Anesthesia for the older adult

INTRODUCTION — Older adults (≥65 years of age) account for a disproportionately large fraction of all surgical procedures performed in the United States (figure 1). Although older age is a risk factor for perioperative mortality, preoperative comorbidities and the invasiveness of the planned surgical procedure are other important predictors in all age groups [1-5].

This topic will discuss age-related physiologic changes that affect anesthetic drugs and techniques and optimal perioperative anesthetic management of older patients.

IMPACT OF AGE-RELATED PHYSIOLOGIC CHANGES ON ANESTHETIC CARE — Aging is associated with a progressive loss of functional reserve in all organ systems (see "Normal aging"). However, there is considerable individual variability in the onset and extent of these changes. Nevertheless, even the healthy older adult has reduced physiologic reserve such that organ systems may be compromised during illness and/or surgical stress. Physiologic changes specifically impact anesthetic care, in part by increasing susceptibility to anesthetic drugs [6,7].

Nervous system — Age-related changes in the central and peripheral nervous system result in pharmacodynamics changes that affect older adults' responses to anesthetics and other medications, and also affect pain perception [8]. Central nervous system changes include reduction in brain size and neuronal density and widening of the sulci and ventricles. Regional reductions in neurotransmitters (eg, dopamine, serotonin, and acetylcholine) and neuroreceptors may occur [9].

●Pharmacodynamic sensitivity – Pharmacodynamic sensitivity increases with age for all intravenous (IV) agents that act within the central nervous system (eg, propofol, fentanyl, midazolam) [8]. Furthermore, there are age-related decreases in the minimum alveolar concentration (MAC) at 1 atmosphere that prevents movement in 50 percent of patients exposed to a surgical incision) [10]. In addition, a decrease in cholinergic receptor activity may explain the older patient's vulnerability to the anticholinergic side effects of medications such as diphenhydramine, meperidine, and scopolamine [9]. (See 'Selection and dosing of anesthetic agents' below and "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Risk assessment'.)

●Decreased ventilatory responses – The normal ventilatory responses of the central nervous system to hypercapnia, and especially to hypoxemia, are diminished with age [5]. Respiratory depressant effects of opioids, benzodiazepines, and volatile anesthetics are exaggerated, with further impairment of responses to hypercapnia and hypoxemia [11-13].

●Cerebrovascular changes – Cerebrovascular autoregulation is impaired, with diminished responses to blood pressure changes, as well as to hypoxemia or hypercapnia [5].

●Higher pain thresholds – Changes in the peripheral nervous system include a reduction in myelinated fibers, with potential alterations in pain perception [14,15]. Higher pain thresholds have been observed in older patients and may contribute to delayed presentation for painful conditions such as acute appendicitis and peritonitis.

●Susceptibility to postoperative delirium – Although the mechanisms are not clear, it is known that postoperative central nervous system complications, particularly postoperative delirium and postoperative cognitive deficits, are primarily a problem in older patients [16]. Furthermore, undiagnosed multi-infarct dementia or neurodegenerative disease may be present in some older patients. (See 'Assessment of baseline cognitive function' below and "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies".)

Cardiovascular system — Normal changes in the older adult's cardiovascular system such as vascular stiffening and autonomic changes influence physiologic responses to anesthetic administration [5,17,18].

●Blood pressure lability – Labile intraoperative blood pressure (BP) is common in older patients. Vascular stiffening renders the vascular system less elastic leading to chronic hypertension. Episodes of intraoperative hypotension are common in the older adult and may be exacerbated by [17,18]:

•Vasodilatory effects of most IV and inhalation anesthetic agents

•Sympatholysis after placement of a neuraxial block

•Certain surgical techniques (eg, laparoscopic insufflation of the abdomen causing reduced venous return)

●Autonomic changes – Autonomic changes in older adults are collectively referred to as the "dysautonomia of aging." Impaired beta receptor responsiveness limits the ability to increase cardiac output by increasing heart rate, so that the patient is more reliant on vascular tone and preload. Significant hypotension can occur when baroreflex responsivity is compromised, particularly in the presence of hypovolemia or underlying ventricular dysfunction.

●Left ventricular hypertrophy – Vascular changes increase impedance to left ventricular (LV) outflow, causing an increase in LV work, myocardial stiffening, and LV hypertrophy. Impairment of diastolic filling and overt diastolic dysfunction is present in approximately one-half of patients older than 65 years of age with a diagnosis of congestive heart failure [17,19-21]. Such patients are extremely dependent on the atrial contribution to filling during diastole (the "atrial kick"). Thus, even brief episodes of atrial arrhythmias during anesthesia may result in development of significant hypotension. Furthermore, diastolic dysfunction increases the risk of development of pulmonary edema during fluid administration. (See 'Fluid management' below.)

Other cardiovascular pathology common in older patients includes asymptomatic ischemic heart disease, calcific aortic stenosis, fibrosis of the cardiac conduction system with an increased incidence of atrial fibrillation or cardiac conduction abnormalities, and hypertension [5].

Respiratory system — Normal aging of the pulmonary system that decreases overall pulmonary reserve includes [5,22-24]:

●Stiffening of the chest wall

●Decreased elasticity of lung parenchyma

●Increased work of breathing

●Increased compliance and increased closing capacity leading to small airway closure

●Increased ventilation/perfusion (V/Q) mismatch

●Reduced forced expiratory volume, vital capacity, and maximal rate of oxygen consumption

●Increased dead space

●Reduction in baseline PaO₂, increased alveolar-arterial gradient, susceptibility to hypoxemia

●Diminished ventilatory response to hypoxemia and hypercapnia

●Decreased respiratory muscle strength and impaired cough mechanism

●Impaired pharyngeal function

Also, undiagnosed chronic obstructive pulmonary disease or obstructive sleep apnea may be present in older patients [5].

Older adults are more susceptible to respiratory compromise during monitored anesthesia care with sedation and during the preoperative and postoperative periods. Exaggerated respiratory depressant effects of opioids, benzodiazepines, and volatile inhalation agents increase risk of hypercapnia, hypoxemia, apnea, and respiratory failure [11-13,25] (see 'Nervous system' above). These risks are exacerbated if reversal of neuromuscular blocking agents (NMBAs) is inadequate, particularly in patients who are frail and more susceptible to fatigue and in those with pulmonary comorbidities. (See 'Neuromuscular blocking agents' below and 'Mortality and morbidity' below.)

Hepatic system — Changes in hepatic function due to normal aging include:

●Decreased hepatic mass and function, as well as decreased hepatic blood flow, resulting in slower metabolism of most IV anesthetic agents [6,26,27].

