Pain management: a key component of anesthesia
A guest blog by Jacob A. Johnson, DVM, DACVAA
It’s difficult to have a conversation about anesthesia without including pain management. The concept is so integrated, that the specialty college changed its name in 2012 to the current nomenclature of American College of Anesthesia AND Analgesia (ACVAA). It’s vital to have a pain management plan for any general anesthesia episode where the patient will be exposed to nociceptive stimulation.
The recognition that animals feel pain and that we, as veterinarians, have an obligation to relieve animal suffering through the use of pain management is unfortunately a relatively new revelation. Even more recent is the recognition that even animals under anesthesia can experience pain and that providing analgesia before, during and after a surgical procedure provides for a safer and smoother experience for the animal, the veterinarian, the veterinary staff and the client.
One of the four goals of general anesthesia (along with unconsciousness, loss of movement and homeostasis) is to reduce or eliminate nociceptive input. Patients that are not provided preventive analgesia tend to experience wide fluctuations in their physiologic parameters during anesthesia, making them a challenge to keep stable, making it stressful for the person responsible for managing anesthesia. These changes in heart rate, respiratory rate and/or blood pressure often lead to higher than necessary requirements for inhalant anesthetics, which can cause cardiovascular and respiratory depression.
Practitioners have many different classes of drugs and/or techniques to provide analgesia, and because of the complexity of the pain pathway, a multimodal approach is beneficial. NSAIDs are superior to other classes in managing inflammatory pain, making them instrumental in the post-operative period. Systemic analgesics, such as opioids and alpha-2 agonists, are key in managing acute incisional pain that occurs during the procedure. Local and regional anesthetic techniques using drugs such as lidocaine and bupivacaine can completely block nociceptive input reducing the dependency and potential side effects of systemically administered drugs. The accuracy and application of regional anesthesia has been enhanced recently through technology such as electrical nerve stimulator guided and ultrasound guided blocks.
Practicing preventive analgesia smooths out the recovery period and improves patient welfare. Patients that wake up painful are predisposed to rough recoveries, demonstrated by vocalization, averse behavior and increases in physical parameters such as heart rate and blood pressure. A major mortality study conducted in the United Kingdom demonstrated that the majority of anesthetic related deaths in small animal occur in recovery and that animals scored as having a rough recovery were 27 to 54 times more likely to die. Preventive analgesia contributes to reducing this risk to patients.
Clients appreciate that their pet is provided appropriate pain management, so it is important to include this information in one’s client communication strategy. Because the drugs and techniques used for our patients are identical to those used in human medicine, clients can often relate with similar surgical experiences in their own lives. After discharge, clients appreciate that their pet is comfortable at home and able to return to normal activity sooner because of the application of appropriate pain management.