Neuropathology of the near-term and midgestation ovine fetal brain after sustained in utero hypoxemia.
OBJECTIVE
The neuropathologic mechanisms of the ovine fetal brain in response to several hours of sustained hypoxemia with variable degrees of metabolic acidemia was investigated in both the preterm and near-term ovine fetus.


METHODS
Three groups of fetuses were studied in each of the near-term and midgestation groups: a hypoxic group, a control group, and an uninstrumented control group. Histopathologic studies were performed after a 40-hour recovery period after experimentation.


RESULTS
Pathologic findings consisted of predominately white matter damage with some adjacent cortical necrosis but no selective neuronal injury. In the near-term group the hypoxia group fetuses demonstrated significantly higher white matter injury scores than did control group fetuses (p < 0.05). Periventricular white matter injury was the predominant pattern seen in the midgestation group.


CONCLUSIONS
In spite of normalization of biophysical and biochemical parameters after hypoxemia both midgestation and near-term fetuses sustained pathologic changes. Presence or extent of injury did not correlate with the degree of hypoxemia or metabolic acidosis achieved.
Penning
D H
DH
Department of Anaesthesia, College of Medicine, University of Iowa, Iowa City 52242-1079.
Grafe
M R
MR
Hammond
R
R
Matsuda
Y
Y
Patrick
J
J
Richardson
B
B
D000138:Acidosis / Q000150:complications; D000818:Animals; D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000209:etiology* / Q000473:pathology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005315:Fetal Diseases / Q000209:etiology* / Q000473:pathology; D005865:Gestational Age; D000860:Hypoxia / Q000150:complications*; D009336:Necrosis; D011247:Pregnancy; D012756:Sheep