Please note that the following is for rodent surgery. For other species, training from a user with expertise must be obtained prior to undertaking a procedure
Non-survival surgery is surgery in which the animal is euthanized while under anesthesia, and does not regain consciousness. Sterile technique is not generally required, however, the surgeon should still wear gloves, the surgical site should be clipped and the instruments and work area should be clean.
Survival surgery is surgery in which the anesthetized animal is revived following the procedure. Survival surgery on rodents requires aseptic techniques to reduce microbial contamination to the lowest possible and practical levels. Infections due to the lack of aseptic surgical techniques are often sub clinical in rodents but can nevertheless have adverse physiological effects, impacting upon the quality of the research.
Requirements for Aseptic Rodent Surgery
1. Surgical Area
-
Surgery must be performed in a (preferly dedicated) area that is maintained clean. If performed in a regular laboratory, surgery must be done in an isolated area of the laboratory, away from the flow of traffic and where contamination from other activities in the lab is minimized.
-
The work surface must be thoroughly cleaned with an approved hard surface disinfectant (e.g. Clidox®, 10% sodium hypochlorite, 70% alcohol) prior to and after each procedure.
-
The work surface may be covered by a disposable pad.
2. Preparation of the surgical instruments
-
Instruments must be sterilized. Sterilization methods include steam, ethylene oxide, chemical sterilants and dry heat. For a small number of instruments a glass bead sterilizer can be used
-
A new instrument kit must be used for each animal or the same kit needs to be sanitized in between animals to offer each one the same quality of care and experimental conditions. This may be done by using a dry bead sterilizer for 7-8 seconds or by liquid sterilization for about 5-10 minutes followed by careful rinse with alcohol.
3. Preparation of the animal
-
Rats and mice are not usually water or food deprived prior to surgery due to their inability to vomit and high metabolic rates. If fasting is required, mice and other similar sized rodents with high metabolic rates should not be fasted for greater than three to four hours.
-
Guinea pigs must be fasted 2-4 hours prior to anesthesia to reduce the volume of gastric contents. Do not withhold water.
-
As rodents are prone to hypothermia during anesthesia, this should be minimized, as it will delay recovery from anesthesia.
-
The animal must be anesthetized (UACC SOP for Anesthesia for specific species) and at an appropriate depth of anesthesia prior to commencement. Signs that indicate a surgical plane of anesthesia include a lack of response to a toe pinch and respirations that are relaxed and regular. Note: Toe pinch reflex should not be used as an indicator of depth of anesthesia in Guinea Pigs.
-
In an area separate from the surgical area, remove the hair for at least 1 cm around the surgical site. Hair can be removed by shaving with a razor, clipping with a #40 blade, plucking a small area in an anaesthetized animal or using a depilatory cream. A vacuum and / or adhesive tape can then be used to minimize loose hairs in the proximity of the surgical site.
-
Place the animal on a circulating hot water blanket that is set on “low” or use gloves filled with warm water placed alongside the animal to minimize hypothermia. Avoid causing thermal injury. A sterile drape placed over the animal will help reduce heat loss and contamination of the surgical site and provides a sterile surface on which to rest surgical instruments and also exteriorized organs.
-
A sterile ophthalmic lubricating ointment is applied to the eyes to prevent corneal drying.
-
As a precaution against dehydration and to help maintain a normal blood pressure, saline can be administered either sub-cutaneously or intra-peritoneally at a dose from 0.2 to 0.5mL/10g body weight of isotonic fluids. The saline should be warmed to about 37 degrees Celsius in order to avoid contributing to hypothermia.
4. Preparation of the surgeon
-
Apparel: Surgical cap (optional), surgical mask, surgical gloves (e.g. sterile latex or latex or nitrile gloves wetted with 70% isopropyl alcohol prior to use) and a clean, designated lab coat or scrub suit must be worn.
-
Hands must be washed thoroughly with an approved surgical scrub solution (e.g. chlorhexidine, povidone iodine) prior to donning gloves.
