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Two principles should be kept in mind when performing preoperative evaluation of a geriatric patient (see Chapter 25 ). First, one should have a high index of suspicion for disease processes commonly associated with aging. Common diseases of the elderly may have a major impact on anesthetic management and require special care and diagnosis. Cardiovascular disease and diabetes are particularly prominent in this population. Pulmonary complications have an incidence of 5.5% and are the third leading cause of postoperative morbidity in elderly patients undergoing noncardiac surgery.[64] Pulmonary diagnosis and optimization cannot be overemphasized preoperatively. Management of cardiovascular disease, diabetes, and pulmonary disorders is discussed elsewhere in this textbook. Second, one should assess the degree of functional reserve of specific, pertinent organ systems, as well as the patient as a whole, before surgery. Laboratory and diagnostic studies, the history and physical examination, and determination of functional capacity should attempt to evaluate the patient's physiologic reserve. Such evaluation
Autonomy is the most important principle in health care decision making with the elderly.[65] However, autonomy implies mental competence. The legal standards for competence include the ability to communicate a choice, understand relevant information, appreciate the current situation and its consequences, and manipulate information rationally.[66] Cognitive and sensory difficulties frequently jeopardize informed consent in frail elderly patients. Dementia, depression, hearing difficulty, and stroke may all interfere with the ability to make independent decisions. If one's ability to make decisions becomes severely impaired, a surrogate must give consent. However, caution must be exercised in this situation. A low rate of agreement has been demonstrated when comparing the health care decisions made by surrogates with the desires of the elderly patients involved.[67] Advance directives, when available, can be extremely helpful, but even with them, difficult problems remain. Issues of consent and end-of-life decisions in the elderly are complex and familiar to the practicing anesthesiologist. Take, for example, the debate surrounding a patient who comes to the operating room with "do-not-resuscitate" orders. Frequently, there are no easy answers to these ethical dilemmas.[68]
Recognizing acute illness and exacerbation of chronic disease in the elderly can be challenging. Oftentimes, acute illness may have an atypical manifestation.[69] For instance, the appearance of pneumonia in the elderly may be heralded by such uncharacteristic features as confusion, lethargy, and general deterioration of condition.[70] [71] It must be kept in mind that there may be significant differences in the manifestation of disease in demented versus nondemented patients. Studies suggest that the nonspecific manifestations of disease in older people are primarily linked to the presence of dementia rather than a characteristic feature of the aging process.[72]
Dementia is common in the elderly population. Alzheimer's disease is present in 6% to 8% of patients 65 years and older. Hospitalization and surgery represent a challenge to the demented patient. Agitation, in particular, is an issue in these patients.
It is important to determine the presence of cognitive deficit during the preoperative evaluation. Preoperative cognitive deficit has a direct bearing on postoperative emergence and perioperative morbidity. For one, cognitive deficits are associated with poorer rehabilitation outcomes[73] and higher surgical mortality.[74] In terms of choice of anesthetic technique, it is controversial whether the administration of general anesthesia accelerates the progression of senile dementia[75] because not all studies support this view.[76] Perhaps most important, dementia is a predictor of postoperative delirium.[77] As discussed elsewhere in this chapter, delirium is a major cause of morbidity and mortality in the elderly. Being able to predict its onset will assist in instituting protocols to decrease its incidence.
Accurate diagnosis of dementia is not always an easy task. For purposes of preoperative evaluation, the Mini-Mental State Examination allows for quick screening of baseline cognitive status.[78] In addition, insight may be gained by speaking with the patient's family concerning baseline function and activities of daily living. The Mini-Mental State Examination is available on numerous websites (e.g., www.fpnotebook.com/NEU67.htm).
