Thyroid Hormone Function And Its Effect On Respiratory Diseases In Very Premature Infants

Objective Thyroid hormone levels of very preterm infants were measured to study the postnatal thyroid function characteristics of preterm infants with different gestational age.The effect of thyroid function on respiratory diseases of premature infants was studied by clinical study.Data and methods In this study,398 cases very preterm infants?32 weeks gestation were collected from the neonatal intensive care unit?NICU?in the affiliated hospital of Qingdao university from January 1,2016 to December 31,2017.?1?According to their gestational age,they were divided into four groups:24-25⁺⁶w?n=21?,26-27⁺⁶w?n=76?,28-29⁺⁶w?n=172?and 30-32w?n=129?.All infants at 10-14 days after birth,were taken venous blood samples?1.5 ml?to detect thyroid stimulating hormone,tetra-iodothyronine and tri-iodothyronine level with electrochemical luminescence immunity analyzer.?2?According to their thyroid function,the observation group was divided into hyperthyrotrophinemia group?TSH?5mIU/L,9pmol/L?T4<19pmol/L?,hyperthyroxinemia group?T4?19pmol/L?,hypothyroxinemia group?T4<9pmol/L?and normal thyroid group.Data which were collected all general perinatal conditions,clinical data on respiratory diseases during hospitalization,including respiratory distress syndrome?RDS?,pulmonary surfactant?PS?,the mechanical ventilation time,the oxygen inhalation time,bronchopulmonary dysplasia?BPD?and outcome were statistically processed.Results?1?Thyroid dysfunction was common among very premature infants?32 weeks gestation,the incidence of which was 65.33%,including hyperthyroidism?37.69%?,hyperthyroxinemia?24.87%?and hypothyroxinemia?2.76%?.?2?T4 level showed positive correlation with gestational age,pearson correlation coefficient was 0.48,p<0.01,whereas TSH level showed no significant correlation with gestational age?p=0.25?.?3?Gestational age and birth weight were associated with thyroid dysfunction in premature infants,as well as gender,1 min Apgar score and type of delivery?p<0.05?.The incidence of hyperthyroxinemia was higher in women,cesarean section,higher gestational age,and higher birth weight.The lower the birth weight,the higher the incidence of high TSH and low T4 group.The application of prenatal hormone,maternal thyroid disease and SGA were not significantly associated with thyroid dysfunction?p>0.05?.?4?Thyroid dysfunction has a certain impact on respiratory diseases and prognosis.The incidence of BPD,non-invasive ventilation time,oxygen inhalation time and length of hospitalization were significantly lower in the hyperthyroxinemia group?p<0.05?.The invasive ventilation time,high-frequency ventilation time and constant frequency ventilation time of hypothyroxinemia group were significantly increased compared with the normal thyroid function group?p<0.05?.There was no significant difference between the hyperthyroidism group and the normal thyroid function group in terms of RDS,BPD,mechanical ventilation time and oxygen inhalation time?p>0.05?.There was no significant correlation between thyroid dysfunction and PS in preterm infants and severe BPD?p>0.05?.Conclusion?1?The incidence of thyroid dysfunction in very premature infants?32weeks gestation was high,and the common types were hyperthyroidism,hyperthyroxinemia and hypothyroxinemia.?2?The level of T4 was positively correlated with gestational age.And the smaller the gestational age,the lower the T4 level.The level of TSH was not significantly correlated with gestational age.?3?Risk factors for thyroid dysfunction were gender,gestational age,birth weight,1 min Apgar score,type of delivery.?4?Thyroid dysfunction was closely related to respiratory diseases.T4abnormalities can significantly affect the incidence of lung diseases in premature infants.The lower the T4 level of,the higher the incidence of lung disease and the longer the length of hospitalization.