Ex 3 - AC for ruminants, camelids, etc Flashcards
Main considerations:
- salivation
- regurgitation and aspiration
- bloat (rimem tympany)
- compromised pulmonary fxn
- size (myopathies and neuropathies)
- temperament
Salivation
50-100L/day (cattle), 6-16 L/day (sheep) –> A LOT!
- difficult to intubate
- aspiration/obstruct airway
Why are anticholinergics controversial for use to dec saliva?
Can make saliva more viscous
Regurgitation
Built to regurgitate! Need to keep the larynx higher than rumen
rumen < larynx > mouth
Fast them, 24-48 hr off-feed
Why do you want to keep ETT inflated during extubation??
Squeegee effect!
Bloat
Recumbency/restraint/GA –> decreases eructation
Impacts respiratory and CV system
- decreases lung volume, compliance
- dec PaO/hypoxemia
- dec venous return
Pulmonary function
Hypoventilation is common
V/Q mismatch
IPPV recommended
Size
Same as horses - they are large!
Increased risk for myopathies and neuropathies
Padding and positioning important
Temperament
Calm and stoic
Tolerant of physical restraint
- well-suited for standing procedures
3 sites for IV injection
jugular, tail, auricular
2 sites for IM injection
neck and shoulder
- avoid hind limb/meat production
Catheter size and location
12-16 G, 14 cm long
- Local block (skin and SQ)
- Pilot hole with blade (full thickness)
Intubation
Visual (large adult cattle)
Visual/laryngoscope; long blade +/- stylet (sheep, goat, calves)
Drugs used in FA
Very FEW sedatives, anesthetic, and analgesics approved for use –> we use off-label
**NEED to know withdrawal times
Website for withdrawal times
www.farad.org
3 anesthetic techniques
- Manual restraint with or w/out sedation and/or local anesthesia –> preferred method
- GA using injectable only
- Induction w/injectable anesthetics, followed by intubation and maintenance w/inhalants
Xylazine
- sedation +/- recumbency (dose-dep)
- Ruminants more sensitive than horses
Goat > sheep > cattle - ABORTION in late pregnancy
- not approved for FA
- antagonist available (tolazoline, yohimbine0
Should you use xylazine in sheep?
No - avoid use in sheep!
- activates pulmonary intravascular macrophages (PIM)
- hypoxemia, pulmonary hemorrhage/edema
- decreases pulmonary compliance
Benzodiazepines
Good sedation for calves/small ruminants
Minimal CV depression
Local anesthetics
Sheep very sensitive to toxic effects
Opioids
Very few studies in ruminants
Efficacy is questionable
Most commonly used= morphine and butorphanol
Ket-stun
Add ketamine at sub-anesthetic doses –> patients are “stunned” and oblivious to surroundings –> very good analgesic
Ket-stun –> what combo of drugs is it?
Butorphenol, Xylazine, and Ketamine
Duration ~ 45 mins
Induction agents
- Ketamine
* in combo w/ xylazine, diazepam or GG - Propofol
* risk of apnea if not titrated carefully - Guaifenesin
* mm relaxation, most used in cattle
Arterial BP in cattle
Generally HIGH during anesthesia and recumbency
Recovery
- quiet, calm environment
- padded while in recumbency
- keep ET tube with cuff inflated
- prop animal into sternal recumbency
- Extubate WITH cuff inflated
SAC - general
Spit/kick
Difficult to assess clinical status
Body weight evaluation difficult (lots of fiber!)
SAC - Catheter placement
High on neck
- more superficial/thicker skin
- away from carotid a.!!!
At the 6th cervical vertebrae level
- medial to transverse process
- thinner skin, closer to carotid a. (be cautious!)
*Jug v. not readily visible, thick skin requires pilot hole, changes in position may cause catheter to kink
SAC - intubation
lidocaine may help
Positioning is important –> “nose to sky”
Protect eyes
SAC - Recovery
- Lavage nasal passages to remove regurgitated material
- keep ETT as long as possible
- watch for signs of dorsal displacement of soft palate
- extend head & neck
- stimulate swallowing
Swine - general
- Tremendous size variation
- dose difference
- Venous access is VERY difficult
- Use ear veins
- IM injections in neck muscle
- need 1.5” needle or longer –> lots of fat you need to go through
- Intubation is very difficult!
Swine - Malignant Hyperthermia
- Heritable defect in sarcoplasmic reticulum
- Excessive influx of Ca++
- HYPERmetabolic state
- excess heat and CO2 production
- inc O2 consumption, muscle rigidity
Swine - MH Triggers
Halothane (or any potent inhaled anesthetic)
Succinylcholine
Other (stress, excitement?)
