Acute Pain: Pathophysiology and Clinical Implications

Progress in postoperative pain management decreases morbidity after surgery. To advance patient care, reduce perioperative morbidity, and decrease healthcare costs, it is critical that we improve acute postoperative pain management. Our armamentarium of drugs for acute pain management has been limited to opioids, controlled delivery of local anesthetics, and nonsteroidal antiinflammatory drugs or acetaminophen. For acute pain management, we operate using guidelines from the early 1990s that reinforced the generous use of opioids for acute pain even though effective dosing is limited by deleterious side effects. Anesthesia-based acute pain services popularized continuous epidural analgesia, which controls pain better during activities and continuous regional techniques for specific surgeries. If the 1990s assured us opioids should be used with confidence, the last 5 years has demanded efficacious alternatives to opioids with fewer side effects and, perhaps, improved outcome. This is in contrast to patients with rheumatoid arthritis who may be treated with drugs that block the action of inflammatory mediators such as tumor necrosis factor or interleukin-1 (IL-1). With increasing new knowledge and techniques come important opportunities and challenges for developing insights into the causes, mechanisms, and treatment of human disease. For anesthesiologists, we have an opportunity to treat surgery and trauma as a disease, and this requires investigation into the pathological processes that occur in the perioperative period. One component of the pathophysiology in surgery is acute postoperative pain. Our long-term goal will be to eliminate postoperative pain. This will require that we develop a better understanding of the mechanisms for surgical pain and prepare to use recent discoveries in biomedical research.