Neuromuscular blockade of the fetus with pancuronium or pipecuronium for intra‐uterine procedures

Abstract

Fetal movement during intra-uterine fetal therapy makes these procedures technically more difficult and increases the likelihood of trauma to the fetus. Pancuronium or pipecuronium were used in a randomised study to temporarily arrest movement in 16 fetuses undergoing intra-uterine procedures. Under ultrasound guidance, pancuronium or pipecuronium 0.2 mg.kg-1 was injected into the fetal gluteal region. Fetal movements ceased within 4.6 +/- 2.3 min in the pancuronium group and 4.5 +/- 2.8 min in the pipecuronium group and returned by 115 +/- 26 min in the pancuronium group and 121 +/- 32 min in the pipecuronium group. No adverse effects of the relaxant were observed in the mothers. There was no evidence of soft tissue, nerve or muscle damage at the fetal injection site after delivery. Both muscle relaxants provided a safer method for diagnostic and therapeutic procedures. However, four cases in the pancuronium group (50%) developed a fetal tachycardia, and two cases in the same group showed loss of beat-to-beat variability. Pipecuronium appeared to be more suitable for intra-uterine procedures.