Chapter 32 Elderly Patients
Why geriatric anesthesiology is important
Age-Related Physiologic Changes
6. How is organ function affected by aging? How might this affect the elderly patient in the perioperative period?
7. What age-related changes in systolic blood pressure, heart rate, cardiac output, stroke volume, and cardiac conduction occur in the elderly?
8. Why are elderly patients more susceptible to congestive heart failure when subjected to fluid overload than younger counterparts?
9. How do drug-induced heart rate changes in the elderly compare with the heart rate response seen in younger patients administered the same drugs?
10. How do reflex-mediated heart rate increases in response to hypotension differ between elderly and younger patients?
11. What age-related changes in gas exchange, the alveolar-to-arterial oxygen gradient, and the ventilation-to-perfusion ratio occur in the elderly?
12. What age-related changes in vital capacity, forced exhaled volume in 1 second, residual volume, and functional residual capacity occur in the elderly?
13. How do ventilatory responses to hypoxia and hypercapnia change with age? Why is this particularly important to the anesthesiologist?
14. Why does pneumonia occur at an increased frequency in elderly patients?
15. What age-related changes in renal blood flow, glomerular filtration rate, and urine-concentrating ability occur in the elderly? What clinical implications do these have?
16. How do plasma concentrations of creatinine change with age?
17. What age-related change in hepatic blood flow occurs in the elderly? What clinical implication does this have?
18. How does the production of albumin change with age? What clinical implication does this have?
19. What age-related changes in esophageal and intestinal motility and gastroesophageal sphincter tone occur in the elderly? What clinical implications do these have?
20. What clinical relevance do the age-related loss of collagen and decreases in skin elasticity have for the anesthesiologist caring for the elderly patient?
21. What clinical relevance do osteoporosis, osteoarthritis, and rheumatoid arthritis have for the anesthesiologist caring for the elderly patient?
22. What age-related changes in the central and peripheral nervous systems occur in the elderly? How does this affect the minimum alveolar concentration (MAC) of anesthesia in the elderly patient?
23. What physiologic changes occur with aging that predispose the elderly patient to hypothermia?
Perioperative care in the elderly
24. Why is it important to inquire about functional status in the elderly patient?
25. What are some elements of the preoperative evaluation that are of particular relevance to elderly patients?
26. What are some examples of activities of daily living (ADL) and instrumental ADLs (IADL)?
27. Should preoperative testing include a routine electrocardiogram (ECG) based on an age cutoff in elderly patients?
28. What are some of the challenges when obtaining a preoperative assessment in an institutionalized patient?
29. Why should certain antihypertensive medications be held on the morning of surgery?
30. What are some of the physiologic consequences that might be observed in elderly patients taking diuretic medications?
31. How are pharmacodynamic changes in the elderly reflected with regard to inhaled anesthetics and opioids?
32. How are pharmacodynamic changes in the elderly reflected with regard to nondepolarizing neuromuscular blocking drugs?
33. What pharmacokinetic changes in the elderly make them susceptible to cumulative drug effects and adverse drug reactions?
34. What age-related changes in the elderly result in a decreased clearance of drugs? Give some examples of drugs whose elimination times may be affected.
35. What age-related changes in the elderly result in changes in the volume of distribution? Give some examples of drugs whose pharmacokinetic properties may be altered.
Choice of anesthesia
36. What is an advantage that regional anesthesia may have over general anesthesia for hip surgery in elderly patients?
37. In an awake, elderly patient, what is the significance of orthostatic hypotension without an associated increase in heart rate?
38. What is the potential significance of mental status changes that occur with extension and rotation of the head?
39. Why should preoperative anxiolytics be used sparingly in the elderly population? What can be used as a substitute?
40. Why might hand ventilation by bag and mask be difficult in the edentulous patient?
41. Why might endotracheal intubation be difficult in a patient with poor dentition or cervical arthritis?
42. How should the induction dose of anesthetic be altered in the elderly patient?
43. Are there any unique risks to the elderly with the reversal of nondepolarizing neuromuscular blocking drugs with anticholinesterase drugs?