In addition to the issue of preoperative cognitive deficit and its effect on outcome, there is also the separate topic of postoperative development of new-onset cognitive dysfunction. Whether anesthesia contributes to postoperative cognitive dysfunction is controversial and an area of intense investigation. After coronary artery bypass grafting there is a 42% incidence of cognitive decline 5 years postoperatively.[79] The importance of perioperative cognitive decline is the strong relationship between neurocognitive functioning and quality of life 5 years after cardiac surgery. Lower 5-year overall cognitive function scores have been associated with lower general health and a less productive working status.[80]
Major noncardiac surgery in patients older than 65 years causes short-term, but not long-term cognitive dysfunction.[81] The reported incidence of postoperative cognitive dysfunction is 26% at 1 week and 10% at 3 months.[82] Postoperative cognitive decline is reversible in most cases but may persist in approximately 1% of patients.[83] Predictors of postoperative cognitive decline include age, low educational level, preoperative cognitive impairment, depression, and the specific surgical procedure. [84] [85] In general, with noncardiac procedures, anesthesia and surgery have a modest impact on long-term cognitive decline of the elderly, although this effect may be more robust in the aged.[75] [86] [87]
Postoperative delirium is one of the most important issues in the perioperative management of elderly patients. Patients in whom delirium develops have higher rates of major complications and higher rates of discharge to long-term care or rehabilitative facilities.[88] Delirium has negative effects such as delaying postoperative mobilization, prolonging treatment on the ward, and preventing early rehabilitation. Subsequently, hospital stay is extended with resultant increased morbidity and delay in functional recovery.[89] [90] Studies clearly show that in certain surgical populations, delirium is one of the most important factors predictive of mortality, [91] as well as poor long-term outcome, even in patients without previous cognitive impairment.[92] [93]
Delirium is a separate entity from postoperative cognitive dysfunction, although it can occur in association with the latter. Delirium is a syndrome manifested by a combination of signs and symptoms. The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) contains the diagnostic criteria for delirium[94] :
Many clinicians have begun using the confusion assessment method (CAM score) to determine the presence of postoperative delirium.[95] The CAM score is determined by using an algorithm that examines the patient for (1) acute and fluctuating changes in mental status, (2) inattention, (3) disorganized or incoherent thinking, and (4) altered level of consciousness. The diagnosis of delirium is met by a positive CAM score. A CAM score is considered to be positive if the patient displays items 1, 2, and 3; items 1, 2, and 4; or items 1, 2, 3, and 4. Although the CAM score confirms the presence of delirium, the weakness of the CAM score lies in its inability to distinguish the severity or duration of delirium.
The two major psychomotor types of delirium are hypoactive and hyperactive. The hyperactive form is the most readily recognizable. However, it is the hypoactive form that appears to be more common and the most easily missed, [96] which may account for the wide range of reported incidences of postoperative delirium. Acute confusion in the elderly has been reported to occur in 15% to 25% of hospitalized patients,[97] [98] [99] with overall postoperative rates of 5% to 15%.[89] More than half the patients undergoing open heart and orthopedic surgery are affected. For instance, postoperative delirium in hip fracture patients has an estimated incidence of 30% to 45%.[100]
The mechanism of delirium is controversial. There is probably no final common pathway to delirium, but rather, delirium is the final common symptom of multiple neurotransmitter abnormalities.[101] Reduced cholinergic function, excess release of dopamine, norepinephrine, and glutamate, and both decreased and increased serotonergic and GABA activity may all be involved in the development of delirium. Another proposed mechanism that may play a role in the occurrence of delirium is increased cerebral secretion of cytokines during physically stressful events. Because cytokines can influence the activity of various neurotransmitter systems, these mechanisms may interact.[102] After cardiac surgery there appears to be a component of brain injury as evidenced by changes in serum levels of S-100-β protein and neuron-specific enolase.[103] It is unclear whether brain injury is an important mechanism of postoperative delirium in noncardiac surgery patients. Blood concentrations of S-100-β protein increase after abdominal surgery and appear to be related to postoperative delirium.[104] Of particular interest are reports demonstrating an association between cerebral microemboli and postoperative neuropsychological changes during total-hip arthroplasty. [105]
