Lecture 11 Ruminant and Camelid Anesthesia Flashcards

1
Q

What are some indications for doing general anesthesia in ruminants

A
  1. umbilical surg.,
  2. penile surgery,
  3. cryptorchidism,
  4. fractures,
  5. septic joints,
  6. tube cystotomy,
  7. research
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2
Q

What are some risks ruminants have when undergoing general anesthesia

A
  1. ruminal reflux,
  2. bloat etc.
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3
Q

What are the 4 special concerns of ruminants

A
  1. Salivation throughout anesthesia
    • Fluid loss, risk of airway occlusion & aspiration
  2. Rumen
  3. Airway protection
    • ET intubation recommended, usually easy but can be challenging
  4. Hypoventilation under general anesth.
    • Mechanical ventilator
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4
Q

Why is the rumen a special concern in anesthesia

A
  1. Never completely empty
    • Passive reflux and aspiration pneumonia
  2. No eructation under anesthesia
    • Bloat & pressure on lungs ® hypoxemia
    • Stomach tube to decompress/trochar
  3. Large & heavy
    • Pressure on lungs when recumbent
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5
Q

Why fast ruminents?

A

–Reduces rumen size

–Decreases microbial activity/gas production

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6
Q

Patient Preparation in:

  1. Adult cattle
  2. Sheep, goats, camelids
  3. Calves, lambs, kids, crias
A
  1. Adult cattle
    • Withhold food for 24-48 hrs & water 8-12 hrs
  2. Sheep, goats, camelids
    • Withhold food for 24 hrs & water 12 hrs
  3. Calves, lambs, kids, crias
    • Withhold food 2-4 hrs (age?)
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7
Q

Side effect of fasting

A

metabolic alkalosis

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8
Q
  1. Premedication advantages
  2. Disadvantages
A
  1. Advantages
    • Preemptive analgesia, reduces induction/maintenance doses
  2. Disadvantages
    • May increase risk of ruminal reflux once recumbent
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9
Q
  1. Are premedications necessary for ruminents?
  2. Why or why not?
A
  1. Often unnecessary
  2. Reasons:
    • Calm animals accept restraint for IV catheter & induction
    • Cattle can be strapped to tilt table
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10
Q
  • What are 2 options for IV access in cattle
  • What are special considerations for using each
A
  1. Jugular vein
    • Thick skin: pilot hole with needle or blade to insert catheter
  2. Auricular vein
    • Can’t inject large volumes e.g. guaifenesin
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11
Q

IV Access – Sheep & Goats

A
  1. Jugular vein
  2. Cephalic vein
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12
Q
  1. Are anticholinergics used as premedications?
  2. Why or why not?
A
  1. NOT used
  2. Salivation does not stop & saliva gets thicker
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13
Q

What are premedication options in ruminants

A
  1. Acepromazine ± opioid (butorphanol) IV or IM
  2. Acepromazine + diazepam IV – sheep & goats
  3. Midazolam + butorphanol IV or IM – sheep & goats
  4. Xylazine IV or IM
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14
Q

What are considerations when using xylazine in ruminants

A
  1. Hypoxemia in all ruminants
    • Sheep can develop pulmonary edema because of their types of macrophages
  2. Increases myometrial contractions
    • Better avoid in last trimester of pregnancy (cattle)
  3. Breeds sensitivity
    • Hereford and Brahman anecdotally more sensitive
    • Breed sensitivity also for sheep and goats?
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15
Q

How much smaller of a dose of xylazine do you use in ruminants compared to horses

A

use 1/10th the equine dose

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16
Q
  1. What % of xylazine do you use in ruminants?
  2. Why?
A
  1. Best to use 2% xylazine
  2. Extremely sensitive compared to horses
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17
Q

What are the 4 induction protocols for cattle

A
  1. Guaifenesin (GG) + Xylazine + Ketamine (large volume)
  2. Ketamine + Xylazine IV (bolus induction)
  3. GG + Ketamine IV
  4. Ketamine + benzodiazepine IV (small volume)
    • 50:50 mix by volume, approx. 1 mL/20 kg
      • Small ruminants & calves primarily
18
Q

3 Small ruminant induction protocols

A
  1. Ketamine + benzodiazepine IV
  2. Ketamine + propofol
  3. Propofol ($$)
    • Cheaper when using on small animals
19
Q

Why can endotracheal intubation be hard in ruminants

A
  1. Narrow mouth & sharp teeth
  2. Larynx can be difficult to visualize
  3. Profuse salivation & risk of reflux
    • Adequate anesthetic plane to avoid regurgitation
    • Quick ET tube insertion & cuff inflation
20
Q

What are the 2 methods of endotracheal intubation and which animals do you do each one on

A
  1. Manual palpation
    • Larynx relatively insensitive vs other species
    • Adult cattle only
  2. Visual
    • Long laryngoscope blade & stylet
    • Small ruminants & camelids
    • Can do in Adult cattle
21
Q

Endotracheal Intubation Equipment

A
  1. Mouth gag/speculum
  2. Roll gauze
  3. Laryngoscope – lung blade
  4. Stylet
  5. Selection of ET tubes
22
Q

