50 Care of the older patient
Activities of Daily Living: Daily self-care activities, including bathing, eating, dressing, toileting, and grooming.
Cognitive Impairment: Reduction in mental functioning that results in cognitive changes, including short-term memory loss and impaired judgment and thinking.
Cultural Competence: The ability to provide culturally relevant and appropriate care to persons with diverse values, beliefs, and behaviors.
Dementia: A loss of brain function that occurs with certain a group of diseases. It affects memory, thinking, language, judgment, and behavior. The most common form of dementia is Alzheimer disease.
Geriatrics: Medical aspect of gerontology in the treatment of acute and chronic conditions in older adults (i.e., a person 65 years of age or older).
Gerontology: The scientific study of age, aging, and the aged using a lifespan, biopsychosocial approach.
Health: A state of physical, mental, and social well-being.
Instrumental Activities of Daily Living: The activities performed by people living independently, including meal preparation, money management, shopping, and taking medications.
Person-Centered Care: Focuses on individual care needs by understanding how the individual experiences his or her situation in order to most effectively address needs and desired outcomes.
Presbycusis: Age-associated hearing changes or the slow loss of hearing as people get older.
Presbyopia: Age-associated visual changes of diminished ability to focus on near objects.
The world’s population is aging at a rapid pace. The current population of adults older than 65 years constitutes 34 million people, or approximately 13% of the population. Projections suggest that by 2030, 69 million individuals will be older than 65 years, or approximately 19% of the population.1 This trend represents two important phenomena: the increase in life expectancy and the aging of the baby boomers (those born between 1946 and 1964) who began to turn 65 in 2011. Older adults are not only living longer; they are doing so free of disease and disability. According to “compression of morbidity theory,” the limit to life span may be stretched significantly with a concurrent delay in the onset of chronic conditions.2 This stretching of the lifespan would result in a population living longer and healthier than any generation to date.
The World Health Organization defines health as a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.3 In this view, older adults may then perceive themselves as healthy despite physical limitations or disease. It is essential in caring for the older patient to recognize overall health from physiologic, psychological, and social perspectives. In assessing an older adult’s health, an appropriate delineation is between an individual’s chronological age versus their functional age. Some individuals who are more judicious in using preventive health measures and who maintain more active lifestyles may have little decline or age-related comorbidities, reflecting greater functioning relative to chronologic age, whereas others may have multiple comorbidities, perhaps at an even earlier age, reflecting functional limitations relative to age. Gerontologists often use the distinctions young-old, old-old, and oldest-old to differentiate between older adults. In terms of functional capacity, gerontologists also describe aging in terms of primary, secondary, and tertiary aging.4 Primary aging represents aging free of disability and disease. Secondary aging encompasses developmental changes affected by lifestyle, disease, or factors that are not inevitable processes of biologic aging. Tertiary aging is rapid loss and decline experienced at the end of life. Differentiation of age and functional capacity is essential to focus attention on the diversity of this population and establish some markers that are helpful in meeting the individual needs of older adults.
Many different chronologic markers are used for governmental determinations and legal purposes (i.e., 40 years of age for age discrimination determination, 50 years of age for AARP membership, and 65 plus years of age for Social Security). As a result, no one definition of old-age, elderly, or older adult is accepted. Because no biomarkers exist, a definition of when old age begins is difficult because individuals age at different rates than is reflected simply by chronologic age. The growing complexity and diversity of the aging population mandates a holistic interprofessional biopsychosocial approach to care to move beyond a simplistic chronologic marker of age toward a more accurate functional assessment.
Care of the older adult patient is particularly important in the postanesthesia care unit because of the normal physiologic changes that occur with aging and may be compounded by multiple comorbid conditions. With advancing age, the potential risks of complications from surgical procedures increases, because of the potential for multiple comorbidity. Morbidity and mortality are at least fourfold more likely in older adults and twentyfold more likely in emergency procedures.5 These conditions include congestive heart failure, insufficient oxygenation of the blood, improper elimination of carbon dioxide, fluid and electrolyte imbalance, diabetes and the associated complications, and drug toxicity.
