BASIC SCIENCE QUESTIONS
1. For each decade of advanced age, cardiac output decreases by approximately
Cardiac complications are the leading cause of perioperative complications and death in surgical patients of all age groups, but particularly among the elderly. This is because they likely have existing cardiac dysfunction, combined with normal physiologic decline and poor functional reserve. The combined effect of depletion of intravascular volume, age-related impairment of response to catecholamines, and increased myocardial relaxation time adversely affects the functioning of an elderly patient under stress in the perioperative period. Aging has been demonstrated to cause a decrease in cardiac output by approximately 1% per year. Older individuals fail to augment heart rate to the same extent as younger individuals. More importantly, the ability to increase cardiac output with aging is dependent on ventricular dilatation, which is determined by preload. This is precisely the reason that careful attention must be paid to volume status in the perioperative period. Dehydration or poor resuscitation may occur in elderly surgical patients for a variety of reasons, and both are poorly tolerated. Over one half of all postoperative deaths in elderly patients and 11% of postoperative complications are a result of impaired cardiac function under physiologic stress. (See Schwartz 9th ed., p 1712.)
2. Maximal pulmonary capacity at age 70 is what percent of maximal pulmonary capacity at age 30?
The result of the changes that occur with the respiratory system with aging limits the maximal breathing capacity by age 70 to 50% of the capacity present at age 30. In addition, there is a decline in the forced expiratory volume in 1 second (FEV1) with advancing age. It is estimated that humans lose 35 mL of their FEV1 per year over the age of 35 years old. There is a slow decline between ages 35 and 65 years old followed by a much more progressive decline at approximately 75 years of age. (See Schwartz 9th ed., p 1712.)
3. Which one of the following changes occurs in the kidney with aging?
A. Increased filtration area
B. Increased creatinine clearance
C. Decreased glomerular filtration rate
D. Decreased sensitivity to many anesthetic agents
Renal size and volume decrease with age, accompanied by intrarenal vascular changes. There is a decrease in the number of glomeruli and nephron mass, resulting in decreased filtration area. Subsequently, serum creatinine concentration is an insensitive indicator of renal function in the elderly. The physiologic changes in renal function in elderly patients increase susceptibility to renal ischemia as well as to nephrotoxic agents. Age-related changes in renal function result from progressive glomerulosclerosis and reduction in renal mass resulting in decreased creatinine clearance and glomerular filtration rate. This is worsened by a decline in cardiac output with increasing age and subsequent decrease in renal blood flow. It has been shown that patients with impaired glomerular filtration rate are more susceptible to volume changes that occur in the perioperative period. Furthermore, decreased drug elimination can potentiate the effects of nephrotoxic drugs and prolong the sedative effects of anesthetics and narcotic used for postoperative pain management. (See Schwartz 9th ed., p 1712.)
1. Which of the following is one of the physiologic changes of aging?
A. Decreased fat mass
B. Decreased pulmonary closing volume
C. Decreased vascular baroreceptor sensitivity
D. Decreased renal glucose threshold
(See Schwartz 9th ed., p 1711.)
2. The most common indication for surgery in the elderly is
A. Obstructive vascular disease
B. Thrombotic vascular disease
C. Biliary tract disease
D. Colorectal disease
Acute appendicitis and acute cholecystitis are examples of common acute surgical pathologies with which elderly patients present late or have delayed diagnosis or misdiagnosis. This often leads to higher rates of perforation and complications that adversely affect morbidity and mortality. In fact, biliary tract disease, including acute cholecystitis, is the most common indication for surgical intervention in the elderly. This is likely related to age-related changes within the biliary system, specifically increased lithogenicity of bile and increased prevalence of cholelithiasis. Delayed diagnosis may lead to complications such as ascending cholangitis and gallstone ileus. (See Schwartz 9th ed., p 1711.)
3. Which of the following tests of function in an elderly patient can be used to predict the time to recover after surgery?
