Acuc.berkeley.edu

GUIDELINES FOR ANESTHESIA AND ANALGESIA IN
LABORATORY ANIMALS
Table of Contents
Background
Federal regulations mandate that animals undergoing potentially painful procedures be provided with adequate anesthesia and analgesia. The standard of care at UC Berkeley is to prevent animal pain whenever possible and to treat animal pain whenever diagnosed. Exceptions to these principles are permitted only if scientific justification is provided in the Animal Use Protocol (AUP) and approved by the Animal Care and Use Committee (ACUC). Anesthetics
For the use of any anesthetic agent, the Office of Laboratory Animal Care (OLAC) veterinarians should be consulted regarding the appropriate agent and dose for the species being used and the procedure being performed. • Inhalant anesthetics (i.e., isoflurane) – Delivery of inhaled anesthetics by mask or endotracheal tube via a precision vaporizer is recommended for all non-aquatic species. Adjusting the inhaled percentage of anesthetic gas to deepen anesthesia is far safer than repeated redosing of injected drugs. Volatile anesthetics are easier to decrease as well, even compared to drugs for which there is an injectable antagonist or reversal agent. A disadvantage of the inhalant anesthetic agents is the lack of residual analgesia once the vaporizer has been turned off; pre-emptive analgesia is necessary. Contact OLAC veterinary staff at 642-9232 for information regarding vaporizer availability and training. • Injectable anesthetics (i.e., ketamine combinations, pentobarbital) – Injectable anesthetics are appropriate for many procedures. There is, however, a great deal of variation in depth and duration of anesthesia among rodent strains and individual animals. • See Table 1 for appropriate dosages and routes of administration by drug for • Immersion anesthetics (i.e., buffered MS-222) – Immersion anesthetics are appropriate for aquatic species, such as amphibians and fish. Different solution strengths may be appropriate for induction and maintenance of anesthesia. • Local anesthetics (i.e., lidocaine, bupivicaine) – Local anesthetics are usually injected at the site of the incision and may be appropriate to consider as supplements to either inhalant or injectable anesthetics. Guinea Pig
*May not provide surgical anesthesia in mice. Consult with an OLAC veterinarian before using this mixture in mice. 2 Xylazine is a potent respiratory depressant. Re-dosing, if necessary, should be done with 1/2 the original dose of 3 Not available as a pharmaceutical, scientific justification in the approved AUP is required for use. Solution must be labeled with the date prepared, stored at 40C, and discarded if any signs of decomposition including discoloration, precipitate or toxicity are observed.
A note regarding urethane: Urethane is a known carcinogen and may only be used for anesthesia in non-survival
surgeries. Scientific justification in the approved AUP is required for use. Analgesics
For the use of any analgesic agent, OLAC veterinarians should be consulted regarding the appropriate agent and dose for the species being used and the procedure being performed. • Opioids (i.e., buprenorphine, morphine) – Opioids are very effective analgesics for surgical pain but may have effects on cardiovascular function and can be sedating. • Non-steroidal anti-inflammatory agents (i.e., meloxicam, carprofen, ketoprofen) – Newer, longer-lasting non-steroidal anti-inflammatory analgesics (NSAIDs) may have longer durations of action than available opioids. These drugs are frequently co-administered with an opioid to combine potency of effect with duration of action. • See Table 2 for appropriate dosages and routes and frequency of administration by drug for some common laboratory animals. Guinea Pig
Best Practices
• Multi-modal drug administration – Using a combination of agents (multi-modal anesthesia and analgesia) is recommended. This practice can help maximize the desired effects while minimizing the side effects that occur with over-reliance on a single agent. • Pre-emptive analgesia – Pre-emptive analgesia or administration of pain relief before the painful stimulus is recommended: o To ensure that pain is being treated as the general anesthetic is wearing o To lower the overall amount of general anesthetic required; and, o To prevent sensitization of pain mechanisms (“ramp up”) • Frequency of analgesic administration – Analgesic doses and frequencies should be carefully considered. Careful planning is required for overnight pain management. Many analgesics administered at 5 pm will wear off before 8 am the next morning. Multimodal analgesia is recommended to combine potency of effect with duration of action. • Additional supportive care – Non-pharmaceutical methods to enhance the administration of anesthetic and analgesic agents should be used and include: o Keeping the animal warm during and after anesthetic procedures o Keeping recovering animals isolated in a quiet area Contact the veterinary staff for additional information on supportive care. • Monitoring – Plans for intra- and post-operative monitoring must be included in the AUP. Monitoring anesthesia includes responsiveness to painful stimuli, character of respiration, and skin or mucous membrane color as seen by observing the ears, tail, and oral mucosa or foot pads. Pedal withdrawal reflex (footpad-pinch) is recommended for assuring adequate depth of anesthesia prior to first incision and as a repeated check throughout the procedure. Depending on the procedure, other monitoring may be indicated such as heart rate, blood pressure, body temperature, and tissue oxygenation. Monitoring should be recorded through the post-operative period to complete recovery. • Dose ranges and titration – All drugs, dose ranges and routes of administration must be listed in the AUP. Dose ranges are starting points which must be titrated up or down for the individual animal, or for the particular application (procedures conducted, animal age and strain differences). When laboratory experience finds that recommended dose ranges are consistently too high or too low for the particular application, the veterinarian should be informed, and a protocol amendment submitted to the ACUC. Anesthetics are always titrated to effect. It is not acceptable to conduct surgical procedures unless the animal is fully anesthetized. • Recordkeeping – Administration of anesthesia and analgesia and peri-operative monitoring should be recorded. Depending on the species, records may be kept in the animal’s individual medical record or in laboratory records and on post-operative card cards. Records should extend through the period of complete recovery, and should document post-operative care and analgesia that is provided. Minimum required documentation includes: • Training – The very best anesthetic plans are only as good as the skill and care with which they are applied. Training is available from the OLAC veterinary staff. Required procedure-specific training will be detailed on the AUP approval letter from the ACUC Chair. The individual to contact for training will be included in the letter. Controlled Substances
• Several commonly used anesthetics and analgesics (i.e., opioids, ketamine) are controlled substances and require special procedures to be completed prior to use in animal research. • More information can be found at the Office of Environment, Health & Safety . Once they are obtained, controlled substances carry special storage and record keeping requirements. Suggested Formularies
References
• Carpenter, J.W. (2005). Exotic Animal Formulary. (3rd Ed.). Philadelphia, PA: • Hawk, C.T., Leary, S., & Morris, T. (2005). Formulary for Laboratory Animals. (3rd

Source: http://www.acuc.berkeley.edu/guidelines/anesthesia.pdf