Effect of head and tail rope-assisted recovery of horses after elective and emergency surgery under general anaesthesia

The recovery phase is a critical period during equine anaesthesia. In an attempt to reduce the risk of recovery, several recovery systems, including head and tail ropes, have been developed over time. However, the clinical safety and efficacy of these systems have not been compared to a nonassisted group in a larger study. The objective of this comparative, retrospective, nonrandomised single-centre study was to determine whether the risk of developing fatal and nonfatal complications after general anaesthesia is reduced in horses assisted with head and tail ropes during recovery compared with horses recovering unassisted. Included were all horses undergoing general anaesthesia at the Large Animal Hospital, University of Copenhagen, Denmark, from 2010 to 2019. Analysed data included age, body mass, American Society of Anesthesiologists grade of physical status (ASA score), type of surgery and anaesthetic duration. Complications were divided into none, fatal and nonfatal. Logistic regression was performed to analyse the risk and predictors of fatal and nonfatal complications using the built-in R function ‘step’. Tukey’s honest significance difference test was applied to determine significance, set at P<0.05, within the categorical variables of the reduced models. The study included 1252 horses: 662 recovered with assistance (group A) and 590 without (group NA). Overall recovery-associated mortality was 1.4%: 0.6% in group A and 2.2% in group NA. Both emergency abdominal surgery (P = 0.004) and duration of surgery (P = 0.0001) affected the risk of fatal complications negatively. Assisted recovery (P = 0.02) significantly reduced the risk of fatal complications after emergency abdominal surgery. The limitation of the study was a lack of randomisation and potentially a larger proportion of sedation among assisted horses. It was concluded that emergency abdominal surgery and duration of anaesthesia are significant risk factors for fatal complications during recovery. Head and tail rope-assisted recovery is a significant factor of reducing fatal complications during recovery after emergency abdominal surgery.