Fetal O2 consumption in sheep during controlled long-term reductions in umbilical blood flow
Anderson, D.F.; Parks, C.M.; Faber, J.J.
American Journal of Physiology 250(6 Pt 2): H1037-H1042
1986
ISSN/ISBN: 0002-9513 PMID: 3717358 Document Number: 270135
Electromagnetic flow sensors and inflatable occluders were placed on the distal aortas of 9 fetal lambs of 111-124 days gestation; indwelling vascular catheters were placed in a lower body artery and vein and the common umbilical vein. After a control period of 7.6 +or- 2.1 days, distal aortic flow was reduced to about 60% of control flow; placental flow fractions of distal aortic flow were 77 +or- 5% (control); 69 +or- 11% during flow reduction. Duration of the flow reductions was 9.6 +or- 6.5 days. Fetal O2 consumption fell from 6.4 +or- 1.5 to 5.3 +or- 1.1 ml/min/kg as umbilical blood flow was reduced from 202 +or- 47 to 116 +or- 36 ml/min/kg. Least-squares polynomial regression analysis showed that O2 consumption was a linear function of umbilical blood flow. With regard to long-term fetal O2 consumption, there was no evidence for a margin of safety in fetal umbilical blood flow.