Physiological and behavioural effects of continuous remifentanil-xylazine administration in donkeys.

Authors: Damasceno Kássia Fernanda Araújo, Mouta Andressa Nunes, Alves Larissa de Sant' Ana, Arcoverde Kathryn Nóbrega, Aragão Herbert Reis, Cavalcante Jerson Marques, Veras de Paula Valéria

Journal: Equine veterinary journal

DOI: 10.1111/evj.70131 PubMed: 41310946Log in to save

Summary

# Editorial Summary: Remifentanil-Xylazine Sedation in Donkeys Whilst remifentanil-xylazine continuous infusions are established for standing surgery in horses, their application in donkeys has remained unexplored—a significant gap given donkeys' distinct pharmacological responses to sedatives. Researchers administered an initial xylazine bolus (0.8 mg/kg) to ten donkeys, followed by continuous infusions of xylazine (0.65 mg/kg/h) and remifentanil (6 μg/kg/h) for 60 minutes, monitoring cardiorespiratory parameters, gastrointestinal motility, sedation depth, ataxia, and head carriage throughout and after the protocol. Heart rate and respiratory rate decreased significantly by M10 and M5 respectively, systolic, mean and diastolic blood pressures fell significantly by M15, and satisfactory sedation was maintained from M15 to M60, with all animals recovering in approximately 7 minutes without adverse effects. Notably, remifentanil did not trigger the excitation sometimes observed in equines, and the rapid recovery time offers practical advantages for standing procedures in donkeys—though the protocol's efficacy under actual surgical conditions with noxious stimuli remains to be demonstrated in future work.

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Practical Takeaways

•This drug combination may provide a viable sedation option for standing procedures in donkeys, though clinical efficacy under painful stimuli remains to be tested
•Recovery time is rapid (7 minutes), which is advantageous for clinical use, but the protocol requires validation with actual surgical stimulus before routine adoption
•Monitor for expected cardiorespiratory depression (heart rate and respiratory rate decrease within 5-10 minutes) and blood pressure reduction when using this combination

Key Findings

•Continuous infusion of remifentanil (6 μg/kg/h) and xylazine (0.65 mg/kg/h) produced satisfactory sedation in donkeys from M15 to M60 minutes
•Heart rate decreased significantly at M10 (p=0.049) and respiratory rate at M5 (p=0.001) compared to baseline
•All donkeys recovered successfully within 7.1±2.4 minutes after infusion cessation with no adverse effects observed
•No excitation or untoward behavioral effects were observed with remifentanil administration in donkeys

Conditions Studied

sedation for standing surgeryanesthesia protocols in donkeys

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