Week 2 Lesson 12 Basic anesthetic considerations for different species

What is a key gastric consequence of high stress and panic in camelids?

Gastric ulceration

Why are camelids considered easy to obstruct during recovery?

They are semi-obligate nasal breathers with a cartilaginous nose

What recovery device may be useful in camelids to maintain airway patency?

A nasal tube

What is the recommended fasting time to reduce the risk of regurgitation in camelids?

Approximately 12 to 18 hours

Why must the dependent eye of a camelid be protected during recumbency?

They have prominent eyes

How should the dependent eye of a camelid be protected under anesthesia?

By closing the eyelids

Why is weight estimation particularly difficult in camelids?

They have a thick coat

What is the estimated weight range of a Llama?

150 to 250 kg

What is the estimated weight range of an Alpaca?

60 to 90 kg

Which jugular vein is most commonly used for catheterization in camelids?

The right jugular vein

What are the two main anatomical reasons why the right jugular vein is preferred over the left in camelids?

The esophagus is on the left, and the carotid artery is closer to the jugular vein on the left side

Why does the jugular vein take a while to fill up during catheterization in camelids?

They have no jugular groove and a long neck

How is the position of the camelid jugular vein different from that of a horse?

The camelid jugular vein is more medial

How thick can the skin on a male camelid's neck be?

Up to 1 cm

Why is venous blood in camelids bright red?

It contains a high percentage of oxyhemoglobin

Which alternative veins can be used for catheterization in a cria or once the camelid is anesthetized?

Cephalic and saphenous veins

Which camelid species is reported to be more resistant to xylazine?

Alpacas

Where should an intramuscular injection of xylazine be administered in camelids?

At the base of the neck, front of the shoulder

What danger is associated with a camelid's neck movement while undergoing sedation?

It may cause harm or self-harm

What is the composition and dosage of the Ketamine Stun combination in camelids?

Ketamine at 0.2 to 0.4 mg/kg combined with xylazine at 0.2 mg/kg IM

What is the duration of the Ketamine Stun chemical restraint?

60 minutes

What is the recommended IV dose of xylazine for Alpacas?

0.2 to 0.4 mg/kg

What is the recommended IM dose of xylazine for Alpacas?

0.3 to 0.5 mg/kg

What is the recommended IV dose of xylazine for Llamas?

0.1 to 0.3 mg/kg

What is the recommended IM dose of xylazine for Llamas?

0.2 to 0.4 mg/kg

What is the expected duration of action of IV xylazine in camelids?

20 minutes

What is the expected duration of action of IM xylazine in camelids?

40 minutes

What drugs compose the BK induction cocktail for camelids?

Butorphanol, Xylazine, and Ketamine

What are the Alpaca IM dosages for the Butorphanol, Xylazine, and Ketamine cocktail?

Butorphanol 0.04 mg/kg, Xylazine 0.4 mg/kg, and Ketamine 4 mg/kg

What are the Llama IM dosages for the Butorphanol, Xylazine, and Ketamine cocktail?

Butorphanol 0.03 mg/kg, Xylazine 0.3 mg/kg, and Ketamine 3 mg/kg

How long does it take for a camelid to become recumbent after IM BK cocktail administration?

3 to 8 minutes

What is the duration of the surgical plane achieved with the IM BK cocktail in camelids?

30 minutes

What are three clinical methods to manage nasal edema in recovering camelids?

Elevate the head, supplement oxygen, and instill phenylephrine in the nostrils

What medication can be instilled in camelid nostrils during recovery to reduce nasal edema?

Phenylephrine

What are three critical complications of general anesthesia to monitor for in recovering camelids?

Regurgitation, hypothermia, and hypoglycemia

What pre-anesthetic blood tests are routinely performed in horses to assess hydration and anemia status?

PCV and Total Solids

What is the normal heart rate range of an adult horse?

30 to 45 bpm

What is the normal Mean Arterial Pressure range for an anesthetized horse?

70 to 100 mmHg

Describe the normal respiratory pattern of a horse.

Biphasic respiratory pattern where inspiration and expiration are both active

What is the normal respiratory frequency of a horse?

8 to 15 bpm

What is the normal tidal volume of a horse?

12 to 15 mL/kg

What normal ECG finding in horses is associated with large atria and high vagal tone?

A biphasic P wave

What is Heaves in horses?

Recurrent Airway Obstruction, a chronic allergy triggered by inhaling dust and allergens

What are the two primary anesthetic risks associated with equine Heaves?

Hypoxemia and airway obstruction at recovery

What muscular disease in horses is linked to a mutation of the SCN4A gene?

Hyperkalemic Periodic Paralysis

What breed of horse is commonly affected by Hyperkalemic Periodic Paralysis?

Quarter horses

What is the physiological mechanism of Hyperkalemic Periodic Paralysis?

"Leaky" sodium channels leading to continuous sodium influx and potassium efflux

What is the mechanism of action of Acepromazine?

Blocks dopamine and serotonin receptors for sedation, blocks alpha-1 receptors for vasodilation, and blocks H1 receptors

Does Acepromazine provide analgesia?

No

Is there a reversal agent for Acepromazine?

No

Why should Acepromazine be avoided in horses with an ASA physical status greater than II?

It causes vasodilation and hypotension

By what percentage does Acepromazine decrease PCV in horses?

20% to 30%

What is the cause of the decreased PCV seen after Acepromazine administration in horses?

Splenic sequestration

What is a specific reproductive risk of Acepromazine administration in stallions?

Penile prolapse or paraphimosis

How does the neck-head angle change in a sedated horse?

