Rodent Anesthesia and Survival Surgery Policy

IACUC Policy: 025-09, Effective Date: 08/06/2001, Last Revision: 05/17/2024

Overview/Purpose

Animals may be placed under anesthesia for a variety of reasons including performance of procedures, survival surgery, or imaging. Animals must be properly managed during the anesthetic event and recovery period to ensure return to normal physiologic status.

Survival surgeries in rodents must be completed using the basic rules of asepsis, gentle tissue handling, and proper post-operative care in accordance with applicable governmental regulations. Researchers performing surgical procedures must have appropriate training to ensure appropriate surgical technique is utilized. All investigators, laboratories, and facilities performing survival surgery on rodent species must adhere to the minimum standards addressed in this policy.

Definitions

• Surgery: animal manipulation specifically involving the creation of an incision through the skin.
• Major survival surgery: penetrates and exposes a body cavity, produces substantial impairment of physical or physiologic functions, or involves extensive tissue dissections or transection.
• Non-survival surgery: a surgical procedure in which the animal is euthanized prior to recovery from anesthesia during the event.

Requirements

Training

Research personnel conducting surgical procedures must have appropriate training in anesthesia, aseptic technique, surgical technique, post-operative care and associated documentation prior to conducting surgery. Lab animal and technique training is available at no charge.

Anesthesia

Anesthetic selection is evaluated during the Institutional Animal Care and Use Committee (IACUC) protocol approval process and additional veterinary consultation is available at all times. Monitoring of the animal’s condition and assessment of anesthetic depth must occur at regular intervals throughout the procedure.

Analgesia

Analgesia must be provided to animals that are likely to experience post-operative pain. Investigators are responsible to ensure that their IACUC-approved analgesic plan is followed and that any exceptions to the use of analgesics is described in the approved IACUC protocol. The IACUC has approved the use of extended-release formulations (Buprenorphine-ER or Ethiqa XR) in lieu of standard buprenorphine as outlined in the Rodent Anesthesia and Analgesia Guideline without submission of an IACUC amendment.

Surgery Location

Rodent surgery may be conducted in a space designated for surgery at the time of use. Preferably the space should be isolated from personnel traffic, be free of overhead storage, be disinfected prior to use for surgery, and used for no other purpose during the time of surgery.

Aseptic Technique 

Aseptic techniques must be followed for all survival surgeries. All surgical equipment, instruments, and supplies that will contact the surgical site must be sterilized before use and must be maintained on a sterile surface during surgery i.e. drape or tray. The surgeon must wear a surgical face mask and a clean surgical gown/scrub top/lab coat for all rodent surgeries. Sterile or properly disinfected gloves must be used. Hair/fur must be removed and the surgical site prepared aseptically using acceptable veterinary practices (e.g. scrubbed three times with a skin disinfectant, such as chlorohexidine or iodophors, alternating each disinfectant scrub with a scrub of sterile water or 70% isopropyl alcohol). Patient preparation (fur removal) should take place at a site other than the location in which the surgery will be performed. 

• If hands contact a non-sterile object, gloves must be changed or properly disinfected.
• If whole instruments are placed on a non-sterile surface or dropped on the ground, they must be replaced with an individually sterilized instrument or an instrument from a new surgery pack.
• If only the instrument tips contact a non-sterile surface, a new sterile pack of instruments must be opened or alternatively, instrument tips must be wiped clean of blood and/or tissue using sterile supplies (wipes and water/saline must be sterile)  and placed in a hot bead sterilizer for 10-20 seconds (at 240-270 °C).
• Batch Rodent Survival Surgeries: For multiple surgeries occurring on the same day, instruments may be used for up to five animals within the same cohort as the sterility of the instruments is maintained. Instrument tips must be wiped clean of blood and/or tissue using sterile supplies (wipes and water/saline must be sterile) and either placed in a hot bead sterilizer or soaked in 70% alcohol for 2 minutes between surgeries. Refer to the Disinfectant and Sterilization Methods Veterinary Guideline for specific details regarding required contact time and other options. Gloves must be changed or properly disinfected between animals or if torn. 

For additional details regarding aseptic technique refer to the Rodent Survival Surgery Veterinary Guideline. For non-survival surgeries, following aseptic technique is not required. However, the surgeon must wear clean gloves, a clean gown or lab coat and use clean instruments.

Anesthetic Recovery/Post-Operative Care

Animals recovering from anesthesia must be monitored by study personnel and provided supportive care until they are fully mobile within the cage. Hypothermia is a major cause of post-operative death in rodents and can be avoided by providing a heat source during the procedure and post-operative period. Following anesthetic recovery, post-operative animals must be monitored by study team members daily for 5 days following surgery then as needed until surgical wounds have healed or as described in the IACUC protocol. Non-absorbable skin sutures and wound clips must be removed between 10-14 days post-operatively.

Surgical Record Keeping

Investigators must maintain accurate records of surgery with the animals including the procedure/date/individual performing surgery, analgesia provided (when applicable), post-operative checks, and the date of suture/wound clip removal if applicable. It must be clear which animals records apply to. Records must be available during the semiannual IACUC inspection.  

A Surgery/Post-op Record must be maintained at the cage level when animals are housed in ULAR and can be used as the formal surgical record for these cases. These cards are available within the animal housing room and must remain on the cage until wounds have healed and/or sutures/wound clips have been removed. Refer to User Guidance on Cage Level Rodent Survival Surgery: Post-operative Monitoring Cards for further guidance and examples of completed cards. 

Multiple Major Surgery: Multiple major survival surgery on a single animal must be clearly described in the animal protocol and approved by IACUC. Scientific justification must be provided.

References

• Keen JN, Austin M, Huang L, Messing S, Wyatt JD. Efficacy of Soaking in 70% Isopropyl Alcohol on Aerobic Bacterial Decontamination of Surgical Instruments and Gloves for Serial Mouse Laparotomies. JAALAS 49(6) p. 832 – 837. 2010
• LeMoine DM, Bergdall VK, Freed C. Performance analysis of exam gloves used for aseptic rodent surgery. JAALAS 54(3):311-6. 2015
• Animal Care and Use Policies and Guidelines 
  • Disinfectant and Sterilization Methods
  • Rodent Anesthesia and Analgesia Guideline
  • Rodent Survival Surgery
  • User Guidance on Cage Level Rodent Survival Surgery: Post-Operative Monitoring Cards
  • Administered Extended Release (ER) Buprenorphine