Adrenal Function in Newborns Undergoing Surgery

OBJECTIVE: To measure cortisol, ACTH-stimulated cortisol and ACTH values in NICU-admitted newborn infants within 48 hours prior to surgery and to describe the relationship of these values to measures of clinical illness before and after surgery. STUDY DESIGN: In this prospective observational study, we measured baseline and ACTH-stimulated cortisol concentrations within 48 hours prior to surgery in newborn infants <44 weeks postmenstrual age and examined the relationship of these values to measures of illness severity both before and after surgery, including the score for neonatal acute physiology (SNAP) and use of vasopressors. ACTH concentrations were measured in a subset of the infants. RESULTS: Twenty-five infants were enrolled and had median [25(th) -75(th) percentile] baseline and ACTH-stimulated cortisol values of 7.1 [3.5-11.1] and 40.4 mcg/dl [22.6-50.6]. Preterm infants had significantly lower ACTH-stimulated cortisol values (median 21.6 vs.44.7 mcg/dl). There was no correlation between any of these values and either the pre-surgical or post-surgical measures of illness severity, nor the increase in SNAP scores after surgery. Infants receiving vasopressors peri-operatively had lower median ACTH-stimulated cortisol values (22.6 vs. 44.7 mcg/dl). CONCLUSION: Pre-surgical cortisol values do not predict clinical response to surgical stress as measured by severity of illness scores but lower values were associated with vasopressor therapy. Further investigation would be required to determine how cortisol values are related to outcome and whether peri-operative glucocorticoid supplementation would be beneficial in this population.