Anesthesia for Older Adults

Educational Objectives

The goal of this program is to improve management of anesthesia in older patients. After hearing and assimilating this program, the clinician will be better able to:

1. Explain the changes in the cardiovascular system associated with age.
2. List the causes of diastolic dysfunction in older adults.
3. Cite physiologic changes associated with hypothermia in older adults.
4. Compare the postoperative cognitive effects of regional vs general anesthesia in older patients.
5. Optimize use of short-acting anesthetic agents in older adults.

Summary

Demographic trends in surgery: in the year 1840, reaching the age of 60 yr placed individuals in the 95th percentile for longevity; by the year 2000, achieving 80 yr was necessary to reach the same percentile; life expectancy continues to rise, and with it, people are living longer, remaining functional, and working later into life; advances in geriatric medical care have contributed to this trend, increasing the likelihood of older patients undergoing surgical procedures; in the year 2000, 35 million individuals in the United States were >65 yr of age, constituting 12% of the population; this group accounted for 35% of all surgeries, resulting in 16 million surgical procedures annually; since then, the population >65 yr of age has doubled to 70 million, leading to a proportional increase in surgeries; the growing number of surgeries is not solely related to a larger population of older individuals but also to improved surgical techniques and safer anesthesia

Mortality rate from anesthesia: was 18 per 10,000 cases in 1950; by 1980, this figure had dropped to 0.7 per 10,000, and by 1989, it further decreased to 0.04 per 10,000, with further improvements since then

Cardiovascular aging: 1) there is a reduction in parasympathetic tone, leading to a dominance of sympathetic tone; 2) vessels and the heart become stiffer; 3) there is a decrease in myocardial mass, although the remaining myocardium generally functions normally; these physiologic changes reduce systemic vascular resistance reserves, impair baroreflex responses, and diminish sensitivity to beta-agonist drugs; despite this, beta-blocker sensitivity remains because of the increased sympathetic tone

Diastolic dysfunction: is common in older adults because of reduced early diastolic filling and reliance on atrial contraction for left ventricular filling; the most frequent dysrhythmia in this population is atrial fibrillation, which may occur intermittently, including during surgery; diastolic dysfunction is a leading cause of congestive heart failure in those >75 yr of age, requiring higher left atrial pressures for ventricular filling; arterial stiffness contributes to increased systolic blood pressure and wider pulse pressure; coupled with reduced myocardial mass, cardiac reserve diminishes, limiting the ability to enhance cardiac output and oxygen delivery during stress; reduced venous compliance further compounds this issue; stiff veins impair the ability to accommodate volume changes, reducing tolerance for hypovolemia

Anesthetic consideration (AC) for cardiovascular aging: volatile anesthetics, which depress myocardial function, reduce systemic vascular resistance, and act as venodilators, lead to significant hypotension; this hypotensive effect is poorly tolerated, especially in patients receiving β-blockers or angiotensin-converting enzyme (ACE) inhibitors; additionally, older patients exhibit a reduced ejection fraction response to stress, increasing their reliance on heart rate to maintain cardiac output; unlike younger individuals who can increase their ejection fraction by 20% during exercise, older patients achieve only a 4% increase; their maximum oxygen consumption is similarly limited, often reaching only 2 to 5 metabolic equivalents compared with 10 metabolic equivalents in younger adults

Assessing functional capacity in older patients: formal stress testing is not always practical, so history-taking is essential; questions about the ability to climb stairs, exercise routines, walking distance, and reasons for exercise limitations help gauge cardiovascular reserve; shortness of breath or chest pain with exertion warrants further investigation

Age changes of lung: most lung volumes decrease, including the inspiratory reserve volume (the amount of air that can be inhaled above normal tidal volume) and the expiratory reserve volume (the amount exhaled below tidal volume); the residual volume, representing the air remaining in the lungs after maximal exhalation, increases; vital capacity declines at a rate of ≈25 mL/yr starting at age 20 yr; although total lung capacity shows a slight decrease, the ratio of functional residual capacity (the air remaining in the lungs at the end of a normal exhalation) to total lung capacity increases because of the rising residual volume; residual volume increases from 25% of total lung capacity at age 20 yr to 40% by age 70 yr; respiratory muscle power also diminishes with age, leading to a reduction in forced expiratory volume in 1 sec by 22 to 28 mL/yr; the effort required for breathing increases because lung compliance decreases, with elasticity changes occurring unevenly; this results in ventilation-perfusion mismatch, although overall airway resistance in healthy individuals remains stable

