or less, who had endotracheal intubation and indwelling arterial access.


RESULTS
Most infants (76%) had baseline cortisol concentrations < 414 nmol/L (15.0 micrograms/dl), and of those, only 36% responded to stimulation with 1-24ACTH, 0.1 microgram/kg. Raising the 1-24ACTH dose to 0.2 microgram/kg resulted in a response rate of 67% (p = 0.09) but decreased the sensitivity of the test. An elevated mean 11-deoxycortisol/cortisol ratio indicated that decreased 11 beta-hydroxylase activity may limit cortisol production in some infants. Infants with baseline cortisol concentrations less than 414 nmol/L (15.0 micrograms/dl) were more likely to have chronic lung disease (p < 0.002) and less likely to have severe intraventricular hemorrhage (p < 0.02). Response to 1-24ACTH was not associated with a detectable difference in outcome.


CONCLUSIONS
Many very low birth weight infants have low cortisol and ACTH concentrations and are unable to mount a cortisol response to physiologic doses (0.1 microgram/kg) of 1-24ACTH. These findings suggest that delayed maturation of adrenal response may result in physiologically inadequate cortisol concentrations in stressed very low birth weight infants. This delayed maturation may contribute to the development of chronic lung disease.
Korte
C
C
Department of Pediatrics, University of California, Davis 95616, USA.
Styne
D
D
Merritt
T A
TA
Mayes
D
D
Wertz
A
A
Helbock
H J
HJ
D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use*; D003687:Dehydroepiandrosterone / Q000097:blood / Q000378:metabolism; D005183:Failure to Thrive; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D008171:Lung Diseases
D003687:Dehydroepiandrosterone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone