Sedation and GA of Ruminants Flashcards
1
Q
Common occult/old bronchopneumonia in ruminants? Consequences of this?
A
Mycoplasma spp.
Pasteurella spp.
Bordatella spp.
Mannheimia spp.
Parainfluenza
Others
most adult and geriatric small
ruminants that are kept pasturing outside a barn are likely to have had or currently
have some degree of bronchopneumonia that can cause consolidation of lung lobes
as shown in the ventral lobes of this lung, and this can lead to respiratory
complications such as hypoventilation and hypoxemia, which can be fatal.
2
Q
HR, RR, and rectal temp of cows?
A
50-80 bpm
12-36 brpm
100.5-102.5
3
Q
HR, RR, and rectal temp of sheep?
A
70-80 BMP
12-20 brpm
102-103.5
4
Q
HR, RR, and rectal temp of goat?
A
70-90 BPM
15-30 brpm
100.5-103.5
5
Q
HR, RR, and rectal temp of lamb/kid?
A
80-150 BPM
20-40 brpm
102-104
6
Q
Ruminants have 4 chamber stomachs. What is the consequence of this for GA?
A
- You will want to fast them of food and H2O for at least 12-24 hrs and occasionally 48 hrs in order to reduce fermentation
- Also because their stomach occupy a large part of the chest it reduces their FRC
7
Q
Why do we avoid excessive fasting in ruminants?
A
it has been shown to change ruminal flora and potentially cause ketosis and
bradycardia, especially in cattle
8
Q
Because ruminants cant eructate under GA what are some issues with that?
A
Methane MUST be vented out because it
cannot diffuse through membranes! SO we have to tube the stomach to vent this out
9
Q
What are some possible complications of GA in ruminants?
A
- Regurgitation —> Aspiration of ruminal content
- Bloating aka tympany
- Choking – Upper airway obstruction
10
Q
Ruminal tympany causes reduced FRC which leads to
A
Hypoventilation
Hypoxemia
The increase in volume of the rumen causes a cranial shift of the diaphragm leading to those things ^^
11
Q
Ruminal tympany causes compression of great vessels which leads to
A
Hypotension
12
Q
To combat the effects of ruminal typmany these are done:
A
Less likely if in sternal
recumbency
Right lateral recumbency is
preferred –> this avoids caval compression and regurg
Pass stomach tube to evacuate
gas
13
Q
How and when does regurgitation occur?
A
- Not a matter of WHEN & not of IF
- Active (during intubation) –> if too light of plane
- Passive (during GA) –> throughout entire process or intermittent
- In any recumbency
- Dorsal>L Lateral>R Lateral>Sternal
14
Q
When is regurg the most in terms of recumbency? and the least?
A
Most: dorsal
Least: sternal
Dorsal>L Lateral>R Lateral>Sternal
15
Q
What should you avoid to prevent regurg?
A
Esophageal Intubation
Intubation under light plane of anesthesia
16
Q
What should you do if regurg is occuring?
A
Make sure ETT is cuffed properly –> 20-22 mm Hg
Tilt head down –> with towel so oral content can drain out
17
Q
When is salivation produced? Complications of it?
A
- Production continues under
sedation/anesthesia
a. 4-6 L/hr adult cattle
b. 0.2-0.6 L/hr SR - Can OBSTRUCT AIRWAY!!!! –> Tilt head down
18
Q
Do anticholinergic drugs help with salivation?
A
- Not alot of evidence to support the use of them
- Antisialogogue properties
- May thicken secretions –> favors upper airway obstruction
- Decrease GI motility
19
Q
What do we need to consider with neonates and juveniles undergoing GA?
A
- Can be considered monogastric if
still on milk - Limited fasting
–> Non-weaned (1-2 h) – Considered
monogastric due to abomasal
groove
–> Weaned with roughing (6 h) - Risk of hypoglycemia - MONITOR
20
Q
Whats the main concern of giving drugs to food animals like ruminants?
A
Considered FOOD, enter food chain –
High concerns about residues
Therefore, there is a legal obligation
to report withdrawal times for milk and meat at discharge.
21
Q
What must we consider with ruminants when moving them?
A
SIZE
Ability to move them
Logistics
Facility
Pasture/Stall?
22
Q
Other things to consider for anesthetic procedures:
A
- Health status
- Temperament
–> Tame to aggressive - Type of surgery/Medical procedure
–> Invasiveness (imaging procedures vs surgeries)
–> Expected Duration
Health and temperament dictate our sedation
23
Q
Dairy cows are used to being handled this means what in terms of how we anesthetize them?
