[Time course of thoracic epidural pressure and saphenous venous pressure changes with oxytocics after fetus delivery in parturients undergoing cesarean section].

BACKGROUND

We examined the effects of oxytotics administered after fetus delivery on epidural and venous pressures in 40 parturients undergoing cesarean section under spinal anesthesia.

METHODS

The subjects received 0.5% isobaric bupivacaine for spinal anesthesia. An epidural catheter placed at T11-12 and a venous catheter placed at left saphenous vein, were connected to pressure transducers to monitor each pressure. The subjects received intravenous methylergometrine 0.2 mg (methylergometrine group: n=20) or oxytocin 10 IU (oxytocin group: n=20) immediately after fetus delivery. Intramyometrial PGF2alpha was additionally administered from 5 minutes after fetus delivery in case of low uterine tone. Statistic analysis was performed with ANOVA.

RESULTS

Epidural pressure in the methylergometrine group increased at placental delivery and the increase continued until 15 minutes after delivery (P<0.05). Epidural pressure in the oxytocin group increased at placental delivery and began to decrease at 5 minutes after delivery (P<0.05). Saphenous venous pressure began to increase at 10 minutes after delivery in the methylergometrine group (P<0.05).

CONCLUSIONS

The increase in epidural pressure within 5 minutes after fetus delivery would be caused by uterine contraction in both groups. The vasoconstrictive effect in the methylergometrine group is likely to cause the epidural pressure increase after delivery.