44. What are some postoperative risks that elderly patients are more prone to than younger patients?
45. What types of procedures that elderly patients are likely to undergo might warrant regional anesthesia as an alternative to general anesthesia?
46. What is the advantage to maintaining consciousness in the elderly patient during a regional anesthetic for a surgical procedure?
47. What are some reasons why elderly patients may be more sensitive to regional anesthesia than younger patients?
48. How might the hypotensive effects of a sympathectomy resulting from regional anesthesia be attenuated?
49. What advantage does epidural anesthesia have over spinal anesthesia that can be of particular benefit in the elderly population?
Postoperative care
50. What are some of the consequences of untreated postoperative pain in the elderly patient?
51. What are some examples of adjuvant nonopioid medication that can be used to treat pain in the elderly patient?
52. What are some of the advantages of postoperative epidural analgesia in elderly patients?
53. How should a regional technique be altered in an elderly patient?
54. What are the most common postoperative neurologic events in elderly patients?
55. When is postoperative delirium in the elderly patient most likely to present?
56. What are some possible clinical manifestations of postoperative delirium in the elderly patient?
57. What are some causes of postoperative delirium in elderly patients?
58. What are some of the consequences of delirium in elderly patients?
59. How is postoperative cognitive dysfunction different from delirium?
Answers*
Why geriatric anesthesiology is important
1. The elderly population represents a heterogeneous group of individuals with widely varying functional and reserve capacity. In some patients there may be a wide disparity between the chronologic and physiologic age. In all individuals, aging is associated with a gradual deterioration of organ function. Even though the rate may vary between individuals, some age-related changes are inevitable. Elderly patients may also exhibit atypical symptoms leading to delays in diagnosis and more advanced disease at presentation. Other challenges include polypharmacy, the high prevalence of dementia and cognitive dysfunction in the very elderly, and the difficulty in estimating functional reserve in patients with limited mobility and multiple comorbid conditions. (568, Table 35-1)
2. Advanced age is a risk factor for surgical morbidity and mortality. Elderly patients who require surgery are also at a greater risk of perioperative complications than their younger counterparts. This is due to a combination of the effects of chronic disease and generalized age-related decreases in organ function. Some examples of common age-related changes include a generalized decrease in maximal breathing capacity, vital capacity, glomerular filtration rate, and basal metabolic rate. In addition, decreases in the elderly patient’s level of activity may lead to deconditioning and a subsequent inability of the cardiovascular system to respond to perioperative stressors. Overall the comorbid conditions found in elderly patients are the most significant contributors to the development of perioperative complications or perioperative death, rather than the age of the patient itself. (568, Figure 35-1)
Morbidity and Mortality Rates
3. The need for emergency surgery is one of the most important predictors for mortality following surgery in older patients. The circumstances of the emergency itself may be compromising the patient’s physiologic status, such as with hemorrhage or dehydration. In these circumstances the older patient with poor baseline function and organ reserve may not be able to respond rapidly to this acute alteration in physiologic state. In addition, emergency cases preclude the preoperative time necessary to control coexisting diseases and maximize organ function. The lack of optimization impacts the ability to withstand the stress imposed by surgery. Other important factors influencing the outcomes in elderly patients include delayed presentation of a condition, high ASA physical status, partial or complete immobility, intracavitary surgery, and congestive heart failure. Older patients tend to present later with more advanced disease and thus be more compromised physiologically at presentation. (569)
4. Complications may be poorly tolerated in very old patients. Patients over 80 years old who developed a postsurgical complication had a fourfold increase in mortality. Complications are also associated with an increase in length of hospital stay and morbidity. The most significant complications include cardiac arrest, renal failure, and myocardial infarction. Avoiding even minor complications is one of the cornerstones of management of geriatric patients undergoing anesthesia and surgery. (569)
