25. Ruminant Anesthesia

1. production vs. pet

2. cost

3. standing (sedation + LA) vs. general anesthesia

what determines the approach to ruminant anesthesia

restraint and local anesthesia

mose simple ruminant anesthesia procedures require...

anesthesia

more complex ruminant procedures will require...

equine

what species is ruminant anesthesia compareable to

standing procedures

these are examples of what kind of procedures

general anesthesia

these ruminant procedures may actually require...

1. PE...can be limited in uncooperative patient

2. bloodwork like PCV/TS/BG

3. fasting may be helpful for general anesthesia

4. IV catheter placement

5. special equipment/personnel

6. drugs

7. intubation can be challenging

8. padding

general considerations for ruminant anesthesia

FARAD

what website can we consult to determine withdrawal times

they can get myopathy or neuropathy

why is padding important for ruminant anesthesia

1. hypersalivation ~50L/day

2. GI tract...bloat leading to decreased venous return and hypoventilation

3. regurgitation leading to potential aspiration pneumonia

4. rumen tube to drain and place head to allow drainage

5. light to inspicy larynx/pharynx before recovery

6. hypoventilation due to issues with recumbency

what are some of the anticipated complications of ruminant general anesthesia

1. immediate reflex airway closure

2. destruction of pulmonary lining due to acidity

3. leads to pulmonary edema, hypoxemia, cyanosis, and potential for death

what happens when there is aspiration of stomach/rumen content

rumen pH and amount of material aspirated

severity of aspiration of stomach contents depends on ____

endotracheal intubation and maintain sternal position with head up to elevate/protect the throat

what is the primary mechanism to prevent aspiration of stomach contents in all our anesthetized farm animals

1. safety of animal and personnel working nearby

2. have enough experienced personnel to situatie the patient on a surgery table

important considerations for ruminant anesthesia

no food for 24-48 hrs, no water for 24 hrs

recommended fasting times for adult large ruminants

no food for 12-18 hrs, no water for 6 hrs

recommended fasting times for sheep and goats

NPO not typically required at <1 month but can withhold food 2-4 hrs if > 1 month

recommended fasting times for calves, lambs, kids

same as a simple stomach

how does the GIT of a ruminant function at <3 weeks of age

as a full ruminant

how does the GIT of a ruminant function at >3 months of age

reserve functional residual capacity

fasting helps to _____ since ruminants have a decreased Vt (tidal volume) compared to horses

bradycardia

fasting can lead to what in cattle

25%

even if fasting precautions are taken as many as _____ adult cattle still regurgitate under anesthesia

use a jugular vein that will be accessed most easily during surgery

considerations for IV catheter placement in ruminants

allows more manipulation and safety for a procedure

why is premedication important for ruminants

not approved for use in food animals by FDA....and Dr. Wilson hates it

use of acepromazine in ruminants

1. not approved for use in food animals by the FDA

2. more potent dose in ruminants so you should use 1/10th the dose as you would in equine

3. stressful environments cause prolonged response

4. can cause rumen atony/bloat and require you to pass a tube

indications of xylazine in ruminants

goats/ sheep as they have a risk for developing pulmonary hemorrhage and edema

what species are the most sensitive to xylazine and how do they respond

oxytocin-like effects that may cause premature delivery during last trimester

effects of xylazine on pregnant cattle

atipamezole, yohimbine, doxapram

what alpha 2-agonists reversals are commonly used in ruminant anesthesia

not commonly used as it causes salivary secretions to become more viscous increasing the risk of airway obstruction as well as bloat

anticholinergic use in ruminants

1. no analgesic effects with minimal sedation

2. midazolam or diazepam

3. flumazenil reversal not commonly done due to $$

functions of benzodiazepines in ruminants

butorphanol

what is the most common opioid used for ruminants

morphine, hydromorphone, buprenorphine

which opioids are not often used in cattle

1. ketamine...commonly combined with benzodiazepine or with guaifenesin as "double drip"

2. telazol

3. propofol...commonly due "ketofol" 2:2 to decrease cost

induction drug options in ruminants

prevent aspiration of saliva or rumen contents

why should we always intubate a ruminant during anesthesia

regurgitation

attempting intubation when patient is too light may result in ____

dorsal

more likely to regurgitate if placed in ____ recumbency

right lateral or sternal

less likely to regurgitate if placed in ____ recumbency

laryngoscope

what should we always use when intubating a ruminant

blind intubation w/ hand in adult cattle and laryngoscope use in small ruminants with hyper extended and elevated head and neck

how do we actually intubate ruminants

patient that is <60kg with a <18 ETT tube

what are the indications for the use of a small anesthesia machine in ruminants

10-30 ml/kg/min

O2 flow rate for ruminants

isoflurane

most common inhalant anesthetic for ruminants

1. padding

2. minimize pressure to radian n.

3. support up leg and align parallel to table

4. head down for saliva/regurge drainage

proper positioning of ruminants during anesthetic episodes includes

reviewed

review the monitoring parameters during ruminant anesthesia

>70 mmHg

what is the MAP we typically try to keep ruminants at during anesthesia

45-50 mmHg

what is the goal ETCO2 for ruminants to avoid hyperventilation as it is a common occurrence for ruminants

bradycardia

hypocarbia may cause ___ in ruminants

Vt at 10-20ml/kg and respiratory rate at 6-12 bpm

how do we utilize IPPV for ruminants to avoid excessive airway pressure

eye will rotate ventrally at induction and then rotate dorsally as depth increases

how can we describe ocular rotation under anesthesia for ruminants

1. leave Et tube until strong laryngeal reflex returns and pull while it is inflated

2. immediately check for airway patency

3. check for regurgitation and bloat

in terms of ruminant recovery

1/10th

the ruminant dose of xylazine is _____ the equine dosage