Numerous predictors and risk factors for delirium have been determined
( Table 62-5
).[97]
[98]
[106]
[107]
[108]
[109]
[110]
The type of anesthesia (regional versus general) and intraoperative hemodynamic
complications have not been associated with delirium.[111]
However, delirium has been associated with greater intraoperative blood loss, more
postoperative blood transfusions, and postoperative hematocrit
| Functional impairment |
| Cognitive impairment |
| Sleep deprivation |
| Immobility/poor physical condition |
| Visual impairment |
| Hearing impairment |
| Dehydration |
| Advanced age |
| Low serum albumin level |
| Alcohol abuse |
| Abnormal preoperative serum sodium, potassium, or glucose level |
| Comorbidity, American Society of Anesthesiologists class III or IV |
| Anticholinergic drugs |
| Depression |
| High-risk surgery per American Heart Association guidelines |
Recognition and treatment of any variables that predispose a patient to delirium are important. Prophylactic treatment includes correction of metabolic and electrolyte disorders, as well as therapy for neuropsychiatric disorders. Other interventions are aimed at removing any triggering agents, such as drugs (for example anticholinergics) or inadequately controlled pain.[114] Most important, recent studies have shown that interventions consisting of standardized protocols for the management of known risk factors for delirium (cognitive impairment, sleep deprivation, immobility, visual impairment, hearing impairment, and dehydration) result in significant reductions in the number and duration of episodes of delirium in hospitalized older patients.[115]
In the community-dwelling aged population, malnutrition has been reported to occur in 16.9% of women and 11.4% of men.[116] Among the hospitalized elderly, the prevalence of malnutrition ranges from 15% to 26%.[117] [118] Surgical patients who are malnourished have increased morbidity and mortality,[119] as well as increased length of stay.[120] The diagnosis of malnutrition should be made on the basis of both the preoperative history and physical and laboratory tests ( Table 62-6 ).
Depression is common in the elderly. In certain surgical populations, such as hip fracture patients, the prevalence has been reported to be 13%.[121] Depression is an important issue because its presence may influence the occurrence of delirium[122] and length of stay[121] and have a significant impact on quality of life postoperatively.[123] If at all possible, antidepressants should be continued during the perioperative period. Discontinuing antidepressants may increase symptoms of depression and confusion. [124]
| Community-dwelling persons |
| Involuntary weight loss |
| Abnormal body mass index |
| Hypoalbuminemia |
| Hypocholesterolemia |
| Specific vitamin deficiencies |
| Hospitalized persons |
| Decreased dietary intake |
| Hypoalbuminemia |
| Hypocholesterolemia |
| Nursing home persons |
| Weight loss |
| Decreased dietary intake |
| From Katz PR, Grossberg GT, Potter JF, Solomon DH: Geriatrics Syllabus for Specialists. New York, American Geriatrics Society, 2002, p. 10.3. |
Bed rest leads to ventricular atrophy, hypovlemia, and orthostatic intolerance.[125] Prolonged bed rest causes decreases in muscle mass, which may influence both activities of daily living and pulmonary function.[126]
Dehydration accounts for approximately 6.7% of Medicare admissions. [127] Dehydration is often associated with hypernatremia and accompanied by infection such as pneumonia and urinary tract infection.
Alcoholism is a relatively common problem in the elderly.[128] Alcohol-related problems in the elderly are often manifested as physical problems in the form of accidents or falls.[129] Alcoholism is an important predictor of postoperative pneumonia in noncardiac surgery patients. [130]
Eighty percent to 85% of persons experience a significant health problem that predisposes them to pain at some time after the age of 65. Chronic pain is frequently undetected,[131] and it is important to evaluate the current use of pain medication. With aging, patients experience less frequent head, abdominal, and chest pain and more frequent joint pain.[132] Surveys of nursing home residents show arthritis to be the most prevalent indication for analgesics (41.7% of residents), followed by bone fracture (12.4%) and other musculoskeletal conditions (9.7%). More residents (76.8%) are reported to have chronic pain than acute pain (19.9%), and 3.0% have both chronic and acute pain.[133]
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