The Study On The Changes Of Blood Cortisol And ACTH In Preterm Infants With Respiratory Failure

ObjectiveCortisol is a crucial hormone to control neonatal development. It has been shown that the level of plasma cortisol in preterm changing according to preterm infants’state because of immaturity of their adrenaline. The aim of this study was to investigate the variation of blood cortisol and adrenocorticotropic hormone (ACTH) levels and to find the regular pattern of hypothalamic-pituitary-adrenal in preterm infants with respiratory failure in and after mechanical ventilation treatment. This work would provide a theoretical basis for the rational use of glucocorticoids (GC) in clinical treatment.MethodsIn this study all the objects were chosen from Neonatal Intensive Care Unit of Anhui Province Children’s Hospital during January to December in 2014. Inclusion criteria:30 preterm infants with respiratory failure getting mechanical ventilation as the observation group,32 full term infants with respiratory failure in need of mechanical ventilation, and the other two groups including 52 preterm infants and 17 full term infants, in which their vital signs were stable, as the control groups. Exception criteria: the mother got glucocorticoid treatment before delivery or the infants got glucocorticoid after birth; the infants with severe congenital deformity, chromosome abnormalities, hereditary metabolic diseases; the infants with immunological diseases, hemolysis icterus morbidity, severe hypoproteinemia; the infants with severe asphyxia resuscitation and operation at birth. The blood of included infants in the morning at the third (at ventilation) and seventh birthday (correct respiratory failure and out of ventilation) were put in different tubes, then frozen at -70℃ after high speed centrifugation. The levels of blood cortisol and ACTH were measured and analyzed statistically by automatic chemical luminescence immunity analyzer.Results1. On the 3rd day. the level of serum cortisol in preterm neonates with respiratory failure was lower than that in the full term newborns who were in respiratory failure and higher than that in preterm control group. the differences were statistically significant (P<0.05).The level of ACTH in observation group on the 3rd day was higher than that in the control group, the differences were statistically significant (P<0.05).2. On the 7th day, the level of serum cortisol in preterm infants with respiratory failure" decreased, and was lower than that in the full term with respireatory failure, the difference was statistically significant (P<0.05). The concentration of ACTH in observation group appeared to lower than that in the full term with respireatory failure, and there was statistically difference (P<0.05).3. The level of serum cortisol in newborns with respireatory failure decreased after correcting respiratory failure not only preterm newborns but also full term infants, there were significant differences (P<0.05),as the same as the concentration of ACTH in preterm infants with respiratory failure.4. The level of serum cortisol in preterm infants was higher than that in the full term newborns, but there was no statistically difference (P>0.05) no matter on the 3rd day or 7th day. There were no significantly differences between the ACTH level of these two groups on the 3rd day or 7th day.Conclusion1. The HPA axis of newborns with respireatory failure has some function of secreting and regulating blood cortisol and ACTH.2. The newborns with respireatory failure are in critical stress, the preterm infants’ response level of serum cortisol is lower than that of the full term infants, while the level of ACTH in the former is higher than that in the latter.3. When the stress disappears, both of the blood cortisol and ACTH recover to the normal level.