Advances in anesthetic care have resulted in a substantial reduction in perioperative morbidity and mortality in the aging population.6 Successful anesthesia care of the older adult patient is highly dependent on the knowledge of the changes associated with aging and the effects of anesthesia on the older patient. Therefore, the focus of this chapter is primarily on the normal aging changes that take place in addition to the disease states associated with aging and their translation to functional status, especially of the cardiovascular system. It is essential to keep in mind throughout this chapter that the rate at which each individual and organ system age is highly individualistic. This phenomenon is referred to as the individuation of aging.7 Individual genes, hormonal balance, diet, medications, environmental exposure, and emotional stress and burden are all factors that influence individual biological aging.
The aging body: an overview
Cardiovascular system
Cardiovascular health is essential to the overall well-being of the older adult. Healthy cardiovascular functioning can be maintained across the lifespan, and disease can be prevented through healthy lifestyle choices and preventive care; however, heart disease remains the leading cause of death for both males and females.8 Of all of the body systems, the cardiovascular system exerts the most influence on anesthesia and general health outcomes.8 Annually, more than 1 million surgeries are complicated by adverse cardiac outcomes, such as postsurgical myocardial infarction or death from cardiac disease.9 This risk can be reduced with a thorough preoperative interview and assessment that examines functional capacity and existing comorbidities and the current treatment regime.8
Functional capacity
The assessment of functional capacity reflects the ability to perform activities of daily living that require sustained aerobic metabolism.10 Exercise tolerance in daily life is the best indicator of the quality of biologic age. It is also one of the most important predictors of perioperative outcomes in older adult patients.11,12 Poor exercise tolerance reflects low functional capacity and greater severity of disease. Functional status is usually reflected in metabolic equivalent (MET) levels. One MET corresponds to a resting oxygen consumption of 3.5 mL/kg/min. MET scores are multiples of resting metabolism, which are used as a point of reference to describe the oxygen demands of any activity.13 Box 50-1 provides examples of MET ratings of activities. Functional status can be ascertained during the preoperative screening. Questions addressing daily activities and assessing lifestyle habits, such as house cleaning, vacuuming, walking, and stair climbing, and any participation in regular exercise should provide adequate information for a subjective assessment of the patient’s functional status.14 Objective assessment can be made via exercise testing. Patients who are unable to regularly meet a 4 MET demand have an increased perioperative cardiac risk.15
BOX 50-1 Estimated Energy Requirements for Various Activities
Adapted from Hlatky MA, et al: A brief self-administered questionnaire to determine functional capacity, Am J Cardiol 64:651–654, 1989; Fletcher GF, et al: Exercise standards: a statement for healthcare professionals from the American Heart Association, Circulation 104:1694–1740, 2001.
Structural changes
There are several structural changes frequently seen with advancing or older age that occur within the cardiovascular system. Changes of the arteries include dilation of the large arteries accompanied by thickening of the arterial walls and changes in wall matrix. An increase in elastin and collagen tissues in the heart and arteries can cause arterial wall thickening and an increase in smooth muscle tone.16–19 Increased vascular stiffness leads to elevated systolic arterial pressure and pulse wave velocity, early reflected pulse pressure waves, and late peak systolic pressure, which trigger a series of cardiac adjustments. A resultant augmenting of aortic impedance and cardiac mechanical load may be seen.
