Sustained Inflation Reduces Pulmonary Blood Flow during Resuscitation with an Intact Cord.

Jayasree Nair,Vikash Agrawal,Lori Nielsen,Satyan Lakshminrusimha,Justin Helman,Sara K Berkelhamer,Lauren Davidson,Praveen Chandrasekharan,Munmun Rawat,Deepika Sankaran,Sylvia Gugino,Carmon Koenigsknecht

doi:10.3390/children8050353

Abstract

The optimal timing of cord clamping in asphyxia is not known. Our aims were to determine the effect of ventilation (sustained inflation–SI vs. positive pressure ventilation–V) with early (ECC) or delayed cord clamping (DCC) in asphyxiated near-term lambs. We hypothesized that SI with DCC improves gas exchange and hemodynamics in near-term lambs with asphyxial bradycardia. A total of 28 lambs were asphyxiated to a mean blood pressure of 22 mmHg. Lambs were randomized based on the timing of cord clamping (ECC—immediate, DCC—60 s) and mode of initial ventilation into five groups: ECC + V, ECC + SI, DCC, DCC + V and DCC + SI. The magnitude of placental transfusion was assessed using biotinylated RBC. Though an asphyxial bradycardia model, 2–3 lambs in each group were arrested. There was no difference in primary outcomes, the time to reach baseline carotid blood flow (CBF), HR ≥ 100 bpm or MBP ≥ 40 mmHg. SI reduced pulmonary (PBF) and umbilical venous (UV) blood flow without affecting CBF or umbilical arterial blood flow. A significant reduction in PBF with SI persisted for a few minutes after birth. In our model of perinatal asphyxia, an initial SI breath increased airway pressure, and reduced PBF and UV return with an intact cord. Further clinical studies evaluating the timing of cord clamping and ventilation strategy in asphyxiated infants are warranted.

Highlights

Birth asphyxia affects 4 million newborn infants worldwide each year [1,2]
Lambs were comparable in birth weight with similar baseline hemodynamic measurements that were obtained after instrumentation
We conclude that higher airway pressures delivered by a 30 s Sustained inflation (SI) breath in near-term asphyxiated lambs with delayed cord clamping (DCC) reduced both umbilical venous (UV) and pulmonary blood flow (PBF) without affecting UA or carotid blood flow (CBF)

Summary

Introduction

Birth asphyxia affects 4 million newborn infants worldwide each year [1,2]. Appropriate resuscitative measures result in a substantial reduction in birth asphyxia-associated mortality and morbidity [3]. Establishing early and effective ventilation is key to successful neonatal resuscitation. Every 30 s delay in the initiation of ventilation increases the risk for early death and morbidity [4]. Sustained inflation (SI) may facilitate the early establishment of functional residual capacity (FRC). Revised European resuscitation guidelines recommend maintaining inflation pressure for 2–3 s for the first five inflations in apneic infants [5]

Objectives

Methods

Results

Discussion

Conclusion