A. Hand grip strength
B. Timed up and go test
C. Functional reach test
D. All of the above
It is important that a thorough preoperative evaluation include an accurate assessment of the functional status of surgical candidates as well as their cognitive level of functioning. This ensures that operative intervention will not significantly impair the quality of life of an elderly surgical candidate. The ability to withstand the stress of surgical interventions is dependent on functional reserve and ability to build an appropriate response to perioperative stress. The ability to perform activities of daily living (ADL) such as feeding, dressing, bathing, and toileting have been correlated with postoperative morbidity and mortality. Preoperative functional assessment can be measured by hand grip strength, timed up and go, and functional reach tests. All of these tests independently predicted better recovery and shorter time to recover ADL after major surgery. In addition, these tests provide an accurate assessment of a patientís muscle mass, nutritional status, coordination, gait speed, balance, and mobility. Proper functional assessment will accurately predict rehabilitation needs, estimate biologic reserve, and even signal complications. (See Schwartz 9th ed., p 1714.)
4. Protein energy malnutrition in an elderly surgical patient can result in
A. Decreased range of motion of major joints
B. Decreased glomerular filtration rate
C. Decreased mucosal proliferation
D. Decreased mental status
Protein energy malnutrition (PEM) also can result from keeping surgical patients who may already have inadequate nutritional reserve NPO. This may occur in a short period in the elderly, malnourished surgical patient in a hypermetabolic state induced by stress of illness and surgery. The physiologic consequences of PEM are multiple and include anorexia, hepatic dysfunction, decreased mucosal proliferation, and sarcopenia. A good marker of PEM is hypoalbuminemia, also shown to be an extremely accurate predictor of surgical outcomes. The incidence of postoperative complications was increased in patients with serum albumin levels 3.5 g/L. In fact, current recommendations indicate that if patients demonstrate compromise of nutritional status as defined by >10% weight loss and serum albumin level 2.5 g/dL, they should be considered for a minimum of 7 to 10 days of nutritional repletion prior to surgery. (See Schwartz 9th ed., p 1714.)
5. Which of the following is an independent predictor of mortality in elderly patients undergoing major cardiovascular surgery?
A. Age >75
B. ASA class 2 or greater
C. Renal insufficiency
D. Reactive airway disease
Interestingly, despite some degree of age bias in referral patterns for elderly patients to undergo major cardiac surgery, advanced age alone is not a predictor of poorer outcomes or increased mortality when compared to younger patients. It has been demonstrated that emergency operations, preoperative New York Heart Association (NYHA) functional class 3 or greater, and chronic renal failure were the main predictors of increased operative mortality. In one study, preoperative renal dysfunction, cerebrovascular disease, valve surgery, and catastrophic state were independent predictors of increased mortality in elderly patients. Elderly patients with nondialysisdependent renal dysfunction had a 60% chance of death during a 5-year follow-up period compared to 25% in elderly patients without a history of renal dysfunction. Similarly, the presence of cerebrovascular disease resulted in a twofold increase in mortality among elderly patients. Even patients who were 80 years of age or more did not have any significant increase in surgical risk and within this population, the 4-year actuarial survival was 70.5% with an event-free survival of approximately 60.6%. (See Schwartz 9th ed., p 1716.)
6. The most common valvular abnormality requiring surgery in elderly patients is
A. Aortic stenosis
B. Aortic insufficiency
C. Mitral stenosis
D. Mitral insufficiency
There also is an increasing percentage of the geriatric population presenting with symptomatic valvular disease requiring intervention. The most common valvular abnormality present in elderly patients is calcific aortic stenosis, which can lead to angina and syncope. The operative mortality from aortic valve replacement is estimated to be between 3 and 10%, with an average of approximately 7.7%. If aortic stenosis is allowed to progress without operative intervention, CHF will ensue. The average survival of these patients is approximately 1.5 to 2 years. If a patient is a candidate for operative intervention, age should not be a deterrent, especially considering the potential to increase life expectancy. (See Schwartz 9th ed., p 1716.)