-
If non-sterile gloves are used, the surgeon should avoid glove contact with the surgical site.
5. Preparation of the surgical site
-
The site must first be cleaned with an approved surgical scrub solution (e.g. chlorhexidine, povidone iodine) in a gradually enlarging circular pattern away from the proposed incision site, avoiding contamination from the periphery to the clean, central area.
-
The skin is rinsed with sterile warm water or 70% alcohol, and the surgical scrub procedure repeated again using a fresh swab or gauze. Avoid wetting the animal’s fur unnecessarily as this will contribute to hypothermia.
6. Intra-operative monitoring
-
An intraoperative record outlining physiologic parameters such as drugs, dosages, routes of administration and all intraoperative complications must be completed and maintained for each animal.
-
The depth of anesthesia and analgesia must be monitored regularly, at least every 10 minutes during the procedure, by checking the following parameters: regular and relaxed respiratory rate, absent withdrawal reflex upon foot pinch, no response to external stimuli. Ensure anesthesia remains deep enough for the suturing step.
-
For painful procedures the first dose of analgesic can be administered prior to the animal regaining consciousness. Pre-emptive analgesia can help to decrease the degree of discomfort/ pain the animal experiences post operatively.
7. Post-operative care
- A post operative record outlining all therapies, complications and interventions must be completed and maintained for each animal for a period of no less that one week post operatively, or until the animal returns to complete normalcy in terms of both behavior and appearance.For the recovery period, place the animal in a warm, draft free cage that is placed on a warming pad, or under a strategically located heat lamp. The animal must be able to move away from the heat source in order to prevent thermal injury.
- For the recovery period, place the animal in a warm, draft free cage that is placed on a warming pad, or under a strategically located heat lamp. The animal must be able to move away from the heat source in order to prevent thermal injury.
- Provide post-operative analgesia as appropriate and preferably prior to the onset of pain symptoms (UACC SOP # 3 Laboratory Animal Analgesia). Investigators should consult with a veterinarian to set up an analgesic regime for ALL species of animals used. It is the responsibility of the investigator to make sure that the necessary staff is available to administer analgesics as prescribed.
- A sterile, warm solution of physiologic saline can be administered subcutaneously or intra-peritoneally at a dose from 0.2 to 0.5mL/10g body weight of isotonic fluids if it has been more than 1 hour since the pre-operative fluids.
- If blood loss occurred during surgery or if an animal is slow to recover from anesthesia, provide additional warm fluids.
- The animal must be monitored carefully at a minimum of 15 minute intervals until it is sternal (able to roll onto its stomach and remain upright)) and conscious. In order to prevent cannibalism or suffocation from its cage mates, the animal should not be returned to its home cage until it is fully ambulatory.
- Monitor the animal's basic biologic functions (food & water intake, urination, defecation, body weight gain) as well as clinical signs of distress (piloerection, reduced locomotion, hypothermia) twice daily for at least the first week following surgery, and daily thereafter once the animal returns to complete normalcy in terms of both behavior and appearance. The person responsible for monitoring the animals is responsible for being familiar with the animal's normal behaviour and posture so as to be able to detect differences which may indicate the animal is in pain.
- Monitor the surgical site for signs of inflammation (redness, warmth, swelling, pain, reduced function) and infection (purulent discharge, unusual smell) twice daily for at least the first week following surgery, and daily thereafter once the animal returns to complete normalcy in terms of both behavior and appearance.
- Skin sutures, wound clips and staples must be removed 7-10 days following surgery.
End of the Advanced Level course material.
If you do NOT need any of the Wildlife courses and you are ready to take the test, contact the animalcare [at] mcgill.ca (subject: TEST%20request) (Training Advisor) (the test is requested, received and submitted by email).
Please note that EACH participant must make the request using his/her own email account. The participant must identify in which investigator’s lab they are working or the course title for which this test is a requirement (if applicable).