Medications to Avoid in the Geriatric Population
5. Aging is associated with decreased central cholinergic reserve, and in elderly patients with dementia this may be significant. Scopolamine is a tertiary quaternary amine and as such crosses the blood-brain barrier. The central anticholinergic effects of scopolamine may lead to significant delirium in elderly patients. Other medications that can similarly cause delirium through central anticholinergic effects include atropine, chlorpheniramine, diphenhydramine, and promethazine. (570)
Age-Related Physiologic Changes
6. Organ function, in general, declines with age. The decline in organ function associated with aging in the elderly has been characterized as a decline in the ability of the elderly patient’s organs to adapt, or compensate, in response to acute stressors. The perioperative period is associated with stressors on numerous organs, leaving elderly patients vulnerable to develop worsening organ dysfunction in the perioperative period. Age-related declines in organ function may be difficult to measure preoperatively and the stress associated with surgery may expose previously underappreciated deficiencies. For example, the presence of mild renal insufficiency with normal laboratory testing may predispose the elderly patient to perioperative renal failure, or previously asymptomatic diastolic dysfunction may predispose the elderly patient to postoperative congestive heart failure. (570, Table 35-2)
7. Age-related changes in the cardiovascular system of elderly people include an increase in stiffness of the vasculature and an increase in the presence of diastolic dysfunction. In the absence of cardiac disease per se, the cardiac output and stroke volume are largely preserved. Alterations in the conduction system are common and older patients are predisposed to developing arrhythmias and heart block. Systemic blood pressure steadily increases with age as a result of the decrease in compliance of arterial walls. Alterations in the cardiac sympathetic nervous system result in a diminished ability to increase heart rate in response to stress. In elderly patients a sedentary lifestyle and deconditioning may lead to diminished cardiac output and reserve capacity. The decrease in cardiac output does not appear to occur in elderly patients who have maintained physical fitness. (571)
8. Aging is associated with increased ventricular stiffening that contributes to delayed left ventricular relaxation during diastole. This is referred to as diastolic dysfunction and leads to a decrease in diastolic filling. Approximately one third of older individuals with normal left ventricular function have diastolic dysfunction. Diastolic dysfunction limits a patient’s capacity to handle excess intravascular fluid, and thus excess fluid loading can lead to the rapid development of congestive heart failure. (571, Figure 35-2)
9. The plasma concentration of adrenergic agents required to produce a specific cardiovascular response is increased in the elderly. When adrenergic drugs such as isoproterenol are administered to elderly patients, the change in heart rate is less prominent than the changes in heart rate seen when isoproterenol is administered to younger patients. This is believed to be due to a decrease in the elderly patient’s responsiveness at the β-adrenergic receptor. The decrease in responsiveness may occur secondary to a reduced affinity of β-adrenergic agents for the receptor and/or the impairment of adenylate cyclase activation. This same effect of decreased cardiovascular response has also been noted with the administration of atropine and α-adrenergic agonists. The reduction in parasympathetic tone is also reflected in the reduction in beat to beat variability. The levels of circulating norepinephrine rise steadily with aging, supporting a reduction in the sensitivity of the receptor. (571)
10. When hypotension occurs in younger patients, there is a baroreflex-mediated increase in heart rate that occurs to help offset the physiologic effects of the hypotension. In the elderly patient, the reflex-mediated increase in heart rate in response to hypotension is much less pronounced and as a result elderly patients are prone to develop orthostatic hypotension. The decline in baroreceptor sensitivity and cardiac autonomic function has been termed the dysautonomia of aging. It appears to be due to a combination of a decrease in sensitivity of the baroreflexes themselves and a decrease in the ability of the adrenergic receptors to respond, limiting the reflex increase in heart rate. (571)
