Blood volume restitution and growth in fetal lambs following acute
hemorrhage.
Kwan, Eddie, Dan W. Rurak, Sandra M. Taylor.
Department of Obstetrics and Gynaecology, B.C. Research Institute
for Child and Family Health, The University of British Columbia,
Vancouver, British Columbia.
APStracts 2:0106R, 1995.
The effects of 15%-50% fetal hemorrhage (at 1%/min) were studied in 13
pregnant ewes at 130-135 d gestation for up to 5 d post-hemorrhage.
The upper limit of acute blood loss appears to be 45%, and the rate
of restoration of blood volume decreases with the severity of
hemorrhage, particularly with hemorrhage >30-40%. The restoration
of fetal blood volume was due primarily to the restoration of plasma
volume; in the animals subject to 40-45% blood loss (n=9), red cell
mass was still only 69.1+/-3.9% of the pre-hemorrhage value at day 5
post-hemorrhage. There appear to be two phases in the restoration of
plasma: plasma volume was restored by 2 h post-hemorrhage, while the
restoration of plasma protein mass occurred primarily from 2-24 h.
There was a significant correlation between blood volume and plasma
protein mass. However, the regression line for the post-hemorrhage
days was shifted significantly upward in relation to that for the
hemorrhage day, due to a significant rise of plasma protein
concentration. This may be important for the maintenance of blood
volume after hemorrhage. Finally, fetal growth rate was determined by
comparing fetal weight estimated in utero (from blood volume) with
birth weight in 12 non-hemorrhaged, control fetuses and in the 9
fetuses subject to 40-45% hemorrhage. The average rate of growth/d
was 1.57+/-0.34%. and -1.82+/-1.02%, respectively. The latter value
is not significantly different from zero, suggesting that the acute
blood loss impaired fetal growth.
Received 16 September 1994; accepted in final form 11 April 1995.
APS Manuscript Number R524-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.