Assessment of recovery from nondepolarizing neuromuscular block has been based on clinical criteria such as; head lift, hand grip strength, adequate tidal volume, vital capscity and inspiratory force which mostly require a cooperative patient. Other criteria, indepent of patient cooperation have been the interpretation of evoked muscle responses to single twich, tetanic and train-of-four stimulation.

The present prospective investigation compare the incidence of residual neuromuscular blockade using train-of-four responses following administration and reversal of pancuronium and vecuronium in obstetric patients.

The results were as follows:

1) The mean TOF ratio(T₄/T₁) in pancuronium group was 0.75±0.05.

2) The mean TOF ratio(T₄/T₁) in vecuronium group was 0.85±0.04.

3) 50% of patients(10/20) in the pancuronium group evidenced a ratio below 0.7, 20% of patients(4/20) in the vecuronium group was evidenced a TOF ratio below 0.7.

In conclusion, the present study emphasizes the potential for residual neuromuscular blockade in patients who received pancuronium. In contrast, patients administered vecuronium appear to have a grater margin of safty postoperatively.