Intravenous administration of d-tubocurarine and pancuronium in fetal limbs.

The purpose of this study was to assess the effects of intravenous administration of d-tubocurarine and pancuronium in fetal lambs. Eighteen experiments were performed in seven chronically instrumented pregnant ewes between 0.8 and 0.9 of timed gestation. Each fetus received 6 ml of study drug intravenously at 1.2 ml/min over 5 minutes (d-tubocurarine 3.0 mg/kg, pancuronium 0.5 mg/kg, or saline solution control). Pancuronium (n = 7) significantly increased both fetal heart rate and mean arterial pressure. d-Tubocurarine (n = 5) significantly decreased both fetal heart rate and mean arterial pressure. Saline solution control (n = 6) did not significantly alter fetal heart rate or mean arterial pressure. The present study suggests that pancuronium is preferable to d-tubocurarine for those intrauterine procedures when an increase in fetal heart rate is desired.