Policy On Analgesia in Animals Undergoing Surgery
This policy has been created to minimize pain and distress to animals undergoing surgical procedures for research, teaching and testing by providing the minimum analgesic duration that is acceptable for various surgical procedures.
The USDA Animal Welfare Act Regulations require procedures to “be performed with appropriate sedatives, analgesics or anesthetics, unless withholding such agents is justified for scientific reasons, in writing, by the principal investigator and will continue only for the necessary period of time1”, but the assessment of pain and distress in animals is difficult and can be subjective. As such, and according to the U.S. Government Principles for the Utilization and Care of Vertebrate Animals Used in Testing, Research, and Training, “unless the contrary is established, investigators should consider that procedures that cause pain or distress in human beings may cause pain or distress in other animals2.”
1 The Animal Welfare Act Regulations (9 CFR, Part 1, Subpart C)
2 Published in the Federal Register, May 20, 1985, Vol. 50, No. 97, by the Office of Science and Technology Policy [FR Doc. 85-12059]. (A PDF version can be found here: https://grants.nih.gov/grants/olaw/references/phspolicylabanimals.pdf)
This policy is applicable to all vertebrate animal activities conducted under the auspices of the University, and applies to all campus locations, including Ann Arbor, Flint, and Dearborn.
For the purpose of the Policy On Analgesia in Animals Undergoing Surgery, pre-emptive analgesia is analgesia administered before or immediately after an animal is anesthetized, but prior to initiation of a painful stimulus, such as skin incision.
A systemic analgesic is a drug that provides pain relief to the entire body.
A local anesthetic is a drug that blocks sensation from a specific area of the body, such as lidocaine or bupivacaine.
Nonsteroidal Anti-Inflammatory (NSAID)
Nonsteroidal anti-inflammatory (NSAID) drugs, e.g., carprofen, meloxicam, flunixin, ketoprofen.
A class of drugs that include natural, semisynthetic, and synthetic opioids.
- Natural opioids (i.e., opiates) include: opium and morphine
- Semisynthetic opioids include: heroine and oxycodone
- Synthetic opioids include: buprenorphine, tramadol and fentanyl
Multimodal analgesia is defined as a combination of systemic analgesics, like an NSAID and an opioid, or a combination of a systemic analgesic/s and a local anesthetic.
Surgical procedures that require withholding analgesics must be justified for scientific reasons in the IACUC approved animal use protocol.
The table below, developed by veterinarians as an assessment tool, standardizes pain relief requirements for surgical procedures based on the procedures level of invasiveness. Any surgical analgesic regimen described in the IACUC approved animal use protocol must follow, at a minimum, the expectations outlined in the table.
Additionally, depending on the nature and invasiveness of a surgical procedure, the ULAM veterinarians may require additional analgesics to be added to the protocol. If pain persists after the required analgesia is provided, or other complications arise, a ULAM veterinarian must be consulted.
Minimum Analgesic Duration Based on Surgery Invasivness
Type I Surgery
Surgical procedures that require use of preemptive analgesia, such as single dose of a systemic analgesic or the local anesthetic bupivacaine.
Though some anesthetic agents have analgesic properties, the duration of that analgesia is insufficient to treat post-operative pain.
Type II Surgery
Surgical procedures that require use of preemptive analgesia and a minimum of approximately 24 hours of postoperative analgesia.
Systemic analgesia should be used and can be combined with local anesthesia.
Type III Surgery
Surgical procedures that require use of preemptive analgesia and a minimum of approximately 48 hours of postoperative analgesia.
Multimodal analgesia is recommended.
Skin incision without deeper tissue manipulation
- Skin biopsy
- Tracheal injection
Skin incision and deeper tissue manipulation
- Subcutaneous implantation with creation of a pocket such as for a pellet, pump, or tissue
- Muscle incision
- Muscle biopsy
- Vessel cannulation
- Vessel biopsy
- Oral soft tissue manipulation
- Craniotomy with minor soft tissue manipulation and small bone defect or hole
- Laparotomy with minor flank incisions
- Laparoscopic surgeries
Any surgical procedure not included
as Type I or Type II
- Laparotomy with midline or major surgical incision
- Craniotomy with extensive soft tissue manipulation and bone defects or incisions
- Direct manipulation of a joint, nerve, or bone (including teeth)
- Ophthalmic surgery
For questions, additional detail, or to request changes to this policy, please contact the Office of the Assistant Vice President for Research, Director of the Animal Care & Use Office at firstname.lastname@example.org or (734) 763-8028.