Fetal breathing movements (FBM) in unanesthetized lambs in utero were correlated with measurements of arterial blood gases. 187 observations, consisting of the incidence of FBM during the hour preceding and the hour after the blood gas determinations, were made on 125 separate days in 30 fetuses of 117 to 146 days' gestational age. 58% of the observations with fetal apnea (FBM 0 to 9% in 2 hours) showed hypoxia (PaO2 ≤ 16 torr), whereas only 4% of the observations with FBM greater than 10% were associated with hypoxia. 78% of the hypoxic and normocarbic (PaCO2 42 to 53 torr) observations demonstrated apnea. However, only 44% of hypoxic plus hypercarbic (PaCO2 57 to 63 torr) fetuses were apneic, and with an elevated PaCO2, apnea tended to develop at a lower level of PaO2. We conclude that FMB may persist in the presence of hypercarbia with hypoxia.
|Original language||English (US)|
|Number of pages||4|
|Journal||American Journal of Obstetrics and Gynecology|
|Publication status||Published - 1980|
ASJC Scopus subject areas
- Obstetrics and Gynecology