Clinical experiences with desflurane inhalational anaesthesia in horses

Reasons for performing study:

Equine general anaesthesia carries a higher risk of perioperative fatality compared with humans and companion animals. Multiple studies have examined the risk factors associated with general anaesthesia, most notably the ongoing confidential enquiry into perioperative equine fatalities (CEPEF) studies initially published by Johnston et al. [1]. Desflurane is a modern inhalational anaesthetic with low solubility and potentially beneficial reduced cardiorespiratory effects, but its use in a large number of horses has not been investigated.

Objectives:

To evaluate the perioperative mortality rates of horses undergoing general anaesthesia maintained using desflurane. Study design: Retrospective analysis.

Methods:

Anaesthetic records of all horses undergoing general anaesthesia over a 4-year period at a single hospital were retrospectively examined. Horses were excluded if general anaesthesia was not maintained using inhaled desflurane. Outcome variables of dead (anaesthetic related), alive or euthanased (for other reasons) were recorded consistent with previous CEPEF studies.

Results:

427 horses met the inclusion criteria, of which 406 (95.1%) were alive at 7 days post operatively, 16 (3.7%) were euthanased and 5 (1.2%) died. Four of the perioperative fatalities suffered cardiac arrest, one suffered a catastrophic fracture. Mean age was 7.6 years (range 1 month–26 years), mean weight was 503.3 kg (range 60–828 kg). Mean duration of anaesthesia was 63.0 min (range 15–200 min). Mean recovery time to standing was 28.3 min (range 5–70 min) with mean recovery score 1.4/5 (range 1–4).

Conclusions:

Use of desflurane led to comparable mortality rates to other inhalational anaesthetics in this small number of horses at a single hospital. Further multicentre studies with larger numbers are warranted to examine any potential benefits.