Effects of Autonomic Blockade with Spinal Anesthesia on Uterine and Fetal Hemodynamies and Oxygen Consumption in the Sheep

Lucas, William F.; Kirschbaum, Thomas H.; Assali, N.S.; Beck, R.; Paler, J.

doi:10.1159/000240026

Cited by 28 publications

(13 citation statements)

References 12 publications

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“…The maternal arterial blood acid base characteristics were similar to those found COMLINE and SILVER [2,3] under nembutal anaesthesia and in chronic preparations; the fetal pH and PO 2 values were a little lower, suggesting some inpairment of the placental circulations due to the spinal anesthesia which was found by LUCAS et al [24]. The plasma amino acid values in the pregnant ewe were lower than in the non pregnant sheep (LEIBHOLZ [20]) s might be expected from the fall in total <%-amino nitrogen observed by CURET et al [4] during gestation in the ewe.…”

Section: Discussionsupporting

confidence: 83%

Placental transfer and fetal uptake of amino acids in the pregnant ewe

Young¹,

Fadyen²

1973

Journal of Perinatal Medicine

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Section: Discussionsupporting

confidence: 83%

Placental transfer and fetal uptake of amino acids in the pregnant ewe

Young¹,

Fadyen²

1973

Journal of Perinatal Medicine

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“…In addition, there was a higher mean value for uterine arterial flow per kg of fetal weight and a lower mean value for utero-placental arteriovenous oxygen content difference. The good correlation between maternal arterial pressure and uterine arterial flow has been noted previously [12]. There was no difference between fractional uterine placental oxygen consumption per kg of fetal weight reported in this study and that reported in the earlier study.…”

Section: Discussionsupporting

confidence: 85%

“…As in previous work [12], technical difficulties limited measurement of uterine arterial blood flow through a single uterine artery. The relation between measured and total uterine flow varied with the sizes and numbers of fetuses in other horns, with fetal well being, and with the effects of the surgical preparation.…”

Section: Failure Of Reduction Of Hemoglobin In Transitmentioning

confidence: 83%

Placental Oxygen Transfer in Pregnant Ewes During Hyperbaric Oxygenation

1969

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ExtractExposure of pregnant ewes to oxygen administration under three atmospheres of pressure produced large increases in maternal arterial blood p02, together with acidosis associated with an increase in pCO,. Although maternal arterial blood pressure tended to increase and uterine arterial blood flow rate tended to fall, the changes had no statistical significance. Simultaneously, it was possible to increase umbilical venous blood PO, within the range 90-550 mm Hg, with corresponding changes in pCO, and pH as occurred in maternal blood. There was a significant decrease in umbilical venous flow rate, which failed to return to control levels after air-breathing was resumed at one atmosphere of pressure. Fetal arterial pressure was unchanged. In five animals studied, umbilical oxygen transfer was also unchanged during hyperbaric oxygenation. SpeculationThe lack of comparable increases in umbilical venous and maternal arterial blood p 0 2 during oxygen administration to gravid ewes and the small reduction in umbilical oxygen transfer rates have been interpreted to be primarily the result of the nonlinearity of sheep oxyhemoglobin dissociation functions. Hyperbaric oxygenation allows umbilical oxygen transfer to occur independently of the function of maternal hemoglobin. The results of this study are consistent with, but do not prove, this hypothesis.

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“…During this period, the base infusion was discontinued, the fetal trachea cannulatcd,and the lungs were expanded and ventilated with a positive-negative pressure Bird respirator using 95% 0 2 and 5% C 0 2. This type o f respirator does not affect appreciably the cardiovascular hemodynamics o f the neonate as shown by various scries o f studies carried out during the last 12 years [8,9,10,11,12]. The umbilical cord was then ligated and three collection periods (15-20 min each) of blood and urine samples were carried out as in the fetal state.…”

Section: Methodsmentioning

confidence: 99%

“…The ewe's lungs were ventilated with compressed air through an endotracheal tube, with 5% CO2 added when needed to counteract the effects of hyperventilation. Fetal and neonatal urine was obtained through bilateral ureteral catheters inserted near the uretero vesical junctions.The operative techniques, including those o f marsupializing the fetus and cannulating the maternal and fetal vessels and the fetal ureters were the same as previously reported [8,9,10,11]. During both fetal and the neonatal state, the lamb was lightly anesthetized from the pentobarbital that was transferred to the fetus across the placenta.…”

mentioning

confidence: 99%