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Institutional Animal Care & Use Committee, Yale University - Policies & Guidelines

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Yale University
Institutional Animal Care
& Use Committee
New Haven CT
USA 06510

G & C Med. G  & C FAS. YARC. Fed Regs. OEHS.

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Yale University Institutional Animal Care and Use Committee (IACUC) Guidelines for Aseptic Rodent Survival Surgery
(Current revision, March 30, 1999)

Aseptic surgery is surgery performed without contamination or exposure to pathogens. These policies and guidelines are provided to help ensure optimal results for aseptic survival surgery using laboratory rodents.


Note: A sterile instrument pack should not be used on more than five individual rodents.

Surgical Area
- benchcoat paper or other clean covering cold disinfectant

Sterilization of Instruments
- cold disinfectant
- cotton tipped swabs
- guaze squares
- water or saline
- glass bead sterilizer (repetitive surgeries)
- sterile drapes

Animal Preparation
- anesthetic (verify within expiration date)
- antiseptic scrub (chlorhexadine or equiv.)
- isopropyl alcohol
- clippers or depilatory cream
- ophthalmic ointment (Paralube or equivalent)
- sterile drapes
- heat lamp
- heating pad

Surgeon Preparation
- sterilized gloves
- gown or clean scrub top
- face mask

Postoperative Recovery
- Heat source: heat lamp, heating pad, hot water bottle (or any tight sealed, flat surfaced container).
- Analgesic (verify expiration date): postoperative analgesia must be given in accordance with the corresponding approved YACUC protocol.
- antibiotic: as required (verify expiration date)

Space requirements
Separate spaces should be used for the following activities:

1) animal preparation
2) surgical area and
3) postoperative recovery

A clean space should be dedicated to surgery and maintained as such during the surgical procedure. Surfaces should be wiped with disinfectant before and after surgery. The surgical area also should be covered with a clean drape or benchcoat paper.

Sterilization of Instruments:

Instruments must be cleaned prior to packaging for sterilization. Sterilization indicators must be used inside the surgical packs and autoclave tape placed on the outside of the pack to ensure sterilization has taken place. Plastic implantables also must be sterilized prior to surgery. Sterilization can be achieved by several methods:

1) Steam: 2500 F., 15 p.s.i., for 30 minutes.
2) Gas-Ethylene oxide: Exposure requires 8-10 hours in a special cabinet(gas autoclave). Plastic implantable materials must be aerated for two to seven days, depending on equipment recommendations.
3) Liquid-Immersion in:
a) 2% glutaraldehyde plus 7.05% phenol (Sporocidin, Cidex, Sonacide) Instruments must be immersed for ten hours in a 1:10 solution. They must be rinsed in sterile water or saline prior to use.
b) Chlorine dioxide (Clidox)- Instruments must be immersed for six hours in a 1:5:1 solution and require rinsing in sterile water or saline prior to use.
4) Physical-Hot beads: Insertion in a bed of hot beads for 10-15 seconds works well for sterilization of instruments used in performing multiple survival surgeries. However, this method only sterilizes the instrument tips. The instruments must be free of organic material prior to contacting the beads. Instruments also must be allowed to cool to avoid burning tissue. Sterilized instruments must be placed on a sterile drape to reduce the chances of contamination. A new sterile instrument pack should be used after every four to five individual rodents.

Animal preparation:

1) Animals should be prepped away from the surgical area.
2) Animals should be properly anesthetized prior to prepping. An area twice the size of the expected surgical field should be prepped.
3) Hair should be removed from the incision site with clippers or a depilatory cream. If depilatory cream is used, the skin must be rinsed well to avoid dermatitis. All loose hair and debris should be removed. Tape works well to ensure that all small, loose pieces of hair are removed.
4) An ophthalmic ointment should be applied to prevent drying and damage to the cornea.
5) The skin should be cleaned with a disinfectant. A two-stage scrub, first with a cotton swab soaked in chlorhexadine or equivalent solution followed by a cotton swab soaked in isopropyl alcohol works well for preparing the surgery site. The surgical site should be cleaned from the center outwards. More than one swab should be used if necessary. The swab should not be returned to the center of the site.
6) After the skin has been prepared, the animal should be placed on a warm surface. Warming helps to reduce hypothermia and quicken the recovery time. A water circulating heating pad is very effective for this purpose. A clean drape should be placed between the animal and the heating pad. A heat lamp directed on the animal also is useful. Close monitoring is essential to ensure that the animal will not sustain a thermal injury from the heating pad and heat lamp.
7) The animal should be draped with sterile covering. For small rodents, sterile gauze pads can be used.

Preparation of the Surgeon:

Persons performing rodent surgery should have appropriate training to avoid complications. Good surgical technique requires asepsis, gentle tissue handling, minimal dissection of tissue, appropriate use of instruments, effective hemostasis and correct use of suture material. The surgeon should scrub hands and arms with a disinfectant soap and don a mask, gown and sterilized gloves.

Postoperative Care:

Animals should be kept warm and dry to prevent hypothermia until they are fully recovered. Animals can be wrapped in a small piece of cloth or gauze square and placed under a heat source to speed recovery. Monitoring the animal=s recovery from anesthesia (breathing pattern, mobility, etc.) and signs of seepage or bleeding from the incision site is strongly encouraged. Animals may be reluctant to reach up to drink after surgery, so moistening normal food and placing it on the cage bottom will ensure access to food and water. Surgical clips should normally be removed within 7-10 days.

Changes in Procedure:

The Guide for the Care and Use of Laboratory Animals states "Some characteristics of common laboratory-rodent surgery, smaller incision sites, fewer people in the surgical team, manipulation of multiple animals at one sitting and briefer procedures, as opposed to surgery in larger species, can make modifications in standard aseptic techniques necessary or desirable." Such changes should be made in a manner that will not compromise the well-being of the operated animals and must be reviewed and approved by the Yale Animal Care and Use Committee.

Record keeping:

The surgeon should keep a logbook with the following information:

1) Date of surgery
2) Animal identification
3) Type of procedure
4) Type of anesthetic including dose and route
5) Type of analgesic, if given, including dose and route
6) Type of antibiotic, if given, including dose and route (note: hamsters and guinea pigs are intolerant of many antibiotics)
7) Postoperative monitoring (time, observations, etc.)
8) Complications
9) IACUC approved protocol number
10) The cage card should also indicate the date of surgery and procedure performed.


(available though YARC, #5-4722 or VCS, #5-2501)

- National Research Council (1996), Guide for the Care and Use of Laboratory Animals Chapter 3 Surgery; Chapter 4 Facilities for Aseptic Surgery
- Cunliffe-Beamer, T. (1993) Applying Principles of Aseptic Surgery to Rodents
- Borkowski, Gary, DVM, (1995) Basics of Aseptic Surgery and Anesthesia in Rodents (video)

Questions or comments about these policies and guidelines should be addressed to the Veterinary Clinical Services at 785-2501.

Prepared by: Margaret Borelli, Susan Morgenstern, Dr. James Macy, Veterinary Clinical Services, Section of Comparative Medicine; Randi Prete, Lynn Pantages-Torok, Regulatory and Safety Services, Yale Animal Resources Center.

Original: September 19, 1997 Revised with Approval: April 1, 1998, March 30, 1999

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Last Modified: November 19, 2003

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