The following guidelines, which are based on the standards set forth in the USDA Animal Welfare Act Regulations and the Guide for the Care and Use of Laboratory Animals, apply to survival surgeries performed on USDA-covered species. In addition to dogs, cats, and non-human primates, USDA-covered species currently include guinea pigs, hamsters, rabbits, and any other warm-blooded animal with the exception of mice of the genus Mus, rats of the genus Rattus, and birds. Investigators are encouraged to read the ARC Policy on Procedures Performed on USDA-Covered Species Involving the Use of General Anesthesia, which specifies the types of procedures that must be performed in a dedicated ARC-approved surgical facility (e.g., CHS 2V-124).
Investigators are responsible for ensuring that all members of their laboratory adhere strictly to the ARC-approved protocol as well as applicable ARC policies and guidelines.
Pre-operative Management and Assessment
- Preparatory steps should be taken to ensure the following:
- All personnel involved have read and understand the approved ARC protocol and are familiar with the procedures to be carried out.
- The surgical procedure will be carried out efficiently, professionally, and with adequate record-keeping (including a record of all drugs administered and the dose, time, and route of administration). Depending on the procedure, this may include dry runs, arranging for the use of specialized equipment, and verifying availability of a suitable operating room.
- The animal's health has been appropriately assessed prior to the surgery in order to minimize risk of complications during and after surgery.
- The surgeon is responsible for:
- Scheduling operating room time, determining the estimated length of the procedure, preparing necessary instruments and equipment, and arranging the anesthetic regimen to be used.
- Contacting the DLAM Covered Species Veterinarian approximately two weeks in advance of the first procedure to schedule a meeting with the veterinary and surgical staff.
- Making appropriate logistical arrangements for intra-operative and post-operative care with the designated surgical assistant (within the investigator's own group) or surgical technician as outlined in # 3 below.
- Ensuring that food is withheld from the animal for an appropriate period of time prior to the procedure. The surgeon or his/her designee should remove food and place an "N.P.O." card on the animal's cage/pen. Investigators may also make arrangements for DLAM to place the card by contacting the facility's Animal Resources Supervisor or the attending veterinarian at least one business day prior to the expected surgical date.
- Assessing the overall status of the animal prior to the surgical procedure is done by the DLAM veterinary staff, but is the responsibility of all working with the animal. This assessment should include visual inspection of the animal and assessment of the behavioral status of the animal. Previously undetected physical or behavioral abnormalities should be discussed with the DLAM veterinary staff prior to commencing surgery.
- The surgical assistant or technician is responsible for:
- Communicating with the surgeon to determine the nature of the procedure, the anticipated duration, the desired anesthetic technique, the necessary monitoring equipment and instruments, and the desired configuration of the operating room.
- Preparing all of the necessary records and informing the surgeon of any other records he/she must complete.
- Consideration should be given to having pre-operative hematology and serum chemistry tests performed prior to surgical procedures. The specific tests considered appropriate should be detailed in the protocol submitted to the ARC.
- Minor surgical procedures usually involve some anesthetic risk, and multiple minor procedures may further complicate this risk. A hematologic assessment of packed-cell volume and total plasma protein may be appropriate in such cases.
- Major surgical procedures involve some anesthetic risk, and the nature of the procedure may further complicate this risk. It may be appropriate to carry out a complete blood cell count (red and white cell parameters, platelets, etc.) plus an assessment of plasma or serum protein and kidney and liver enzymes. The need for these tests is heightened if there are induced or spontaneous medical or surgical abnormalities.
- Surgical preparation of the species, surgeon, and instruments will be as described in the ARC protocol.
- Acute (terminal) and chronic (recovery) surgical procedures that may cause more than momentary or slight pain or distress require the appropriate use of anesthetics, analgesics, and tranquilizers (AATs) as addressed in the Animal Welfare Act and the Guide for the Care and Use of Laboratory Animals, and as determined in consultation with the veterinarian during preparation of the research protocol. All surgeons are expected to be familiar with the drug treatment regimen(s) specified in the approved protocol.