●Diminished albumin levels, resulting in larger free-drug concentrations of highly protein-bound drugs such as propofol [6].

Renal system — Aging causes variable declines in glomerular filtration rate, creatinine clearance, and renal functional reserve that may be underestimated by the serum blood urea nitrogen and creatinine alone [28,29]. Comorbidities that are common in older adults (eg, diabetes, hypertension, and vascular disease) can cause further decline in renal function. Implications of these changes include:

●Increased plasma concentration of renally excreted IV agents [6,26,27,30].

●Decreased ability to maximally dilute urine; thus, the older patient has decreased ability to handle a salt or water load. (See 'Fluid management' below.)

●Increased susceptibility to nephrotoxic effects of IV contrast or medications such as nonsteroidal antiinflammatory drugs (NSAIDs).

Hematological system — Anemia due to iron deficiency, chronic disease/inflammation, malnutrition, or bone marrow malfunction, is common in older adults [5]. (See "Diagnostic approach to anemia in adults", section on 'Older adults'.)

Pharmacokinetic changes — Decreased total body water (by 10 to 15 percent) and muscle mass result in a lower central compartment volume result in higher initial plasma drug concentration (ie, effective concentration) for many anesthetic agents (eg, an induction dose of propofol) [5,8,26]. Increased body fat (by 20 to 40 percent) also results in a larger volume of distribution for lipid-soluble agents, with slow release from this relatively large adipose reservoir that prolongs the clinical drug effect [5,6,8,26,27]. Finally, elimination half-life may be longer and clearance may be decreased due to renal and hepatic changes, leading to greater drug effects after repeated or continuous dosing of anesthetic agents [5,6,8,26,27,31,32]. (See 'Selection and dosing of anesthetic agents' below and "Drug prescribing for older adults" and "Normal aging".)

PREANESTHESIA CONSULTATION — The preoperative anesthetic consultation includes assessment of presence and stability of medical conditions and treatments, functional reserve of individual vital organs, and the patient as a whole, including cognitive ability and risk factors for delirium (table 1). However, the impact of absolute age on perioperative outcomes is modest and should not be used as a sole criterion to guide decisions regarding patient selection for a surgical procedure or preoperative testing [5,33]. In fact, the American Society of Anesthesiologists (ASA) Physical Status score, an established predictor of adverse outcomes after surgery that focuses on severe systemic disease, does not specify age as a risk factor (table 2). (See "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Advanced age'.)

Much of the perioperative risk associated with age is due to increasing likelihood of comorbidities that confer excess risk, presence of overt frailty or delirium, and invasiveness and/or urgent nature of the surgical procedure [34]. A 2022 study in 992 older adults (mean age 79.2 ± 7.1 years) noted that mortality at one year after major surgery was fourfold higher in frail patients (27.8 percent, 95% CI 21.2-34.3 percent) compared with those who were not frail (6.0 percent, 95% CI 2.6-9.4 percent) [35]. Patients with dementia also had higher mortality (32.7 percent, 95% CI 24.3-41.0 percent) compared with those without dementia (11.6 percent, 95% CI 8.8-14.4 percent). Furthermore, nonelective surgery was associated with higher mortality (22.3 percent, 95% CI 17.4-27.1- percent) than elective surgery (7.4 percent, 95% CI 4.9-9.9 percent). (See 'Assessment for frailty' below and "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies".)

Medical history and physical examination — Details regarding the ASA practice advisory for preanesthesia evaluation regarding review of the medical history and an anesthesia-directed physical examination are found in a separate topic. (See "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Clinical evaluation' and "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Advanced age'.)

Assessment for frailty — Frailty in older patients is defined as an aging-related syndrome of physiologic decline and reduced tolerance to medical and surgical interventions (see "Frailty", section on 'Concepts and definitions'). Frail older patients often present with an increased burden of symptoms including weakness and fatigue, medical complexity, and a decrease in physiologic reserve that may exceed that expected from advanced age alone [36]. Frailty predicts postoperative mortality and morbidity including delirium or cognitive impairment, as well as longer hospital stay, discharge to a skilled nursing facility, and long-term functional decline [36-52]. (See 'Outcomes' below.)

Estimates of the prevalence of frailty are approximately in 30 percent in older patients (mean age 70 years) undergoing nononcologic surgery, and may be as high as 50 percent in older patients who require cancer surgery [53,54], and is common in critically ill surgical patients [55,56]. Identification of frailty in the preoperative period can be helpful to inform patient and family discussions regarding surgical techniques, postoperative recovery strategies, and likely outcomes [5,36,43,53,57-59]. (See 'Outcomes' below.)

In some cases, such discussions include a decision regarding whether or not the surgical procedure is appropriate due to adverse impact on quality of life, and/or consideration of a palliative care consultation [5,53,58,60].

It has been suggested but not yet proven that surgical outcomes may be improved in some older frail patients by optimizing preoperative condition and improving physiologic reserve with a prehabilitation program that may include smoking cessation, as well as exercise training, nutritional supplementation, and a multidisciplinary approach to postoperative care and discharge planning that includes a geriatrician [5,53,57,61-70]. (See "Smoking or vaping: Perioperative management" and "Overview of prehabilitation for surgical patients".)

Thus, several multidimensional tools have been used to assess preoperative frailty [37-39,42-44,71-78]. The Clinical Frailty Scale (CFS) is used in many centers (figure 2). Compared to the Frailty Phenotype (FP) or Frailty Index (FI), the CFS appears to improve all measures of predictive performance to the greatest extent and across outcomes, and is easy to use and requires less time than the FP [77].

An older assessment tool is the physical frailty screening tool (ie, Fried Frailty Tool or Frailty Phenotype [FP]), an in-person assessment for weight loss, exhaustion, gait speed, decreased physical activity, and weakness (decreased grip strength) (table 3 and table 4) [37]. Although a well-validated instrument, this tool is not routinely incorporated into most preoperative anesthesia practices as it requires additional time and space, patient cooperation, and specialized equipment (eg, grip strength dynamometer and timing capability for gait speed). (See "Frailty", section on 'Instruments developed to identify frailty'.)

An alternative approach is the frailty index (FI), which is based on the accumulation of illnesses, functional and cognitive decline, and social situations that are added together to calculate frailty [78] (see "Frailty", section on 'Instruments developed to identify frailty'). This approach does not require an in-person assessment; it may be conducted using surveys and or review of the medical record.

