Rabbits Flashcards
How are the effects of drugs different in rabbits
Higher metabolic rate, smaller reverses of glycogen predisposes to hypoglycemia
Higher oxygen consumption reduced tolerance to hyoxia
Have 30 seconds to respond to breath holding spells
Hypothermia
High body surface to volume ratio
Radiant heat loss – cover patient
Evaporative heat loss
Clip as minimal as necessary
Minimize use of scrub and alcohol solution
How are the resp system of rabbits different
Visualization of larynx difficult
Prone to laryngospasm
Obligate nasal breathers
Thoracic cavity: very small, small tidal volume (4-6mL/kg)
Clinical and subclinical resp disease
Be careful with positioning
Large abdominal organs push against diaphragm
How does the digestive system of rabbits function
Allow water up to premedication
Can not vomit
Fast rabbits 1-2 hours to reduce presence of food in oral cavity
Check for food in the oral cavity – clean with cotton swabs (guinea pigs!)
Post op ileus is common
Predisposing factors: pain, starvation, stress, diet change, drugs
Encourage to eat in post anesthetic period
What do you need to consider during rabbit anesthsia
Accurate dosing of drugs
Accurate bodyweight
Dilute drugs of necessary
Use appropriate syringe size
Anesthesia protocols
Don’t extrapolation from other species
Compression of thoracic cavity: hands, instruments, drapes …
What is the blood volume of a rabbit
Blood volume: 50-78ml/kg
Less tolerance for hemorrhage
Cotton tip applicator: 0.17mL blood
4x4 gauze sponge: 7ml
What is the anesthetic mortality of rabbits
Overall risk of anaesthetic related death 1.39-4.8%
Sick rabbits: 7.37%
64% of mortality occurred post anesthesia
Peri anestheic GI complications (38%)
What increases the anestehtic risks for rabbits
Stress
Underlying disease
Failure to address perioperative issues
Lack of familiarity and expertise
- Size
- Endotracheal intubation is technically demanding
- Free veins that are easily accessible for catheterization
- Pain
Increased risk of hypothermia (slow metabolism, delayed recovery)
Prolonged procedures – anaesthesia time (ileus)
Supportive care will reduce anaesthetic morbidity and mortality
How do you minimize a rabbits stress under anesthesia
Provide a rabbit friendly enviro
Use premed to reduce stress during induction
Minimize handling
Pain management
What are common underlying diseases of rabbits that could affect anesthesia
Malnourishment (dental treatment) and dehydration
Sub clinical resp disease (Pasteurellosis)
Uterine carcinoma
What is a normals rabbits preop blood tests look like
PCV: 34-43%
TP: 5.0-7.5 g/dl
BG: 4/1-8.2 mmol/L
Blood glucose can be sued as a prognostic indicator (stress, clinical disease)
BUN 15-30 mg/dl
What is a normal TPR of a rabbit
HR: 200-300
RR: 32-60
Temp: 38.5-39.5
How do you avoid issues when it comes to rabbit anesthesia
Be prepared
Know normal parameters
Full clinical examination and history
Consider preoperative blood work
Stabilize condition before anesthesia
Don’t starve
Accurate weight
Always calculate doses for anaesthetic agents, reversals and emergency drugs
What are common anesthesia complications with rabbits
Hypothermia
Hypotension
Hypoventilation
Hypoxemia
Bradycardia
What are common procedure related complications with rabbits
pain, heamorrhage
What are common species related complications with rabbits
Hypoglycemia, ileus
Possible underlying subclinical disease
Corneal ulcers
Increased risk of hypothermia
Injury (back fracture)
Why do you premed rabbits
Reduces stress during handling, induction, pre oxygenation
Anesthetic sparing
Analgesia
What are common premeds for rabbits
Ace
Midazolam
Dexmed
Bup
Torb
Hydro
Methadone
Anticholinergics
How do you use ace in rabbits
0.1-0.25 mg/kg (IM, IV, SQ)
Long duration, not reversible – prolonged recovery
Peak effect after 30-45 min
Hypotension: peripheral alpha 1 receptor blockade - vasodilation
Only use in healthy animals
Not ideal as it can last 6-8 hours
Characteristics of midazolam in rabbits
0.5-2 mg/kg (IM, IV, SQ)
Water soluble can be administered IM
Minimal cardiopulmonary effects
Produces moderate sedation and muscle relaxation
Reversal: flumazenil (0.05-0.1mg/kg IV, IM)
Combine with an opioid
Great for average rabbits
Characteristics of dexmed in rabbits
0.02-0.05 mg/kg (IM, SQ)
Mild to profound sedation
Resp and cardio depression
Peripheral vasoconstriction
Reversible with atipamezole
Combine with an opioid
Characteristics of opiods in rabbits
Provide analgesia and will increase sedation
Reversible with naloxone (0.01-0.1 mg/kg IM, IV)
Buprenorphine
- 0.05-.01 mg/kg (im, SQ, IV) 6-8 hours
Butorphanol
- 0.5-2mg/kg (IM, SQ, IV) 2 hours
Hydromorphone
- 0.1-0.3 mg/kg (IM, SQ, IV)
Methadone
- 0.3-0.7 mg/kg (IM, SQ, IV)
Characteristics of anticholinergics in rabbits
Not routinely administered as premed
Used to treat bradycardia
Negative effects on gastrointestinal motility
Atropine
- 0.1-0.2 mg/kg (IM, SQ, IV)
- 61% of rabbits possess atropine esterase
Glyopyrrolate
- 0.01-0.1mg/kg (IM, SQ, IV)
how do you induce rabbits
Always pre oxygenate
Always have a person monitor patient during induction/intubation
Have monitoring attached to patient
IV catheter
Have enough induction agent
Masking induction should not be first option for rabbits
Humane exposure
Stressful
