AUTHOR=Brouwer Emma , Knol Ronny , Hahurij Nathan D. , Hooper Stuart B. , Te Pas Arjan B. , Roest Arno A. W. TITLE=Ductal Flow Ratio as Measure of Transition in Preterm Infants After Birth: A Pilot Study JOURNAL=Frontiers in Pediatrics VOLUME=9 YEAR=2021 URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2021.668744 DOI=10.3389/fped.2021.668744 ISSN=2296-2360 ABSTRACT=

Background: Cardiovascular changes during the transition from intra- to extrauterine life, alters the pressure gradient across the ductus arteriosus (DA). DA flow ratio (R-L/L-R) has been suggested to reflect the infant's transitional status and could potentially predict neonatal outcomes after preterm birth.

Aim: Determine whether DA flow ratio correlates with oxygenation parameters in preterm infants at 1 h after birth.

Methods: Echocardiography was performed in preterm infants born <32 weeks gestational age (GA), as part of an ancillary study. DA flow was measured at 1 h after birth. DA flow ratio was correlated with FiO₂, SpO₂, and SpO₂/FiO₂ (SF) ratio. The DA flow ratio of infants receiving physiological-based cord clamping (PBCC) or time-based cord clamping (TBCC) were compared.

Results: Measurements from 16 infants were analysed (median [IQR] GA 29 [27–30] weeks; birthweight 1,176 [951–1,409] grams). R-L DA shunting was 16 [17–27] ml/kg/min and L-R was 110 [81–124] ml/kg/min. The DA flow ratio was 0.18 [0.11–0.28], SpO₂ 94 [93–96]%, FiO₂ was 23 [21–28]% and SF ratio 4.1 [3.3–4.5]. There was a moderate correlation between DA flow ratio and SpO₂ [correlation coefficient (CC) −0.415; p = 0.110], FiO₂ (CC 0.384; p = 0.142) and SF ratio (CC −0.356; p = 0.175). There were no differences in DA flow measurements between infants where PBBC or TBCC was performed.

Conclusion: In this pilot study we observed a non-significant positive correlation between DA flow ratio at 1 h after birth and oxygenation parameters in preterm infants.