Comparison of rocuronium-induced neuromuscular blockade in second trimester pregnant women and non-pregnant women.

BACKGROUND: This study set out to compare the onset and duration of rocuronium-induced neuromuscular blockade in second trimester pregnant women and non-pregnant women receiving general anesthesia. METHODS: Forty-seven pregnant (Group P) and forty-seven non-pregnant (Group C) women were enrolled. Anesthesia was induced with propofol 2.0 mg/kg and rocuronium 0.6 mg/kg, and neuromuscular blockade was assessed with an accelerometric sensor using train-of-four stimulation (TOF-Watch® SX). Tracheal intubation was performed at maximum depression of the first twitch (T1) and anesthesia was maintained with sevoflurane 1.5-2.5% and 50% oxygen in air. We recorded the times to maximum T1 depression and 5% and 25% T1 recovery, as well as the mean arterial pressure and heart rate at baseline, injection of rocuronium, intubation, and 5% and 25% T1 recovery. RESULTS: The onset of rocuronium-induced neuromuscular blockade (time to maximum T1 depression) did not differ significantly between the groups. The duration (time to 25% T1 recovery) was significantly longer in Group P than in Group C (45.7 ±â€¯12.9 min vs 40.6 ±â€¯10.4 min, P <0.037). During the recovery period from the blockade, the mean arterial pressure was significantly lower in Group P than in Group C. CONCLUSION: Our data showed that the rocuronium-induced neuromuscular blockade did not significantly differ in onset but lasted significantly longer in second trimester pregnant women compared with non-pregnant women.