Abstract
Background: Delaying umbilical cord clamping until after aeration of the lung (physiological-based cord clamping; PBCC) maintains cardiac output and oxygenation in preterm lambs at birth, however, its efficacy after intrauterine inflammation is not known. Given the high incidence of chorioamnionitis in preterm infants, we investigated whether PBCC conferred any benefits compared to immediate cord clamping (ICC) in preterm lambs exposed antenatally to 7 days of intrauterine inflammation.Methods: Ultrasound guided intraamniotic injection of 20 mg Lipopolysaccharide (from E. coli:055:B5) was administered to pregnant ewes at 0.8 gestation. Seven days later, ewes were anesthetized, preterm fetuses exteriorised via cesarean section, and instrumented for continuous measurement of pulmonary, systemic and cerebral pressures and flows, and systemic, and cerebral oxygenation. Lambs were then randomized to either PBCC, whereupon ventilation was initiated and maintained for 3 min prior to umbilical cord clamping, or ICC where the umbilical cord was cut and ventilation initiated 30 s later. Ventilation was maintained for 30 min.Results: ICC caused a rapid fall in systemic (by 25%) and cerebral (by 11%) oxygen saturation in ICC lambs, concurrent with a rapid increase in carotid arterial pressure and heart rate. The overshoot in carotid arterial pressure was sustained in ICC lambs for the first 20 min of the study. PBCC maintained cardiac output and prevented the fall in cerebral oxygen delivery at birth. PBCC lambs had lower respiratory compliance and higher respiratory requirements throughout the study.Conclusion: PBCC mitigated the adverse effects of ICC on oxygenation and cardiac output, and therefore could be more beneficial in preterm babies exposed to antenatal inflammation as it maintains cardiac output and oxygen delivery. The increased respiratory requirements require further investigation in this sub-group of preterm infants.
Highlights
Preterm birth is still the commonest cause of neonatal death and morbidity worldwide [1]
Given that intrauterine inflammation has significant consequences on the pulmonary, cardiovascular and cerebral systems, which result in an altered cardiovascular transition at birth, the aim of this study was to determine whether physiologicalbased cord clamping (PBCC) can improve the cardiovascular transition at birth in preterm lambs exposed to intrauterine inflammation
The presence of intrauterine inflammation was confirmed by the presence of CD45+ inflammatory cell infiltration in the fetal membranes, and was not different between groups (PBCC: 54.1 ± 16.8 vs. immediate cord clamping (ICC): 46.7 ± 10.1)
Summary
Preterm birth is still the commonest cause of neonatal death and morbidity worldwide [1]. Preterm infants often require extensive immediate postnatal care They are at risk of respiratory and cardiovascular diseases and more likely to have neurodevelopmental disability [1] their term counterparts. Initiation of ventilation prior to cord clamping in preterm lambs increases pulmonary blood flow (PBF) before the cord is clamped, allowing for the pulmonary circulation to sustain left ventricular filling and cardiac output upon cord clamping, and establishing the role of pulmonary gas-exchange from the placenta [9]. Delaying umbilical cord clamping until after aeration of the lung (physiological-based cord clamping; PBCC) maintains cardiac output and oxygenation in preterm lambs at birth, its efficacy after intrauterine inflammation is not known. Given the high incidence of chorioamnionitis in preterm infants, we investigated whether PBCC conferred any benefits compared to immediate cord clamping (ICC) in preterm lambs exposed antenatally to 7 days of intrauterine inflammation
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