The tof-guard neuromuscular transmission monitor and its use in horses

Abstract

It has been emphasized in the human medical literature, that when using a neuromuscular blocking agent, it is of vital importance the monitoring of the neuromuscular block and that these agents should never be used without it. The purpose of this study was to evaluate the use of the neuromuscular transmission monitor TOF-Guard in horses. Twelve horses were randomly assigned whether to receive pancuronium or atracurium as the neuromuscular blocking agent. All horses were pre-medicated with romifidine, anaesthesia induced with diazepam and ketamine and maintenance with halothane. Abolition of spontaneous ventilation was accomplished by the administration of atracurium or pancuronium. The time from injection of the muscle relaxant agent to the onset of maximum block (T1=0), recovery of T1 to 25% and the recovery of TOF ratio to 0.7 were recorded, as was the time for recovery of T1 from 25 to 75%. It was concluded that it is very important the neuromuscular transmission monitoring during the use of a nondepolarizing neuromuscular blocking agent, since it provides a safer anaesthetic and surgical procedure with the use of adequate dosages and due to the impossibility of a superficialization of the neuromuscular blockade during a surgical procedure. The TOF-Guard showed to be a good option for neuromuscular monitoring in horses.

Observations on the muscle relaxant rocuronium bromide in the horse – a dose–response study

“…1983) with mechanomyography has been reported. Acceleromyography is a relatively new technique for monitoring neuromuscular blockade and Bechara et al. (1999) used different nerve‐muscle units to demonstrate that the acceleromyography was a reliable technique in horses.…”

“…Stimulation of the peroneal nerve (Klein et al 1983) with mechanomyography has been reported. Acceleromyography is a relatively new technique for monitoring neuromuscular blockade and Bechara et al (1999) used different nerve-muscle units to demonstrate that the acceleromyography was a reliable technique in horses. Stimulation of the peroneal nerve with an acceleromyograph, in the manner described, was feasible in this study.…”

“…The acceleration transducer was fixed to the dorsal tip of the hoof using adhesive tape. Method of limb fixation and position of the electrodes were as described by Bechara et al. (1999) and Jones & Prentice (1976) and adapted for the acceleromyography by Auer et al (2002).…”

“…The acceleration transducer was fixed to the dorsal tip of the hoof using adhesive tape. Method of limb fixation and position of the electrodes were as described by Bechara et al (1999) and Jones & Prentice (1976) and adapted for the acceleromyography by Auer et al (2002). The nerve was electrically stimulated in a train-of-four (TOF) mode at 2 Hz (four stimuli delivered over 2 seconds) every 15 seconds with two needle electrodes placed subcutaneously directly over the nerve.…”

“…The first reports of the use of muscle relaxants in horses were by Booth & Rankin (1953) with curare and by Belling & Booth (1955) with the depolarizing agent succinylcholine. A number of nondepolarizing muscle relaxants (NDMR) including gallamine, pancuronium, atracurium and vecuronium have been introduced into equine anaesthesia in the last three decades (Dykes 1973;Klein et al 1983;Hildebrand & Arpin 1988;Hildebrand et al 1989;Bechara et al 1999).…”