TY - JOUR
T1 - Hemodynamics and organ blood flow in fetal sheep subjected to chronic anemia
AU - Davis, L. E.
AU - Hohimer, A. R.
PY - 1991
Y1 - 1991
N2 - To investigate cardiovascular adaptation to chronic anemia we studied eight ovine fetuses made anemic by serial isovolemic hemorrhage and seven nonanemic controls. After 1 wk carotid arterial oxygen content was reduced to 1.6 ± 0.2 ml/dl and hematocrit to 13.3 ± 1.6% in anemic fetuses compared with 6.9 ± 1.2 ml/dl and 32.4 ± 3.9% in controls. Cardiac output was higher in the anemic group (753 ± 102 vs. 490 ± 66 ml·min-1·kg fetus-1) as stroke volume and heart rate both increased. Blood flow to the carcass, skin, kidneys, intestines, brain, and heart was increased. Vascular resistance fell in all tissues except the placenta. Central venous pressure, arterial pH, plasma total protein, and blood volume were not different although extravascular fluid accumulated in six of the anemic fetuses. The estimated capillary hydrostatic pressure was greater in anemic (7.6 ± 1.8 mmHg) than control fetuses (5.0 ± 1.5 mmHg) and the ratio of precapillary to postcapillary resistance was less. We conclude that reduction in the ratio of precapillary to postcapillary resistance in chronic fetal anemia increases blood flow, oxygen delivery, and capillary hydrostatic pressure.
AB - To investigate cardiovascular adaptation to chronic anemia we studied eight ovine fetuses made anemic by serial isovolemic hemorrhage and seven nonanemic controls. After 1 wk carotid arterial oxygen content was reduced to 1.6 ± 0.2 ml/dl and hematocrit to 13.3 ± 1.6% in anemic fetuses compared with 6.9 ± 1.2 ml/dl and 32.4 ± 3.9% in controls. Cardiac output was higher in the anemic group (753 ± 102 vs. 490 ± 66 ml·min-1·kg fetus-1) as stroke volume and heart rate both increased. Blood flow to the carcass, skin, kidneys, intestines, brain, and heart was increased. Vascular resistance fell in all tissues except the placenta. Central venous pressure, arterial pH, plasma total protein, and blood volume were not different although extravascular fluid accumulated in six of the anemic fetuses. The estimated capillary hydrostatic pressure was greater in anemic (7.6 ± 1.8 mmHg) than control fetuses (5.0 ± 1.5 mmHg) and the ratio of precapillary to postcapillary resistance was less. We conclude that reduction in the ratio of precapillary to postcapillary resistance in chronic fetal anemia increases blood flow, oxygen delivery, and capillary hydrostatic pressure.
KW - Capillary hydrostatic pressure
KW - Vascular resistance
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U2 - 10.1152/ajpregu.1991.261.6.r1542
DO - 10.1152/ajpregu.1991.261.6.r1542
M3 - Article
C2 - 1750577
AN - SCOPUS:0026343053
SN - 0002-9513
VL - 261
SP - R1542-R1548
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 6 30-6
ER -