Not enough time to intubate
What are common injectable agents for rabbit induction
KETAMINE (1-5 mg/kg, IV, IM)
- Combine with benzodiazepine (midazolam 0.5mg/kg)
- High doses (up to 25mg/kg) can provide surgical anesthesia
PROPOFOL (2-8 mg/kg, IV)
- Requires IV access prior to induction
ALFAXALONE (1-4 mg/kg IV)
- Could be given IM–large volume
Give to effect to avoid induction apnea
Why dont you use volatile agents to induce rabbtis
Should only be 2nd choice to IV induction
Always use with premedication to reduce:
Stress
Struggling (back fracture)
Beware of breath holding
Apnea induced bradycardia
Introduce volatile gradually
Pre-oxygenate if possible
Oxygen flow rates greater than 100mL/kg/min will well fitted mask
What are common volatile agents used to induce rabbits
ISOFLURANE
- MAC: 2.5%
- Pungent smell–breath holding more likely
- Induction apnea
SEVOFLURANE
- MAC 3.5-4.1%
- Less pungent–better tolerated
- Faster induction ?-Depth of anesthesia may alter more rapidly
- Induction apnea
How do you use a face mask for induction with rabbits
Close-fitting:
- Reduce environmental contamination
- Avoid inhalation of room air
- Diaphragm can be adapted using an exam glove
- Clear: visual assessment
- Low volume: minimize dead space
Why do you use a lidocaine CRI in rabbits
Prokinetic effects
Improved food intake and fecal output in rabbits following OHE
Anesthetic sparing (reduces isoflurane MAC)
Analgesic
Anti inflammatory/ anti endotoxin
How do you intubate a rabbit
Mask
V-gel
Intubation
Blind
Direct visualisation
Videoendoscope
Laryngoscope
Otoscope
Why would you intubate a rabbit
Protects airway
Allows efficient oxygen supplementation
Allows positive pressure ventilation
Reduces human exposure
2.0-3.5 mm (un)cuffed ET tube
Ensure rabbit is adequately anaesthetised
Pre oxygenate
Prone to laryngospasm: use lidocaine (careful toxic dose)
Sternal recumbency with hyperextended neck
To align the larynx and the trachea with the oropharynx
Continuously monitor HR during induction/intubation
How do you blind intubate a rabbit
Technically difficult initially
Easy and quick to perform once experienced
No extra cost
Possible damage to glottis and risk of laryngospasm
Possible unsuccessful due to entrapment of epiglottis
Risk of aspiration if unnoticed presence of food in the pharynx
Premeasure ETT/atomizer to level of larynx
Sternal recumbency and hyper-extend neck
Insert ET tube to pre measured point
Condensation appearing in tube during expiration
Instill lidocaine 2% (neat) via small catheter/atomizer through ET tube
Gently advance ET tube during inspiration while:
Listening at the connector end of the tube
Watching capnograph
How do you confirm tracheal intubation in rabbits
Ventilate and listen for respiratory sounds on both sides of thorax
Use capnograph
Coughing
Watch for condensation (fogging of tube during expiration)
Repeated attempts of intubation are not recommended
Risk of laryngeal trauma and spasm → respiratory obstruction
How do you intubate a rabbit using a laryngocope/otoscope
Direct visualization possible
Can move soft palate and expose the glottis if necessary
Technically challenging compared to dog/cat
Unexperienced user can cause tissue damage
Minimal equipment necessary: laryngoscope/otoscope + stylet
How do you intubate a rabbit with direct visualisation
Sternal recumbency and hyper-extend neck
Requires an assistant to open the mouth
Hold rabbit’s mouth wide open
Use bandage material as retractor
Gently pull tongue out of mouth
Use small laryngoscope
Insert ET tube
How do you intubate a rabbit with an endoscope
Direct visualization allows rapid and accurate intubation
Technical challenging–learning curve
No risk of aspiration or soft tissue damage
Expensive equipment needed
Side-by-side or endoscope can act as stylet
Rabbit intubation complications
Difficult placement
Laryngospasm
Trauma to the oropharyngeal soft tissue
Tube dislodgement, occlusion, and kinking
Postintubation oropharyngeal swelling
Supraflottic airway device: V-gel is used when and how in rabbits
Some experience necessary (online training)
Always use with capnograph!
Can be easily dislodged when animal is moved
Faster placement than ET-intubation
Less trauma than blind intubation
How and where do you gain IV access in a rabbit
In conscious rabbit–apply local anesthetic cream (EMLA)
Cephalic vein
Lateral saphenous
Marginal auricular vein
Complications: sloughing, chemical phlebitis, mechanical irritation from catheter or bandage
Don’t use central auricular artery
What is the fluid rates for rabbits
Fluids: 10 mL/kg/h (+/- 2.5-5% dextrose)
How do you monitor a rabbit under anesthesia
Anesthetic depth:
- Palpebral reflex, eve position: unreliable
- Nictitans membrane will move over cornea
- Corneal reflex should be maintained
Cardiovascular System
- Auscultation
- Doppler
- Pulse oximetry: ear, tongue, digit
- ECG
- Temperature (Avoid Hypo and Hyperthermia)
What analgesia would you give a rabbit post op
- NSAIDS: Meloxicam 0.5-1 mg/kg SC
- OPIOIDS: Buprenorphine, Hydromorphone, Butorphanol
What post op care is needed in rabbits
ANALGESIA:
Stress free environment
Continue monitoring!!
Prolonged recovery → check for:
- Hypothermia
- Hypoglycemia
- Residual drug effects (reversal)
Feed as soon as possible
