Avian Anesthesia Flashcards
What are the two distinct functional components of the bird respiratory system ?
Ventilation: trachea, bronchi, air sacs, thoracic skeleton
Gaseous exchange: parabronchial lung composed of shallow depressions which contain 3-6 funnel shaped ducts
T/F: birds have no diaphragm
True
-liver lobes border the apex of the heart
Is the glottis in a bird easily visualized
Yes
T/F: birds have no vocal cords or epiglottis
True
How does the avian trachea differ from mammals?
Birds have complete tracheal rings
Mammals have incomplete tracheal rings
How does dorsal recumbency affect inspiration in birds?
Normally sternum moves forward and ribs downward
Dorsal recumbency compresses air sacs and hinders chest movement
What is the flow of air during a respiratory cycle in the bird?
Inspiration 1: air flows mostly to caudal air sacs
Expiration 1: from caudal air sacs across the lungs
Inspiration 2: air passes to the cranial sacs
Expiration 2: air exhaled from cranial air sacs
When would you intubate the thoracic or abdominal air sacs?
Obstructed trachea
Surgical procedures around cranial airways
What type of exchange occurs between the air in blood in the birds respiratory system ?
Counter current and cross current
PaO2 (arterial) > PO2 (parabronchial)
PCO2 (air)>PCO2 (venous)
What is the structure of the bird heart?
Avian heart: 4 chambers
Relatively larger and more efficient SV than mammalian —> lower heart rates but higher stroke volume and CO
Ventricles and atria innervated by high density sympathetic and parasympathetic fibers —> more susceptibility to adverse effects from anesthesic drugs, stress, and pain
Quick depolarization due to Purkinje fibers that penetrate the myocardium
What is the renal portal system?
Unique to avian and reptilian circulation
In external iliac vein, a valve can direct blood from the caudal extremities to the central circulation or the to the kidneys.
T/F: the hind limb muscles of birds serve as good places to inject anesthetic drugs
False
Due to renal portal system, drugs can cause nephrotoxicity or reduced drug effect due to elimination
What is normal temperature for birds?
37-42C
How do birds thermoregulate?
No sweat glands
Cooling: panting and gular flutter
Heating: shivering, pilo-ecrection, eating, and basing
**thermoregulation is affected by anestherics—> overhead heat sources are most effective (heat lamp)
When is sedation/immobilization indicated for birds?
Facilitate minor procedures
- physical exam
- blood collection
- diagnostic imaging
- bandaging
Why is restraint methods so important for birds?
Small birds can die easily from the stress of improper restraint
Restrain to control wings and legs
Control neck in long-necked birds
Should birds be fasted prior to anesthesia?
Small birds become hypoglycemic quickly: high metabolic rate and poor glycogen reaper se
Empty crop or allow it to empty
Bird <200g BW: no fasting/at most 2hours
Pittaines (400-1000g): 4-6hours
Raptors/ratites: 6-12hours
What are the IM injection sites for birds?
Pectoral (most flying birds)
Thigh muscles: non flying birds
What are the SQ injection sites in birds ?
Over back of wings
Wing web and leg web
Inguinal fold
What are IV sites of injection in birds?
Medial metatarsus
Brachial vein
Right jugular vein
What are the intraosseous injection sites in birds?
Proximal ulna
Tibiotarus
T/F: inhalation anesthesia is more common in avian practice
True
Easier to administer
Safer (rapid recovery)
—> injectables mor practicable in wild/large birds
What drugs are used for sedation/analgesia in birds?
Weak opioids (butorphanol/buprenorphine) with benzodiazepines (midazolam)/ A2 agonists (medetomidine)
IV or IM
What drugs are used for IMMOBILIZATION of birds
Weak opioids (butorphanol/buprenorphine) with benzodiazepines (midazolam)/ A2 agonists (medetomidine)
+ Ketamine
IV or IM
