The number of individuals aged 65 years or older in the United States has grown rapidly since 2010. In particular, the 65-and-older population grew by over a third during the past decade.1 With the graying of the nation's population, the number of older patients presenting for surgery also increases. During the preoperative evaluation for this patient population, anesthesiologists are often concerned about the multiple comorbidities that frequently exist in older patients and their impact on perioperative care. A number of underlying conditions raise concerns regarding management during anesthesia and surgery, particularly cardiovascular or pulmonary conditions. However, recent advances in anesthesia, medicine, and surgery have rendered the incidence of perioperative cardiac adverse events to a relatively low level, to less than 3% in unselected patients undergoing non-cardiac surgery.2,3 Similarly, perioperative stroke rate is also infrequent, occurring at less than 3% in non-cardiac and non-carotid surgical patients.4 In contrast, cognitive problems are common in this subset of the surgical patient population. The incidence of postoperative delirium is prevalent in older hospitalized adults, particularly after surgery, affecting 10%-60% of patients.5 Delirium is an acute confusional state defined by alterations in attention, consciousness, and disorganized thinking.5,6 Delirium has been shown to be associated with decreased long-term physical and cognitive functioning.7,8 One of the most important independent risk predictors for postoperative delirium is preoperative cognitive impairment.9 Despite this important risk factor, few perioperative providers assess preoperative cognitive function before surgery. As the number of older patients requiring surgery is expected to increase over the next decade, the preoperative assessment must be expanded to include neurocognitive function and other potential deficits that impact perioperative management and patient outcomes.
Preoperative cognitive screen
Preoperative cognitive impairment is associated with the development of postoperative delirium, an observation seen in numerous prior studies.10 Given the prevalence of postoperative delirium in older surgical patients and its prognostic significance, the focus of preoperative evaluation of older adults should include not only evaluation of the cardiac and pulmonary status, but also the cognitive status of the individuals. As evident in popular press, the claim that postoperative delirium's toll on mental function may linger certainly sensationalizes this syndrome and adds weight to patients' complaints that the “altered memory and thinking after surgery” is a direct result of medical error or substandard care. Accordingly, as perioperative physicians, we should strongly advocate for including preoperative cognitive screen status as the sixth vital sign, so we have a more objective estimate of the baseline cognitive functioning of older adults awaiting surgery.
Based on this background, screening for cognitive impairment should become a routine part of the preoperative evaluation for older patients to risk stratify and to assign at-risk patients into the appropriate perioperative pathway for delirium reduction. Historically, the assessment was time-consuming, so the implementation of a preoperative cognitive screen is hampered by limited clinical time and resources. In a prior review, we identified six screening tools that can be administered in 2.5 minutes or less.11 While helpful, it should be noted that cognitive impairment detected by these tools is not diagnostic for dementia or mild cognitive impairment, but rather a screen only. Therefore, it would be prudent to discuss a positive screening with the patient and family to ensure referral to a primary care physician, neurologist, or psychiatrist for further evaluation before or after surgery depending on the urgency of the proposed procedure.
