Retrospective evaluation of clinical use of cis-atracurium in horses.

This research article deals with an evaluation of the use of cis-atracurium, a neuromuscular blocking agent, in horses. The goal was to understand the onset and duration of paralysis caused by different doses and to determine an appropriate dosage for sustained neuromuscular blockade.

Objective and Methodology of the Study

• The aim of this retrospective study was to evaluate the efficiency of cis-atracurium, a drug commonly used in anaesthesia to induce paralysis, in horses which had not been previously reported. The primary goal was to assess the time of onset and the duration of the neuromuscular blockade (NMB) caused by three different doses of this drug and, consequently, determine an appropriate dosage to maintain a sustained NMB.
• The research data was collected from horses at the Equine Teaching Hospital of the University of Liège, which received cis-atracurium as part of a balanced anaesthetic protocol between March 2014 and June 2017. Out of 37 horses, only 23 had complete records and were included in the study.

Measurements and Results

• A train-of-four (TOF) stimulation pattern was employed to evaluate the NMB. Several factors were recorded and analysed, such as the induction dose of cis-atracurium, the onset and duration of action, the number and totals of supplementary boluses of cis-atracurium per horse, the total duration of the NMB, recovery time, the use of an antidote, and any side effects caused by the drug.
• Three different dosages of cis-atracurium (50 μg/kg, 75 μg/kg, and 100 μg/kg) were used. The 50 μg/kg dose failed to induce NMB in 3 horses. It was also observed that there was negligible difference in the onset of action between the three dosages (approximately 5 minutes).
• The duration of the NMB was, however, found to be dose-dependent. The calculated dosage of cis-atracurium needed to maintain a NMB was measured to be around 2.3 μg/kg/minute, calculated by dividing the sum of the induction dose and the supplementary boluses by the duration of the NMB.

Conclusions and Implications

• The study concludes that cis-atracurium might be a viable alternative to other neuromuscular blocking agents (NMBA) in horses. However, it also acknowledges that the findings will need to be verified with a prospective study in order to confirm these results.
• This research adds valuable knowledge to the field of equine medicine, especially in relation to anaesthesia and surgery, providing a potential new option for NMB in horses.