A
Mild physical restraint + local or regional
24
Q
Beef cattle are infrequently handled how does this affect our anesthetic protocol?
A
Require more physical restraint
Heavy sedation
Larger doses of sedatives/anesthetics
25
We performed standing sedation in what bovine?
Dairy cows
Anesthesia for standing sedation
Light sedation
Lower doses of sedatives/anesthetics
26
What is recommended for GA in bovine (both dairy and beef)?
Endotracheal intubation is recommended due to risk of regurg and upper airway obstruction
27
Describe recovery of anesthesia in dairy and beef cattle?
Dairy: Recovery usually is smooth
Beef: Recovery can go rough sometimes
depending on animal’s disposition
28
Why is restraint useful during sedation?
Reduction of stress response
Handling, transportation
Improves operator/patient safety
29
What are some minor DX procedures and medical procedures?
Minor Diagnostic Procedures
- Radiography, US
Medical Procedures
- Physical examination
- Catheterization
- Wound care
Improves quality of induction of, maintenance of, and recovery from GA
30
Sheeps and goats are what compared to bovines? Because of this most procedures are done with?
Easier to handle
Most procedures done with:
- Mild physical restraint +
- Light-to-moderate sedation +
- Local anesthesia
For Major procedures theyll require GA and minor procedures we use ^^ that above
31
When sedating ruminants theyre likely to become:
recumbent (dose and drugdependent)
Sternal
Lateral
32
Is recumbency always desired?
There are situations in which recumbency is not desirable, such as a C-section in a cow or any other standing procedure we have planned.
33
What drugs are used fir sedation in ruminants?
Opioids
Benzodiazepines
α2-Agonists (x10 times more
sensitive)
Acepromazine (seldom used)
34
What are the reversals for common sedatives? and why do we use them?
alpha-2 agonists: Yohimbine, Tolazoline, Atipemazole
opioid: Naloxone
Benzo: Flumazenil
use:
Speeding up of recovery time
Emergency treatment for adverse
effects (CV or Resp)
35
After you restrain animal whats the next step?
Establish IV access
Venous Access Options
- Jugular Vein
- Caudal Auricular Vein***
Administer sedation
36
Whats your goal of sedation?
Decreasing drug requirements for induction
37
What is an important aspect of alpha-2 adrenergic agonists in cattle?
- Ruminants are VERY sensitive to
Xylazine
--> CNS sensitivity x10 that of horses
--> Meaning you will need <0.1
mg/kg!!!!!!!!!
38
Should you use alpha-2s in neonates/juveniles?
it causes Pronounced
Sedation so try to avoid it if you can
39
Why are cattle so sensitive to xylazine?
- Not fully understood
- Different drugs act on different
alpha2-subtype (?)
--> α2A Xylazine
--> α2B Detomidine
- High density of α2A in ruminants
ruminants express predominantly alpha 2A subunits in their CNS, theoretically leading to greater sensitivity to the clinical effects of xylazine compared for example to those of
detomidine.
40
What are the cattle breed differences in terms of sensitivity to xylazine?
Brahmans are more sensitive than Herefords, and Holsteins are the least sensitive of
the bovine breeds, so doses can be adjusted accordingly.
41
What are some side effect of alpha-2 agonists?
- Increase uterine tone
--> Abortion???
- Placental crossing!!!!
--> result in prolonged sedation if
the newborn once removed from the uterus during a C section
- GI Stasis
--> Ruminal Atony
--> Ruminal Tympany
--> Regurgitation
42
What is the major consequence of xylazine in sheep?
- Pulmonary edema, increased airway pressure, parenchymal damage, bronchospasm and venospasm
- Profound hypoxemia from increased V/Q mismatch, cardiorespiratory collapse, and
death
- Mostly after IV administration of >0.1 mg/kg and >0.5 mg/kg IM
- In response to α2-adrenergic receptor activation in the alveoli (onset = around 3-12
minutes)
Macrophagic response --> Release of cytokines --> Damage to alveolar type I cells, endothelium, lung parenchyma
The onset is very quick after administration of
xylazine and it usually manifests with pink foam coming out of the ET tube.
Mechanical ventilation and reversal of xylazine within 12 minutes may reverse this
process.
43
NEVER use xylazine at what concentration?
