Evaluation of adrenal function in critically ill children

Summary Objective There is no consensus on adequate adrenal response to critical illness. We aimed to evaluate adrenal function in critically ill children and its association with clinical outcome. We hypothesized that salivary cortisol would be a more appropriate tool to evaluate adrenal function in critically ill children. Methods This was a prospective cohort study. The concentrations of serum total and salivary cortisol were measured in 34 critically ill children before and after stimulation with 250 μg adrenocorticotropic hormone (ACTH), and values were compared to a control group of healthy children (n = 15). Association between outcome and adrenal insufficiency defined by an increment in serum cortisol ≤250 nm (9 μg/dl) post‐ACTH was assessed. Results Serum total and salivary cortisol concentrations pre‐ and post‐ACTH were significantly higher in patients, and they were correlated at baseline (r = 0·67; P 250 nm (9 μg/dl) post‐ACTH. An inverse correlation between salivary cortisol post‐ACTH and vasoactive inotropic score (r = −0·56; P = 0·0008) was observed. A salivary cortisol concentration post‐ACTH of ≤226 nm (8·2 μg/dl) had a sensitivity of 79% and a specificity of 62% to discriminate need for vasoactive or inotropic support (area under receiver operating characteristic (ROC) curve 0·74). Conclusion Adrenal insufficiency defined by the ‘delta criterion’ was not associated with outcome. A post‐ACTH salivary cortisol of ≤226 nm (8·2 μg/dl) may be suggestive of an insufficient adrenal response to critical illness.