11. There is an age-related decrease in gas exchange in the elderly patient. The most significant age-related change in the lung of the elderly patient is a deterioration of lung elastin. As a result of the degenerative changes in the lungs, there is a breakdown of alveolar septa. This is accompanied by an increase in both anatomic and alveolar dead space and an increase in ventilation-to-perfusion mismatch. These are reflected by an increase in the alveolar oxygen pressure and a decrease in the PaO2 by about 0.5 mm Hg per year after 20 years of age. There are no age-related changes in the PaCO2. (571)
12. Age-related changes in the pulmonary system of elderly people include a decrease in vital capacity, a decrease in the forced exhaled volume in 1 second, an increase in residual volume, and an increase in functional residual capacity. These occur as a result of the decreased elasticity of the lungs and increased stiffness of the thorax. (571)
13. Elderly patients have a decreased ventilatory response to hypercapnia and hypoxia. When compared with younger patients, this response can be decreased by about one half. It is important that the anesthesiologist be cognizant of this, because this response is further decreased by the administration of opioids and inhaled anesthetics. (571-572)
14. Elderly patients have decreases in pulmonary reserves; a decreased level of laryngeal, pharyngeal, and airway cough reflexes; and an increased propensity to aspirate pharyngeal secretions. Elderly patients also have depressed immune function, probably due to involution of the thymus gland and altered function of T lymphocytes. Together these may explain the increased risk of pulmonary aspiration and an increased incidence of pneumonia in elderly patients when compared with younger patients. (571)
15. Decreases in renal blood flow, glomerular filtration rates, and urine-concentrating abilities accompany aging. These changes are due to alterations in the renal vasculature and may be at least partially due to the age-related decrease in cardiac output. There are also progressive decreases in the total number of nephrons and glomeruli units with age. Clinically, this has some implications for the anesthesiologist caring for the elderly patient. First, elderly patients may be more sensitive to, and less able to adapt to, fluid deprivation or fluid overload. Second, the elderly may be at an increased risk for renal ischemia in the perioperative period. Third, elderly patients have limited ability to concentrate urine and are therefore predisposed to hyponatremia. Finally, drugs that are cleared renally may have a prolonged duration of effect, thereby decreasing the dose requirements of these drugs in the elderly patient. (571)
16. Although renal function decreases with age, in the absence of concomitant renal disease, plasma creatinine concentrations do not change with age. This is because the increase in creatinine that would be expected to accompany the age-related decline observed in the glomerular filtration rate (GFR) is offset by the decrease in muscle mass. There is a decreased production of creatinine secondary to this decrease in muscle mass. (572)
17. Decreases in hepatic blood flow are seen in the elderly as a direct result of decreases in hepatic tissue mass and decreases in cardiac output. Clinically, a delayed clearance of hepatically cleared drugs may result from the decrease in hepatic blood flow in elderly patients. Drugs that may be affected include opiates, barbiturates, benzodiazepines, propofol, etomidate, and most nondepolarizing neuromuscular blocking drugs. (572)
18. The production of albumin is decreased in the elderly, and this may be exacerbated by poor nutrition. Clinically, the reduced albumin may result in a decrease in the binding of drugs administered to elderly patients, and an increase in the free, active portion of the drug. A low preoperative albumin level has been associated with increased mortality after surgery. (572)
19. Esophageal and intestinal motility decrease with age, as does gastroesophageal sphincter tone. Clinically, these age-related changes in gastrointestinal function may lead to an increased risk of pulmonary aspiration in elderly patients undergoing general anesthesia. (572)
20. A loss of collagen and decreases in the elasticity of the skin of elderly people put them at an increased risk of sustaining injury to their skin during surgical procedures, particularly during prolonged procedures. Elderly patients are vulnerable to sustaining decubitus ulcers and injury during the removal of adhesive electrocardiogram pads or tape.
21. Osteoporosis, osteoarthritis, and rheumatoid arthritis occur most frequently in elderly people. These diseases must be considered while positioning the patient for a surgical procedure, as well as while positioning the head and neck for intubation of the trachea. Intubation of the trachea may be more difficult as a result of these diseases.
