An unusual reaction in a horse during anaesthesia

Authors: Anderson IL
Publication: New Zealand Veterinary Journal, Volume 31, Issue 5, pp 85, May 1983
Publisher: Taylor and Francis

Animal type: Horse, Livestock
Subject Terms: Adverse drug reaction, Allergy, Anaesthesia/analgesia/sedation, Animal remedies/veterinary medicines, Surgery
Article class: Correspondence

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Abstract: A six-year-old thoroughbred gelding, weighing 500kg, was presented for carpal surgery. Pre-operative examination revealed no abnormalities apart from the surgical indication. Pre-anaesthetic medication consisted of acetylpromazine 25mg intramuscularly 25 minutes prior to induction, and anaesthesia was induced with guaiphenesin (Equinesin) 250ml 10% solution intravenously followed by 3.0gm thiopentone i/v followed by a further 250ml 10% guaiphenesin i/v. (This is the standard equine anaesthetic induction procedure used at Massey University for the last 3-4 years). Anaesthesia was maintained (through endotracheal intubation) by a halothane-oxygen mixture administered via a large-animal semi-closed circle system. Prior to induction the horse appeared to be normally tranquillized. During the administration of the guaiphenesin the horse became restless, frequently flicked its tail, kicked out with its hind legs and generally appeared agitated. However, induction was successfully completed, the animal immediately intubated and halothane-oxygen administration commenced. Within 30 seconds of the animal becoming recumbent, generalised skin swellings 1-2cm in diameter were observed over the ventral abdomen and inside of the thighs. During the next 2-3 minutes similar swellings became apparent over the entire animal. In several regions these swellings coalesced to form large diffusely swollen areas…

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