- Most of the commonly used AATs can have both short-term and long-term effects on an animal's ability to maintain homeostasis. Monitoring of physiologic functions provides important indices of the animal's homeostatic state.
- Animals that are unconscious and/or intubated must not be left unattended.
- Monitoring is to be done by trained staff from DLAM or the investigator's laboratory.
- Heart rate must be monitored continuously by ECG, blood pressure monitor, or pulse oximetry. The heart rate must be recorded every 15 minutes.
- Mucous membrane color and capillary refill time may be monitored periodically to help assess cardiac output and oxygen saturation.
- Blood pressure monitoring (by direct or indirect methods) should be considered for major surgical procedures lasting more than 2 hours. Mean blood pressure should be maintained at a species-appropriate level in order to maintain organ function.
- Hypotension may occur due to anesthetic agents, blood loss, and evaporative water loss of exposed tissues or expired gases. Blood pressure should be maintained through the use of appropriate intravenous fluid therapy, generally 5-15 ml/kg/hr IV of crystalloids. If this is inadequate to maintain blood pressure, additional agents such as crystalloid boluses, colloids, and vasoconstrictors may be needed. These should be guided by a DLAM veterinarian if not described in the ARC-approved protocol.
- If the animal is intubated, auscultation of the chest should be done to assure adequate placement of the endotracheal tube. Airflow should be audible in all lung fields.
- Pulmonary function must be monitored. This can be done via continuous capnography and/or pulse oximetry, observation of the respiratory rate, or auscultation. The pulmonary function should be recorded at least every 15 minutes.
- Pulse oximetry and capnography are required for all major surgical procedures in non-rodent species.
- Blood gas monitoring and recording should be considered for major surgical procedures lasting more than 3 hours.
- Mucous membrane color can be used to assess overall ability to oxygenate, but is not a very sensitive measure.
- Body temperatures should be monitored by digital or conventional rectal thermometers or by electronic temperature probes placed in the rectum or esophagus. The temperature should be checked and recorded at least every 15 minutes.
- Core body temperature should be maintained with circulating water blankets, heated surgical tables, warmed intravenous fluid therapy, or other appropriate methods.
- Anesthetic depth
The animal's anesthetic depth should be monitored throughout the surgical procedure. Depending on the species, this can be done by observing responses to manipulation, jaw tone, abdominal muscle relaxation, toe pinch, palpebral reflexes and position of the eye. In an appropriately anesthetized animal, there should be no response to any manipulation, and the animal's jaw tone should be slack. In most animals, the abdominal muscles will be relaxed; however, in a well-muscled animal such as most pigs, this may not be the case. After pinching the toe of an adequately anesthetized animal, the animal should not withdraw its leg or otherwise respond. Touching the medial canthus of the eyelids should elicit no flickering of the lids or other response. In most dogs and cats, the eyeballs rotate ventromedially (forward and downward) when in an appropriate plane of anesthesia, but then return to a central position as anesthetic overdose occurs. However, this is not a reliable sign in all individuals, and it is not reliable in most species other than dogs and cats.
Post-operative Care and Monitoring
- Adequate post-operative care enhances the animal's recovery, minimizes pain and distress, and is a requirement of both professional and regulatory federal agencies. Adequate post-operative care includes monitoring and documenting the animal's recovery during the anesthetic recovery period, the acute post-operative period, and the long-term post-operative period.
- Post-operative care must be arranged by the Principal Investigator in consultation with the Attending Veterinarian. In some cases, surgical staff may perform part of the post-operative care. The Attending Veterinarian has appropriate authority to ensure provision of adequate veterinary care during all phases of the post-operative period. Communication between the Principal Investigator's staff and the DLAM veterinary staff is crucial.
- Animals that are unconscious or intubated must not be left unattended.
- Endotracheal tubes should not be removed until an animal has regained a swallow reflex. Animals must be monitored using a continuous monitoring device until they are conscious, sternal when lying down and able to ambulate (walk).
