Fetal hind limb oxygen consumption and blood flow during acute graded hypoxia

David W. Boyle, Kathryn Hirst, Gary O. Zerbe, Giacomo Meschia, Randall B. Wilkening

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Hind limb blood flow and O2 uptake, mean blood pressure, and heart rate were measured in six fetal sheep at 127-141 d gestation in the control state and at different levels of hypoxia that were induced by partial occlusion of the maternal terminal aorta. Blood flow was measured by an ultrasonic flow transducer. Control fetal arterial O2 content ([O2]a) in the descending aorta was 3.25 + 0.17 mM. In response to graded acute hypoxia, blood flow first increased (22.2 versus 19.9 mL.min-1.100 g-1, p = 0.003) and then decreased abruptly at approximately 1.5 mM [O2]a.O2 uptake decreased about 12% (14.74 versus 16.71, p = 0.03) as [O2]a decreased to 1.5 mM, and then fell markedly, tending toward zero for [O2]a = 0.9 mM. In the 2.7- to 1,5-mM [O2]a range, heart rate increased above control (194 versus 169 min1, p = 0.0024), whereas mean blood pressure did not change significantly. For [O2]a. < 1.5 mM, heart rate decreased to 148 min-1 (p = 0.0005) and mean blood pressure increased above baseline (55 versus 47 torr, p = 0.0001). In conjunction with previous evidence, these results define a state of acute moderate hypoxia in which the whole fetus can sustain a relatively high rate of oxidative metabolism, and a state of acute severe hypoxia ([O2], between 1.5 and 1.0 mM) in which O2 uptake by some fetal organs is selectively and markedly decreased.

Original languageEnglish (US)
Pages (from-to)94-100
Number of pages7
JournalPediatric Research
Volume28
Issue number2
DOIs
StatePublished - Aug 1990
Externally publishedYes

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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