EFM Fetal Oxygenation and Acid-Base Balance 2

Question 1

Metabolic acidosis in the fetus is primarily caused by:

Accepted Answer

Accumulation of lactic acid from anaerobic metabolism

Answer

When oxygen delivery is insufficient, the fetus shifts to anaerobic metabolism, producing lactic acid that accumulates and causes metabolic acidosis.

Question 2

Compared to umbilical artery blood, umbilical vein blood would normally show:

Accepted Answer

Higher pH and lower PCO2

Answer

Umbilical vein blood returns from the placenta with higher pH and lower PCO2 because CO2 has been exchanged at the placenta and O2 has been loaded.

Question 3

An elevated fetal PCO2 in cord blood gas analysis most directly indicates:

Accepted Answer

Impaired CO2 clearance across the placenta

Answer

Elevated PCO2 indicates that CO2 produced by fetal metabolism is not being adequately cleared by the placenta, typically due to acute uteroplacental insufficiency or cord compression.

Question 4

The normal lactate level in umbilical artery blood is approximately:

Accepted Answer

< 4.8 mmol/L

Answer

Normal umbilical artery lactate is less than 4.8 mmol/L; values above this suggest significant anaerobic metabolism and fetal metabolic acidosis.

Question 5

The bicarbonate buffer system in fetal blood primarily serves to:

Accepted Answer

Neutralize excess hydrogen ions produced by anaerobic metabolism

Answer

Bicarbonate is the primary extracellular buffer and neutralizes excess H+ ions from anaerobic metabolism, maintaining pH during periods of hypoxia.

EFM - Electronic Fetal Monitoring Practice Test

EFM - Electronic Fetal Monitoring Practice Test

EFM Fetal Oxygenation and Acid-Base Balance 2