It increases from a neutral 90-degree angle to greater than 100 degrees as the head drops down

Why is it critical to keep a sedated horse's head up?

A lowered head facilitates kicking with both rear limbs

What are five clinical signs of adequate sedation in a horse?

Lowered head carriage, partially closed eyelids, relaxed drooping lip, drooping ears, and a wide-base stance

What cranial nerve is targeted during local block procedures of the equine head?

Trigeminal Nerve (Cranial Nerve V)

Which nerve block is used for upper arcade, incisor, premolar, and molar dental extractions in horses?

Maxillary nerve block

What equipment is used to perform a maxillary nerve block in horses?

An 18 to 20 Gauge, 3.5-inch spinal needle

What anatomical areas are desensitized by an infraorbital nerve block in horses?

The ipsilateral lip, nostril, and face

What anatomical areas are desensitized by a mandibular nerve block in horses?

The ipsilateral mandible, dental structures, and potentially the tongue

What is the goal of a caudal epidural block in horses?

Achieve surgical regional anesthesia of the tail and perineum while preserving hindlimb motor function

What anatomical structures are desensitized by a caudal epidural block in horses?

The anus, rectum, perineum, vulva, vagina, urethra, and bladder

What are the injection sites for a caudal epidural in horses?

Sacro-coccygeal (S-Co1) or intercoccygeal (Co1-Co2)

What are four common uses for standing sedation in horses?

Dental surgery, diagnostic imaging, urogenital procedures, and wound management

Why is a very painful horse not a good candidate for standing sedation?

Pain increases the risk of sudden movements that can harm the horse or personnel

What are three mandatory clinical requirements when performing standing sedation in horses?

IV catheter placement, urinary catheter placement, and head support

Why is a urinary catheter mandatory under standing sedation using alpha-2 agonists in horses?

Alpha-2 agonists stimulate diuresis

What are three physiological benefits of fasting horses prior to general anesthesia?

Decreased GI contents, reduced lung compression (less atelectasis), and reduced vena cava compression (improved venous return)

What are two complications of fasting a horse for longer than 4 hours?

Increased gastric acidity (ulcer risk) and decreased GI motility (postoperative ileus risk)

What is the recommended fasting duration before a scheduled equine anesthetic procedure?

6 to 8 hours

Why is washing the horse's mouth with a large syringe mandatory prior to induction?

To remove food material and prevent aspiration or ET tube occlusion

How does IV Sodium Penicillin affect systolic arterial pressure in the anesthetized horse?

It can decrease systolic arterial pressure by 15 to 20 mmHg

What is the most common class of induction drug used in horses?

Dissociatives, specifically Ketamine or Tiletamine

What is the standard induction dose of Ketamine in horses?

2 to 3 mg/kg IV

Why must Ketamine always be combined with benzodiazepines during horse induction?

Ketamine must be combined with benzodiazepines to achieve adequate muscle relaxation

What endotracheal tube size is used for an adult horse weighing 400 to 500 kg?

24 to 26 mm, up to 30 mm

What endotracheal tube size is used for a foal weighing 40 to 50 kg?

10 to 11 mm

What are the components of the "Triple Drip" infusion used for equine TIVA?

Guaifenesin 5%, Ketamine, and Xylazine

What central acting muscle relaxant used in equines can accumulate and cause ataxia during recovery?

Guaifenesin

Where is the negative lead (RA) placed in the base-apex ECG system for horses?

In the jugular furrow

Where is the positive lead (LA) placed in the base-apex ECG system for horses?

Behind the left elbow, at the apex of the heartbeat

What is the gold standard method of monitoring blood pressure in horses under anesthesia?

Invasive direct arterial catheterization

What four arteries are commonly used for direct arterial catheterization in horses?

Facial, transverse facial, coccygeal, and metatarsal arteries

What threshold must Mean Arterial Pressure be kept above during equine anesthesia?

Above 70 mmHg

What is the pathophysiology of Post-Anesthetic Myopathy in horses?

If MAP is less than 30 mmHg above intra-compartment pressure, muscle perfusion stops, leading to ischemia

What class of anesthetic maintenance drug is most associated with systemic hypotension and PAM in horses?

Inhalant anesthetics

What drug is administered as a CRI to restore MAP and treat hypotension in anesthetized horses?

Dobutamine at 0.25 to 5.0 mcg/kg/min

What are three major risk factors for Post-Anesthetic Myopathy in horses?

General anesthesia duration greater than 90 minutes, prolonged hypotension, and heavy breed

Why must the halter be removed from a horse during general anesthesia?

To protect the facial nerve from compression and neuropathy

What percentage of perioperative deaths in horses occur during the recovery phase?

42%

What dose of phenylephrine is administered into each horse nostril 30 minutes before extubation to reduce nasal edema?

5 mL of 0.15% phenylephrine

What nerve functions are typically affected by equine peripheral neuropathy post-anesthesia?

Laryngeal, facial, radial, and femoral nerves

What clinical position is indicative of central neuropathy or myelomalacia in horses post-recovery?

A "dog-sitting" position

What are three clinical signs of rhabdomyolysis in recovering horses?

Increased CK values, myoglobinuria (coffee-colored urine), and muscle pain

Are ruminants considered food-producing animals even when kept as pets?

Yes, they must always comply with food-animal drug regulations

What are three subclinical conditions of concern in small ruminants pre-anesthesia?

Pulmonary disease, chronic GI blood loss due to Haemonchus contortus, and low BCS

How does clinical mastitis affect an anesthetized cow's physiological state?

It can cause fever, increased HR, anorexia, pain, and endotoxemia

What is the typical daily saliva production of a sheep?

6 to 16 liters per day