22. Age-related changes occur in both the central and peripheral nervous systems of elderly people. In the central nervous system there is a progressive decline in central nervous system activity and a loss of neurons. This is especially marked in the cerebral cortex and is reflected as a reduction of brain size in radiographic studies. Cerebral blood flow decreases in proportion to decreases in cerebral mass. The autoregulation of cerebral blood flow remains intact. In the peripheral nervous system, there is a decrease in the conduction velocity of peripheral nerves and possibly a decrease in the number of fibers in the spinal cord tracts as well. This is reflected in the increase in the thresholds for the perception of stimuli from virtually all the senses, including pain. These physiologic changes in the central and peripheral nervous systems of elderly people result in a decrease in the MAC by as much as 30% from young adult values. This corresponds to a decreased dose of volatile anesthetic required to achieve a given physiologic central nervous system response in elderly patients. (572)
23. There are several factors which together predispose the elderly to hypothermia in the perioperative period. The reduction in metabolic rate that occurs with aging results in a reduction in heat production. Peripheral vasoconstriction is also less efficient in the elderly person, leading to a diminished ability to conserve heat through redistribution. Shivering is also diminished, and when it occurs it may lead to increased oxygen consumption that may not be tolerated in patients with significant cardiac disease. (572)
Perioperative care in the elderly
24. Establishing baseline functional status is one of the most important aspects of the preoperative evaluation of elderly patients. Elderly patients with an excellent functional capacity have a reduced risk of postoperative complications. (572)
25. The preoperative evaluation of the elderly patient scheduled to undergo a surgical procedure should include the routine preoperative elements for any other patients. An additional goal of the preoperative evaluation of elderly patients is to stratify and minimize risk. The preoperative evaluation should include some key elements that are more relevant to patients in this age group in order to achieve this goal. The patient’s functional capacity is one of the most important aspects of the elderly patient’s preoperative assessment. This includes an evaluation of the patient’s physical fitness, as well as their ability to perform their activities of daily living. In addition, a brief assessment of cognition can be used to identify if a patient is at increased risk for developing postoperative cognitive problems such as delirium. A careful inventory of all medications, including over-the-counter drugs, should be documented. For patients on multiple medications it can be helpful to have the patient bring the vials to the hospital on the day of surgery or admission. Polypharmacy is common in the older population and can lead to negative drug interactions perioperatively. Drug and alcohol dependence must also be considered in the elderly patient scheduled for surgery. Finally, the preoperative visit provides an opportunity to begin a discussion on advanced health care directives. (573)
26. Activities of daily living describe common behaviors that allow an assessment of an elderly person’s function within their living situations. The basic five ADLs are bathing, dressing, toileting, transferring, and eating. Instrumental activities of daily living (IADLS) describe more advanced activities that would be expected in persons living independently. These include the ability to use the telephone and public transport, do shopping, prepare a meal, do basic housekeeping and budgeting, and the ability to manage one’s own medications. (573, Table 35-3)
27. Routine preoperative testing based on age cutoffs leads to unnecessary testing and the risk of false positive and unchecked results. Although it has been popular in the past to use an age cutoff for preoperative ECGs, this approach is not recommended. The preoperative ECG should be ordered when the patient’s history or symptoms suggest significant cardiac disease. Since cardiovascular disease is common in older patients, ECGs will still probably remain one of the most commonly ordered preoperative tests. Elderly patients frequently have abnormal baseline ECGs and part of the preoperative evaluation will need to include comparisons to prior ECGs to establish if the observed changes are new findings. (573)