Rapid frailty screening tools have also been used in the perioperative setting. One example is the FRAIL scale, a verbal assessment that takes only minutes to perform, evaluates Fatigue; Resistance (difficulty climbing stairs); Ambulation (difficulty walking one block); Illnesses that include hypertension, congestive heart failure, angina, asthma, arthritis, stroke, and kidney disease; and weight Loss [79,80]. Perhaps the most rapid assessment is the CFS based on self-reporting of comorbidities and the need for help with activities of daily living (ADLs) [81]. This simple screening tool may have advantages for routine preoperative clinical assessment because it incorporates activity levels (between 1 [very fit] and 7 [severely frail]) with medical conditions and other elements. Despite the availability of these rapid tools, preoperative frailty screening is not routinely performed in many centers due to lack of agreement on which tool is optimal, and difficulty with implementing additional assessments into busy clinical practices. (See "Frailty", section on 'Rapid screening tools'.)

Other frailty assessment tools employ multidimensional scoring based on specific comorbidities, dependence on others for activities of daily living, malnutrition, dementia, and self-rated health, rather than physical assessment alone [5,43,71,72]. Notably, some centers do perform routine preoperative screening for cognitive impairment, as well as for frailty, in all older adults (≥60 or 65 years of age) [5,82,83] (see 'Assessment of baseline cognitive function' below). Both accuracy and feasibility of the selected assessment tools are important to successfully implement routine preoperative screening for frailty [43,71].

Details regarding evaluation and management of frailty in older patients are available in a separate topic. (See "Frailty".)

Assessment of baseline cognitive function — The ASA Brain Health Initiative guidelines suggest that baseline cognition should be evaluated in patients older than 65 years, particularly those with risk factors for preexisting cognitive impairment [84]. Older patients should be informed of risks for postoperative neurocognitive disorder (eg, confusion, inattention, and/or memory problems) [5,50,84]. However, these effects of anesthesia and surgery are usually temporary. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies".)

Evaluation of the institutionalized patient — The preoperative assessment of the institutionalized older patient presents a particular challenge for the anesthesiologist. These patients usually have extensive comorbidities and may exhibit frailty. Furthermore, dementia is estimated to be present in one-half to two-thirds of nursing home residents (see "Risk factors for cognitive decline and dementia", section on 'Age'). Furthermore, these patients usually have extensive comorbidities and may exhibit frailty. (See 'Assessment for frailty' above.)

An additional visit to the hospital for preoperative consultation and testing may be impractical and "low yield" in patients with dementia or significant physical disabilities. Often, a member of the anesthesia team will preview the patient's medical conditions and most recent laboratory tests in order to determine if further testing is likely to be useful. If not, the final preoperative assessment is completed on the day of surgery at the hospital or ambulatory center. In such cases, it is particularly important to communicate to the outside facility regarding instructions regarding the need to administer or withhold each chronically administered medication, and to explain timing for ensuring nothing by mouth (nil per os [NPO]) status. Furthermore, for patients who are incompetent and unable to provide consent (eg, due to dementia), arrangements to obtain telephone consent from a family member or guardian are planned [85].

Medication history — Obtaining an accurate medication history, including both prescription and over-the-counter medications, may require extra effort since older adult patients often forget or confuse their medication regimen [86,87]. The incidence of adverse drug-related events is high in older patients taking multiple medications (polypharmacy) [88-90]. Thus, the opportunity for reconciliation of the medication schedule is one distinct benefit of a scheduled patient visit to the preoperative clinic [91].

Examples of medications commonly used by older patients that are potentially relevant for anesthetic care include (see "Perioperative medication management"):

●Antiplatelet agents or oral anticoagulants must be managed if a neuraxial anesthetic is planned. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication".)

●Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) administered within 12 hours of anesthetic induction are associated with increased risk of intraoperative hypotension. In many centers, ACE inhibitors and ARBs are held for a period of 24 hours prior to surgery or are administered the evening dose before surgery (and not on the morning of surgery), as discussed separately. (See "Anesthesia for patients with hypertension", section on 'Antihypertensive medication management'.)

●Benzodiazepines are minimized or avoided as they are associated with increased risk of perioperative delirium [92]. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Intravenous agents associated with higher risk'.)

PREOPERATIVE TESTING — Routine preoperative testing is not recommended before minor procedures in older adults. In a prospective randomized trial that included more than 18,000 older patients having cataract surgery, no differences in complications were noted in those who received routine preoperative testing (complete blood count, and measurement of serum levels of electrolytes, urea nitrogen, creatinine, and glucose) compared with those who received tests only if indicated by medical condition(s) [93]. (See "Preoperative medical evaluation of the healthy adult patient".)

Notably, the following caveats apply to older adults:

●ECG – An electrocardiogram (ECG) for patients with coronary heart disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, or other significant structural heart disease and known cardiovascular risk factors undergoing intermediate or high cardiac risk surgery is reasonable (table 5 and table 6) [94]. (See "Evaluation of cardiac risk prior to noncardiac surgery".)

Age alone is not an indication for ECG [34], although some institutions had historical guidelines recommending a preoperative ECG in adult patients older than 55 years. These guidelines were based on the observation that older patients have a high incidence of preoperative changes on the ECG [95,96], despite data showing little predictive value of the preoperative ECG [97,98]. In a prospective observational study of 513 older adult patients undergoing noncardiac surgery, 75 percent had at least one abnormality on the baseline ECG [99]. However, these abnormalities were not associated with increased risk for cardiac events. Rather, a higher ASA score (>3) as an indication of the presence and severity of comorbidities, as well as a history of chronic heart failure, were significant predictors of postoperative cardiac complications in this study [99].

●Chest radiograph (CXR) – In general, a preoperative chest radiograph (CXR) is unnecessary for older patients undergoing elective non-thoracic surgery [34]. In patients with symptomatic cardiac or pulmonary disease, a CXR may be obtained before high-risk surgery if not performed within the past six months. (See "Evaluation of perioperative pulmonary risk".)

●Laboratory tests – There is no consensus on the specifics of routine testing in older patients.

Hemoglobin and hematocrit are not routinely recommended [34], but are typically obtained before major surgical procedures with significant expected blood loss (eg, procedures with >10 percent chance of needing a transfusion or >500 mL blood loss), and in individuals likely to have preoperative anemia due to a known underlying condition. Depending on the cause and degree of anemia, the urgency of the procedure, and the expected amount of blood loss and other risk factors, surgery may be postponed to diagnose the cause and correct anemia when feasible (algorithm 1). (See "Perioperative blood management: Strategies to minimize transfusions", section on 'Selective laboratory testing' and "Perioperative blood management: Strategies to minimize transfusions", section on 'Treatment of anemia'.)

