Fetal oxygen content is restored after maternal hemorrhage and fluid replacement with polymerized bovine hemoglobin, but not with hetastarch, in pregnant sheep.
We investigated the ability of hemoglobin-based oxygen carrying solutions (HBOCs) to alleviate fetal hypoxemia from maternal hemorrhage. Fifteen pregnant ewes (132-day gestational age) were hemorrhaged 20 mL/kg over 1 h; they were randomized to receive 20 mL/kg IV of HBOC, hetastarch (HTS), or autologous blood (BLD) (n = 5 each) over 30 min and were monitored for 2 h. Hemorrhage significantly (P < or = 0.05) decreased maternal mean blood pressure (from 98 to 48 mm Hg, median), arterial oxygen content (from 12.2 to 11.1 mL/dL), and fetal arterial oxygen content (from 8.1 to 3.9 mL/dL). Fluid replacement restored maternal blood pressure in all groups, although maternal oxygen content immediately returned to baseline only after BLD or HBOC. Maternal oxygen saturation decreased after HBOC (from 98% to 88%). Fetal oxygen content rapidly returned to baseline with either BLD (7.1 mL/dL) or HBOC (8.0 mL/dL) but was never restored with HTS (4.7 mL/dL), and, 60 min after fluid replacement, it was higher with HBOC (8.3 mL/dL) than with HTS (4.7 mL/dL). Fetal plasma-free hemoglobin did not change after HBOC. In conclusion, maternal fluid replacement with HBOC or BLD effectively restored fetal oxygenation, primarily by restoring maternal oxygen content, whereas HTS did not.


CONCLUSIONS
Hemoglobin solutions eliminate many limitations of blood transfusions. Our results show that fluid replacement with either blood or a hemoglobin solution, compared with hetastarch, restored fetal oxygenation in pregnant ewes after hemorrhage. If applicable to women, these results suggest a potential for the use of hemoglobin solutions in obstetrics.
Moon
P F
PF
Department of Clinical Sciences, The Cornell University Hospital for Animals, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401, USA. pfm4@cornell.edu
Bliss
S P
SP
Posner
L P
LP
Erb
H N
HN
Nathanielsz
P W
PW
D000818:Animals; D001784:Blood Gas Analysis; D002417:Cattle; D005260:Female; D005311:Fetal Hypoxia / Q000097:blood / Q000188:drug therapy*; D005331:Fetomaternal Transfusion / Q000150:complications*; D005440:Fluid Therapy; D006340:Heart Rate, Fetal / Q000187:drug effects; D006400:Hematocrit; D006439:Hemodynamics / Q000187:drug effects; D006454:Hemoglobins / Q000378:metabolism / Q000494:pharmacology*; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects*; D010952:Plasma Substitutes / Q000494:pharmacology*; D011247:Pregnancy; D012756:Sheep
D006454:Hemoglobins; D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes