Ron Mandsager, DVM, DACVA
4/1/03

General considerations for the exotic patient:

• stress response to capture and/or restraint
• limited preanesthetic evaluation
• limited knowledge base
• drug idiosyncrasies
• Small body size

Avian anesthesia:

Anatomy and physiology

• epiglottis absent
• vocal cords absent
• thyroid cartilage absent
• syrinx present
• small compact lungs
• slightly expandable lungs
• anastomosing parabronchi
• air sacs present
• rudimentary diaphragm
• larynx: easy to intubate
• trachea: inexpandible, complete tracheal rings
• lungs: small, relatively inexpandible
• small functional residual capacity
• air sacs: not involved in gas exchange
• Lack of large superficial veins and arteries
• High metabolic rate

Preparation for anesthesia

• history & physical exam: as much as possible depending on the patient
• appropriate restraint: don't restrict movement of the sternum-impede respiratory function
• adjustment period to new environment: 12 to 24 hours prior to anesthesia if possible
• laboratory evaluation: may be limited, but have improved methods for small samples available
• preanesthetic fluid therapy
• fasting: not recommended in small birds, due to high metabolic rate, unless surgery involves the crop

Anesthesia: general goals

• minimize stress
• provide adequate analgesia
• rapid recovery

Injectable anesthesia (not routinely used except in large birds, such as the ostrich)

• ketamine, alpha-2 agents
• ketamine combinations
• telazol
• benzodiazepines
• IM, IV injection sites

Local anesthesia

• watch local anesthetic over dose…make dilution before injection
• lidocaine with out epinephrine
• procaine is toxic!

Inhalant anesthesia

• most popular method currently
• Isoflurane or sevoflurane are preferred agents
• can use a mask or chamber
• intubation is recommended
  • non-cuffed tube (risk of mucosal necrosis w/ cuff inflation)
• non-rebreathing system for small birds

Assessing anesthetic depth

• light: reflexes present, lack of voluntary movement
• medium: palpebral reflex absent, pedal and corneal reflex sluggish; respiration slow, regular, and deep
• deep: all reflexes absent, respiration slow, irregular, shallow, may become apneic!

Monitoring and support during anesthesia

• heart rate, ECG
• respiratory rate, exhaled CO2 concentrations
• SpO2 (hemoglobin saturation)
• keep warm
• hemostasis critical!

Recovery

• rapid, quiet recovery desired
• may need some restraint
• resume eating and drinking as soon as possible

Anesthesia for rabbits & rodents:

General considerations

• small size
• limited venous access
• small muscle mass
• high metabolic rate
• interspecies variation common
• difficult to intubate

Preparation for anesthesia

• physical exam and history
• proper physical restraint
• minimize stress
• fasting
• preanesthetic stabilization

Injectable anesthesia

• xylazine with ketamine combinations
• telazol^®
• medetomidine with ketamine combination
• Opioids can be added for analgesia

Inhalant anesthesia

• sensitive to respiratory depression
• compliant rib cage predisposes to atelectasis
• difficult to intubate due to anatomy
• Isoflurane or sevoflurane agent of choice

Monitoring anesthesia

• respiratory rate, rhythm, depth
• heart rate, SpO2, ECG, blood pressure
• ferrets and rabbits blood pressure monitoring may be done with non-invasive blood pressure monitor
• reflex responses
• mucous membrane color
• muscle relaxation
• body temperature.

Ferrets

• Similar to small cats
• Catheterization may be difficult
• Small airways - usually size 2 or 3 ET tube
• Usual anesthetic protocol is mask induction (sevoflurane or isoflurane), maintenance with inhalant
• Ketamine/xylazine or medetomidine IM also reasonable choice, depending on physical status
• Butorphanol or buprenorphine for pain management
• Keep them warm!

Exotic Cats

Awake - small but not friendly!

Injection of medetomidine + ketamine

Mask w/ sevoflurane

Maintain with sevoflurane - treat like any other cat at this point...

Fish anesthesia

An 'anesthetic machine' for fish:

(from: Pneumocystectomy in a Midas cichlid, JAVMA 207:319-321, 1995)

Remember: Tricaine methanesulfonate!

Reptiles, Amphibians

Camelids

Mom

Baby

Alpaca cria

Primates

And the list goes on, and on, and on...

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© 1996-2003, Oklahoma State University College of Veterinary Medicine, all rights reserved Last modified October 19, 2007 by Ron Mandsager, DVM, DACVA Questions? Comments? Contact me at aerrane@okstate.edu

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