Relationship between graded degrees of anemia and amniotic fluid volume in the ovine fetus

Sohl, Bryan D.; Brace, Robert A.

doi:10.1016/s0002-9378(99)70403-5

Cited by 10 publications

(6 citation statements)

References 20 publications

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“…In addition to the hypoxic hypoxia model used in the current study, there are several other experimental methods for creating fetal hypoxia and these are variously associated with elevated, unchanged, or reduced AF volume depending on the method and severity of the hypoxia. 8,[12][13][14][15] It is unknown whether the different methods, when used over several days, would result in a similar lack of change in swallowed volume as occurred in the current study.…”

Section: Commentmentioning

confidence: 75%

“…Over the past few years, it has become clear that the AF volume response to experimentally induced fetal hypoxia depends on both the cause of the hypoxia as well as the severity. That is, AF volume increases during moderate to severe anemic hypoxia, 12 decreases during severe 13 but not moderate 14 placental insufficiency, and changes little during hypoxic hypoxia induced by reducing uterine blood flow and/or lowering maternal inspired oxygen content. 8,15 In humans, fetal hypoxic hypoxia in women living at relatively high altitude (6000 feet) is associated with an increase in AF volume rather than no change.…”

mentioning

confidence: 99%

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Swallowing, urine flow, and amniotic fluid volume responses to prolonged hypoxia in the ovine fetus

Thurlow

Brace

2003

American Journal of Obstetrics and Gynecology

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Section: Commentmentioning

confidence: 75%

mentioning

confidence: 99%

Swallowing, urine flow, and amniotic fluid volume responses to prolonged hypoxia in the ovine fetus

Thurlow

Brace

2003

American Journal of Obstetrics and Gynecology

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“…Another concern was that amniotic fluid volume may have increased due to a decrease in hematocrit (18). Although the hematocrit decreased 2% during the exchange period, the oxygen content increased from 6.5 ϩ 0.8 to 8.0 ϩ 0.7 ml/100 ml.…”

Section: Discussionmentioning

confidence: 99%

Regulatory response to washout of amniotic fluid in sheep

Yang¹,

Davis²,

Hohimer³

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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To test the hypothesis that a substance present in the amniotic fluid could serve as a regulator of amniotic fluid volume, we drained and discarded amniotic fluid while replacing it with lactated Ringer solution that was isotonic to amniotic fluid. Seven ewes with singleton fetuses at 119 +/- 1 days of gestation (mean +/- SE) were instrumented with multiple indwelling catheters in the pedal artery, pedal vein, and amniotic cavity. During the exchange periods, an average of 3,019 +/- 171 ml/day of lactated Ringer solution was infused into the amniotic cavity while an equal amount of amniotic fluid was pumped out and discarded. During the control period, amniotic fluid composition and volume were not altered. Exchange and control periods started with the same amniotic fluid volume, lasted 3 or 4 days, and were randomized with regard to order. Amniotic fluid volume measured by vacuum drainage was 556 +/- 98 ml at the end of the control period and 986 +/- 209 ml (P = 0.03) at the end of the exchange period. Fetal arterial blood gases, hemodynamic parameters and the osmolality gradient between fetal plasma and amniotic fluid were not altered by the exchange process. A linear relationship between the control amniotic fluid volume and the volume at the end of the exchange period (P = 0.003) suggests that the animals with larger control volumes responded to isovolumic dilution with a larger volume increase. We conclude that amniotic fluid may contain a substance that regulates amniotic volume.

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“…In brief, under inhalation anesthesia using aseptic techniques, indwelling plastic catheters were placed through fetal and maternal femoral arteries into the descending aorta. Prophylactic antibiotics (22) were given at the time of surgery and on the 5 subsequent days. Amniotic fluid volume responses in these animals have been reported elsewhere (22).…”

Section: Methodsmentioning

confidence: 99%

“…Prophylactic antibiotics (22) were given at the time of surgery and on the 5 subsequent days. Amniotic fluid volume responses in these animals have been reported elsewhere (22).…”

Section: Methodsmentioning

confidence: 99%

Erythropoietin responses to progressive blood loss over 10 days in the ovine fetus

Sohl

Cheung

Widness

et al. 2001

American Journal of Physiology-Regulatory, Integrative and Comp

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Long-term loss of fetal blood can occur with fetomaternal hemorrhage, vasoprevia, or placental previa. Our objective was to determine the effects of progressive fetal blood loss over 10 days on fetal plasma erythropoietin (EPO) concentration and its relationship to arterial PO(2), hematocrit, and the volume of blood loss. Late-gestation fetal sheep (n = 8) were hemorrhaged daily at a rate of 1 ml/min over 10 days. The extent of hemorrhage differed in each fetus and ranged from 30 to 80 ml/day, with the cumulative volume removed ranging from 78 to 236 ml/kg estimated fetal weight. Four fetuses served as time controls. EPO concentration measurements were by radioimmunoassay. Statistical analyses included regression, correlation, and analysis of variance. We found that EPO and arterial PO(2) were unchanged until the cumulative hemorrhage volume exceeded 20-40 ml/kg. Once this threshold was exceeded, plasma EPO concentration increased progressively throughout the study and averaged 14.3 +/- 3.2 times basal values on day 10. EPO concentration, arterial PO(2), and hematocrit changes were related curvilinearly to cumulative hemorrhage volume (P < 0.01), whereas the relationship between plasma EPO and arterial PO(2) was log linear (P < 0.001). We conclude that 1) fetal plasma EPO concentration and arterial PO(2) are insensitive to a slow, mild-to-moderate blood loss over several days; 2) unlike the rapid return of EPO to normal within 48 h after acute hemorrhage, fetal EPO concentration undergoes a progressive increase with moderate-to-severe blood loss over several days; 3) the long-term hemorrhage-induced changes in EPO are best correlated with arterial PO(2); and 4) the fetal EPO response to hemorrhage does not appear to be limited by the fetus's ability to produce EPO.

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Relationship between graded degrees of anemia and amniotic fluid volume in the ovine fetus

Cited by 10 publications

References 20 publications

Swallowing, urine flow, and amniotic fluid volume responses to prolonged hypoxia in the ovine fetus

Swallowing, urine flow, and amniotic fluid volume responses to prolonged hypoxia in the ovine fetus

Regulatory response to washout of amniotic fluid in sheep

Erythropoietin responses to progressive blood loss over 10 days in the ovine fetus

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