28. Chronically institutionalized patients can present a unique challenge with regard to their preoperative assessment. These patients frequently have complex medical and medication histories, and in addition may have limited ability to communicate. It may not be practical to request a separate visit to a preoperative clinic for these patients. In these cases a thorough review of the medical record may be performed before the surgery. In all cases, it is important to establish who will be providing consent for the surgery and anesthesia prior to the surgery date. (573)
29. Although most antihypertensive medications are recommended to be taken on the morning of surgery, persistent and difficult to treat postinduction hypotension has been observed in patients treated with ACE inhibitors. For that reason it is recommended that ACE inhibitors be withheld the morning of surgery or for 10 to 12 hours preoperatively. Other antihypertensive medications should generally be continued on the day of surgery. (573)
30. Diuretic medications, in combination with decreases in organ function, may result in electrolyte abnormalities in elderly patients. Common abnormalities include hypokalemia, mild hyponatremia, and contraction alkalosis. These abnormalities can be detected in preoperative laboratory tests. (573)
31. Pharmacodynamic changes in the elderly lead to an increase in sensitivity to certain medications and necessitate a decrease in recommended doses in these patients. The plasma concentration of inhaled anesthetics, opioids, and the benzodiazepine midazolam that is required to produce a specific effect in an elderly person is decreased compared to younger counterparts. For example, the dose of fentanyl and alfentanil required to achieve a given effect in an elderly patient may be decreased by as much as 50% compared to a young adult. The increased sensitivity to anesthetics seen in elderly patients parallels the decrease in cerebral cortex tissue mass and cerebral metabolic rate. This is subsequently reflected as a decrease in the MAC of anesthesia in elderly patients. (574-575, Table 35-5)
32. The plasma concentration of nondepolarizing neuromuscular blocking drugs required to produce a specific twitch response effect is similar in both elderly and younger people. This implies that the sensitivity of elderly patients to nondepolarizing neuromuscular blocking drugs does not change with age. (575)
33. Pharmacokinetics, the absorption, distribution, metabolism, clearance, and excretion of a drug, accounts for the concentration of a drug at the end-organ site or receptor level. Pharmacokinetic changes in the elderly include decreases in drug clearance and changes in the volume of distribution, making the elderly more susceptible to cumulative drug effects and adverse drug reactions. The plasma concentrations of thiopental, propofol, and etomidate required to produce a specific response are similar in both elderly people and younger people. However, age-related pharmacokinetic changes, especially with respect to distribution, may necessitate a reduction in the initial dose of these medications. (574)
34. A decreased clearance of drugs in the elderly can be attributed to decreases in renal blood flow, decreases in the glomerular filtration rate, decreases in hepatic blood flow, and decreases in hepatic microsomal enzyme activity. Decreases in renal blood flow and decreases in the glomerular filtration rate together may result in the prolongation of the effects of pancuronium, digoxin, and several antibiotics in elderly patients. Likewise, decreases in hepatic blood flow and decreases in hepatic microsomal enzyme activity together may result in the prolongation of the effects of vecuronium, lidocaine, propofol, and propranolol in elderly patients. (574)
35. The volume of distribution can be divided into the central volume of distribution and the peripheral volume of distribution. The central volume of distribution refers to the volume of the heart and great vessels, and the venous volume. A decreased central volume of distribution in the elderly produces an increased initial concentration of drug in the plasma after a bolus injection. The decrease in the central volume of distribution has been thought to be due to decreases in total body water in elderly patients. More recently, this theory has come under scrutiny. Nevertheless, higher initial plasma concentrations of drug after the initial bolus of conventional doses of the drug are seen in elderly patients.
