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DOI: 10.1055/s-0028-1103029
Umbilical Arterial-Venous Blood Gas Difference: A Novel Expression of Placental Respiratory Function
Publication History
Publication Date:
21 November 2008 (online)
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ABSTRACT
We applied the concept of umbilical arterial and venous (A-V) blood gas difference in evaluating placental respiratory function to establish normative values for these relationships. Umbilical A-V cord blood gas samples were obtained in standardized fashion in uncomplicated singleton pregnancies. A-V pO2 and A-V pCO2 differences were related to obstetric factors, placental weight, and gestational age. Mean absolute differences in uncomplicated vaginal deliveries between umbilical artery and umbilical vein were: pO2 11.4 ± 7.0 mm Hg and pCO2 11.9 ± 6.8 mm Hg. Values in nonlabor cesarean section cases did not differ significantly from those of cases delivered vaginally. A-V pO2 differences did not vary significantly across gestation (Pearson's r = 0.05, p = 0.43) and did not correlate with birth weight (r = 0.06, p = 0.30). A-V pCO2 differences showed increases with gestational age (r = 0.15, p = 0.008) and with birth weight (r = 0.18, p = 0.002). Results similar to those of women delivered vaginally were seen in nonlabor cesarean deliveries. Duration of labor did not impact the A-V blood gas relationship. Umbilical A-V oxygen differences reflect placental respiratory function independent of gestational age, birth weight, duration of labor, and mode of delivery. They are easy to collect and represent a potentially valuable resource for assessment of placental function.
KEYWORDS
Arterial-venous blood gas difference - placenta - oxygenation - umbilical cord blood gas
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Koji MatsuoM.D.
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine
University of Maryland Medical Center, 22S Greene Street, P.O. Box 290, Baltimore, MD 21201
Email: koji.matsuo@gmail.com