Hypothalamic-pituitary-adrenal (HPA) axis sufficiency was evaluated by IIHT in 59 premature infants enrolled in a randomized trial of inhaled steroid for prevention of chronic lung disease. IIHT was conducted on study day 21 to compare plasma cortisol response in patients treated with inhaled beclomethasone v. placebo. Infants had IV access, were NPO and without glucose infusion for 2 hours prior to IIHT. Regular insulin (0.1 U/kg) was injected IV at time 0 (T0). Blood glucose screens were obtained at T0 and q 5-10 minutes after insulin administration. Serum glucose and cortisol were obtained at T0 and any time glucose screens <35 mg/dl. Glucose screens decreased to <35 mg/dl within a mean time of 33 minutes (10-60 min). When glucose screens<30 mg/dl, serum glucose and cortisol were obtained, IV glucose infusion was begun. T test procedure was used to compare the two groups.

Results: Table

Table 1
Full size table

Conclusion: Basal cortisol was significantly lower in the steroid group. There was an inadequate cortisol response to hypoglycemia in both placebo and steroid treated groups and no difference between groups. This may reflect immaturity of the HPA axis of very premature infants to respond to hypoglycemia as a stress stimulus. (Supported by NIH U01 HL49803 and FDA FD-R-000917).