NEUROMUSCULAR EFFECTS OF VECURONIUM AND NEOSTIGMINE IN MONTREAL AND PARIS

The potency of vecuronium was reported to be greater in Montreal than in Paris. This study was designed to determine whether there were diff erences in onset, duration, and reversibility with neostigmine between both centres. Twenty ASA I or II adults (ten men, ten women), aged 18 -65 yr were studied in each of the two cities, during a standard thiop entone-fentanyl-nitrous oxide (60-70%) - isoflurane 0.5% end-tidal ana esthetic. Train-of-four stimulation was applied every 20 sec to the ul nar nerve at the wrist and the force of contraction of the adductor po llicis muscle was measured. Vecuronium, 0.1 mg.kg(-1) was given as a b olus, and neostigmine, 0.04 mg.kg(-1) was administered, with atropine 0.02 mg.kg(-1), at 25% first twitch height recovery. Onset time to max imum blockade was (mean +/- SD) 3.9 +/- 1.3 min in Paris vs 4.5 +/- 1. 3 min in Montreal (NS). Duration from injection to 25% first twitch re covery was shorter (28.5 +/- 6.8 min) in Paris than in Montreal (39.1 +/- 23 min) (P < 0.0001). Time from injection of neostigmine to a trai n-of-four ratio of 70% was not different in Paris (6.3 +/- 2.2 min) fr om Montreal (5.6 +/- 1.9 min). It is concluded that the duration of on ''intubating'' dose of vecuronium is longer in Montreal, but, when gi ven at 25% first twitch recovery, neostigmine has the same efficacy in Montreal as in Paris