2.2 Equine sedation and incomplete general anesthesia.

What are the common methods of short-term sedation in adult horses?

Bolus of alpha2 agonist, with or without opioid.

When is an opioid combined with an alpha2 agonist?

When heavy sedation or additional analgesia is required. Opioid MUST be given after alpha2 to avoid opioid-induced excitement.

What are the indications for standing sedation?

Stomatology, diagnostic imaging, farriery, sinus surgeries, urogenital, orthopedic procedures.

What are the advantages of standing sedation?

• Less risky for the horse

• Better for some surgeries.

• Smoother recovery than GA

• Cheaper than GA (sometimes)

• Less bleeding in head surgeries than when recumbent

What are common drug groups used for sedation?

• Alpha2 agonists

• Phenothiazines

• Opioids

• Benzodiazepines

What are the commonly used alpha2 agonists for sedation?

Xylazine, detomidine, metedomidine.

What are the effects of alpha2 agonists?

Sedation, analgesia, bradycardia, hyperglycemia.

What is the most common phenothiazine used for sedation?

Acepromazine.

What are the effects of acepromazine?

Mild tranquillizing effect, decreases MAC of volatile anesthetics, decreases histamine release, vasodilation, anti-arrhythmetic.

What are the commonly used opioids for sedation?

Butophanol, morphine, buprenorphine, meperidine.

What are benzodiazepines and how are they used for sedation?

Not used alone due to dysphoria or excitement. IV administration, not recommended for adult horses due to muscle-relaxing and ataxia-inducing properties. Can be used for very young foals.

What are the methods of standing sedation?

IV boluses, controlled rate infusion (CRI).

What are the risk factors associated with standing sedation?

Poor patient temperament, noxious stimuli, irregular or slippery floor surfaces, inadvertent overdoses, intra-arterial drug administration.

What are the special considerations for sedating foals?

Circulatory system, metabolism of drugs, susceptibility to hypothermia and hypoglycemia.

What drugs should be avoided in foals?

Drugs that lower heart rate (xylazine, detomidine) or decrease preload (acepromazine).

What should be done when sedating foals?

Support the foal until it assumes recumbence.

What are the recommended sedatives for foals?

Alpha2 agonists, benzodiazepines, benzodiazepines and ketamine.

How do the doses of alpha2 agonists differ in foals?

Young foals: minimum dose

Older foals: sedated as adults but higher dose due to higher metabolism

What are recommendations for the use of benzodiazepines in foals?

• Slow administration

• Don’t repeat or give high dose

• Not analgesic

What are the recommended dosages for foals?

Alpha2 agonists: lower doses than in adults. Benzodiazepines: 0.05-0.1mg/kg IV. Ketamine: 2-3mg/kg IV.

What are the indications for sedation?

Dental, wound examination and treatment, etc.

What drugs are best for dental procedures?

Xylazine and butorphanol; (morphine)

What nerve blocks are necessary for dental extractions?

Mandibular, mental, maxillary, infraorbital

What drug can be used in combination with xylazine and butorphanol to reduce chewing reflex/deeper sedation under oral cavity surgery?

Acepromazine