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15 Complications of Sedative and Anesthesia Medications
Rachel C. Hector DVM, MS, DACVAA and Khursheed Mama DVM, DACVAA
Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado
Overview
This chapter will highlight key concerns and briefly address management of complications associated with use of sedative and anesthesia medications and drug‐induced recumbency in horses.
List of Complications Associated with Sedative and Anesthesia Medications
Complications during standing sedation
Complications during general anesthesiaUnanticipated movementHypotensionCardiac arrhythmiasHypoventilationHypoxemiaAberrations in body temperature
Complications during anesthetic recoveryPoor recovery quality
Other complications associated with sedative and anesthetic drugsIncreased urine outputBlood glucose abnormalitiesDecreased gastrointestinal motility
Complications During Standing Sedation
Definition
Many surgical procedures can be performed safely in horses using standing sedation. However, one cannot always predict an individual animal’s response to the drug or drug combinations used to facilitate the procedure, and a variety of behaviors may manifest that could result in injury to the horse or personnel. These include unexpected movements (kicking/striking), panic, ataxia, or even collapse.
Risk factors
Poor patient temperament (e.g. flighty, restless, fractious, or aggressive horse)
Noxious stimulus from the surgical procedure
Irregular or slippery floor surfaces
Unexpected environmental sounds or stimuli
Inadvertent overdoses of medications by epidural or systemic route
Inadvertent intra‐arterial (e.g. intra‐carotid) drug administration
Pathogenesis
Ataxia is a common manifestation of alpha‐2 adrenergic agonists, the most frequently used sedatives in equine practice. Ataxia is considered to be less profound with romifidine as compared to detomidine and xylazine [1]. Anecdotally, phantom limb movements (i.e. kicking) or aggressive behaviors (such as biting) in even normally amenable horses following alpha‐2 agonist administration have also been
