Journal of Applied Physiology, Vol 65, Issue 1 26-33, Copyright © 1988 by American Physiological Society
Pulmonary effects of acute prenatal asphyxia in ventilated premature lambs
D. Berry, A. Jobe, M. Ikegami, S. Seidner, A. Pettenazzo and T. Elkady
Department of Pediatrics, University of California, School of Medicine, Harbor-UCLA Medical Center, Torrance 90509.
The effect of profound repetitive prenatal asphyxial insults on the
cardiopulmonary function of premature ventilated lambs was studied.
Twenty-nine fetal lambs (approximately 138 days gestational age) were
exteriorized. In 16 of these lambs, the umbilical cord was occluded for 4
min then released for 10 min. This asphyxial episode was repeated until the
arterial pH was approximately 7.00, and the mean arterial blood pressure
was less than 40 mmHg and falling. The 13 control lambs were simply
exteriorized with the umbilical circulation intact. The lambs were then
ventilated for 3-4 h. There were no differences between the control vs.
asphyxiated lambs in pulmonary compliances (0.57 and 0.58 ml.cmH2O-1.kg-1)
wet-to-dry weight ratios (8.18 and 7.55), cardiac outputs (177.8 and 141.8
ml.kg-1.min-1), surfactant-saturated phosphatidylcholine pool sizes, or
atrial and/or ductal shunts. Asphyxia did not interfere with the
redirection of blood away from atelectatic lung segments created by
bronchial obstruction with balloon catheters. Also, although the
bidirectional flux of protein into and out of the airways of these preterm
lambs was large relative to term lambs, there was no effect of asphyxia on
this protein leak. In this animal model, prenatal asphyxia did not impact
negatively on the severity of the respiratory failure.
