Adapted from Mukherjee D, Eagle KA: Perioperative cardiac assessment for noncardiac surgery: eight steps to the best possible outcome. Circulation 107:2771–2774, 2003.
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.
Table 50.2
Changes in Cardiovascular Physiology in Healthy Individuals Between Ages 20 and 80 Years of Age
| Cardiovascular Physiology | Change in Peak Response Between 20 and 80 Years |
| LV end-diastolic volume | ↑ 20% males; ↔ females |
| LV end-systolic volume | ↑ 20% males; ↔ females |
| Ejection fraction | ↔ |
| Stroke volume | ↑ 20% males; ↔ females |
| Heart rate | ↓ 10% |
| Cardiac output | ↔ males; ↓ 15% females |
| Stroke work | ↑ 15% |
| Early diastolic filling rate | ↓ 50% |
| Systolic arterial pressure | ↑ 15% |
| Systemic vascular resistance | ↔ males; ↓ 45% females |
Heart
It is difficult to determine which changes in the cardiovascular and circulatory systems represent “normal” aging and which are pathologic; more research on healthy older adults is needed to address this issue. Current research suggests that overall heart size in healthy older adults does not change significantly with age.27 However, there are many cellular and biochemical changes associated with older age.16,24,28 These changes include altered growth-controlling factors, impaired excitation-contraction coupling, impaired calcium homeostasis, increased myocyte apoptosis, and an increase in atrial natriuretic peptide secretion.
Table 50.2 outlines expected changes in cardiovascular physiology among healthy adults. Cardiac senescence can result in a number of functional impairments, which can include decreased mechanical and contractile efficiency, prolongation of the contraction phase, stiffening of myocardial cells, stiffening of valves and mural connective tissue, decreased number of myocytes, increased myocyte size, increased rate of myocyte apoptosis, and a blunted beta-adrenoceptor–mediated inotropic response.29–31
There is tremendous variability in both the level and intensity of age-related changes to the heart. In nonstressful conditions, the normal aging heart functions appropriately. Under stress or with damage from disease, the effects of age become more profound and can lead to functional limitations and reduced quality of life for the patient.
Respiratory System
The structural and age-related changes that can occur in the respiratory system are clinically influential to the perioperative care of the older adult patient. Structurally, an increase in chest wall rigidity increases the work of breathing. By the time an individual is 70 years of age, an approximately 20% decrease in respiratory muscle strength and endurance and a 15% decrease in alveolar surface area are seen. Older patients have an attenuated response to hypoxemia and hypercapnia. Changes in lung volume include a 20- to 40-mL/yr decrease in vital capacity, a 30% increase in residual volume by the age of 70 years, increased closing volume, and a 0.05% annual decrease in gas exchange.32
These changes in the older adult patient may hinder the ability of the patient to meet additional postoperative workloads, thus increasing the risk for acute respiratory failure. The older adult patient is more likely to develop apnea in response to opioids and benzodiazepines. The blunted response to hypoxia and lower baseline arterial oxygen tension increases the risk of postoperative hypoxemia, which can contribute to myocardial ischemia and infarction.25
Renal System
The kidneys have a crucial role in fluid and electrolyte balance. As with other body systems, the aging process affects the efficiency of the kidneys and the urinary and renal systems. Age-related changes in renal function can elevate cardiovascular risk in older adults and make them more prone to hypervolemia and hypovolemia, hypertension or hypotension, and heart failure. By the age of 70 years, glomerular filtration rate decreases at least 30% and as much as 50%; cortical nephrons are decreased; decreases are seen in renal blood flow, ability to concentrate urine, ability to conserve sodium, and tubular secretion; thirst perception is lowered; and a 10% to 15% reduction in total body water is seen.33
Attention to fluid and electrolyte balance is of the utmost importance in the perianesthesia care of the older patient. Altered thirst, rennin response, and ability to concentrate urine are likely to facilitate sodium and volume depletion, which may disrupt the Starling mechanism and challenge the older patient’s ability to maintain cardiac output and arterial pressure during periods of increased demand.
Hepatic Function
By the time an individual is 80 years old, an approximate 40% reduction in hepatic mass and a 40% decrease in hepatic and splanchnic blood flow are seen. Decrease in the activity of hepatic cholinesterase and microsomal demethylation pathway may also accompany increasing age.34,35 These changes lead to an impaired ability to meet the increased demands of metabolism, biotransformation, and protein synthesis after surgery. Drugs that rely on hepatic metabolism have a prolonged effect for older adults. For prevention of hepatic injury from medication, hypoxia, or transfusion, careful attention to appropriate drug dosage and adequate oxygenation should be made.