Preoperative creatinine and albumin may be measured before moderate- or high-risk surgery in frail older patients or those with a known history of liver disease or chronic illness since these patients have a relatively high incidence of renal dysfunction and malnutrition [100]. (See "Preoperative evaluation for anesthesia for noncardiac surgery", section on 'Advanced age'.)

●Other screening tests – Other screening tests (eg, echocardiography, pulmonary function testing) are ordered according to criteria used for adult patients of any age since there are no data demonstrating that routine use of such testing is useful to predict or manage postoperative complications in older adults [101]. (See "Evaluation of cardiac risk prior to noncardiac surgery", section on 'Testing to further define risk' and "Evaluation of perioperative pulmonary risk", section on 'Preoperative risk assessment'.)

ANESTHETIC TECHNIQUES — The choice of anesthetic technique for the older patient should be guided by the requirements of the surgical procedure, coexisting disease(s), the need to prevent postoperative complications, and patient preferences.

Neuraxial versus general anesthesia — Choice of neuraxial or another regional anesthetic should be guided by the requirements of the surgical procedure, coexisting disease(s), the need to prevent postoperative complications, and patient preferences [102]. Although the results are not consistent, some studies have noted that neuraxial or other regional anesthetic techniques may reduce pulmonary complications and need for postoperative mechanical ventilation compared with general anesthesia, particularly in older patients with chronic obstructive pulmonary disease [103-108]. (See "Anesthesia for patients with chronic obstructive pulmonary disease", section on 'Choice of anesthetic technique' and "Anesthesia for orthopedic trauma", section on 'Choice of anesthetic technique for hip fracture'.)

However, general anesthesia may be preferable in the following clinical scenarios (see "Anesthesia for orthopedic trauma", section on 'Choice of anesthetic technique'):

●Patients receiving anticoagulant or antiplatelet medication or with coagulopathy due to other reasons, such that neuraxial anesthesia and deep peripheral nerve blocks are relatively contraindicated. (See "Neuraxial anesthesia/analgesia techniques in the patient receiving anticoagulant or antiplatelet medication" and "Lower extremity nerve blocks: Techniques", section on 'Side effects and complications'.)

●Patients with decreased cardiac preload (eg, due to hypovolemia or expected major blood loss) that would be exacerbated by sympathetic blockade with resultant severe hypotension.

●Requirement for deep sedation due to patient inability to lie comfortably in the position necessary for surgery.

●Anxiety, reluctance to be awake, or inability to cooperate or communicate (eg, due to dementia).

●Anticipated prolonged duration of a surgical procedure.

Costs are another outcome that may be influenced by anesthetic choice. In a large database that included >800,000 patients undergoing total knee replacements and >370,000 patients undergoing total hip replacements, lower hospital costs were found in centers frequently employing a neuraxial technique for these procedures compared with those where a neuraxial technique was used less often [109]. Furthermore, discharge to a post-acute care facility following total hip replacement, rather than discharge home, may be more common when general anesthesia rather than a neuraxial technique is employed [110].

Monitored anesthesia care with sedation — A monitored anesthesia care technique is often selected for older adults who require a diagnostic or therapeutic procedure, especially in remote locations such as endoscopic gastrointestinal or interventional radiology suites [111-113]. (See "Anesthesia for gastrointestinal endoscopy in adults", section on 'Choice of anesthetic technique' and "Considerations for non-operating room anesthesia (NORA)", section on 'Selection of anesthetic technique'.)

During monitored anesthesia care, short-acting agents are administered to provide analgesia, sedation, and anxiolysis as necessary; however, excessive anesthetic depth is avoided, and rapid recovery is desired. Notably, progression from a "light" level of sedation to "deep" sedation (or unconsciousness) is not uncommon and may occur rather suddenly [8]. Since older patients are particularly susceptible to developing airway obstruction, hypoxemia, hypercapnia, or aspiration (due to reduced pharyngeal sensitivity), doses of all administered sedative and analgesic medications are reduced [8,114]. Also, supplemental oxygen is typically administered to reduce the risk of hypoxemia because older patients have a lower baseline arterial oxygen tension (PaO₂) [115]. Continuous vigilant monitoring is necessary, including constant communication and monitoring of respiratory rate [8]. Routine use of end-tidal carbon dioxide (ETCO₂) level monitoring is recommended in spontaneously breathing older patients since significant hypercapnia may develop even when oxygen saturation levels remain normal [8,116]. (See 'Selection and dosing of anesthetic agents' below.)

Similar to considerations for neuraxial or regional anesthesia, general anesthesia may be preferred in some older adults if deep sedation is likely to be necessary, in patients with anxiety, reluctance to be awake, or inability to cooperate or communicate, or if the procedure is prolonged in duration. (See 'Neuraxial versus general anesthesia' above.)

Details regarding management of patients undergoing surgical or other invasive procedures during MAC are available in a separate topic. (See "Monitored anesthesia care in adults".)

INTRAOPERATIVE MANAGEMENT

Monitoring

●Standard monitoring – Standard American Society of Anesthesiologists (ASA) monitors are employed in older adults, including pulse oximetry, electrocardiography, noninvasive blood pressure device, temperature monitor, measurement of end tidal carbon dioxide, inspired oxygen concentration, and the use of low oxygen concentration and ventilator disconnect alarms [117]. Also, quantitative monitoring of the volume of expired gas is strongly encouraged, particularly for older adults [8]. If a neuromuscular blocking agent (NMBA) is administered, a peripheral nerve stimulator should be used to guide dosing. (See "Basic patient monitoring during anesthesia".)

There are few data regarding the value of more invasive monitoring in older patients compared with younger patients undergoing similar procedures. Monitoring choices are based on patient-specific and surgery-specific considerations.

●Brain function monitoring – Raw or processed electroencephalography (EEG) such as the bispectral index (BIS) or other brain function monitors are often used in older adults (table 7). Goals include avoiding excessive anesthetic depth, which has been associated with development of postoperative neurocognitive disorder (NCD) and other adverse outcomes, as well as avoiding awareness with recall after anesthesia [84,118]. Details are discussed in other topics. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Avoid excessive depth during general anesthesia' and "Accidental awareness during general anesthesia", section on 'Brain monitoring'.)

Positioning — Older patients are often more susceptible to nerve and other pressure point injury due to poor peripheral circulation and friable skin [119]. Details are discussed in a separate topic. (See "Patient positioning for surgery and anesthesia in adults".)