Closing capacity: increases with age; it refers to the lung volume below which small airways collapse, causing atelectasis; by age 70 yr, the closing capacity can encroach upon tidal volume, contributing to impaired oxygenation; atelectasis leads to perfused but nonventilated lung regions, causing intrapulmonary shunting; this reduces arterial oxygen tension at all inspired oxygen concentrations; in older individuals, reduced alveolar surface area further compounds oxygenation challenges; patients exhibit increased susceptibility to altitude-induced hypoxemia, making it essential to assess tolerance to higher elevations

Risk for aspiration: age-related weakening of laryngeal and gag reflexes, combined with increased gastroesophageal reflux, raises the risk for chronic aspiration; this risk is further elevated in patients using sedative medications; impaired airway protection makes aspiration a greater concern during anesthesia

Ventilation: becomes less efficient with age; enlargement of the large airways increases anatomic dead space, which refers to ventilated but non-perfused areas of the lung; this results in a higher dead space-to-tidal volume ratio, exacerbating carbon dioxide retention; coexisting pulmonary conditions, including chronic obstructive pulmonary disease (COPD), asthma, and autoimmune diseases (eg, lupus, sarcoidosis, scleroderma) further impair gas exchange; infectious lung diseases, including pneumonia, tuberculosis, and fungal infections (eg, coccidioidomycosis, aspergillosis) are additional contributors to pulmonary dysfunction

AC for age changes of lung: from an anesthetic perspective, these age-related changes and comorbidities influence oxygen delivery; oxygen consumption at rest is ≈250 mL/min, with total oxygen delivery reaching ≈1 L/min; effective oxygen delivery requires adequate hemoglobin, cardiac output, and efficient pulmonary gas exchange; age-related decreases in any of these factors reduce oxygen supply to tissues; aspiration risk necessitates consideration of airway management strategies, including awake extubation, particularly in obese patients with COPD; elevating the head of the bed before extubation minimize aspiration risk; intraoperatively, monitoring peak airway pressures is essential, as older patients are more prone to atelectasis from inadequate ventilation and barotrauma from excessive pressures; postoperatively, continuous pulse oximetry is recommended, with supplemental oxygen provided as necessary; caution is advised when weaning oxygen, as pain relief reduces respiratory drive, increasing the risk for hypoventilation; so, vigilance for delayed respiratory depression because of anesthetics and sedatives is critical

Age changes of renal and urinary systems: the kidneys shrink, leading to a reduction in the number of nephrons and a decreased glomerular filtration rate (GFR); despite the lower GFR, serum creatinine levels remain unchanged because of the concurrent loss of muscle mass; there is a slower drug clearance rate, decreased ability to concentrate or dilute urine, and reduced sodium retention; combined with a diminished thirst reflex, these factors increase the risk for hypovolemia; common comorbidities (eg, diabetes mellitus, hypertension, atherosclerosis) exacerbate these renal issues, making older patients more susceptible to fluid imbalances and poor tolerance to hypovolemia

Temperature regulation: also deteriorates with age; older adults experience decreased thermoregulatory responses, including reduced skin blood flow and impaired vasodilation or vasoconstriction; these challenges are amplified by anesthetic agents; muscle mass and subcutaneous fat are typically diminished, further compromising thermal regulation; hypothermia poses additional risks by shifting the hemoglobin oxygen dissociation curve, making oxygen less available to tissues; shivering, a response to hypothermia, significantly increases oxygen consumption, worsening oxygen delivery problems; coagulopathy is another concern, as prothrombin time rises with lower body temperatures; dysrhythmias (eg, atrial fibrillation) become more likely; hypothermia is also associated with increased infection risk

Neurologic age changes: are another concern, particularly in the context of anesthesia and surgery; postoperative delirium is common in older patients, characterized by transient confusion, reduced alertness, and disorientation; unlike younger individuals who exhibit agitation, elderly patients tend to withdraw and present with hallucinations or misperceptions; delirium has a high incidence rate, particularly following major joint surgeries or cardiopulmonary bypass, with possible associations with microemboli traveling to the brain; while unproven, this theory highlights the increased vulnerability of the older population

