[Comparison of the effects of midazolam and thiopental on the neuromuscular response of vecuronium, atracurium, and pancuronium]. / Comparación de los efectos del midazolam y del tiopental en la respuesta neuromuscular del vecuronio, atracurio y pancuronio.

To assess the possible interactions of midazolam and thiopental with the muscular relaxants vecuronium (0.08 mg/kg), atracurium (0.5 mg/kg), and pancuronium (0.1 mg/kg), a comparative analysis was undertaken in two groups of 18 and 32 patients treated respectively with midazolam (0.3 mg/kg) and thiopental (5 mg/kg). The beginning of the effect, maximal blockade, duration of the clinical response, and the spontaneous recovery index were measured on electromyographic recordings of action potentials evoked by train of four supramaximal stimuli delivered every 20 sec on the ulnar nerve. Conditions for intubation were assessed 2 minutes after administration of muscular relaxant. There were no significant differences in neuromuscular parameters in either of the two groups of patients treated with midazolam or with thiopental independently of the relaxant drug administered.

[Use of vecuronium and atracurium in continuous infusion. A comparative study using electromyography and accelerometry]. / Utilización del vecuronio y atracurio en infusión continua. Estudio comparativo con electromiografía y acelerometría.

Vecuronium and atracurium, muscle relaxant agents of intermediate action, were administered in continuous infusion to 175 patients undergoing prolonged surgical operations with the purpose of achieving serum concentrations inducing maintained blocking of neuromuscular function. We used a 0.08 mg/kg or 0.5 mg/kg bolus intubation dose followed by a continuous infusion of vecuronium (72 patients) or atracurium (103 patients) 10 minutes after, at the necessary pace to maintain inhibition of neuromuscular transmission over 90%. Monitoring of relaxation was done by means of four supramaximal stimuli trains which were repeated every 20 seconds and applied to the cubital nerve. Composite electromyogram (electromyography) and thumb acceleration (mechanomyography-accelerometry) were simultaneously recorded. Infusion was interrupted 15 minutes before ending the operation; reversion occurred spontaneously in 143 patients and 32 patients had to be reversed with neostigmine. Beginning of action, total duration of infusion, infusion speed, and 25-75 spontaneous and after decurarization recovery index were measured. Initial dose allowed an easy tracheal intubation and the constant relaxation achieved with 0.068 mg/kg/h and 0.46 mg/kg/h infusion of vecuronium and atracurium was adequate for all operations. Spontaneous recovery is often adequate at the end of operations in carefully monitored patients. Both monitoring methods are useful for clinical evaluation of neuromuscular transmission.