Ruminant and Camelid Anesthesia Flashcards
True/False: it is generally easily to restrain ruminants for a procedure without anesthesia or sedation.
True. Procedures can be done either standing or laying down. Keep procedure time to a minimum when laying down.
What is special anatomically about ruminants compared to other species?
They have a 4 compartment stomach with a rumen that does not fully empty.
What is special about camelids compared to other species?
3 compartment stomach; no jugular groove; RBC have greater oxygen carrying capacity; obligate nasal breathers
What are the aspects of a pre-anesthetic evaluation?
Physical exam: auscultation of heart and lungs; temperament
Bloodwork: PCV/TS are a minimum, glucose if neonate
True/False: we fast ruminants in order to minimize bloat and regurgitation pre-op.
True
How long do we fast sheep and goats?
Off feed 12-18 hours, off water for 4 hours
How long do we fast adult cattle and camelids?
Off feed 12-18 hours, off water 8-12 hours
How long do we fast large mature bulls?
Off feed and water 24-36 hours
How long do we fast calves, lambs, and kids?
No fasting if > 1 month but not adult
What is a side effect of fasting cattle?
Causes bradycardia
Where do we place the catheter in cattle, goats, and sheep?
IV catheter in jugular vein. Can also use auricular vein, coccygeal vein, or cephalic vein in small ruminants and camelids
What size catheter is used in ruminants?
Adult cattle: 12-14 gauge
Calves, goats, sheep: 16-18 gauge
Where do we place the catheter in camelids?
3-4 cm dorsal to angle of ventral border of mandible, or cranial to the ventral process of 5th cervical vertebra. NOT in between –> carotid artery puncture.
What are some common complications in ruminants and camelids?
Hypersalivation, bloat, hypoventilation, regurgitation (possible aspiration pneumonia), and metabolic alkalosis (secondary to fasting)
True/False: intubation is done blindly in all ruminants and camelids.
False. Blind intubation and palpation in cows and large calves, visualization required in small ruminants and camelids.
Why is intubation difficult in small ruminants and camelids?
Elongated, narrow oral cavity; torus linguae; laryngospasm; regurgitation
What size ET tube should be used in ruminants?
Adult cattle: 20-30 mm ID
Calves: 8-12 mm ID
Adult sheep and goats: 7-12 mm ID
True/False: acepromazine may be used for premedication in all ruminants.
False! It’s not approved for use in food animals by FDA.
What are the pharmacodynamics and pharmacokinetics of acepromazine in ruminants?
Slow onset, prolonged effects, and long elimination time
What are some side effects of acepromazine in ruminants?
May increase risk of regurgitation, contraindicated in hypovolemic or debilitated patients, can cause penile priapism in bulls
True/False: xylazine is not approved for use in food animals by FDA.
True
What are some species and breed differences in sensitivity to xylazine?
Goats are most sensitive; more potent in ruminants than in horses (use ~1/10th equine IV dose); Herefords and Brahmans are more sensitive than other cattle; a stressful environment can cause a prolonged response in cattle
What are the CV effects of xylazine in ruminants?
Bradycardia, AV dissociation, myocardial depression (decreased CO); may cause hypoxemia and hypercapnia and pulmonary edema (extreme caution in sheep)
What are some other side effects of xylazine in ruminants?
Uterine contraction in cows and sheep; rumen atony and bloat, hyperglycemia, hypoinsulinemia, increased urine production
What are the 2 options for reversal of Alpha-2 agonists in ruminants?
Atipamezole and yohimbine
True/False: romifidine, medetomidine, and dexmedetomidine are more potent than xylazine in ruminants.
True
What are the effects of benzodiazepines in ruminants?
No analgesic effects, minimal sedation
True/False: benzodiazepines are typically used alone for induction in ruminants.
False. Typically used with ketamine.
How are benzodiazepines reversed in ruminants?
With flumazenil
What are some side effects of opioid use in ruminants?
May cause excitement or vocalization; can be detected in the milk up to 36 hours
True/False: anticholinergics are typically used for anesthesia in ruminants.
False
What are some side effects of anticholinergics in ruminants?
Salivary secretions become more viscous and could obstruct the airway; decreases GI motility (causes bloat)
What are some side effects of telazol in ruminants?
Can have a prolonged recovery; can cause CV depression
What are some side effects of propofol in ruminants?
Apnea and hypotension may occur with rapid administration.
What is the oxygen flow rate for ruminants?
10-20 mL/kg/min
What is the MAC for Iso in ruminants?
Cows: ~1.14%
Goats: 1.2-1.5%
Sheep: 1.58%
What is the MAC of Sevo in ruminants?
Can be set at 2.0-3.5%; 2.33 % in goats
What is the normal heart rate for ruminants?
Adult cattle: 60-90 bpm
Calves, sheep, goats: 90-130 bpm
Camelids: 80-100 bpm (100-125 bpm in juveniles)
What is the normal blood pressure in ruminants?
Cattle: SAP 120-150 mmHg, DAP 80-110 mmHg, MAP 90-120 mmHg
Sheep, goats, camelids: SAP 80-110 mmHg, DAP 60-80 mmHg, MAP 60-100 mmHg
Where can you do direct BP monitoring in ruminants?
Caudal auricular artery, saphenous artery, common digital artery
What is the normal spontaneous breathing rate for ruminants?
Adult cattle: 20-30 breaths/min or higher
Calves, sheep, goats: 20-40 breaths/min
Camelids: 15-30 breaths/min (20-35 breaths/min in juveniles)
How do we monitor anesthetic depth in ruminants?
Eye signs: palpebral reflex is unreliable, especially in camelids; spontaneous ventral eyelid movement implies light plane
Spontaneous swallowing: indicates a light plane of anesthesia, but may be present with patient at adequate plane for surgery
Muscle tone and movement
What happens to the palpebral reflex in ruminants when light anesthesia is reached?
It disappears
What happens with the eyes at induction in ruminants?
The eyeball rotates ventrally and the cornea is obscured partially by lower lid
What happens to the pupil with deepening anesthesia in ruminants?
It becomes completely hidden by the lower lid
What happens to the eyeball as you get a further increase in anesthetic depth in ruminants?
Dorsal rotation to central positioning
True/False: during recovery of ruminants, you leave the ET tube in place until the patient begins to chew on it.
True. ET tube is left in place until a strong swallowing reflex returns and the patient is able to remain sternal and hold its head up
