INTRODUCTION AND DEFINITION OF ELDERLY
Healthcare providers have become increasingly focused on providing effective management of acute perioperative pain in all patients, but especially older adults, as the size of this patient population has steadily increased in recent years.(1) Advances in anesthetic and surgical techniques, an improved understanding of the pathophysiology of pain, the development of new opioid and nonopioid analgesic drugs, the incorporation of regional techniques that reduce or eliminate reliance on traditional opioid analgesics, and novel methods of drug delivery have all led to greater numbers of older patients undergoing major surgery.(2,3) An increased prevalence of chronic medical conditions among older individuals may also lead to higher degrees of acute and chronic pain (including acute-on-chronic pain). For instance, acute exacerbations of arthritis, osteoporotic fractures of the spine, cancer pain, and pain from acute medical conditions (eg, ischemic heart disease, herpes zoster, peripheral vascular disease) must be properly addressed in order to maximize multimodal perioperative pain management.(4) In addition, older individuals are adopting more active lifestyles that can predispose them to trauma and orthopedic injuries that require surgery.
The term elderly encompasses both chronologic and physiologic factors. Chronologic age is the actual number of years an individual has lived, whereas physiologic age refers to functional capacity or reserve within organ systems defined in pathophysiologic parameters. The chronologic component can be divided into two separate groups: the “young old” (65 to 80 years of age) and the “older old” (greater than 80 years of age).(5) Physiologic reserve describes the functional capacity of organ systems to compensate for acute stress and traumatic derangements. When present, comorbid disease states such as diabetes mellitus, arthritis, renal insufficiency, ischemic heart disease, and chronic obstructive pulmonary disease (COPD) can all decrease a patient’s physiologic reserve making it difficult for him or her to recover from traumatic or surgical injury.
There are a host of additional factors that may compromise the ability to provide optimal and effective acute pain management to older patients. A consequence of the comorbid diseases that afflict this patient population with increased frequency is the medications used in treatments for such diseased conditions, along with a subsequent increased risk of drug-to-drug and disease-to-drug interactions. An improved understanding of age-related changes in physiology, pharmacodynamics, and pharmacokinetics must be incorporated into any acute pain medicine care plan for older individuals. Altered responses to pain among the elderly population along with difficulties in pain assessment for certain individuals with cognitive dysfunction are potential problems that must also be considered.
Several theories have been advocated to describe the multi-dimensional aspects and consequences of aging that underscore the complexities and difficulties encountered in developing optimal regional anesthetic and analgesic choices for elderly patients. Therefore, the focus of this chapter is to outline the physiologic and pharmacologic implications of aging on surgical anesthesia and acute pain management, as well as the potential risks and benefits of neuraxial blockade along with peripheral nerve/nerve plexus blockade in geriatric patients.