Lung function in very preterm infants with patent ductus arteriosus under conservative management: an observational study

Abstract

BackgroundPersistent 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.MethodsVery 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.ResultsFifty-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.ConclusionUnder 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.

Persistent Ductus Arteriosus in Critically Ill Preterm Infants

“…As in other studies the current data showed a significant association between PDA and BPD (p=0.002) (Table 4) [6,9,15,20,21,25,41,42,47,[66][67][68][69]. An almost similar risk was reported by Marshall et al in VLBW infants (BW <1500 g) [69].…”

“…Ductus arteriosus persistence was also associated with an increased risk of NEC in very preterm infants, and other studies [11,21,43,44,47,70]. The current study also showed an increased incidence of NEC in preterm infants ≤ 32 weeks gestation, but the low number of NEC cases may explain the lack of significance of this association (Table 4).…”

“…The increased proportion of preterm infants with PDA treated using the INSURE strategy (INtubate-SURfactant-Extubate on CPAP) is explained only by the appliance of national and European guidelines for RDS treatment recommending a non-invasive approach in preterm infants that do not require assisted ventilation at birth. Similarly, according with current recommendations, a very high proportion of the preterm infants in both study groups were treated using CPAP support, (Table 3) and an increased proportion of infants with PDA needed mechanical ventilation (p=0.004), and mean duration of oxygen therapy, CPAP support, and mechanical ventilation were significantly increased compared to premature infants without PDA (p<0.05) demonstrating that increased severity of RDS is associated with higher risk for PDA after the seventh day of life [16,21,22,60,63] ( Table 3).…”

“…In the short term, PDA is associated with decreased blood pressure [5,8], decreased renal function [5], cardiac congestive failure [18,37,38], pulmonary haemorrhage [8,39], apnea and ventilator-dependency [6,38], bronchopulmonary dysplasia (BPD) [5,14,20,21,25,34,41,42], necrotizing enterocolitis (NEC) [8,9,11,19,20,34,39,43,44], intraventricular hemorrhage (IVH) [5,19,20,39,42,45,46], periventricular leukomalacia (PVL) [5], retinopathy of prematurity (ROP), cerebral palsy [24], delayed growth [11], and increased mortality rate [6,34,45,[47][48][49][50].…”

“…Multiple risk factors have been described in association with PDA such as lower GA and BW [14][15][16]21,22], chorioamnionitis and neonatal sepsis, [3,15,[22][23][24][25], maternal diabetes mellitus, [14,26] antepartum hemorrhage, multiple pregnancy, male gender [14], small for gestational age (SGA), [27] lower Apgar scores, need for resuscitation at birth, asphyxia [16], severe respiratory distress syndrome (RDS) [16,22,28,29], excessive fluid administration during the first days of life [30], Furosemide administration [31], decreased platelets number during the first day of life [22,32], oxygen administration [16], lower oxygen saturation targets [33,34], surfactant administration [16,28,35,36], increased duration of mechanical ventilation and respiratory support [22], metabolic acidosis [16], phototherapy [37], and high altitude [6].…”