Postoperative cognitive dysfunction: is a more prolonged concern that may last for months or become permanent; this condition can lead to longer hospital stays and a higher likelihood of requiring long-term care; family members often notice subtle cognitive changes that are not evident to medical providers; while various mechanisms are proposed, anesthetic agents are commonly implicated; comparing regional anesthesia with general anesthesia (GA) shows inconsistent results, though speaker prefers regional approaches because of possibility it lowers risk for cognitive decline; processed electroencephalography monitoring can provide valuable information on brain activity, particularly burst suppression, which indicates periods of brain electrical silence; prolonged burst suppression correlates with an increased risk for postoperative delirium and subsequent cognitive dysfunction; recent studies suggest a link between postoperative delirium and long-term cognitive decline, underscoring the importance of prevention

AC for neurologic age changes: avoiding anticholinergics, which can precipitate confusion, and exercising caution with certain narcotics (eg, meperidine) have more pronounced adverse effects in older patients; H2 blockers (eg, cimetidine) are also associated with psychosis and should be used judiciously; H1 blockers (eg, diphenhydramine) pose similar risks; regional anesthesia or monitored anesthesia care offer some protection against delirium, although the evidence remains mixed; the American Society of Anesthesiologists (ASA) has introduced a Brain Health Initiative emphasizing the identification of high-risk patients, educating providers and patients about the risks for delirium, and promoting orientation through the use of hearing aids, glasses, and family presence

Other aspects of age changes: certain aspects of physiologic function remain well-preserved in older patients; the intrinsic contractility of the heart muscle does not weaken with age, and older adults often exhibit increased resistance to motion sickness, which correlates with a lower incidence of postoperative nausea and vomiting; long-term factual memory remains relatively intact, with declines primarily affecting short-term memory; older patients are less prone to developing spinal headaches

AC for comorbidities: most older patients in the United States present with coexisting diseases, including obesity, COPD, asthma, coronary artery disease, valvular heart disease, cerebrovascular disease, peripheral vascular disease, cancer history, endocrine disorders, hypothyroidism, and rheumatoid arthritis; anesthesiologists must be thoroughly aware of all such conditions, as they significantly influence treatment plans and the risk of complications

Complication rates: increase with the presence of multiple comorbidities; data show that patients aged 35 to 75 yr with zero or one coexisting disease experience only a modest 40% increase in complication rates; those with 2 or 3 comorbidities face a tripling of the complication rate in the same age range

AC for medications: knowledge of all concurrent medications is essential because of potential interactions with anesthetic drugs; medications commonly encountered include beta-blockers, beta-agonists, calcium channel blockers, ACE inhibitors, vasodilators, diuretics, steroids, antidepressants, sleep aids, pain medications, and herbal supplements; phosphodiesterase 5 inhibitors for erectile dysfunction are increasingly common; comprehensive understanding of these medications, their effects, adverse effects, and interactions with anesthetic drugs is crucial; anesthesiologists administer drugs that can be considered toxic in sublethal doses, so selecting the appropriate agent and dosage is vital, especially in older patients

Regional anesthesia vs GA: regional anesthesia or monitored anesthesia care serve as alternatives to GA; regional techniques can reduce the risk for cognitive dysfunction, minimize cardiac depression, and decrease postoperative nausea and vomiting; awake patients also provide superior neurofunction monitoring; reduced blood loss is another advantage, especially in some procedures (eg, hip replacements); sudden sympathectomy from spinal anesthesia can result in significant hypotension, which is less tolerable in older patients because of reduced compensatory mechanisms; high spinal blocks above the hips impair accessory respiratory muscles; contraindications for regional anesthesia include hypovolemia, infection, coagulopathy, increased intracranial pressure, and an inability to remain still; studies offer conflicting conclusions on long-term cognitive dysfunction associated with regional vs GA; while one 2010 study found no difference, a 2023 ASA report suggested better outcomes with spinal anesthesia in hip arthroplasty patients

Precautions for regional anesthesia: pre-hydration and continuous catheter techniques for gradual, controlled blockade application are recommended; continuous spinal or epidural catheters allow for precise management of sympathetic blockade and volume status; these catheters are beneficial for postoperative pain management, reducing the need for opioids

AC for drug metabolism: in cases where general anesthesia is necessary, understanding the effect of age on drug metabolism and response is essential; the minimum alveolar concentration for volatile anesthetics declines by ≈6% per decade; for instance, a patient aged 80 yr requires 30% less anesthetic than a younger patient; older individuals often experience greater blood pressure and cardiac output reductions despite lower anesthetic requirements; drug half-lives also lengthen with age; fentanyl’s half-life extends from 250 min in young adults to 925 min in older adults; so, short-acting agents (eg, remifentanil) are preferable; similarly, midazolam is preferred over longer-acting benzodiazepines, and esmolol is ideal for beta-blockade when not previously indicated; short-acting vasodilators (eg, nitroglycerin, nitroprusside) should be used with caution because of the risk for cyanide toxicity

