Related Experiment Video
Updated: Aug 15, 2026

Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings
Published on: October 25, 2015
Umbilical cord acid base changes associated with perinatal cardiac failure
H S Brar1, M K Wong, T H Kirschbaum
1Department of Obstetrics and Gynecology, University of Southern California, School of Medicine, Los Angeles.
Two infants delivered by emergency cesarean section because of fetal distress are described, and the umbilical blood acid-base findings are discussed. One fetus was stillborn, the other died in the immediate neonatal period, and both showed signs of cardiac dilation and failure on postmortem examination. Umbilical cord blood gas determination at the time of delivery showed almost normal values of pH, PcO2, and PO2 in the umbilical vein but acidotic pH with high PCO2 and low PO2 values in the umbilical artery samples. These findings are probably the result of a prolonged umbilical blood circulation time because of fetal cardiac failure. This sluggish perfusion allows the equilibration of fetal blood with maternal intervillous blood, and the findings in the fetal umbilical vein approximate maternal uterine venous values. Umbilical cord acid-base determinations in perinatal surveillance are commonly recommended without specific details. Umbilical artery samples must be obtained to properly assess the metabolic status of the fetus at the time of birth.
Two infants delivered by emergency cesarean section because of fetal distress are described, and the umbilical blood acid-base findings are discussed. One fetus was stillborn, the other died in the immediate neonatal period, and both showed signs of cardiac dilation and failure on postmortem examination. Umbilical cord blood gas determination at the time of delivery showed almost normal values of pH, PcO2, and PO2 in the umbilical vein but acidotic pH with high PCO2 and low PO2 values in the umbilical artery samples. These findings are probably the result of a prolonged umbilical blood circulation time because of fetal cardiac failure. This sluggish perfusion allows the equilibration of fetal blood with maternal intervillous blood, and the findings in the fetal umbilical vein approximate maternal uterine venous values. Umbilical cord acid-base determinations in perinatal surveillance are commonly recommended without specific details. Umbilical artery samples must be obtained to properly assess the metabolic status of the fetus at the time of birth.
More Related Videos
Related Concept Videos
Acid-Base Balance
When the pH of arterial blood rises above 7.45, it results in a condition called alkalosis. Conversely, a drop below 7.35 leads to...
Respiratory Regulation of Acid-Base Balance
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...
Disorders of Acid-Base Balance
Respiratory Acidosis and Alkalosis
Respiratory acidosis occurs due to an increase in the partial pressure of carbon dioxide PCO2 in the blood. It often arises from shallow breathing or impaired gas exchange caused by...
Diagnosing Acidosis and Alkalosis
First, the pH level is assessed to determine whether the blood pH is normal (7.35–7.45), low (acidosis), or high (alkalosis).
Next, the PCO2 and HCO3− values are examined to...
Acute Respiratory Failure-III
Cardiomyopathy VII: Pre and Post Operative Nursing Management