Selection and dosing of anesthetic agents

Anesthetic depth: General considerations — Older adult patients are more sensitive to drugs due to age-related changes in pharmacokinetics and pharmacodynamics [5,6,8,26,27]. Thus, there is an enhanced response to a given drug dose, and anesthetic dosing should be age-adjusted. (See 'Impact of age-related physiologic changes on anesthetic care' above.)

As noted above, brain function monitoring is often employed (see 'Monitoring' above). We avoid aggressive efforts to maintain low brain function monitor values and we avoid high doses of anesthetic agents, in agreement with guidelines from the ASA Brain Health Initiative [84]. Avoiding excessive anesthetic depth is particularly important in older adults who develop hypotension or blood pressure significantly lower than baseline values. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Avoid excessive depth during general anesthesia'.)

The following approaches can help avoid excessive anesthetic depth and other side effects of anesthetic agents (eg, hypotension):

●Reducing doses of anesthetic agents

●Increasing the interval between repeat doses

●Using shorter-acting agents

Intravenous anesthetic and adjuvant agents — The doses of intravenous (IV) anesthetic induction agents (eg, propofol, etomidate) are reduced in older adults, with a longer interval between repeat doses, and bolus injections should be administered slowly [6]. These recommendations are based on studies that indicate that the drug sensitivity is increased and drug clearance is decreased in older patients. (See 'Impact of age-related physiologic changes on anesthetic care' above.)

Doses of anesthetic agents are also reduced during the maintenance phase of anesthesia, particularly if several anesthetic agents are coadministered. (See "Maintenance of general anesthesia: Overview", section on 'Intravenous anesthetic agents and techniques'.)

Specific considerations for individual anesthetic agents include the following:

●Propofol – Older adult patients have an altered pharmacodynamic response to propofol. As judged by the electroencephalography (EEG), older subjects are approximately 30 percent more sensitive to its effects [120]. In addition, clearance of propofol is decreased [26].

The initial induction dose of propofol and subsequent bolus doses should be reduced by 40 to 50 percent to 1 mg/kg to 1.75 mg/kg, and should be slowly administered [6,26,121,122] (see "General anesthesia: Intravenous induction agents", section on 'Propofol'). Similarly, maintenance doses during an ongoing infusion of propofol must be decreased by 30 to 50 percent, in order to avoid a doubling of recovery time [26]. (See "General anesthesia: Intravenous induction agents", section on 'Dosing'.)

●Etomidate – Etomidate is often the preferred anesthetic induction agent for older patients with known cardiovascular compromise or hemodynamic instability, since it has minimal hemodynamic side effects [18]. Notably, the plasma concentration of etomidate at any given dose is higher in the older patient because of a decreased volume of distribution and diminished clearance. Thus, although the standard induction dose of etomidate is 0.3 mg/kg, this dose is often reduced to 0.2 mg/kg. (See "General anesthesia: Intravenous induction agents", section on 'Etomidate'.)

●Ketamine – Ketamine is rarely used for anesthetic induction in older patients because of its unique cardiovascular effects (increases in blood pressure and heart rate due to a centrally-mediated sympathetic response), as well as the undesirable side effect of postoperative delirium [18,123]. However, ketamine may be selected for those with hemodynamic compromise caused by hypovolemia or cardiomyopathy in the absence of coronary artery disease. Also, since ketamine is a bronchial smooth muscle relaxant, it may be useful in older patients with reactive airway disease. (See "General anesthesia: Intravenous induction agents", section on 'Ketamine'.)

●Opioids – All opioids are approximately twice as potent in older patients. Also, since opioids have the potential to cause respiratory depression, the increased brain sensitivity and decreased clearance of opioids in older patients can result in severe hypoventilation or apnea [124]. (See "Perioperative uses of intravenous opioids in adults: General considerations", section on 'Dosing considerations'.)

•Short-acting opioids – For fentanyl, sufentanil, and alfentanil, respiratory depression is primarily a pharmacodynamic effect due to age-related increased brain sensitivity to opioids [26].

For remifentanil, there are also changes in pharmacokinetics due to decreased volume of the central compartment and decreased clearance, so that only half of the bolus dose is required.

•Long-acting opioids – For morphine, the volume of distribution is increased in older adults, and renal clearance is reduced for the parent drug, as well as its active metabolite, morphine-6-glucuronide [30,125]. Thus, there is an enhanced analgesic effect and prolonged duration of action after each dose of morphine. Clearance is further reduced in patients with renal insufficiency.

For hydromorphone, initial doses are reduced by 25 to 50 percent to avoid a prolonged duration since hydromorphone has primary renal clearance [30]. (See 'Renal system' above.)

●Medications to avoid or use with caution – Several medications are minimized or avoided in older adults [5]:

•Benzodiazepines – Benzodiazepines are avoided if possible. If necessary to alleviate anxiety, an initial IV dose of midazolam is usually only 0.25 to 1 mg, and the interval between additional doses may be longer than in younger patients. Both pharmacodynamic changes (ie, increased brain sensitivity) and pharmacokinetic changes (ie, decreased clearance due to decreased hepatic perfusion and increased volume of distribution due to increased body fat) occur in older adults, necessitating reduction of midazolam doses [6,26,120,126] (see 'Impact of age-related physiologic changes on anesthetic care' above). Cautious dosing is particularly necessary when an opioid or other anesthetic agent is concurrently administered since respiratory depression is a dose-related side effect of each drug, and effects can be synergistic. Occasionally, midazolam causes paradoxical worsening of agitation in older patients. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Intravenous agents associated with higher risk'.)

•Other agents – Meperidine, anticholinergics (particularly scopolamine), diphenhydramine, and metoclopramide increase risk for postoperative delirium and other forms of perioperative neurocognitive disorder [5]. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Intravenous agents associated with higher risk'.)

Antipsychotic agents such as haloperidol are avoided in older patients who have dementia with Lewy bodies due to the possibility of severe reactions (eg, impaired consciousness, autonomic dysfunction, neuroleptic malignant syndrome, irreversible parkinsonism). (See "Clinical features and diagnosis of dementia with Lewy bodies", section on 'Antipsychotic sensitivity' and "Prognosis and treatment of dementia with Lewy bodies", section on 'Antipsychotic drugs'.)

Inhalation anesthetic agents — The minimum alveolar concentration (MAC) at 1 atmosphere preventing movement in 50 percent of patients exposed to a surgical incision of all inhalation agents decreases by approximately 6 percent per decade after age 40 years (figure 3 and figure 4 and figure 5). By age 90 years, MAC is reduced by 30 percent [10,127,128]. Similarly, the anesthetic requirement to produce unconsciousness (ie, absence of response to commands [MAC_awake] is decreased with age). Although reasons for age-related decline in MAC and MAC_awake are not fully understood, likely mechanisms include a combination of age-related effects on synaptic activity and neurotransmitter function in the brain, cerebral atrophy, and changes in cerebral circulation [127,128]. (See "Inhalation anesthetic agents: Clinical effects and uses", section on 'Influence of patient-related factors'.)