Modifiable factors of postoperative delirium
Given the prevalence and prognostic significance of postoperative delirium, the identification of modifiable factors and therapies used to limit its occurrence is of clinical and research importance. Of all the preventative strategies, non-pharmacologic multi-component therapy has the most positive evidence to date.12,13 In contrast, prophylactic pharmacologic therapy produced mixed results.12 Among potential intraoperative modifiable factors, whether the use of processed electroencephalogram (EEG)-guided anesthesia can reduce delirium has gained recent widespread interest. Despite early evidence from some randomized controlled trials suggesting there may be a lower incidence of postoperative delirium with processed EEG-monitored care,14-17 a more recent large trial demonstrated the lack of efficacy of using processed EEG in reducing postoperative delirium, despite the evidence of minimizing EEG burst suppression.18 Despite the variable evidence of value of EEG monitoring, there are ongoing trials in this area; a recent smaller study suggested that processed EEG may have efficacy in reducing postoperative delirium in certain types of surgery.19 Until more definitive larger studies are available, the clinical value of using processed EEG to reduce the occurrence of postoperative delirium through a reduction in burst suppression, particularly those with preoperative cognitive impairment, remains to be determined.20
Opioid-sparing techniques for postoperative pain management
While opioids have been the main therapy for acute pain management after major surgery, recent evidence documents that persistent opioid use after surgery represents a risk of opioid use disorder as a common postoperative complication.21 Many of the current pain management pathways advocate for the use of multi-modal therapy to minimize the need for opioids and their side effects.22 One study suggests that regional techniques targeting postoperative pain control in hip fracture patients may reduce the likelihood of postoperative delirium.23 However, a more recent Cochrane review did not confirm the decreased risk of delirium with the use of peripheral nerve blocks, although the number of participants included in the meta-analysis was small and the quality of evidence was low.24 Similarly, we conducted a large, prospective, randomized controlled trial to determine if perioperative administration of gabapentin would reduce delirium and found that although gabapentin was opioid-sparing, the rate of delirium was unchanged in the gabapentin treated group compared to the standard care group.25
While convincing data are lacking to support the hypothesis that opioid-sparing techniques lead to a reduction in postoperative delirium, there is still value to reducing or avoiding the use of postoperative opioids and considering either a regional technique either as part of the anesthetic management or administered specifically to optimize the approach to providing postoperative analgesia, thereby minimizing the need for opioids and the associated side effects.
Increasing education to anesthesia trainees and practitioners
Another critically important aspect of our practices is to understand some of the unique challenges associated with the care of the aging population. ASA has recognized the unique characteristics of this patient population and the importance of understanding the anesthetic implications. To emphasize its importance, ASA has created a “Geriatric Anesthesiology Curriculum” (asahq.org/education-and-career/clinical-resources/geriatric-curriculum). The curriculum was created through collaborative efforts of the members of the Committee on Geriatric Anesthesia and the Society for the Advancement of Geriatric Anesthesia (SAGA). While anesthesia education has focused on a disease approach curriculum, this new curriculum addresses broader topics of concern to providers caring for the geriatric patient population. This is a critically important time to formally introduce to our trainees and practicing anesthesiologists the concept of “geriatric syndromes,” which encompass those clinical conditions in older persons that do not fit neatly into discrete disease categories, such as postoperative delirium and frailty. Similarly, the Perioperative Brain Health Initiative, developed by ASA to promote perioperative brain health (asahq.org/about-asa/newsroom/news-releases/2021/01/6-simple-steps-physician-anesthesiologists-can-lead), also supports the importance of training and education for all staff who care for older patients to identify and manage patients at risk for delirium and other complications.
In summary, the perioperative care of older patients is a growing field. It is anticipated that the demand for anesthesiologists with expertise in geriatrics will expand as the aging surgical population and life expectancy increase. To meet this need over the next decade and beyond, anesthesiologists should be proactive in learning and understanding the principles of geriatrics and how they may impact perioperative care. Gaining expertise in the care of the aging surgical population also represents a new opportunity for anesthesiologists to expand their scope of practice to address this increasing need. Given that most hospitals do not have a dedicated team in geriatrics to take care of our older surgical cohort, coupled with the fact that there is a shortage of geriatricians, it is incumbent upon us to develop a curriculum of training in geriatric anesthesiology, including implementation of fellowship programs and continuing education programs devoted to the care of older patients so we can leverage our expertise to participate in the perioperative care of the older surgical patient and support the needs of the health care systems with which we work.
Disclosure: Dr. Leung has a research collaboration (unrelated to the topics discussed) with Masimo Corporation. Dr. Leung's effort is in part funded by the National Institutes of Health, 5RO1NR017622-03 and 3RO1NR017622-02S1.