Author:
Polglase Graeme R,Blank Douglas A,Barton Samantha K,Miller Suzanne L,Stojanovska Vanesa,Kluckow Martin,Gill Andrew W,LaRosa Domenic,te Pas Arjan B,Hooper Stuart B
Abstract
BackgroundPhysiologically based cord clamping (PBCC) has advantages over immediate cord clamping (ICC) during preterm delivery, but its efficacy in asphyxiated infants is not known. We investigated the physiology of PBCC following perinatal asphyxia in near-term lambs.MethodsNear-term sheep fetuses (139±2 (SD) days’ gestation) were instrumented to measure umbilical, carotid, pulmonary and femoral arterial flows and pressures. Systemic and cerebral oxygenation was recorded using pulse oximetry and near-infrared spectroscopy, respectively. Fetal asphyxia was induced until mean blood pressure reached ~20 mm Hg, where lambs underwent ICC and initiation of ventilation (n=7), or ventilation for 15 min prior to umbilical cord clamping (PBCC; n=8). Cardiovascular parameters were measured and white and grey matter microvascular integrity assessed using qRT-PCR and immunohistochemistry.ResultsPBCC restored oxygenation and cardiac output at the same rate and in a similar fashion to lambs resuscitated following ICC. However, ICC lambs had a rapid and marked overshoot in mean systemic arterial blood pressure from 1 to 10 min after ventilation onset, which was largely absent in PBCC lambs. ICC lambs had increased cerebrovascular injury, as indicated by reduced expression of blood–brain barrier proteins and increased cerebrovascular protein leakage in the subcortical white matter (by 86%) and grey matter (by 47%).ConclusionPBCC restored cardiac output and oxygenation in an identical time frame as ICC, but greatly mitigated the postasphyxia rebound hypertension measured in ICC lambs. This likely protected the asphyxiated brain from cerebrovascular injury. PBCC may be a more suitable option for the resuscitation of the asphyxiated newborn compared with the current standard of ICC.
Funder
Research Foundation of the Cerebral Palsy Alliance
Victorian Governments Operational Infrastructure Support Program
National Institute of Health
National Heart Foundation of Australia
National Health and Medical Research Council
Subject
Obstetrics and Gynecology,General Medicine,Pediatrics, Perinatology and Child Health
Cited by
60 articles.
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