How to do Endotracheal Intubation by Palpation

A
  1. Adult cattle only
  2. Mouth gag or speculum
  3. Direct insertion or with stylet
    • Reflect epiglottis & palpate arytenoids
  4. Ideally mouth lower than poll
    • Drain saliva and reflux
23
Q

How to do Endotracheal Intubation by Visualization

A

Small ruminants & camelids

  1. Keep sternal for intubation after induction
  2. Visualize larynx with laryngoscope
  3. Camelid: lidocaine spray on aritenoids
  4. Insert small diameter stiff stylet
  5. Tube over stylet into trachea, inflate cuff, tie tube to mandible
  6. Position on the surgery table

Adult cattle

  1. Usually strapped to tilt table – lateral recumbency
  2. Very long laryngoscope blade
24
Q

What is special about camelid endotracheal intubation

A

–lidocaine spray on aritenoids

25
Q

Positioning

A
  1. Head elevated and mouth below poll
    • Saliva & passive reflux drain downwards and out
  2. Considerations for large, heavy animals as for horses
    • Myopathy and neuropathy
    • Padding, limb position
26
Q

What drugs do you use for Anesthetic Maintenance by IV only

A
  1. “Double drip”
    • GG + Ketamine
    • Shorter procedures < 20 minutes
  2. “Triple drip”
    • GG + Ketamine + Xylazine
  3. ET tube and O2 supplementation
27
Q

What is important to know about using guaifenesin in cattle

A
  • 5% GG preferred in cattle
  • Hemolysis at higher %
28
Q
  1. What gas inhalents do you use on ruminants
  2. What is special about the anesthetic machine vs small animals
A
  1. Isoflurane or $evoflurane
  2. With mechanical ventilator
29
Q
  1. What is the minimum flow rate for ruminants?
  2. Why is IPPV required?
A
  1. Minimum O2 flow 5 mL kg-1min-1
  2. Usually IPPV required because:
    • High respiration rate & low tidal vol. –>
    • Hypercapnia & hypoxemia and Poor alveolar absorption of anesth –>
    • Light anesthetic plane
30
Q
  • What happens to eye position and palpebral reflex in light, moderate, and deep planes of anesthesia
  • Also include if they respond to painful stimuli
A
  1. Light: eye central & palpebral reflex present
    • responds to painful stimuli
  2. Moderate: eye rotated ventrally & palpebral reflex absent
    • does not respond to usual surgical stimuli
  3. Deep: eye central & palpebral reflex absent
    • may be necessary for very painful procedures, e.g. fracture repair
31
Q

Shoud jaw be taught or relaxed in a good anethestic plane

A

•Jaw should be relaxed

32
Q
  1. Expected heart rate in ruminants
  2. At what HR do you treat for bradycardia?
    • How to treat?
A
  1. Expected heart rate:
    • 70-80 bpm
  2. Treat bradycardia if < 60 bpm
    • Isoproterenol CRI (beta agonist)
33
Q
  1. How do you monitor blood pressure in ruminants?
  2. What should the MAP be?
  3. How to treat hypotension?
  4. Another benefit of using invasive blood pressure monitoring
A
  1. Catheter in auricular artery
  2. MAP > 60 mm Hg
  3. Dobutamine CRI for hypotension
  4. Arterial samples for blood gas analysis
34
Q

How do you recover a ruminant

A
  1. Extubate when animal chews, swallowing or coughs
    • Leave ET tube cuff inflated
  2. Place in sternal recumbency, nose down, well supported – allows eructation
  3. Leave the stall when animal can lie sternal without support
35
Q

Why do you leave ET tube cuff inflated when extubating a ruminant?

A

just in case there is any fluid or food particles sitting on it

36
Q
  1. Can food reflux from stomach in camelids?
  2. How long do you fast?
  3. Water with held?
A
  1. Content of compartment 1 of the stomach may reflux
  2. Fast for 24 hours,
    • Do not fast cria if < 1 month old
  3. withhold water for up to 12 hours
37
Q
  1. What is special about IV catheterization in camelids
  2. Are they sensative to xylazine?
  3. Are they normal breathers, semi-obligate nasal breathers or obligate nasal breathers?
A
  1. IV catheterization
    • No jugular furrow
    • Valves along jugular veins may impede catheter advancement
  2. Less sensitive to xylazine than ruminants
  3. Semi-obligate nasal breathers
38
Q

Explain why jugular vein IV access is hard to obtain

(check notes)

A
39
Q

What are different vein options in camelids

A
  1. Jugular commonly used but has valves
    • 16 – 18 G x 5” catheter
    • 14 G x 1.5” needle or scalpel for pilot hole
  2. Auricular
  3. Cephalic
  4. Saphenous
40
Q

Why would you use nasotracheal intubation in camelids

A
  1. Are semi obligate nasal breathers
  2. For oral cavity/dental surgery
  3. Post recovery if nasal congestion impairs breathing
    • If head is low there would be edema
41
Q

How do you do Anesthesia Recovery in camelids

A
  • Semi-obligate nasal breathers
    • Risk of airway obstruction
    • Naso-tracheal intubation possible
  • Position in sternal recumbency, nose down
  • Extubate when able to lift head and swallow