Clinically elevated left ventricular afterload causes an increase in myocyte size and thickening of the left ventricular wall.18 When combined with augmentation of aortic impedance, elevated afterload prolongs myocardial contraction. This adaptive measure preserves cardiac function by lengthening the amount of time available for the heart to eject blood into stiffened vasculature. The resultant prolonged myocardial contraction delays ventricular relaxation time, which manifests as a decrease in early ventricular filling.19–23
Between the ages of 20 and 80 years, the rate of early diastolic filling decreases by 50%.24 This decrease may be the result of a prolonged isovolumetric relaxation time between aortic valve closure and mitral valve opening. With aging, alterations in calcium release from the myoplasm to the sarcoplasmic reticulum may contribute to the changes in early diastolic filling.16,23
For maintenance of stroke volume, end diastolic filling is increased.16 The effectiveness of this strategy is dependent on the atrial contribution to end diastolic filling; therefore left atrial size increases.20 Enlargement of the atria raises the likelihood of atrial fibrillation among elders, thus underscoring the importance of stable hemodynamics to ensure normal sinus rhythm.
Gender differences may be found in certain age-related changes in cardiac function.16 Men seem to have different compensatory mechanisms than women. To maintain stroke volume in the presence of the age-associated decrease in heart rate, men have an increase in left ventricle end-systolic volume and left ventricle end-diastolic volume. This mechanism preserves cardiac output in aging men, whereas a 15% decrease is seen in cardiac output in women. Table 50-1 summarizes cardiac changes in response to exercise that occur with age.25
Table 50-1 Changes in Cardiovascular Response to Exercise with Comparison of 20 and 80 Years of Age
| CARDIOVASCULAR PHYSIOLOGY | PEAK RESPONSE AT AGE 20 YEARS | CHANGE IN PEAK RESPONSE BETWEEN 20 AND 80 YEARS |
|---|---|---|
| LV end-diastolic volume | ↔,↓ | ↑30% males; ↔ females |
| LV end-systolic volume | ↓ | ↓100% |
| Ejection fraction | ↑ | ↓15% |
| Stroke volume | ↑ | ↔ |
| Heart rate | ↑ | ↓25% |
| Cardiac output | ↑ | ↓25% |
| Stroke work | ↑ | ↑15% males; ↔ females |
| SVR | ↓ | ↑30% |
| Oxygen consumption | ↑ | ↑50% |
| Plasma catecholamines | ↑ | ↑ |
| Myocardial contractility | ↑ | ↓60% |
| Beta-adrenergic stimulation | Fully functional | ↓ |
LV, Left ventricular; ↔, no change; ↑, increase; ↓, decrease; SVR, systemic vascular resistance.
Adapted from Eagle KA: Perioperative cardiac assessment for noncardiac surgery: eight steps to the best possible outcome, Circulation 107:2771–2774, 2003.
The most clinically relevant age-related changes in cardiovascular function are increased myocardial stiffness and all of the subsequent compensatory actions and blunted beta-adrenergic responses. During increased oxygen demand, the most relevant changes in the older patient are autonomic reflex dysfunction and beta-adrenoreceptor responsiveness. See Table 50-1 for cardiovascular age-related changes to upright peak exercise.
Cardiovascular risk assessment
Preoperative risk assessment is an important component in minimizing perioperative morbidity and mortality. This assessment is best achieved through the work of an interdisciplinary team that consists of the patient, the primary care physician, the surgeon, and the anesthesia professional. In addition, training and expertise are essential to the quality care of older adult patients. This assessment relies on the evaluation of the interaction of clinical markers, functional capacity, type of surgical procedure, and age. When risks are identified, measures should be used to minimize the risks before surgery and to improve immediate periprocedural outcomes and long-term clinical outcomes. Some clinical markers act as predictors of perioperative cardiovascular risk. These markers can be categorized by the perioperative risk associated with them (Box 50-2) as major, intermediate, and minor perioperative risk.11
In addition, the type of surgery coupled with the degree of hemodynamic stress incurred during the surgery are the major determining factors of perioperative risk.11,12 Emergency surgeries are particularly high risk, especially in older patients. Other high-risk surgeries include vascular, cardiac, abdominal, and thoracic surgeries.26 Box 50-3 categorizes surgery-specific risk according to the incidence rate of cardiac death and nonfatal myocardial infarction for noncardiac surgical procedures.
BOX 50-3 Cardiac Risk Stratification for Noncardiac Surgical Procedures*