As noted above, the ASA Brain Health Initiative guidelines suggest avoiding excessive anesthetic depth (see 'Anesthetic depth: General considerations' above). We continuously monitor and initially target an age-adjusted end-tidal anesthetic concentration (ETAC) to maintain adequate anesthetic depth (figure 3 and figure 4 and figure 5) [84]. Subsequently, anesthetic concentrations are continuously titrated according to the individual patient's responses. The ASA guidelines also suggest that neuromonitoring such as EEG may be useful to guide titration of a volatile agent and maintain optimal anesthetic depth [84]. Notably, no particular volatile anesthetic agent has been associated with an increased risk of NCD in older adults. (See "Accidental awareness during general anesthesia", section on 'End-tidal anesthetic concentration' and "Accidental awareness during general anesthesia", section on 'Brain monitoring' and "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Inhalation anesthetic agents'.)

Neuromuscular blocking agents — Notably, various neuromuscular blocking agents (NMBAs), including succinylcholine, may have a prolonged onset time as well as a prolonged duration in older patients. Likely mechanisms include decreased muscle blood flow and decreased cardiac output [129].

In general, we use NMBAs sparingly when possible. Shorter-acting NMBAs are typically selected because age-related reductions in hepatic metabolism and renal excretion may result in prolonged duration of action for certain agents (eg, vecuronium, rocuronium) [5,129]. However, age has little effect on NMBAs eliminated by other means, such as ester hydrolysis and Hoffmann degradation (eg, atracurium, mivacurium, and cisatracurium). Notably, recovery of muscle function after administration of sugammadex, which facilitates rapid reversal from neuromuscular blockade induced by rocuronium, is slower in older patients [130].

A peripheral nerve stimulator should be used to guide dosing of all NMBAs. It is particularly important to ensure reversal of neuromuscular blockade if extubation is planned at the end of the surgical procedure. Even a small amount of residual neuromuscular blockade can impair pharyngeal function in older patients, predisposing them to development of aspiration pneumonia [8,131].

Furthermore, older patients with Alzheimer disease and other forms of dementia may be taking cholinesterase inhibitors (eg, donepezil, rivastigmine, galantamine). Chronic administration of these medications may lead to reduced plasma cholinesterase, thereby prolonging the duration of succinylcholine [85]. Cholinesterase inhibitors may also interfere with the action of anticholinesterase agents such as neostigmine, and cause unpredictable responses to these agents.

Fluid management — The overall goals of intraoperative fluid management are to avoid dehydration, maintain an effective circulating volume, and prevent inadequate tissue perfusion [132]. Optimal fluid management has been a challenging area of research in the general surgical population, particularly in older patients. Little to no generalizable evidence exists to guide therapy. Clinical judgment based upon available measures of volume status and tissue perfusion is the most important factor. (See "Intraoperative fluid management".)

Fluid management in older patients with heart failure can be especially challenging. IV fluid restriction may not prevent the development of heart failure. In fact, reducing the effective circulating volume may have a negative effect upon cardiac function since adequate preload is necessary for myocardial contractility. (See "Perioperative management of heart failure in patients undergoing noncardiac surgery".)

Hemodynamic management — As noted above, changes in the older adult's cardiovascular system such as vascular stiffening and autonomic changes may lead to hemodynamic instability during anesthesia and surgery [17] (see 'Cardiovascular system' above). Prevention and management of perioperative hemodynamic aberrations is discussed separately. (See "Hemodynamic management during anesthesia in adults".)

In particular, periods of intraoperative hypotension may contribute to adverse cardiac events in older patients [3]. Some require an intraoperative mean arterial pressure target higher than the typically targeted 65 mmHg, particularly those with chronic hypertension [133,134]. (See "Anesthesia for patients with hypertension", section on 'Determination of target blood pressure values'.)

Avoidance of hypothermia — Perioperative hypothermia is more frequent, pronounced, and prolonged in older adults, who have compromised ability to quickly regain thermoregulatory control [135]. Prevention and management of hypothermia (or hyperthermia) during the perioperative period are discussed in a separate topic. (See "Perioperative temperature management".)

POSTOPERATIVE PAIN MANAGEMENT — Although there is an age-related decrease in pain perception [136], postoperative analgesia is a critical aspect of perioperative anesthetic care for the older patient [137]. Although opioids may precipitate or worsen delirium, inadequate pain relief is also associated with a greater likelihood of delirium and subsequent morbidity in older patients [138,139]. To reduce the risk of delirium and other opioid-related side effects, we employ a multimodal approach to pain management [30,140]. (See "Hospital management of older adults" and "Approach to the management of acute pain in adults".)

Management begins with careful assessment of postoperative pain, which may be challenging in older patients with some degree of chronic pain, or extremely difficult in those with mental status changes [141]. Although numerical verbal pain scales are superior to nonverbal methods of assessment, cognitively impaired patients may not understand these scales [142]. Patients with advanced dementia and those who are nonverbal may respond best to visual analog scales that use faces expressing pain and sadness.

For mild postoperative pain, acetaminophen 650 to 1000 mg administered every six hours is the nonopioid of choice, unless contraindicated due to hepatic disease. The addition of scheduled acetaminophen to a morphine patient-controlled analgesia (PCA) results in improved pain scores and lower overall opioid doses in some patients [143]. Intravenous (IV) acetaminophen may be used in patients in whom oral or rectal administration is not an option. (See "Nonopioid pharmacotherapy for acute pain in adults", section on 'Acetaminophen'.)

Other nonopioid alternatives include nonsteroidal anti-inflammatory drugs (NSAIDs), such as ketorolac [137,144]. However, NSAIDs carry a significant risk of transient platelet dysfunction and bleeding, as well as gastrointestinal hemorrhage and renal insufficiency. Thus, the dose of ketorolac should be reduced to 15 mg every six hours in older patients, with no more than 60 mg administered in a 24 hour period [145]. (See "Nonselective NSAIDs: Overview of adverse effects".)

For selected patients, continuous epidural analgesia is appropriate as the planned primary method for controlling pain [123,146,147] (see 'Neuraxial versus general anesthesia' above). Peripheral nerve blocks and adjuvant techniques such as local anesthetic infiltration are also commonly used to reduce the need for systemic opioids. (See "Overview of peripheral nerve blocks", section on 'Indications'.)

