Use of vecuronium bromide and atracurium besylate in continuous intravenous infusion in urologic surgery

The effects of continuous i.v. infusion of atracurium and vecuronium monitored by TOF supplied by an ABM monitor have been compared in 60 patients subdivided into four groups and submitted to anaesthesia with isoflurane for urological surgery interventions. Groups A and V received respectively an initial bolus of 0.5 mg/kg atracurium and of 0.08 mg/kg vecuronium followed immediately by continuous i.v. infusion of 5.5 micrograms/kg/min. Atracurium or 0.9 micrograms/kg/min of vecuronium; recovery of neuromuscular function happened spontaneously. Groups A' and V' differed by virtue of the use of 0.04 mg/kg prostigmin in the recovery phase. Average consumption of atracurium and vecuronium were respectively 5.1 +/- 1.75 micrograms/kg/min (2.6-9.03) and 0.75 +/- 0.20 micrograms/kg/min (0.5-1.2) in groups A-A' and V-V'. In groups A and V Recovery time 25-75" of T1 and TR presented a statistically significant difference (p less than 0.05) in favour of atracurium. In groups A' and V' the same parameters presented a statistically non-significant difference (p greater than 0.05). The ratio TI/TR does not vary to a statistically significant extent in the 4 groups. The number of infusion rate variations needed to maintain stable neuromuscular block was lower in the atracurium groups.