Head and tail rope-assisted recovery improves quality of recovery from general anaesthesia in horses undergoing emergency exploratory laparotomy

Abstract

Background: In equine anaesthesia, the recovery period is critical, accounting for most anaesthesia-related fatalities reported. Horses may recover unassisted or may be assisted, for example, using a head and tail rope recovery method.

Objectives: To compare the impact of head and tail rope and unassisted recovery method on quality of recovery in horses undergoing colic surgery under general anaesthesia (GA).

Study design: Single centre retrospective cross-sectional study, with prospective model performance analysis.

Methods: Clinical data were obtained from horses undergoing emergency exploratory laparotomy over a 6-year period. Multivariable logistic regression analysis was used to identify the perioperative factors that affect quality of recovery. The final prediction model was assessed prospectively.

Results: Records from 502 general anaesthetics (490 horses) were included. Multivariable logistic regression analysis showed that head and tail rope recovery (OR 2.2, 95% CI 1.4-3.3, P < .001) and sevoflurane administration (OR 1.6, 95% CI 1.2-2.3, P = .02) were associated with better quality of recovery when compared with unassisted recovery and isoflurane administration respectively. Increasing GA duration (OR 1.0, 95% CI 0.99-1.0, P = .03), increasing intraoperative dosages (in mg/kg) of thiopental (OR 0.85, 95% CI 0.75-0.98, P = .02) or ketamine (OR 0.67, 95% CI 0.46-0.99, P = .04) were linked to poor quality of recovery. No statistically significant difference was found between recovery groups in terms of mortality.

Main limitations: The clinical prediction model obtained is only applicable to the specific facilities, recovery methodology, referral population and anaesthetic protocols practiced at our institution.

Conclusions: Head and tail rope recovery is significantly associated with better quality of recovery, compared with unassisted recovery, in horses undergoing emergency exploratory laparotomy. Sevoflurane administration, in detriment of isoflurane, was associated with better quality of recovery. Other risk factors, such as increasing GA duration, the use of higher intra-operative dosages of ketamine and/or thiopental, were associated with poor quality of recovery.

Keywords: complications; horse; morbidity; mortality; rope-assisted recovery; unassisted recovery; veterinary anaesthesia.