Postoperative pain management: necessitates careful planning; older patients experience pain as acutely as younger individuals; regional anesthesia, catheter-based approaches, and nerve blocks minimize opioid use and mitigate risks for respiratory depression, hypoxia, and hypercarbia; untreated pain can lead to hypertension, respiratory compromise, atelectasis, and pneumonia; patient-controlled analgesia (PCA) can be effective, though it requires supervision to prevent misuse; a phenomenon known as PCA by proxy, where family members improperly administer doses, must be strictly prohibited; clear instructions should be provided to ensure only the patient uses the PCA device

Perioperative mortality: rates increase with age, particularly in individuals >80 yr of age; although intraoperative mortality is a concern, the most significant rise in mortality occurs ≤6 days postoperatively; survival through surgery and initial recovery does not guarantee favorable outcomes, necessitating vigilant postoperative monitoring and care

Readings

Ahmed B, Rahman AA, Lee S, et al. The implications of aging on vascular health. Int J Mol Sci. 2024;25(20):11188. doi:10.3390/ijms252011188; Cho SJ, Stout-Delgado HW. Aging and lung disease. Annu Rev Physiol. 2020;82:433-459. doi:10.1146/annurev-physiol-021119-034610; Friesen KJ, Falk J, Bugden S. The safety of meperidine prescribing in older adults: a longitudinal population-based study. BMC Geriatr. 2016;16:100. doi:10.1186/s12877-016-0275-5; Lim BG, Lee IO. Anesthetic management of geriatric patients. Korean J Anesthesiol. 2020;73(1):8-29. doi:10.4097/kja.19391; Liu M, Qi L. The related factors and countermeasures of hypothermia in patients during the anesthesia recovery period. Am J Transl Res. 2021;13(4):3459-3465. Published 2021 Apr 15; Luca E, Schipa C, Cambise C, et al. Implication of age-related changes on anesthesia management. Saudi J Anaesth. 2023;17(4):474-481. doi:10.4103/sja.sja_579_23; Mahender A, Chavan SS, Saroa R, et al. Recent advances in geriatric anaesthesia. Indian J Anaesth. 2023;67(1):152-158. doi:10.4103/ija.ija_1029_22; Miller D, Lewis SR, Pritchard MW, et al. Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery. Cochrane Database Syst Rev. 2018;8(8):CD012317. doi:10.1002/14651858.CD012317.pub2; Murthy S, Hepner DL, Cooper Z, et al. Controversies in anaesthesia for noncardiac surgery in older adults. Br J Anaesth. 2015;115 Suppl 2(Suppl 2):ii15-ii25. doi:10.1093/bja/aev396; Pellegrini CN, Buzkova P, Oesterle A, et al. Dysregulated carbohydrate and lipid metabolism and risk of atrial fibrillation in advanced old age. Heart. 2023;109(8):606-611. doi:10.1136/heartjnl-2022-321633; Punjasawadwong Y, Chau-In W, Laopaiboon M, et al. Processed electroencephalogram and evoked potential techniques for amelioration of postoperative delirium and cognitive dysfunction following non-cardiac and non-neurosurgical procedures in adults. Cochrane Database Syst Rev. 2018;5(5):CD011283. doi:10.1002/14651858.CD011283.pub2; Roman MA, Rossiter HB, Casaburi R. Exercise, ageing and the lung. Eur Respir J. 2016;48(5):1471-1486. doi:10.1183/13993003.00347-2016; Sung VW, Johnson N, Granstaff US, et al. Sensitivity and specificity of stroke symptom questions to detect stroke or transient ischemic attack. Neuroepidemiology. 2011;36(2):100-4. doi: 10.1159/000323951. Epub 2011 Feb 10. PMID: 21311197; PMCID: PMC3214935; Wijsenbeek M, Suzuki A, Maher TM. Interstitial lung diseases. Lancet. 2022;400(10354):769-786. doi:10.1016/S0140-6736(22)01052-2.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Barker is a consultant for Masimo Corp. Members of the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Barker was recorded exclusively for Audio Digest. Audio Digest thanks Dr. Barker for his cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 1.75 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 1.75 CE contact hours.

Lecture ID:

AN672101

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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