If systemic opioids are necessary for pain control in the immediate postoperative period, doses are reduced (see "Perioperative uses of intravenous opioids in adults: General considerations", section on 'Dosing considerations' and 'Impact of age-related physiologic changes on anesthetic care' above) [26,30,125,140-142]. Notably, initial titration of opioids to successfully control pain in older patients requires extra time and may necessitate a longer stay in the post-anesthesia care unit [148,149]. If additional IV opioid doses are needed after initial titration, PCA should be implemented [144]. If delirium or other factors preclude use of PCA, regularly scheduled age-adjusted opioid dosing is an option. Subcutaneous administration may be employed when no reasonable alternatives exist, but absorption may be erratic or inadequate in older adults with edema or regional hypoperfusion.

OUTCOMES — Older age and frailty are risk factors for adverse outcomes after surgery, as noted above.

Mortality and morbidity

●Mortality – Older age is a risk factor for perioperative mortality, but preoperative comorbidity, frailty, and invasiveness of the surgical procedure are other important predictors of mortality in this age group [1-4,47,150-152].

The following studies illustrate the mortality rate in large outpatient and inpatient settings in the United States:

•In a Medicare database study of over 560,000 patients undergoing outpatient surgery, death occurred in 0.23 percent on the same day of surgery, increasing to 0.66 percent within 30 days of surgery [4]. Factors significantly associated with mortality were greatly advanced age (≥85 years), invasiveness of the surgical procedure, and recent need for hospitalization.

•In the Veterans Affairs National Survey Quality Improvement Project (NSQIP) database of inpatient noncardiac surgery, patients >80 years suffered a significantly higher mortality at 30 days compared with younger patients (8 versus 3 percent) [1]. Although mortality varied widely depending on the type of surgery, the overall adjusted odds ratio (OR) for each additional year of age was 1.05 (ie, a 5 percent increase in mortality risk for every year of age over 80).

In other studies, risk factors for mortality and morbidity after noncardiac surgery include greatly advanced age (≥85 years) [4], and also invasiveness of the surgical procedure [1,2,4,150,151,153-155], a high American Society of Anesthesiologists (ASA) score [1,2,150,151], and a preexisting diagnosis of heart failure [3,153,154,156]. In a study of older patients undergoing noncardiac surgery, death occurred in 9 percent of patients with ischemic or nonischemic heart failure, which was significantly higher than patients with coronary artery disease (3 percent) [154]. Risk is higher in older heart failure patients after both major surgery [153,154] and minor outpatient procedures (ie, colonoscopy, cataract surgery, or cystoscopy) [154]. Emergency surgery is also a risk factor in older patients [1-3,150,151,154,156,157]. For those with hip fracture, an associated risk factor is the wait time for emergency repair; expeditious surgery has been associated with better patient outcomes [157,158]. (See "Hip fracture in older adults: Epidemiology and medical management", section on 'Timing of surgical intervention'.)

Mortality specifically related to anesthesia has been studied in approximately 106 million patients undergoing surgery during the years 1999 to 2005 [159]. Anesthetic issues caused death in 8 per million surgical patients, with patients ≥85 years old suffering the highest death rate (approximately 20 per million).

●Cardiac complications – Advanced age has not been definitively proven to independently increase perioperative risk for postoperative cardiac death or major cardiac complications, including nonfatal myocardial infarction and heart failure. Age is noted as a minor risk factor in the 2014 American College of Cardiology/American Heart Association (ACC/AHA) perioperative guidelines, since perioperative myocardial infarction confers a higher mortality in older adults [94]. (See "Evaluation of cardiac risk prior to noncardiac surgery" and "Perioperative management of heart failure in patients undergoing noncardiac surgery", section on 'Severity of heart failure syndrome'.)

●Pulmonary complications – Even healthy older patients have a substantial risk of pulmonary complications after surgery [25] (see "Evaluation of perioperative pulmonary risk"). The most important complications are atelectasis, pneumonia, respiratory failure, and exacerbation of underlying chronic lung disease.

In a 2006 systematic review, patients aged 50 to 59 years, 60 to 69 years, 70 to 79 years, and ≥80 years had odds ratios of 1.50 (95% CI 1.31-1.71), 2.28 (95% CI 1.86-2.80), 3.90 (95% CI 2.70-5.65), and 5.63 (95% CI 4.63-6.85), respectively, compared with patients <50 years old [25].

Significant risk factors for pulmonary complications include preexisting chronic obstructive pulmonary disease, chronic heart failure, and invasive surgical procedures (eg, abdominal surgery, aortic aneurysm repair, and non-resective thoracic surgery) [25]. Risk may be mitigated by cessation of smoking for more than three months before surgery in those who use tobacco [160] (see "Smoking or vaping: Perioperative management"). Also risk of respiratory failure is exacerbated if reversal of neuromuscular blocking agents (NMBAs) is inadequate, particularly in frail patients more susceptible to fatigue (see 'Neuromuscular blocking agents' above) [131].

●Acute kidney injury – Risk for development of acute kidney injury, defined as an increase in serum creatinine of at least 2 mg/dL or acute renal failure requiring dialysis, is increased in older patients [161].

●Delirium – Advanced age is a risk factor for perioperative neurocognitive disorder (NCD) [162-167]. In particular, postoperative delirium is common in older adults undergoing major surgery (ranging from 4 to 55 percent), with the highest incidence occurring after emergency, cardiac, or major orthopedic surgery [92,164,168-177]. Notably, up to 40 percent of older adults who develop postoperative delirium never return to their preoperative cognitive baseline [164,178]. (See "Perioperative neurocognitive disorders in adults: Risk factors and mitigation strategies", section on 'Prognosis'.)

Recovery

●Functional recovery – Functional recovery after surgery (ie, for activities of daily living and independent activities of daily living) is highly variable in older adults. Factors influencing recovery include preoperative physical conditioning, depression, and serious postoperative complications. On average, following major abdominal surgery, recovery to preoperative levels of function may require three to six months [179].

●Hospital readmission – In a large Medicare database study that included more than 560,000 patients, the rate of admission to an inpatient hospital within 30 days after outpatient surgery was significantly higher in patients ≥80 years of age [4]. In another Medicare database study that included approximately 160,000 patients undergoing inpatient surgery, the readmission rate was 8 percent in those without a preexisting diagnosis of heart disease, 11 percent for patients with a prior diagnosis of coronary artery disease, and 17 percent for those with a prior diagnosis of heart failure [153].

