Anesthesia and Postoperative Pain Control

Abstract

Fractures in the elderly are common. There is frequent need for surgical intervention. Anesthesiologists can safely use a variety of techniques to assist the orthopedic surgeon and help provide the kind of postoperative pain relief that is necessary for patients to recover successfully. General anesthesia, systemic analgesics, and regional techniques for operative anesthesia or postoperative pain relief all represent important tools in the total process, from injury to rehabilitation. As a discipline, anesthesiology has been slow to embrace the idea of specialized geriatric care. The American Society of Anesthesiologists (ASA) and The Society for the Advancement of Geriatric Anesthesia (SAGA) have made progress in correcting that deficiency. There is a notable lack of evidence upon which to base anesthetic practices. Except for clear guidelines about neuraxial blockade when patients are anticoagulated, we are left to propose plans that draw on our knowledge of anesthesia broadly, interpreting it with what we know about physiologic changes that occur with aging. If we knew how anesthesia worked in the brain, and what its possible toxic effects on tissues were, it would be easier to posit explanations and justifications for what is best for geriatric patients. What we do know is that older patients have decreased functional reserve in nearly all organ systems. They are more fragile than younger patients. However, age alone is not a significant risk factor for general anesthesia but the higher incidence of co-morbidities is, especially those that affect the most vital organs. Polypharmacy also is an issue. The nature of orthopedic injuries is such that the surgeon typically needs to intervene sooner rather than later. This can leave little time for extensive preoperative evaluation, so investigations should focus on functional status. In situations where further workup might alter anesthetic plans, and these are rare, the quickest and least invasive testing should be utilized. Routine tests have little value except when targeted at specific conditions or when needed for a baseline set of values; they rarely influence anesthetic management. All general anesthetics are cardiac depressants, contribute negatively to gas exchange in the lungs, and affect the brain in undefined ways. The liver and the kidney play a critical role in the clearance of intravenous anesthetic drugs and systemic analgesics that frequently have unpredictable distribution and protein binding because of changing body composition, often accompanied by poor nutritional status in elderly people. To avoid the need for general anesthesia some practitioners use regional techniques, although "casual empiricism" indicates that training programs have focused less and less on these methods in the past 15 years. Even with regional anesthesia, many patients will require sedation and get exposed to anesthetic drugs anyway. Some practitioners combine regional techniques with general anesthesia to avoid deep levels and to provide pain relief in the postoperative period. All practitioners should expect perioperative cardiovascular and neurologic instability to which older patients are predisposed. Interestingly, neither hypotension nor hypoxemia independently seems to cause adverse outcomes. No investigations have demonstrated that regional anesthesia is superior to general anesthesia for surgery, for postoperative analgesia, or for preventing postoperative cognitive dysfunction (POCD). Anesthesia providers should provide care with which they are familiar. Good postoperative analgesia plays a prominent role in reaching rehabilitative milestones; inadequate analgesia is a risk factor for the development of POCD. There are scant, but emerging, data to indicate that a "multimodal" approach to postoperative analgesia positively influences long-term recovery. However, this enthusiasm should be tempered by the fact that good systemic analgesia may do the same in most circumstances; many modalities and medications are available. The fundamental principles of good pain relief revolve around frequent and adequate assessment in an attempt to provide baseline analgesia plus the means by which to treat incident pain associated with activity. The realities of the operating room, the time constraints surrounding surgical correction of orthopedic injuries, the skill sets of the involved practitioners, all dictate that decisions about perioperative care of geriatric patients should be made cooperatively, always taking into account patient preferences. The rule for the anesthesiologist in the operating room is to do what we do best take things slowly, know our limits, and be vigilant. One hopes that recent efforts to promote geriatric anesthesia enjoy success.