Clinical trial of xylazine with ketamine in equine anaesthesia

Abstract

One hundred anaesthetics were administered in a clinical trial to 95 equine patients, ranging in age from nine months to 19 years and in weight from 140 to 1270 kg, undergoing a variety of surgical procedures. Acepromazine maleate premedication (0.01 to 0.03 mg per kg intramuscularly) was given to seven animals, the remainder were not premedicated. Xylazine (1.1 mg per kg) was injected intravenously over a two minute period and after a pause of two minutes ketamine (2.2 mg per kg) was injected rapidly by the same route. For 30 procedures no other anaesthetic was given but in 59 cases anaesthesia was prolonged with halothane-oxygen while in 11 additional intravenous agents were administered. Recumbency followed one-and-a-half to two minutes after completion of the ketamine injection and limb movements occurring immediately after the animal lay down gradually subsided over the next 30 to 60 seconds. On 26 occasions when no other agent was given satisfactory operating conditions were produced for a mean (+/- sd) of 20 +/- 7 minutes and on four occasions when absence of complete muscle relaxation was observed surgery was still possible. When no other agent was given the onset of recovery was abrupt but recovery was always extremely quiet; the animals stood 33 +/- 10 minutes after induction of anaesthesia and showed a remarkable absence of ataxia. A similar recovery was seen in the 56 animals receiving halothane-oxygen and all stood 28 +/- 14 minutes after disconnection from the anaesthetic system. Heart block was observed during induction of anaesthesia bu otherwise cardiovascular and respiratory parameters were well maintained. It was concluded that the xylazine-ketamine combination had advantages over other current techniques of inducing anaesthesia in horses.

A field trial of ketamine anaesthesia in the horse

“…The horse made repeated attempts to stand, staggering in an incoordinated manner and physical restraint was useless. This incident may be similar to the one reported by Hall and Taylor (1981). Kaka, Klavano and Hayton (1979) reported that when repeated doses of ketamine were given within 5 mins of the initial dose, such a reaction was not observed.…”

“…THERE is a need for reliable short term anaesthesia in the horse, under field conditions, with a rapid, quiet induction, good analgesia and muscle relaxation, minimal cardiovascular and respiratory changes and a quick smooth recovery with minimal after effects so that the horse can be left unattended. Brouwer, Hall and Kuchel (1980) reported on the use of ketamine in horses after xylazine premedication and clinical trials of this combination of drugs have also been reported (Hall and Taylor 1981). This communication records the use of ketamine in equine veterinary practice.…”

Use of guaiacol glycerine ether in clinical anaesthesia in the horse

“…This may reflect a tendency towards inadequate administration of halothane during early gaseous anaesthesia through reducing the vaporiser setting too rapidly during the induction phase. The situation may be likened to that encountered by Hall and Taylor (1981) when prolonging xylazine-ketamine anaesthesia with halothane and oxygen; it was found necessary to administer high inspired concentrations of halothane immediately after intubation in order to be able to maintain a steady level of anaesthesia as the effects of the xylazine-ketamine combination declined.…”

Short duration general anaesthesia in the horse using guaiacol glycerine ether and thiopentone sodium

“…There remains a need in equine practice for a short duration anaesthetic technique that is safe and simple to use while producing adequate surgical conditions and uncomplicated recoveries. Many anaesthetic techniques have been described for field use (Crispin 1981;Taylor 1983) and, in particular, the combination of xylazine with ketamine (Hall and Taylor 1981) has been advocated. The combination of GGE with thiopentone has been shown to produce calm, controlled inductions together with smooth recoveries (Jackson and Lundvall 1970;Bishop 1978).…”