Adrenal function of neonates with respiratory failure

Objective To observe the adrenal function in neonates with respiratory failure(neonatal respiratory distress syndrome,pneumonia and severe wet lung),the incidence of adrenal insufficiency,and the relationships between adrenal function and lung diseases.Methods Fifty-five cases of neonates(the preterm group of 33 cases,the term group of 22 cases)were enrolled the study.Serum cortisol values and plasma adrenocorticotropic hormone(ACTH)concentration were detected in the morning.Peak serum cortisol values were detected after 30 minutes low-dose(1 μg/1.73 m2)ACTH stimulation test.Adrenal insufficiency was defined as the peak serum cortisol values ＜ 200 μg/L.Results The mean basal serum cortisol values of the preterm group was significantly higher than that of the term group[(139.2±85.4)μg/L vs(92.1±75.0)μg/L,P=0.0407],and the mean poststimulation increase cortisol level[(122.3±56.4)μg/L vs(198.2±77.9)μg/L,P=0.000 1]and the mean ACTH level[(5.22±2.40)ng/L vs(8.66±5.41)ng/L,P =0.008 4]of the preterm group were significantly lower than that of the term group.The total incidence of adrenal insufficiency in neonates with respiratory failure was 20.0%(11/55),and the incidence of adrenal insufficiency was 21.2%(7/33)in the preterm group and 18.2%(4/22)in the term group.Neonates who had the ventilatory requirements had significantly higher incidence of adrenal insufficiency than neonates who did not have the requirements(29.4% vs 4.8%,P = 0.037).None neonate with adrenal insufficiency died.Conclusion The adrenal and the pituitary function of preterm infants are poor than term infants.The incidence of adrenal insufficiency in neonates with respiratory failure is high,especially in the neonates who have the ventilatory requirements.We do not found relationship between the mortality and adrenal insufficiency.The low-dose ACTH test could be a valuable tool in assessing the function of HPA-axis in neonates with respiratory failure. Key words: Respiratory failure; Cortisol; Adrenocorticotropic hormone; Adrenal gland diseases