Choice of Anesthesia
36. Regional anesthesia may be advantageous over general anesthesia for hip surgery in elderly patients. Regional anesthesia may be associated with decreases in perioperative blood loss and decreases in the incidence of deep venous thrombosis. There is no evidence, however, that one method of anesthesia is safer than the other. (576)
37. In an awake, elderly patient being evaluated for orthostatic hypotension, the lack of an increase in heart rate upon assuming the upright position in the presence of hypotension may reflect autonomic dysfunction. Other signs of autonomic dysfunction include a lack of beat-to-beat heart rate variability or an absence of sinus arrhythmia with respiration. Autonomic dysfunction may occur secondary to aging and vascular stiffening, coexisting diseases such as diabetes or renal failure, or drug effects. (571)
38. The elderly patient who experiences changes in mental status with extension and rotation of the head may have vertebrobasilar insufficiency or cervical osteoarthritis. In the case of vertebrobasilar insufficiency, cerebral ischemia may result. It is therefore useful to evaluate the elderly patient for symptoms with extension and rotation of the head should this position be necessary for the surgical procedure. (574)
39. Preoperative anxiolytics should be used sparingly in the elderly population because they can cause undesirable levels of sedation and confusion in these patients. In addition, the residual effects of these medicines may persist even after the surgical case has been completed. In lieu of the preoperative anxiolytic medicines, a detailed explanation of the events that will occur before and after the surgical procedure may be a useful anxiolytic substitute. (575)
40. Hand ventilation by bag and mask may be difficult in the edentulous patient secondary to a poor mask-to-face fit. It is often easier to hand ventilate by bag and mask when the edentulous patient’s dentures are left in place or an oral airway is used. (574)
41. Endotracheal intubation may be difficult in a patient with poor dentition or cervical arthritis. Difficulty in patients with poor dentition arises because of the need to avoid loose teeth during direct laryngoscopy to avoid dislodgment of the teeth. Patients with cervical arthritis may be difficult to endotracheally intubate because of the decreased range of motion, especially extension, of the neck. (574)
42. The induction dose of an anesthetic should be reduced for an older patient compared to a younger patient. The reduction appears to be mostly due to pharmacokinetic changes. Aging leads to a reduction in the central volume of distribution and clearance of an induction agent such as propofol. The net result is that the drug administered for induction exerts its pharmacologic effects in the circulation for a longer amount of time and the receptors are exposed to a larger initial concentration. The induction dose of anesthetic in the elderly patient is not decreased for pharmacodynamic reasons, because the plasma concentration of induction drug required to produce a desired effect is equal in elderly and younger patients. (574-575)
43. The reversal of nondepolarizing neuromuscular blocking drugs in the elderly patient does not warrant any special considerations for the anesthesiologist, because there are not any unique risks of this in the elderly patient population. The incidence of cardiac dysrhythmias after the administration of glycopyrrolate or neostigmine may be increased in elderly patients who have cardiovascular disease. (575)
44. Several postoperative complications are more common in older patients compared to younger patients. These include cardiovascular events such as myocardial infarction and congestive heart failure, especially from diastolic dysfunction. This is most likely related to the frequency of cardiovascular disease in the elderly population and underlying age-related changes. Central nervous system complications are the next most commonly encountered postoperative complication in the elderly patient. Although cerebral vascular accidents are more common in older patients than in younger patients, they are still uncommon and usually occur in a patient with preexisting cardiac or vascular disease. More common central nervous system events are postoperative delirium and postoperative cognitive dysfunction. These are especially common in older patients with preexisting dementia, depression, and cognitive impairment, for example patients who have had a cerebral vascular accident in the past. Pulmonary complications include postoperative hypoxia and pneumonia. It is possible that early ambulation may minimize some of the pulmonary risks. (576-577)
45. Regional anesthesia is an alternative to general anesthesia for elderly patients undergoing surgical procedures such as transurethral resection of the prostate, gynecologic procedures, inguinal hernia repair, or the treatment of hip fractures. Regional techniques such as peripheral nerve blocks are becoming increasingly popular and may be a valuable adjuvant to general anesthesia in elderly patients. They may reduce the amount of anesthesia needed and improve postoperative pain control. (576)
