Lecture 11 Swine Anesthesia Flashcards
1
Q
How long do pigs need to be fasted
A
Pigs fasted 24 hours before surgery
2
Q
Reasons to anesthetize pigs
A
- Farm animals
- Castration, hernia
- Pets
- Variety of conditions
- Biomedical Research
- Experimental surgery
- Organ transplant
- Bypass surgery
3
Q
Problems with Pig Anesthesia
A
- Wide range of sizes
- Manual restraint is difficult
- Physical exam often impossible
- History important for physical status
- IM injection
- drugs deposited into fat
- Limited IV access options
- Endotracheal intubation
- Malignant hyperthermia
- Extra label drug use
4
Q
- Do pigs have small or large hearts relative to body mass
- rapid or slower heart rates
- Does tachycardia reduce cardiac output?
A
- Small heart relative to body mass
- Rapid heart rate
- Tachycardia markedly reduces cardiac output
5
Q
- Do pigs have a low or high incidence of rhinitis
- low or high incidence of pneumonia and pleuritis?
- Upper airway easily or not obstructed?
- Lots or little airway secretions
A
- High incidence of rhinitis
- High incidence of pneumonia, pleuritis
- Upper airway easily obstructed
- Airway secretions easily obstruct airway
6
Q
- IM injections for comercial pigs
- Pet pigs
- Short or long needles?
A
- Commercial pigs
- close to the ear base
- Pet pigs
- thighs, epaxial muscle
- Use long needle
7
Q
IV access sites
A
- auricular vein (dorsal surface of ear)
- Limb veins OK once asleep
- Use elastic band to help raise the vein
8
Q
What are the different sedatives and anesthetic agents used in pigs
A
- Butyrophenones
- Azaperone
- Acepromazine
- a2 agonists
- Xylazine, dexmedetomidine
- Opioids
- Hydromorphone, butorphanol
- Midazolam
- IM or intranasal
- Dissociative agents
- Ketamine, Telazol
- Propofol ($)
- Anticholinergics
9
Q
What is special about mode of administration of midazolam in pigs
A
IM or intranasal
10
Q
- What type of drug is Azaperone
- Side effects are similar to what other drugs
- What can it be used for?
A
- Butyrophenone
- Similar effects and side-effects to acepromazine
- Uses:
- Short acting tranquillizer used by pig farmers
- Can be useful as premed
11
Q
- Azaperone can be given through what mode?
- What is another butyrophenone
A
- IM only
- Excitement IV
- Droperidol
12
Q
- What are the alpha-2 agonists used in pigs?
- Alpha-2 Agonists are mixed with what drugs with pigs?
A
- Xylazine and Dexmedetomidine
- In combination with ketamine- very effective.
- Limited effect if used alone
- Need higher doses e.g. 2 mg/kg
- Limited effect if used alone
13
Q
How can you do injectable anesthesia in pigs? (what drugs)
A
- For induction and maintenance
- Xylazine-Telazol-Ketamine (TKX) IM
- Additional drugs IV if needed
14
Q
How do you do inhalational general anesthesia in pigs
A
- •Isoflurane or $evoflurane
- •Face mask
- –To induce anesthesia in piglets
- –To complete induction after heavy IM sedation
- •ET tube for anesth. maintenance
15
Q
What are considerations of Endotracheal Intubation with pigs
A
- Jaws don’t open widely
- Soft palate is long
- Larynx and trachea set at an angle
- Prone to laryngospasm
- Narrow trachea
- Tracheal bronchus can be occluded by ET tube
16
Q
Endotracheal Intubation Equipment
A
- Face mask for preoxygenation
- Bandage to hold open mouth
- Choice of ET tubes
- Lidocaine (spray on larynx)
- Laryngoscope
- Stylet
17
Q
If impossible to visualize larynx what other method can you use to administer oxygen/ inhalent anesthesia
A
- Bilateral nasal tubes
- 6-8 mm ID
- Inflate cuff inside nasal cavities
- Carlen adapter to connect to breathing system
18
Q
At what weight do you switch to using the large animal anesthesia machine for pigs?
A
- If ET tube 16 mm
- If body weight > approx. 200 kg
19
Q
- What should the HR be for pigs under anesthesia?
- BP?
A
- HR 60-90 bpm
- Blood pressure
- syst. > 90 mmHg or
- mean > 60 mmHg
20
Q
What are methods to measure BP in pigs
A
- Non invasive - oscillometer or Doppler
- Limbs taper (cone shape) and cuffs don’t fit well
- Invasive - auricular artery
21
Q
- What temperature do pigs generally run in under anesthesia (cold or hot)
- Why?
A
- Hyperthermia
- Small body surface area relative to body mass
22
Q
How do you test depth of anesthesia
A
-
Jaw tone is helpful
- Absent for surgical level of anesthesia
-
Pedal reflex
- Can squeeze a toe with a hemostat in small swine
- Eyes are of limited value
- Sunken and palpebral reflex hard to evaluate
23
Q
How do you recover a pig
A
- Extubate trachea when swallowing reflex
- Help to sternal recumbency
- Usually smooth process
- No need for further sedation
24
Q
- What causes Malignant Hyperthermia
- What breeds commonly get it?
A
- Inherited genetic disorder
- Ryanodine receptor on sarcoplasmic reticulum leads to lots of Ca++ release
- Breeds:
- Duroc
- Landrace
- Pietrain
25
Q
What can cause malignant hyperthermia
A
- Stress, transport, drugs
- Anesth. gases, suxamethonium
26
Q
What signs do you see with malignant hyperthermia
A
- Tachycardia
- Hypercapnia
- Muscle rigidity
- Hyperthermia (109 °F)
27
Q
Treatment of Malignant Hyperthermia
A
- Discontinue the trigger agent – e.g. isoflurane
- Change anesthetic machine
- Dantrolene – intracellular muscle relaxant
- Cool the body – ice and cool IV fluids
- Oxygen
- Supportive therapy
- Human - http://www.mhaus.org/
- Let us know if this exists in your ancestry
28
Q
What are important things to know about Analgesia in Food Animals
A
- All animals feel pain
- Assessment may be challenging
- Prey species/behavioral differences
- Response to drugs (e.g. opioids)
- Some signs
- Dull appearance, grinding of teeth
- Refusal of food, no rumination
- Abnormal posture, vocalization
- Multi-modal approach when possible
- At least local anesthetics & NSAIDs
- ELDU - check Farad