Thermoregulation
Due to changes in the dermis and hypodermis, fat cells become thinner with age, which may affect temperature regulation. Changes to temperature regulation affect the shivering and sweating responses and, therefore, perioperative hypothermia, which can impose increased demands on the cardiovascular system, should be considered.17,36–39 Specifically, perioperative hypothermia exerts a number of adverse effects including prolonged drug action,40 negative postoperative oxygen balance,41 immune dysfunction,42 and subsequent increased incidence of wound infection.43 Cardiac changes include a leftward shift of the hemoglobin-oxygen saturation curve, increased vascular resistance, cardiac arrhythmias, and up to a fourfold increase in cardiac output and oxygen consumption associated with rewarming and shivering.42 Special care to maintain normothermia can minimize the risk of postoperative ischemia and angina in older patients.
Sensory System
Although sensory changes are significantly affected by lifestyle, by midlife most individuals experience presbyopia (age-associated vision change) and presbycusis (age-associated hearing change). Being mindful of sensory changes improves the care for patients.
Communication with a person with age-associated hearing loss, or presbycusis, can be improved by:
• Always approaching the patient from the front. Face the patient when you speak. This action enhances the patient’s ability to hear you and demonstrates interest and respect.
• Identifying yourself, stating your name and the intention of your visit.
• Including the patient in the conversation unless the patient tells you otherwise.
• Addressing the person by last name unless asked to do otherwise. Avoid elderspeak or pet names such as “honey” and “sweetie.”
• Using good eye contact. Use a positive friendly facial expression. Elders are much better at interpreting social cues and notice negative messages much easier than younger people.
• Using expanded speech and speaking in a lower pitch, rather than raising the voice. This action is helpful because presbycusis is marked by loss of high pitches, and raising your voice also raises your pitch. Also, a lower pitch is more calming.
• Using proper enunciation. Presbycusis affects “S” and “F” sounds most frequently.
• Encouraging the patient to use any assistive devices they normally use.
• Being certain that the environment is communication friendly and is a low-distraction and low-noise environment. Presbycusis specifically affects a person’s ability to filter ambient sound.
• Using multiple methods of communication is helpful, providing both verbal and written instructions. Use written instructions if hearing loss is significant.
Communication with a person with age-associated vision loss, or presbyopia, can be improved by:
• Using large-print (sans serif, high-contrast print is best).
• Approaching an individual face-to-face.
• Certifying that an older adult has sufficient time to adjust to light changes and that stairs and walkways are clutter-free and clearly marked. Presbyopia specifically affects the ability to adjust between light and dark surroundings and depth perception.
A person-centered approach and respectful language are foundational to providing quality care and assisting patients to maintain a sense of self. Frequently, ageist stereotypes lead to inaccurate assumptions about the patient’s values and goals for recovery. It is important to be aware of use of ageist language in communication with both patients and family members regarding adherence and performance. Poor cognitive performance, once thought to be the result of age-related cognitive decline, is now understood to be the result of extraneous variables such as sensory changes, fatigue, educational differences, hypermotivation, and polypharmacy.
The Aging Mind: An Overview
Memory and Cognition
The majority of older adults perform well cognitively in day-to-day functioning throughout late life. Although cognitive changes do not significantly affect day-to-day functioning in the majority of elders, anyone in a vulnerable state (e.g., hospitalization, illness, injury) may show poor concentration, confusion, and disorganized thought patterns. Long-term memory is not altered as a part of normal aging, but attentional abilities and working memory are often affected as part of normal aging. By 80 years of age, these affects may be amplified due to stress, illness, and injury.
Compared with younger cohorts, older adults may need more time to encode new information as deeply; this may affect information retrieval. This difference is the result of age-related factors (anatomic changes in the brain, slower sensory encoding, cohort differences in the use of memory strategies, and difficulty filtering irrelevant environmental stimuli and noise) as well as ability-extraneous variables such as fatigue, education, and hypermotivation. Gerontological research indicates that older adults trained in memory strategies can improve performance on cognitive tasks. Although these changes do not typically affect day-to-day functioning, they can affect understanding and compliance to the care plan, particularly in high-stress situations in which cognitive and physical reserve are challenged. Therefore, avoidance of inaccurate assumptions from ageist attitudes and careful communication are essential to quality care. Implementing adult-learning techniques and providing care plan information in multiple formats (verbal and print) can be helpful.
Dementia and Delirium
Differentiating dementia, cognitive impairment, and delirium is essential for the anesthesia provider. Whereas true dementias are inherently irreversible, delirium and cognitive decline are potentially reversible if properly diagnosed and treated. Interprofessional assessment from qualified gerontologically trained professionals is essential to accurate diagnosis.
It is well established that dementia is not a normal or inevitable part of the aging process. Although Alzheimer disease (AD) is the most common type of dementia and accounts for 60% to 70% of all dementias, other forms of dementia also affect older adults. For example, vascular dementia, Lewy body dementia, and frontotemporal dementia are also prevalent forms.
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