Exotics Anesthesia Flashcards
What is important to understand about birds prior to restraint?
they are prey animals —> will have a fight or flight response and try to lunge, bite, or escape
- observe, allow time to calm down, and get an idea of their temperament
What equipment is commonly used for avian restraint?
- towels
- person for restraint and for examination
- curtains or blinds to prevent flight into window
(ensure all doors, windows, and other escape routes are closed)
How are birds properly restrained? What 3 things are avoided?
- use a towel to wrap wings with head out
- firm grip on head with one hand and the other hand supporting the body
- squeezing chest —> no diaphragm!
- pressure one eyes
- gloves —> harder to grip, can’t feel own strength
What are 3 major differences in the avian cardiovascular system?
- larger heart with 4 chambers
- higher CO and BP
- relatively lower HR relative to size
How does handling and excitement affect the avian cardiovascular system?
increases NE and EPI, which contributes to arrhythmia development
What aspects of anesthetics cause changes in the avian cardiovascular system?
hypoxia and hypercapnia depress CV function
How does the avian ECG look?
different morphometry, which looks like V-tach
What parts of the avian pulmonary system take part in ventilation and gas exchange?
VENTILATION - trachea, bronchi, air sacs, thoracic skeleton, respiratory muscles
GAS EXCHANGE - parabronchial lung
What 3 things make intubating bird difficult?
- oropharyngeal anatomy - long beaks!
- sizing of ETT not small enough, so IVC without stylets are commonly used = obstruction with mucous is worse!
- tracheal rupture with cuff overinflation is most commonly longitudinal due to complete rings - limit or do not inflate cuffs
How can mucous plugging of the smaller ET tubes be avoided in birds?
Atropine or Glycopyrrolate IM
- can thicken secretions!
Where is the avian larynx found?
base of tongue
What is the avian trachea like? What are 3 aspects of its anatomy?
complete cartilaginous rings
- saccules
- double tracheas possible
- loops/coils
What is the purpose of the syrinx? Where is it found?
sound production
junction of the trachea and brainstem bronchi —> PPV of intubated birds can create sounds!
What is the anatomy of cranial and caudal group air sacs? What is their purpose?
- CRANIAL = 2 cervical, clavicular, 2 cranial thoracic
- CAUDAL = 2 caudal thoracic, 2 abdominal
- volume in both groups is equal
provide tidal air flow to the avian lung, which is relatively rigid
What is avian ventilation like?
inspiration and expiration are active
- INSPIRATION = air flows from atmosphere into air sacs and across gas exchange surfaces of the lung
- EXPIRATION = air flows from air sacs and pulmonary system to the environment
How does anesthesia affect avian ventilation? What recumbency is avoided?
abdominal viscera can compress abdominal air sacs nd reduce tidal volume
sternal —> reduces keel movement and ventilation
What does the avian lung lack? What is recommended?
FRC
- limited tolerance for apnea
- ventilation - can flow a continuous gas stream through the trachea and lungs and out of a cannulated air sac
What does fasting of avian species depend on?
- size
- species
- concerns for regurgitation
What anesthetic concern does improper restraint cause?
hyperthermia!
- restraint for SQ/IM/IV injections can be difficult, so inhalant induction is commonly used —> pollution and personnel exposure possible
What are 4 signs of pain in avians?
- crouching
- immobility
- failure to groom/overgrooming
- withdrawal from flock or normal interactions
difficult to assess!
What is the most common analgesic used in avians?
opioids
What temperatures are reptiles kept at during anesthesia?
higher end of preferred
What is a common disorder affecting the reptile cardiovascular system? In what 3 ways does this affect anesthesia?
R-L shunting
- hypoxia induced hypothermia
- thermoregulation impacted
- induction of IV drugs is faster
What venous access is used in reptiles?
- tail - coccygeal
- jugular
- cephalic
How does the respiratory system of reptiles differ from other species?
- some contain air sacs
- no coughing, diaphragm
- episodic respiratory pattern with active inspiration and inactive expiration
What causes increased/decreased ventilation in reptiles?
INCREASED = hypercapnia, NOT hypoxia
DECREASED = hyperoxia, hypocapnia
How does the renal-portal system in reptiles affect anesthesia?
drugs injected into the caudal half of the body may be cleared by kidneys/liver before entering systemic circulation, so nephrotoxic or high renal clearance drugs should not be injected into hind limbs
- need higher doses to make effects last
What is induction and recovery of reptiles like? What is critical to maintain?
prolonged, unpredictable
temperature —> keep a little higher
- use reversible drugs!
- avoid 100% O2 if possible
What monitoring is recommended for reptile anesthesia?
- depth indicators not reliable - CV, respiratory systems
- HR - stethoscope, doppler, ECG
- capnograph
- pulse ox
- blood gas analysis
- body temp
What disease is commonly seen in rabbits and not recognized by owners? What pre-anesthetic evaluation is especially important?
respiratory disease
- PE, Hx
- bloodwork
- thoracic radiographs
What fasting is recommended for rabbits?
1 hour max
- unable to vomit
What IV access is available for rabbits? What is especially helpful for restraint?
ear veins, cephalic once sedated
support the back —> bunny burrito with a towel for IM injections
How are rabbits usually intubated?
- blind + capnograph
- otoscope attachment, endoscope > laryngoscope
- stylet
- retrograde —> invasive!
- Vgel - goes into trachea and occludes esophagus + capnograph
What are some common drugs used for rabbit anesthesia?
- Ketamine IM
- Buprenorphine IM
- Midazolam IM*
- Propofol, Alfaxalone IV at titrated doses
- Meloxicam post-op
What anticholinergic is preferred for rabbits? Why?
Glycopyrrolate
naturally produce atropine esterase, which breaks down Atropine
What is critical to preparing rabbits for anesthesia? What is common in recovery?
ocular lubrication
hypothermia —> small, high metabolic rate, non-rebreathing system used
