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Laboratory Animal Resources Center

Current Investigators

Anesthetic Gas Scavenging

The LARC provides investigators and their staff with a portable anesthesia machine to be used for IACUC approved procedures.  Some investigators have purchased their own anesthetic equipment.

It is important to reduce the exposure to waste gases produced in laboratories.  Anything higher than 2 ppm (according to the American 1-h ceiling concentration) is considered high for stand-alone use of halogenated inhalation anesthetic agents.

We require that investigators maintain weight logs of F/Air canisters.  These logs demonstrate the increase in canister weight with the absorption of isoflurane vapor, and indicate when the canister must be replaced. Often, for convenience, the weight log is marked on the side of the canister. The log will be reviewed by the IACUC and OHS programs during semi-annual inspection to assure the canister is not expired and functioning properly.

Ways to Minimize Exposure to Waste Gases

If a mask is used, make sure it has a tight seal around the animal's face.  If using F/Air canisters, record the weight before initial use and after each use.  After a 50-gram increase, place the canister in a plastic bag before it is discarded.  Thoroughly clean the induction chamber immediately after each use to avoid residual anesthetic waste release into the environment (which can continue to be released for up to three hours).  Before removing the animal from the induction chamber, close the in-line valve.  The vaporizer must be professionally calibrated at least once per year.

Scavenging System Options

**BEST:  Perform all procedures, including use of the induction chamber, under a fume hood.  No F/Air canister required

**BETTER:  Connect a long corrugated hose from your breathing system (and/or induction chamber) to an exhaust outlet.  These outlets can be found by the wall vent.  The Physical Plant division can assess this for you.  Waste gases will be taken out through the vent in to the outside.  No F/Air canister required

**GOOD:  When using F/Air canisters, the manufacturer recommends replacing the canister after 50 grams of increment in weight relative to the initial weight and/or after 12 hours of use.  Smith and Bolon demonstrated significant release of isoflurane waste into the environment when canisters continued to be used beyond accumulation of 50 grams increment.  Accordingly, F/Air canisters must be replaced at that point.

Note:  The above recommendations are based on:  Smith, J.C., & Bolon, B.  (2002).  Atmospheric waste isoflurane concentrations using conventional equipment and rat anesthesia protocols.  Contemporary Topics, 41(2).

Maintaining Appropriate Animal Medical Records

The Animal Welfare Act requires that a medical record on all USDA-covered (regulated) species ("animal") be maintained from the day they arrive at the LARC until the day they have finished their requirement for the research.

The Animal Welfare Act defines "animal"  as "any live or dead dog, cat, nonhuman primate, guinea pig, hamster, rabbit, or any other warm blooded animal, which is being used, or is intended for use for research, teaching, testing, experimentation, or exhibition purposes, or as a pet.  This term excludes:  Birds, rats of the genus Rattus, and mice of the genus Mus bred for use in research.

The research staff is responsible for documenting every research and clinical procedure in the animal's medical record daily progress notes.  Examples of documentation required include anesthesia, medication, dosage, route of administration, surgery, and euthanasia.  Any medical treatment given to the animal should be recorded on the pink treatment record card (for treatments not related to surgery) or on the green surgery card (for procedures/treatments/medications relevant to the surgery performed).

Note:  Treatments for clinical reasons may be administered by the research staff ONLY after receiving approval by the LARC veterinarian.  In addition, regulatory agencies require that the medical record for each regulated animal (except for USDA-covered rodents) be retained for at least three years after the animal is no longer in use in the animal facility.  Please, return all completed animal medical records to the LARC once the animal study is completed.

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