100 mg/mL
ONLY and EXCLUSIVELY use the 20 mg/mL
formulation so you don’t accidentally overdose them, which is very easy to do with
the 100, and it is NOT pretty or fun to deal with.
44
Butorphanol will cause:
- Synergistic effect with other sedatives
--> Augments sedation
- No MAC reduction
- Mild analgesia (1-2 h)
45
Morphine will cause:
- Moderate/Profound Analgesia (4-6 h)
- Usually sedative (excitement is rare)
- Reduces MAC
46
What are the effects of benzos in cattle?
- Short term sedation (in
combination with other
sedatives)
--> Muscle relaxation
- Lack analgesic properties
- Mainstem of pediatric sedation
- Mainstem of induction (in
combination with ketamine)
47
What is ketamine stun and what is the effect of it?
combination of low doses of ketamine and
xylazine, can be used to produce short term restraint and recumbency.
It is dose dependent --> low doses will produce short term restraint and recumbency
Immobility and analgesia is increased with the addition of butorphanol
48
Whats an option for induction of GA?
Midazolam 0.11 mg/kg +
Ketamine 3.3 mg/kg
there are many other options we can use. Just keep in mind the size of the animal and the price of the drugs you are intending to use because for this size animal, it can get pretty expensive with drugs like propofol alone.
49
What are your supplies for intubation of bovines?
Your arms
Mouth Gag (speculum)
Appropriate size ETT
--> Adult Cattle: 20-30 mm
--> Calf: 10-16 mm
50
Whats the technique of intubation for bovines?
- ALWAYS PERFORMED if under GA
- In sternal recumbency
- Manual (Palpation) --> dominant hand
- YOUR HAND IS THE GUIDE FOR THE ETT
- Tip: Take your rings, bracelets, and watch
off… or else…
Left hand passes tube into oral cavity and right hand will depress epiglottis and use the fingers to guide the ETT into the trachea
51
What are the supplies needed to intubate small ruminants?
- Small Animal Set-Up
- Appropriate size ETT
- Goats/Sheep: 5.0-14 mm
--> Calf: 10-16 mm
--> Laryngoscope
- Stylet
I also like to have ready a forceps with some 4x4s to clean the oral cavity from any saliva or regurged material that can accumulate during
intubation
52
Whats the technique of intubation in small ruminants?
- ALWAYS PERFORMED if under GA
- In sternal recumbency
- Neck hyperextended
- Visualization of Arytenoid
Cartilages & Tracheal Opening
- Spray with lidocaine (prone to
laryngospasm)
- Intubate
53
What are some things to expect when intubating ruminants?
- BE PREPARED FOR REGURGITATION and UPPER AIRWAY OBSTRUCTION
- THICK epiglottis and base of the tongue and There is also a sharp angle of the larynx you’ll need to overcome with your tube
- Small target and FAR with small opening between maxilla and jaw (SR)
- Technical skills – Learning Curve
54
Whats a common complication of intubation?
- Endobronchial intubation --> intubation of one bronchus or one lung
- If ETT is too long and seeded
too far in to the trachea so now the murphy eye and opening of the ETT are past the tracheal bronchus which supplies the right cranial lung
- Blockage of the tracheal
bronchus (aka pig’s bronchus)
--> Present in all artiodactyls (from
goats to giraffes)
55
What does endobronchial intubation cause?
V/Q mismatch &
hypoxemia
56
Where is the ideal ETT position?
Cranial to 2nd-3rd intercostal space
Here there is no exclusion of any lung lobes
57
What are the positioning requirements for ruminants in GA?
- MATS FOR PADDING
- Soft, thick, and
comfortable surface
- Avoid stretching limbs
- Dependent limbs pulled
forward in lateral recumbency to limit nerve damage
- Non-dependent legs supported to prevent nerve damage (hanging them)
- Head tilted to drain oral contents
58
You can place comfy cushions under ruminants in GA. We can place something under the front legs to prevent injury to what?
Prevention of radial nerve injury
59
Neuropathies and myopathies are dependent on the patients:
- Weight
- Time recumbent
60
What nerves are most susceptible to damage in ruminants resulting in neuropathies?
Superficial nerves compressed on hard
surfaces (NP)
- Radial
- Femoral
- Peroneal
61
Why is myopathy an issue in ruminants? and what does it lead to?
Heavy muscular masses on hard
surfaces (MP)
leads to Poor tissue perfusion due to
hypotension = Ischemia (MP)
62
How is anesthesia maintained in bovines?
