Date:   January, 2008
 Reference:       Administrative Panel on Laboratory Animal Care

DIRECTIONS: Review the following material. Keep copies of guidelines with applicable protocols. You may find it helpful to post a copy of these guidelines in your laboratory. Questions should be forwarded to the A-PLAC office, 723-4550.

TRAINING: Training in these techniques and the humane treatment of laboratory animals during the procedures is taught by the Veterinary Service Center (VSC) Staff. All new personnel who will be performing these techniques should contact VSC staff for training (725-9901).

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GUIDELINES FOR THE USE OF NEUROMUSCULAR BLOCKING AGENTS (PARALYTICS) IN ANESTHETIZED ANIMALS

While it is recognized that the systemic administration of skeletal muscle relaxants may be a necessary component of a particular protocol, the use of these agents renders assessment of the level of general anesthesia much more difficult than is usually the case. Thus, the A-PLAC has adopted the following guidelines to ensure that anesthetized, paralyzed animals do not experience pain or distress. Any departures from these guidelines will require adequate scientific justification.

1. Paralysis should not be induced unless the animal has previously been anesthetized to a level judged to be no less than "light surgical anesthesia": (i.e., Stage III, Plane 1: for reference see Kitchell and Erickson, 1983). The regimen utilized for anesthetic maintenance should be sufficient to continuously maintain at least light surgical anesthesia during the entire period of paralysis. If the procedure involves potentially painful manipulations, the anesthetic plane should be adjusted accordingly in order to prevent the animal from perceiving pain while paralyzed.
2. The use of modern, short-duration paralytic agents is encouraged, since the short half-life of these agents can facilitate the assessment of the level of anesthesia during the procedure. Where it does not seriously interfere with the proposed experiments, Protocol Directors should periodically reassess the level of anesthesia in paralyzed animals by temporarily withholding muscle relaxants.
3. If there is any question regarding the adequacy of the proposed anesthetic regimen, a trial study can be done. The trial is performed by subjecting a nonparalyzed animal to an anesthetic regimen and experimental manipulations which are identical in character and duration to those proposed for use in paralyzed animals. Anesthesia can be considered adequate if the trial study provides physiologic evidence which demonstrates that the nonparalyzed animal showed no evidence of pain perception. Protocol Directors are encouraged to consider performing a trial study when appropriate, and in some cases the A-PLAC might make this a requirement for protocol approval.
4. A stable plane of anesthesia must be established and documented for a minimum of 30 minutes before the neuromuscular blocking agents are given.  To ensure that appropriate anesthetic depth is maintained throughout the procedure, the animal's heart rate and blood pressure must be monitored at minimum every 15 minutes.  Temperature should be monitored and remain within normal limits throughout the period of paralysis, and provision must be made for voiding urine. 
5. Written documentation of all parameters monitored and all anesthetic/paralytics administered (including route of administration, time of administration, dosage, and frequency) must be kept on file for each procedure.
6. Because of the technical complexity of these procedures, individuals who will perform them must have been adequately trained, or they must operate under the direct supervision of the faculty member who signs the Protocol for Care and Use of Laboratory Animals. Training is available from VSC staff.

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References

Kitchell, R.L. and Erickson, H.H.: Animal Pain: Perceptions and Alleviation. Bethesda, Maryland, American Physiological Society, 1983.

Oberdorfer, Michael: "Anesthesia and Paralysis in Experimental Animals: Report of a Workshop held in Bethesda, Maryland, October 27, 1984" Visual Neuroscience (1988) 1, 421-426.

Drummond, J.C., Todd, M.M., and Saidman, L.J. Use of Neuromuscular Blocking Drugs in Scientific Investigations Involving Animal Subjects: The Benefit of the Doubt Goes to the Animal Anesthesiology (1996) 85: 697-699.

National Research Council Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research Washington, DC: National Academy Press (2003) 88-91.

ILAR Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research, The National Academies Press, Washington, D.C, 2003.