Fetal oxygen store is about 42 mL; how long would it take to deplete during an interruption of oxygen delivery?

Fetal oxygen store is about 42 mL; how long would it take to deplete during an interruption of oxygen delivery?

• A. 30 seconds
• B. 1 minute
• C. 2 minutes
• D. 5 minutes

Answer: (C)

When oxygen delivery to the fetus is interrupted, the fetus relies on its finite oxygen stores for a short period. The fetal oxygen store is about 42 mL. Depletion time is determined by how quickly the fetus uses oxygen, so you estimate by dividing the total store by the rate of oxygen consumption. With typical fetal metabolism, this results in a depletion time on the order of a couple of minutes, roughly around two minutes. That’s why a two-minute interruption is considered about the limit before hypoxia becomes a concern, emphasizing the importance of restoring placental oxygen delivery or delivering promptly.

When oxygen delivery to the fetus is interrupted, the fetus relies on its finite oxygen stores for a short period. The fetal oxygen store is about 42 mL. Depletion time is determined by how quickly the fetus uses oxygen, so you estimate by dividing the total store by the rate of oxygen consumption. With typical fetal metabolism, this results in a depletion time on the order of a couple of minutes, roughly around two minutes. That’s why a two-minute interruption is considered about the limit before hypoxia becomes a concern, emphasizing the importance of restoring placental oxygen delivery or delivering promptly.