46. An advantage to maintaining consciousness in the elderly patient during a regional anesthetic for a surgical procedure is that the anesthesiologist is able to communicate with the patient during the procedure. Changes in mental status can herald the onset of a developing adverse event. For example, confusion during a transurethral resection of the prostate may be an early warning sign of the development of hyponatremia or fluid overload. Similarly, a patient may complain of chest pain or shortness of breath signaling the presence of myocardial ischemia. Additionally, there may be decreased immediate postoperative confusion in elderly patients after having received a regional anesthetic as compared with a general anesthetic. (576)
47. Elderly patients may be more sensitive than younger patients to regional anesthesia, especially spinal anesthesia. Possible reasons why this may be true include decreased vascular absorption from the spinal space, decreases in vertebral column length, and a decreased reflex compensatory sympathetic nervous system response. Together, these may manifest as a prolonged duration of action, increased anesthesia level, and exaggerated decreases in blood pressure following a spinal anesthetic. (576)
48. Attenuation of the hypotensive effects of a regional anesthetic may be achieved by the prophylactic administration of an intramuscular dose of ephedrine before administering the spinal anesthetic. Adequate hydration minimizes the effects of a sympathectomy on blood pressure, but does not consistently eliminate the hypotensive effects of spinal anesthesia in elderly patients. (576)
49. Epidural anesthesia is advantageous over spinal anesthesia in that it may be administered more slowly than a spinal anesthetic, with the onset of the resulting sympathectomy being more gradual. This may result in a more gradual decrease in the elderly patient’s blood pressure than that seen with a spinal anesthetic. (576)
Postoperative care
50. Untreated postoperative pain in elderly patients is associated with serious consequences in elderly patients. These include increased length of hospital stay, morbidity, pulmonary complications, and delirium. (576)
51. Acetaminophen can be used to reduce opioid requirements in elderly patients. NSAIDs can also lead to lower narcotic requirements, but the dose must be adjusted to reduce the risk of renal insufficiency or gastrointestinal side effects such as bleeding. Gabapentin is another medication that can be used in the perioperative period to reduce opioid use. It is renally excreted and the dose should be reduced in older patients. (576)
52. Postoperative epidural analgesia in elderly patients has been associated with improved pulmonary function, reduced atelectasis, easier extubation of the trachea, and shorter ICU stays in patients that have had thoracic and upper abdominal surgeries. (576)
53. The metabolism and excretion of local anesthetic drugs is reduced in the elderly. When administering a regional anesthetic in elderly patients, the overall dose should be reduced. (576)
54. The most commonly encountered neurologic events in elderly patients are delirium and postoperative cognitive dysfunction. Postoperative delirium has been estimated to occur in at least 10% to 15% of elderly patients undergoing surgical procedures. It may occur in as many as 40% to 60% of patients undergoing acute repair of a hip fracture. (576-577)
55. Postoperative delirium is most likely to present one or more days after surgery in elderly patients. This type of delirium is termed interval delirium. This is in contrast to emergence delirium commonly seen in pediatric patients that occurs within minutes after the emergence from anesthesia. (576-577)
56. Clinical manifestations of postoperative delirium in elderly patients may include alterations in attention, cognition, and sleep-wake cycles; a reduced level of consciousness; and increases or decreases in psychomotor behavior. These patients are often disoriented to time, place, and person. Close monitoring of these patients is essential to prevent patients from harming themselves by attempting to get out of bed or by pulling out catheters. (577)
57. Causes of postoperative delirium in the elderly patient include drug toxicity, fluid and electrolyte imbalances, and underlying medical problems, such as myocardial ischemia, congestive heart failure, infection, pain, or depression. Antiparkinsonian drugs, antihypertensives, and anticholinergic and psychotropic medications tend to increase the risk of drug interactions with anesthetics and postoperative analgesics to produce postoperative delirium. A deficiency of neurotransmitters such as acetylcholine and dopamine is hypothesized to be the underlying physiologic cause of postoperative delirium. (577)
58. Delirium in elderly patients has been associated with increased mortality, length of hospital stay, and loss of independence evidenced by an increased risk of transfer to an assisted living and nursing home. Delirium can persist for weeks or even months in elderly hospitalized patients. (576)
59. Postoperative cognitive decline is a subtle alteration in cognitive function and mental ability. Unlike delirium, postoperative cognitive dysfunction is not associated with acute confusion or agitation. Neuropsychological testing is required for its diagnosis. (577)