- Injectable or Inhalant-Based Regimen
--> Isoflurane (MAC 1.14%)
--> Sevoflurane (MAC 2.1%)
- Similar side effects to other species
- Machine & Ventilation: Similar to Horses
--> Mechanical ventilation highly
recommended
- On FiO2 of 1 (100% O2)
63
How is anesthesia maintained in small ruminants?
- Injectable or Inhalant-Based Regimen
--> Isoflurane (MAC 1.2% goats, 1.58% sheep)
--> Sevoflurane (MAC 2.33%)
- Similar side effects to other species
- Machine & Ventilation: Small animal machine set up, similar to big dogs
--> Mechanical ventilation highly recommended
- On FiO2 of 1 (100% O2)
64
Whats the main difference of maintenance of anesthesia in bovines and small ruminants?
This is similar to any other species, with the
main difference being slightly lower anesthetic requirements and MAC values.
65
What are some TIVA options in ruminants for maintenance of anesthesia?
- propofol
- ketamine
- tiletamine-zolazepam
- Triple drip: guaifenesin. ketamine, xylazine
66
Whats an important difference of triple drip in bovine compared to horses?
the content of xylazine in the ruminant triple drip is 1/10th of the equine dose
67
Monitoring anesthetic depth: Describe bovine eyeball position?
- Plane III Stage 1 and 2 = Ventral
Position (only sclera is visible, D in
image)
--> Compared to ventromedial in other
species
- Plane III Stage 3 and IV – Central (WE DONT WANT THIS either too deep or too light)
68
Monitoring anesthetic depth: Describe Small ruminant eyeball position?
Inconsistent and unreliable
Generally, in central position
69
Whats a more reliable thing to check for anesthetic depth in SR?
Jaw tone more reliable for depth
of anesthesia
70
What are the BP monitoring parameters in ruminants?
SR: Same as small animal
Bovine:
- 140/95 mm Hg, even under GA --> higher and this is normal
- Often mistaken for hypertension
71
How do you monitor temperature in ruminants?
- Nasopharynx
- Esophagus --> this can induce secondary wave movements
- Support with:
--> Bair Hugger (warm-air
blanket)
--> Hot Dog (resistive blanket)
--> Warm water blanket
72
What should recovery be like in ruminants in terms of positioning?
ALWAYS in sternal recumbency to favor eructation of methane and CO2 that were trapped in rumen
ALWAYS elevated, supported head
73
When should you extubate?
Extubate when ruminating motions are consistent
We want to make sure theyre awake enough to sustain this rumination
74
When should you remove IV catheter?
ALWAYS keep IV catheter for as long as possible
75
What are some potential post-anesthetic complications?
- Regurgitation (may lead to aspiration
pneumonia)
- Airway Obstruction --> saliva, solid bolus that was being ruminated on before GA
- Chocking
- Ruminal tympany (impeded eructation)
- Prolonged recovery (reversal?)
- Neuropathy (nerve damage)
- Myopathy (rare in small ruminants)
- Hypothermia
76
Drug residues and AMDUCA
- Use of off-label drugs protected by the
AMDUCA via ELDU --> permitted when animal health is threatened or death may result if a
condition is untreated
- Few drugs labeled for use in SR
- Consult FARAD for recommendations to
the client
- Make sure these info is included in the
discharge of your patient EVEN IF THE
ANIMAL IS A PET!!!!
77
What is phenylbutazone?
Drug that is prohibitted in female dairy cattle
older than 20 months of age for ALL USES due to severe idiosyncratic reactions and carcinogenesis in people consuming contaminated milk
78
Anesthetic compications of GA can be severe therefore whats the preferred technique?
sedation + LR (Locoregional technique)
79
What doesnt stop during GA?
Salivation and regurg
80
Alpha-2 agonists can have adverse effects on pulmonary function in sheeps primarily because:
They stimulate pulmonary intravascular macrophages to release cytokines
81
To anesthetize the flank area of a bovine for a vertical incision, which of the following nerves must be anesthetized? (Animal must remain standing).
T13, L1, L2
82
For which of the following reasons is Tolazoline used in ruminants?
Reversal of xylazine-induced sedation
83
Regarding species sensitivity to the sedating effects of xylazine, select the correct answer
Goats are not sensitive to xylazine
Pigs are very sensitive to xylazine
Llamas are more sensitive than cattle
**Cattle are more sensitive than pigs **
