Faculty Bibliography

A case of vasa previa in twin pregnancy associated with a sinusoidal heart rate was observed. A review of the world literature revealed eight previously reported cases of vasa previa in twins. No first twin survived, and 62.5% of second twins eventually died from partial or complete exsanguination. This is the first reported case of sinusoidal fetal heart rate in association with vasa previa. Continuous fetal monitoring suggested the diagnosis of funic presentation and of fetal bleeding. A high index of suspicion, use of amnioscopy, ability to detect fetal blood in the vaginal pool, continuous fetal heart rate monitoring and ultrasonography may help in reducing the high perinatal mortality associated with vasa previa

Fetal umbilical artery blood was analyzed for pH and lactate at intervals over a 3-hour period. No significant change occurred in pH over the first 30 minutes, despite a progressive rise in plasma lactate. The pH changes paralleled the lactate in an inverse relationship, but remained within the error of the method for the first hour. Lactate analysis should be considered for clinical use, for confirmation of pH observations. Also pH assays may be used in any hospital with a blood-gas capability, since a 30-minute delay within the assay does not materially alter the results. A laboratory in the delivery room area is not essential to proper use of fetal blood pH analysis

Umbilical blood was analyzed for pH, pO2, pCO2, HCO3-, base excess, and plasma lactate to evaluate possible errors of fetal scalp blood analysis. Two studies to determine the effect of delayed collection and exposure to air on fetal blood acid-base measurement analyzed anaerobically collected umbilical blood in syringe and capillary samples. In the first study, 37 samples were analyzed and then placed in small droplets on a glass slide and exposed for 30 seconds and 60 seconds respectively. These samples were then collected and reanalyzed. No significant change was noted through 1 minute of exposure in any of the acid-base parameters measured. In the second study, 34 samples were again analyzed and then exposed in droplets for a full 5 minutes. Differences in measurement of pO2, base excess, and plasma lactate remained insignifiicant even up to 5 minutes. The results of this study demonstrate that the occasional slow scalp blood collection or admixture with air do not present a significant obstacle to proper use of fetal acid-base analysis

Eleven patients with moderate fetal bradycardia in labor were studied by fetal scalp blood pH, continuous tissue pH, and umbilical arterty pH at delivery. The neonatal outcomes and biochemical data demonstrated that moderate fetal brdycardia does not indicate fetal distress

Bolus injection of T-1824-albumin, test indicator, and tritiated water into a jugular vein of the anesthetized dog and sequential sampling of blood from a carotid artery yielded multiple-indicator outflow patterns for the lung. Permeability-surface products of the test indicator for the lung endothelial barrier were obtained by comparison of test indicator with T-1824-albumin on the upslope of the test-indicator curve and correction for backdiffusion. The derived endothelial permeability coefficients, based on surface area/wet lung weight-500 cm2/g (mean +/- 2 SE, 10(-5) cm s(-1)), were: sodium ion, 2.9 +/- 0.8; ethylene glycol, 7.3 +/- 1.5; 1, 3-propranediol, 7.9 +/- 3.2; 1, 2-propanediol, 10 +/- 4; 1, 4-butanediol, 14 +/- 8; 1, 5-pentanediol, 21 +/- 6; 1, 6-hexanediol, 41 +/- 11; formamide, 16 +/- 9; acetamide, 13 +/- 4; propionamide, 31 +/- 12; butyramide, 42 +/- 24; valeramide, 79 +/- 12; tritiated water, 150 +/- 50. The backdiffusion correction varies from 8% for sodium to 75% for valeramide. A parallel-pathway model of blood-tissue passive exchange of small nonelectrolyte solutes is compatible with these results, with a lipid pathway through endothelial cells and an aqueous pathway possibly through interendothelial clefts.