- All animals must be given analgesics unless scientific justification for withholding such agents is provided by the investigator and approved by the ARC. Analgesics must be given such that these agents become effective before the animal emerges from anesthesia. Therefore, analgesia must be administered before surgery and re-dosed as needed during the procedure.
- The animal's status must be recorded in the animal's post-operative chart every 15 minutes. The following parameters should be monitored and recorded at least every 15 minutes during the anesthetic recovery period:
- Respiratory rate, as assessed by observation, auscultation, capnography or other appropriate method. Any abnormal or deviant pattern or respiration should also be noted.
- Heart rate, as assessed by auscultation, palpation, ECG, pulse oximetry or other appropriate method.
- Temperature until normal.
- It is the responsibility of the investigator to arrange for appropriate monitoring during the anesthetic recovery phase, either by a member of the investigator's laboratory or the surgery room staff.
- During the anesthetic recovery period, the animal's core body temperature should be monitored (e.g., as described under Intraoperative Monitoring, 5. Temperature) and maintained in a normal range using circulating warm water blankets or warm water bottles. The core body temperature of most species is greater than the core body temperature of human beings.
- To avoid aspiration pneumonia, airway obstruction, pulmonary edema, tissue necrosis or edema at pressure points, a recumbent animal's position should be adjusted every 15 minutes. In addition, capillary refill time, mucous membrane color, condition of the wound, and anesthetic plane of the animal should be monitored.
Acute Post-operative Period
- The acute post-operative period is that period when the animal regains stable physiologic functions, usually over 24-48 hours. Monitoring during this time is usually done 2-3 times daily depending on the type of surgical procedure and the condition of the animal. The Principal Investigator's staff will monitor and record the post-operative condition of these animals at least once daily. A DLAM veterinarian or veterinary technician will also check these animals at least once daily.
- The acute post-operative period may require further treatments to stabilize the animal, such as fluid therapy, analgesics, antibiotics, and more intensive monitoring. Analgesia is required in all animals, excluding those in Pain Category E, as described in the ARC Policy on Post-operative Analgesia.
- Appropriate parameters for monitoring animal recovery during the acute post-operative phase should be determined in consultation with the veterinarian. Depending on the species, parameters that may be monitored during this time include: respiratory rate and character; mucous membrane color; capillary refill time; hydration status; appetite; condition of the surgical wound; state of arousal; heart rate; core body temperature; indices of pain or discomfort.
- Post-operative treatments (analgesics, antibiotics, fluid therapy, etc.) should be administered to the animal according to the Principal Investigator's research protocol, or as determined by the DLAM veterinary staff in consultation with the Principal Investigator during the veterinary pre-review. This should be done by the Principal Investigator's staff, but arrangements may be made in advance to have this done for a fee by the DLAM veterinary staff. All medications, including name, dose, route, and time of administration, must be recorded in the animal's post-operative record.
Long-Term Post-operative Period
- The long-term post-operative period is from the time of physiologic stabilization to normalization. This usually takes a minimum of 10 days for the animal to totally recover from most survival surgical procedures. Daily monitoring should continue during this time. Parameters that should be monitored/recorded during this time include: state of arousal; indices of pain or discomfort; condition of the surgical wound; appetite; hydration status; capillary refill time; mucous membrane color; fecal and urine production; and any medication administered.
- At the end of the long-term post-operative period (e.g., 10-14 days), all non-absorbable sutures or staples should be removed and the animal's post-operative record should be closed. The record is then to be submitted to DLAM (records should be placed in the "Clinic" mail box in CHS 1V-211).
- Some surgical manipulations may require an extended period of post-operative monitoring. The appropriate duration and extent of monitoring can be determined by the DLAM veterinary staff in consultation with the Principal Investigator. Some situations that may constitute prolonged monitoring periods are animals with chronic debilitating disease states (e.g., diabetes mellitus), animals having organ transplantation or immunosuppressive therapy, and animals with chronically implanted instruments or catheters.
Approved 6/9/03; Updated 9/24/04, 9/26/06, 7/27/09, 9/23/13, 12/2/13