Analysis Of Risk Factors And Clinical Outcome Of Early Pulmonary Hypertension In Preterm Infants Born At Gestational Age ≤32 Weeks

Objective:The clinical data of preterm infants born at gestational age≤32 weeks were retrospectively collected to investigate the risk factors for early pulmonary hypertension in preterm infants born at gestational age≤32 weeks and to analyse the impact of early pulmonary hypertension on the hospital outcome of preterm infants born at gestational age≤32 weeks.Methods:183 preterm infants with gestational age≤32 weeks treated in the neonatal department of the Affiliated Hospital of Qingdao University from October 2017 to May2021 were selected as the research objects,Retrospective analysis of their medical records.According to the echocardiographic results within 3 days to 2 weeks after birth,the subjects were divided into early pulmonary hypertension（PH）group and control group.The general conditions,complications and hospitalization outcomes of the two groups were statistically analyzed.Results:During the study period,183 very preterm infants with gestational age≤32 weeks were treated in our hospital.The average gestational age was 29.7±2.4 weeks and the average birth weight was 1290.1±326.5g.There were 24 children with early PH,accounting for 13.1%.1.General conditions and complications:the proportion of birth asphyxia in the early PH group was significantly higher than that in the control group（50%vs29.5%,P=0.046）,and the proportion of hemodynamically significant ductus arteriosus（hs PDA）was higher than that in the control group（96.7%vs9.4%,P<0.001）,The proportion of fraction of inhaled oxygen（Fi O₂）≥30%in the early PH group was higher than that in the control group（70.8%vs29.6%,P<0.001）.There was no significant difference between the two groups in gestational age,weight,gender,mode of production,maternal complications during pregnancy,oligohydramnios,premature rupture of membranes,chorioamnionitis,placental abnormalities,intrauterine distress,infants younger than gestational age,neonatal pneumonia,neonatal respiratory distress syndrome（NRDS）,respiratory failure,pneumothorax and pulmonary hemorrhage（P>0.05）.2.Outcome:1)Respiratory system:the proportion of early PH combination and late PH was significantly higher than that in the control group（20.8%vs3.8%,P=0.007）.In the early PH group,there were 13 BPD cases,which was higher than that in the control group（54.2%vs33.3%,P=0.048）,especially with grade III BPD（12.5%vs1.9%,P=0.036）.There was no significant difference in invasive ventilator time,noninvasive ventilator time and total oxygen inhalation time between the two groups.2)Extrapulmonary outcome:the proportion of early PH combination with intracranial hemorrhage（25%vs6.3%,P=0.009）was higher than that of the control group,and the use of antibiotics was significantly longer（23.3±18.7vs10.0（5.0-21.5）days,P=0.004）.There was no significant difference in the length of hospital stay,the proportion of retinopathy of prematurity（ROP）and necrotizing enterocolitis（NEC）between the two groups.Among all premature infants,3 cases gave up treatment/died,and the death rate was1.9%.All of them were premature infants with grade III bronchopulmonary dysplasia（BPD）.There was no significant difference between the two groups.3.Analysis of risk factors:Fi O₂≥30%（OR=2.849,95%CI:1.048-8.372）and hs PDA（OR=11.781,95%CI:4.192-33.108）within 6 hours after birth are independent risk factors for early PH.4.Correlation analysis:among all preterm infants,66 cases were combined with BPD,the incidence rate was 36%,of which 25 cases（37.9%）were grade I BPD,35 cases（53%）were grade II BPD,and 6 cases（9%）were grade III BPD.The risk of BPD in premature with early PH was significantly increased（54.2%vs33.3%,RR=1.625,95%CI:1.058-2.495）,especially grade III BPD（12.5%vs1.9%,RR=6.625,95%CI:1.418-30.955）.Children with early PH had a significantly increased risk of late PH（20.8%vs3.8%,RR=5.521,95%CI:1.826-16.693）.The risk of late PH complicated with BPD was also significantly increased（63.4%vs34.3%,RR=1.855,95%CI:1.134-3.035）,especially grade III BPD（18.2%vs2.3%,RR=7.818,95%CI:1.604-38.115）.There was no significant correlation between early PH and late PH and grade I and II BPD.Conclusion:1.Fi O₂≥30%and hs PDA within 6 hours after birth are independent risk factors for early PH in preterm infants≤32 weeks gestational age.2.Early PH in preterm infants≤32 weeks gestational age increases the risk of intracranial haemorrhage and prolongs the duration of antibiotic use.3.Early PH in preterm infants≤32 weeks gestational age increases the risk of developing late PH and BPD.Early PH and late PH are significantly associated with severe BPD.