Lung function in very preterm infants with patent ductus arteriosus under conservative management: an observational study.
BACKGROUND
Persistent patent ductus arteriosus (PDA) during hospitalization is thought to be associated with adverse pulmonary outcomes in very preterm infants. This observational study aimed to compare the lung function in very preterm infants with and without PDA at discharge.


METHODS
Very preterm infants, admitted to our neonatal intensive unit, who required respiratory support soon after birth and had undergone a lung function test at discharge, were enrolled. Infants with a need for positive-pressure support (either an invasive ventilator, or nasal continuous positive airway pressure without oxygen) or supplemental oxygen at a postmenstrual age of 36 weeks were defined as having bronchopulmonary dysplasia (BPD). Echocardiography was performed weekly for each of the very preterm infants with PDA to confirm closure of the PDA. The data were collected retrospectively.


RESULTS
Fifty-two very preterm infants received lung function tests before discharge during the study period, 28 of whom had PDA and received conservative management, and 20 who did not. The other 4 infants who were given active treatment for PDA were excluded. Gestational age was significantly smaller in the PDA group than in the no-PDA group (27.1 ± 2.0 vs. 28.6 ± 1.6 weeks, p = 0.009). Birth weight did not differ significantly in those with and those without PDA (0.98 ± 0.26 vs. 1.12 ± 0.26 kg, p = 0.074). Significantly more infants with PDA had BPD (p = 0.002) and required respiratory support for a longer period (p = 0.001) than those without PDA. However, functional residual capacity (ml/kg) at discharge was comparable between the two groups after adjusting for gestational age and postmenstrual age at testing (21.6 ± 8.4 vs. 21.5 ± 6.7 ml/kg, p = 0.894). Other lung function test parameters were also comparable.


CONCLUSIONS
Under a definition of BPD (including infants needing CPAP but without oxygen) other than the conventional definition, the very preterm infants in our study who received conservative management for PDA had a higher percentage of BPD than the infants without PDA. The parameters of the lung function test and lung clearance index were comparable between these two groups at discharge.
Department of Respiratory Therapy, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. ch840062@kmu.edu.tw.|Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. ch840062@kmu.edu.tw.
Hsiu-Lin
HL
Chen
School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. rechya@cc.kmu.edu.tw.|Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. rechya@cc.kmu.edu.tw.
Rei-Cheng
RC
Yang
Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. weite@kmu.edu.tw.
Wei-Te
WT
Lee
Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. palent0728@gmail.com.
Pei-Lun
PL
Lee
School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. jhh936@yahoo.com.tw.|Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. jhh936@yahoo.com.tw.
Jong-Hau
JH
Hsu
School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. jirewu@kmu.edu.tw.|Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. jirewu@kmu.edu.tw.
Jiunn-Ren
JR
Wu
School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. zenkong@kmu.edu.tw.|Department of Pediatrics, Kaohsiung Medical University Hospital, No.100 , Tzyou 1st Road, San Ming District, Kaohsiung, 807, Taiwan. zenkong@kmu.edu.tw.
Zen-Kong
ZK
Dai
D045422:Continuous Positive Airway Pressure / Q000379:methods*; D016861:Cyclooxygenase Inhibitors / Q000627:therapeutic use; D004374:Ductus Arteriosus, Patent / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D007213:Indomethacin / Q000627:therapeutic use*; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000503:physiopathology*; D008297:Male; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D013990:Tidal Volume / Q000502:physiology*
D016861:Cyclooxygenase Inhibitors; D007213:Indomethacin