SUMMARY AND RECOMMENDATIONS

●Age-related physiologic changes – Aging is associated with a progressive loss of functional reserve in all organ systems. However, there is considerable individual variability in the onset and extent of these changes (see 'Impact of age-related physiologic changes on anesthetic care' above):

•Age-related pharmacodynamic changes in the central and peripheral nervous system resulting in increased sensitivity to anesthetic agents

•Vascular stiffening and autonomic changes leading to blood pressure lability

•Decreased overall pulmonary reserve

•Decreased hepatic mass, function, and blood flow, resulting in slower metabolism of most anesthetic agents

•Variable declines in glomerular filtration rate, creatinine clearance, and renal functional reserve

•Decreased total body water and increased adipose tissue resulting in pharmacokinetic changes for many anesthetic agents (eg, higher effective drug concentrations and prolonged effects)

●Preanesthetic consultation – The preoperative anesthetic consultation includes assessment of presence and stability of medical conditions and treatments, functional reserve of individual vital organs, and the patient as a whole including cognitive ability and risk factors for delirium (table 1) (see 'Preanesthesia consultation' above). Emphasis is placed on assessment of:

•Frailty – Preoperative frailty is identified (table 3 and table 4). Frailty influences patient and family discussions regarding surgical techniques, postoperative recovery strategies, and likely outcomes (eg, mortality and morbidity including delirium or cognitive impairment, as well as longer hospital stay, discharge to a skilled nursing facility, and long-term functional decline).

•Cognitive function – Ideally, baseline cognitive function is also evaluated. (See 'Assessment for frailty' above and 'Assessment of baseline cognitive function' above.)

•Current medications – Obtaining an accurate prescription and over-the-counter medication history is important to identify drugs potentially relevant for anesthetic care, and affords an opportunity for reconciliation of the patient’s medication schedule. (See 'Medication history' above.)

•Assessment of institutionalized patients – Challenges include dementia and the likely presence of multiple comorbidities and/or frailty. (See 'Evaluation of the institutionalized patient' above.)

●Preoperative testing – Routine preoperative testing is not recommended before minor procedures in older adults. Specific considerations include (see 'Preoperative testing' above):

•An electrocardiogram (ECG) is not required based on age criteria, but is reasonable for patients with known cardiovascular disease and/or risk factors if intermediate or high risk surgery is planned (table 5 and table 6).

•A chest radiographs (CXR) is only ordered if symptomatic cardiac or pulmonary disease is suggested by clinical evaluation and/or thoracic surgery is planned.

•Hemoglobin may be obtained before major surgical procedures with significant expected blood loss, and in individuals likely to have preoperative anemia (eg, due to a known underlying condition) unless the scheduled procedure is minor. In some cases, surgery may be postponed to diagnose the cause and correct anemia when feasible (algorithm 1).

•Preoperative creatinine and albumin may be measured before moderate- or high-risk surgery in frail older patients or those with a known history of liver disease or chronic illness.

●Choice of anesthetic technique – The requirements of the surgical procedure, coexisting disease(s), the need to prevent postoperative complications, and patient preferences guide the selection of anesthetic techniques. Neuraxial or other regional anesthetic techniques may reduce pulmonary complications and need for postoperative mechanical ventilation compared with general anesthesia, particularly in older patients with chronic obstructive pulmonary disease. However, general anesthesia may be preferred due to patient-specific factors such as chronically administered anticoagulant or antiplatelet medications, hypovolemia, or patient anxiety, reluctance to be awake, or inability to cooperate, communicate, or lie comfortably in the position necessary for surgery. (See 'Neuraxial versus general anesthesia' above.)

●Dosing of anesthetic agents – Dosing should be age-adjusted to avoid excessive anesthetic depth since older adults are more sensitive to these agents due to age-related changes in pharmacokinetics and pharmacodynamics; older adults may also have slower clearance of these agents. (See 'Selection and dosing of anesthetic agents' above.)

•Intravenous (IV) agents – We suggest using reduced doses with a longer interval between repeat doses and slow administration of bolus injections (Grade 2C). Specific dosing recommendations are outlined above. (See 'Intravenous anesthetic and adjuvant agents' above.)

•Inhalation agents – We suggest targeting an age-adjusted end-tidal anesthetic concentration (Grade 2C). Subsequently, continuous monitoring is used to maintain adequate anesthetic depth, with the goal of avoiding concentrations that are either too low or excessively high (figure 3 and figure 4 and figure 5). (See 'Inhalation anesthetic agents' above.)

•Neuromuscular blocking agents (NMBAs) – We use NMBAs sparingly when possible, and we use a peripheral nerve stimulator to guide dosing. Age-related reductions in hepatic metabolism and renal excretion may result in prolonged duration of action. It is important to ensure reversal of neuromuscular blockade if extubation is planned at the end of the surgical procedure. (See 'Neuromuscular blocking agents' above.)

●Monitoring – Older patients undergoing general anesthesia or monitored anesthesia care with sedation require vigilant intraoperative monitoring of oxygen saturation, respiration, and end tidal carbon dioxide levels since they are particularly susceptible to developing airway obstruction, hypoxemia, hypercapnia, or aspiration (due to reduced pharyngeal sensitivity). (See 'Monitoring' above and 'Monitored anesthesia care with sedation' above.)

●Postoperative pain management – Although opioids may precipitate or worsen delirium, inadequate pain relief is also associated delirium and other morbidity. To reduce these risks, we employ a multimodal approach to pain management with acetaminophen, other nonopioid alternatives such as nonsteroidal antiinflammatory drugs (NSAIDs), and/or continuous epidural analgesia, peripheral nerve blocks, or local anesthetic infiltration when feasible. If IV opioids are necessary for pain control in the immediate postoperative period, doses are reduced. If additional systemic opioid doses are needed, patient-controlled analgesia (PCA) should be implemented. (See 'Postoperative pain management' above.)

●Outcomes

•Mortality and morbidity – Although older age is a risk factor for perioperative mortality and morbidity (delirium, cardiovascular, pulmonary, or renal complications), the impact of pre-existing functional status, coexisting comorbidities, frailty, and invasiveness of the surgical procedure are more important predictors of recovery. (See 'Mortality and morbidity' above.)

•Recovery – Functional recovery after surgery (ie, for activities of daily living and independent activities of daily living) is highly variable in older adults. Hospital readmission is significantly higher after either inpatient or outpatient surgery in older patients, particularly those with heart failure or coronary artery disease. (See 'Recovery' above.)

ACKNOWLEDGMENT — The editorial staff at UpToDate acknowledge Jeffrey H Silverstein, MD, now deceased, who contributed to an earlier version of this topic review.