Neuromuscular and cardiovascular effects of atracurium administered to healthy horses anesthetized with halothane.
Abstract: Neuromuscular and cardiovascular effects of atracurium, a nondepolarizing neuromuscular blocking agent, were evaluated in 10 halothane-anesthetized adult horses. Hind limb digital extensor tension (hoof twitch) was measured with a strain gauge to quantitate the muscle relaxant effects of atracurium. Response of facial muscles was compared with hoof twitch. Five injections of atracurium were given. Initial mean (+/- SEM) dosage of 0.07 +/- 0.01 mg of atracurium/kg of body weight caused 98.6 +/- 0.8% reduction of the preinjection hoof twitch. Subsequent dosages of 0.04 +/- 0.003 mg/kg induced a degree of relaxation similar to that induced by the initial dose. Duration of paralysis from maximal effect to 10% recovery of twitch was 12.2 +/- 1.5 minutes for the first injection. This was significantly (P less than 0.05) different from subsequent paralysis periods, which lasted approximately 7 minutes. The 10% to 75% recovery time after all injections was similar-approximately 16 minutes. The facial muscles were less affected objectively by atracurium than was the hind limb. Atracurium did not cause cardiovascular changes. When the hoof twitch had recovered to 95% of its tension before atracurium administration, 0.5 mg of edrophonium/kg, was given to antagonize neuromuscular blockade. Within 5 minutes of edrophonium administration, twitch tension exceeded that measured before atracurium administrations. Within 2 minutes of edrophonium administration, blood pressure began to increase and continued to increase approximately 10 mm of Hg above the value measured before edrophonium administration. Heart rate was not affected by edrophonium. Other muscarinic side effects of edrophonium were not observed. Of the 10 horses, 9 had good, unremarkable recovery to standing position. One horse had a violent recovery period.
Publication Date: 1988-07-01 PubMed ID: 3421529
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research examined the neuromuscular and cardiovascular impacts of a drug known as atracurium on healthy horses anesthetized with halothane, focusing particularly on muscle relaxation effects and vascular responses, as well as recovery times.
Experiment Design
- The researchers used 10 adult horses in their study, which were under anesthetization using halothane.
- The specific muscle response that the researchers focused on was the hoof twitch in the horse’s hind limbs, measured using a strain gauge.
- Facial muscle responses were also evaluated alongside the hind limb response.
- The horses were administered five injections of the nondepolarizing neuromuscular blocking agent, atracurium.
Results and Findings
- The initial dosage of atracurium injected, with an average of 0.07 mg per kg of body weight, led to a reduction of the pre-injection hoof twitch by approximately 98.6%.
- Sequential doses of around 0.04 mg per kg induced similar levels of muscle relaxation as the initial dose.
- The time frame of paralysis from the most intense effects to 10% recovery of twitch was on average 12.2 minutes after the initial injection. This duration differed significantly from subsequent paralysis periods, on average lasting approximately 7 minutes.
- Atracurium had no significant effect on cardiovascular health.
- The facial muscles were less influenced by atracurium compared to the hind limb.
Recovery and After-Effects
- When the hoof twitch recovered to 95% of its initial tension, the horses were administered 0.5 mg of edrophonium per kg to counteract the neuromuscular blockage.
- The twitch tension surpassed the tension measured prior to atracurium administration around 5 minutes post-edrophonium administration.
- Blood pressure began to rise about 2 minutes after edrophonium was given, and kept increasing approximately 10 mm of Hg above its value prior to edrophonium administration.
- The horse’s heart rates were unaffected by edrophonium and no muscarinic side effects were reported.
- Out of the total horses, nine showed good and uneventful recovery to a standing position while one experienced a violent recovery phase.
Cite This Article
APA
Hildebrand SV, Arpin D.
(1988).
Neuromuscular and cardiovascular effects of atracurium administered to healthy horses anesthetized with halothane.
Am J Vet Res, 49(7), 1066-1071.
Publication
Researcher Affiliations
- Department of Surgery, School of Veterinary Medicine, University of California, Davis 95616.
MeSH Terms
- Anesthesia, Inhalation / veterinary
- Animals
- Atracurium / administration & dosage
- Atracurium / pharmacology
- Blood Pressure / drug effects
- Edrophonium / pharmacology
- Halothane
- Heart Rate / drug effects
- Horses / physiology
- Muscle Contraction / drug effects
- Muscle Relaxation / drug effects
Citations
This article has been cited 2 times.- Gozalo-Marcilla M, Ringer SK. Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature. Animals (Basel) 2021 Jun 14;11(6).
- Tutunaru A, Dupont J, Gougnard A, Ida K, Serteyn D, Sandersen C. Retrospective evaluation of clinical use of cis-atracurium in horses. PLoS One 2019;14(8):e0221196.
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