Abstract
As immaturity increases the vulnerability to hypoxic brain injury, this study tested regional cerebral responses of very immature fetal lambs of ≤0.7 gestation, giving emphasis to those brain regions susceptible to damage in the preterm infant. Regional cerebral flow (CBF, ml.100g−.min−) and oxygen delivery (COD, mM.100g−.min−) were measured (n=20) in eight lambs using radioactive microspheres. Cerebral regions examined were: cerebral hemispheres, cortex, white matter, hypothalamus, caudate nucleus, choroid plexus, cerebellum, midbrain and pons-medulla. Arterial oxygen content (CaO2) was varied from 1.41 to 4.03 mM. CBF increased at low levels of CaO2 in all cerebral regions with the exception of the choroid plexus. The increase in flow was sufficient to maintain COD only to the pons-medulla, midbrain, hypothalamus, white niane; and caudate nucleus. Thus, COD to cerebral hemispheres, cortex, cerebellum and choroid plexus fell with decreasing CaO2. We conclude that i.i [he very immature brain; 1) there are substantial regional differences in the response to hypoxemia; 2) low and absent responsiveness in specific regions may contribute to vulnerability lo hypoxic injury before and after birth.
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Walker, A., Johnson, P., Oates, A. et al. 27 REGIONAL CEREBRAL BLOOD FLOW RESPONSES TO HYPOXIA IN VER IMMATURE LAMBS. Pediatr Res 30, 632 (1991). https://doi.org/10.1203/00006450-199112000-00057
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DOI: https://doi.org/10.1203/00006450-199112000-00057