The Effects of Variations in Paco2on Brain Blood Flow and Cardiac Output in the Newborn Piglet
作者:
NANCY HANSEN,
ANN-MARI BRUBAKK,
DAG BRATLID,
WILLIAM OH,
BARBARA STONESTREET,
期刊:
Pediatric Research
(OVID Available online 1984)
卷期:
Volume 18,
issue 11
页码: 1132-1135
ISSN:0031-3998
年代: 1984
出版商: OVID
数据来源: OVID
摘要:
ABSTRACT.The acute effects of normoxemic hypocarbia and hypercarbia were examined in six newborn piglets. Brain blood flow was maintained during hypocarbia until extremely low Paco2(<15 mm Hg) levels were achieved at which time total brain and cerebral blood flow decreased significantly from baseline values. Blood flow to the thalamus, cerebellum and brain stem was unchanged from baseline conditions during hypocarbia. This suggests that the newborn brain is relatively insensitive to moderate degrees of hypocarbia. Extreme hypocarbia (Paco2<15 mm Hg) was associated with a significant increase in heart rate, accompanied by a significant decrease in mean arterial blood pressure; however, cardiac output was not significantly different from baseline determinations. Hypercarbia with normoxemia was associated with significant increases in total brain blood flow, with greater blood flow to the brain stem, cerebellum, and thalamus than to the cerebrum. The percentage of cardiac output received by the brain was also significantly increased, although total cardiac output was unchanged. This demonstrates that the newborn cerebral vasculature is sensitive to hypercarbia and that regional differences in sensitivity may account for the greater increments in blood flow to the caudal portions of the brain than that to the cerebrum.
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