[Influence of fetal position on respiratory function and its modification by epidural anesthesia in supine pregnant women].
We investigated the influence of fetal position on respiratory function and its modification by epidural anesthesia in supine pregnant women. We found that supine pregnant women in whom the fetus was in the right occipital anterior position (ROA) had lower inspiratory reserve volume (IRV) and vital capacity (VC) than controls in whom the fetus was in the left occipital anterior position (LOA). When the analgesic level was up to Th7 or lower, epidural anesthesia increased the VC of women with a ROA fetus and also increased IRV. With higher analgesic levels up to Th4-Th6, tidal volume (TV) and VC increased independently of fetal position. We speculate that the pressure caused by the ROA fetus on thorax of the mother is stronger and that after epidural anesthesia this pressure decreases even though the analgesic level is low, and with the analgesic level up to Th4-Th6, the level used for Cesarean section, the displacement of the uterus makes respiration during rest easier regardless of fetal position.
Kamitani
H
H
Department of Anesthesiology, Nippon Medical School, Tokyo.
Ukiya
K
K
Kinoshita
T
T
Marumo
H
H
Shimada
Y
Y
Ogawa
R
R
D000767:Anesthesia, Epidural; D000773:Anesthesia, Obstetrical; D005260:Female; D005333:Fetus / Q000502:physiology*; D006801:Humans; D011187:Posture / Q000502:physiology*; D011247:Pregnancy / Q000502:physiology*; D012119:Respiration / Q000502:physiology*