Impact of bradycardia and hypoxemia on oxygenation in preterm infants requiring respiratory support at birth

Ilia Bresesti,Alexander Avian,Marlies Bruckner,Corinna Binder-Heschl,Bernhard Schwaberger,Nariae Baik-Schneditz,Georg Schmölzer,Gerhard Pichler,Berndt Urlesberger

doi:10.1016/j.resuscitation.2021.05.004

Abstract

Aim of the studyAnalysis of the impact of bradycardia and hypoxemia on the course of cerebral and peripheral oxygenation parameters in preterm infants in need for respiratory support during foetal-to-neonatal transition. MethodsThe first 15 min after birth of 150 preterm neonates in need for respiratory support born at the Division of Neonatology, Graz (Austria) were analyzed. Infants were divided into different groups according to duration of bradycardia exposure (no Bradycardia, brief bradycardia <2 min, and prolonged bradycardia ≥2 min) and to systemic oxygen saturation (SpO2) value at 5 min of life (<80% or ≥80%). Analysis was performed considering the degree of bradycardia alone (step 1) and in association with the presence of hypoxemia (step 2). ResultsIn step 1, courses of SpO2 differed significantly between bradycardia groups (p = 0.002), while courses of cerebral regional oxygen saturation (crStO2) and cerebral fractional tissue oxygen extraction (cFTOE) were not influenced (p = 0.382 and p = 0.878). In step 2, the additional presence of hypoxemia had a significant impact on the courses of SpO2 (p < 0.001), crStO2 (p < 0.001) and cFTOE (p = 0.045). ConclusionOur study shows that the degree of bradycardia has a significant impact on the course of SpO2 only, but when associated with the additional presence of hypoxemia a significant impact on cerebral oxygenation parameters was seen (crStO2, cFTOE). Furthermore, the additional presence of hypoxemia has a significant impact on FiO2 delivered. Our study emphasizes the importance of HR and SpO2 during neonatal resuscitation, underlining the relevance of hypoxemia during the early transitional phase.

Highlights

Continuous monitoring of heart rate (HR) and peripheral oxygen saturation (SpO2) by using pulse-oximetry is currently considered standard of care during stabilization of preterm infants in the delivery room (DR)
Our study shows that the degree of bradycardia has a significant impact on the course of SpO2 only, but when associated with the additional presence of hypoxemia a significant impact on cerebral oxygenation parameters was seen
Our study emphasizes the importance of HR and SpO2 during neonatal resuscitation, underlining the relevance of hypoxemia during the early transitional phase

Summary

Introduction

Continuous monitoring of heart rate (HR) and peripheral oxygen saturation (SpO2) by using pulse-oximetry (plus ECG optionally) is currently considered standard of care during stabilization of preterm infants in the delivery room (DR). There is still uncertainty regarding the optimal initial supplemental oxygen concentration (FiO2) to start resuscitation in preterm infants,[3,4,5] but there are recommended SpO2 targets to reach.[1] Increased incidence of mortality and adverse outcomes such as intraventricular haemorrhage (IVH) has been reported in those infants not reaching SpO2 80% at 5 min after birth.[6] Increase in HR is often reflection of adequate respiratory support, but there is still an ongoing debate to define normal ranges. It has been shown that preterm neonates who experience prolonged bradycardia during DR resuscitation are at increased risk for death and/or IVH.[7]

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Methods

Conclusion