7. Renal transplantation in elderly patients
A. Should be considered only if predicted life expectancy is >5 years
B. Requires greater immunosuppression than in younger recipients
C. May be accomplished by transplanting two kidneys from “extended criteria donors”
D. Results in worse graft function than in younger recipients
In the last decade, there has been a shift favoring the transplantation of kidneys from older donors as well as transplantation of donor grafts to older recipients. A new strategy is the use of “extended criteria donors” (ECDs) for elderly recipients, using dual kidney transplantation to increase the net total nephron mass, resulting in favorable outcomes. The increased nephron mass achieved with dual kidney transplantation compensated for the possible decreased renal function with advancing age. The net result is that recipients demonstrate similar postoperative graft function when compared to single kidney transplantation. Elderly recipients of ECD kidneys demonstrated a 25% decrease in risk of mortality compared to waitlisted patients on hemodialysis.
Successful kidney transplantation is preferred treatment for ESRD and long-term patient survival is higher in elderly patients who have been transplanted compared to those that remain on hemodialysis. The projected life span for patients currently on the transplant waiting list who are age 60 to 74 years old is approximately 6 years. This increases to 10 years posttransplantation. For comparison, the expected life span of a 70-year-old patient in the general population is 13.4 years. Among dialysis patients ages 70 years and older, renal transplantation was associated with a 41% lower risk of death compared to age matched wait-listed patients. A clear survival advantage also has been demonstrated in carefully selected patients 75 years and older. A benefit is observed among patients whose life expectancy is expected to exceed 1.8 years.
Elderly patients have better graft function, with decreased incidence of delayed graft function and fewer episodes of acute rejection, than do younger patients. This may be the result of decreased immune competence with aging. (See Schwartz 9th ed., p 1717.)
8. What percent of breast cancers in the United States are diagnosed after 75 years of age?
It is projected that there will be a 72% increase in the number of elderly women diagnosed with breast cancer in the United States by 2025. Furthermore, 50% of breast cancers occur after the age of 65 years old and 25% after the age of 75 years old. The estimated risk for development of new breast cancer is one in 24 women aged 60 to 79 years old compared to one in 24 in women aged 40 to 59 years old. (See Schwartz 9th ed., p 1719.)
9. Which one of the following lung cancers is more common in elderly patients than younger patients?
A. Small cell
B. Squamous cell
D. Large cell
Non–small cell lung cancer accounts for roughly 80% of all lung cancer cases, and >50% of these patients are >65 years of age. Interestingly, approximately 30% of these patients are 70 years or older at diagnosis. Lung cancer is highly prevalent among elderly patients, so much so that a 2-cm, asymptomatic, solitary pulmonary nodule in a 70-year-old male smoker has a >70% chance of being an occult lung cancer. Squamous cell carcinomas are more common among elderly patients than among younger patients, and these tumors are associated with a higher incidence of local disease, tend to have lower recurrence rates, and have longer survival times than nonsquamous cancers. In cases of resectable primary lung cancer, surgery remains the treatment of choice independent of age. (See Schwartz 9th ed., p 1720.)
10. Thyroid cancer in the elderly, when compared to younger patients
A. Has a lower mortality rate
B. Has a lower risk of metastases
C. Is more likely to have vascular invasion
D. Is proportionally less likely to be follicular carcinoma
Papillary carcinoma in elderly patients tends to be sporadic with a bell-shaped distribution of age at presentation, occurring primarily in patients aged 30 to 59 years old. The incidence of papillary carcinoma decreases in patients >60 years of age. However, patients >60 years of age have increased risk of local recurrence and for the development of distant metastases. Metastatic disease may be more common in this population secondary to delayed referral for surgical intervention because of the misconception that the surgeon will be unwilling to operate on an elderly patient with thyroid disease. Age is also a prognostic indicator for patients with follicular carcinoma. There is a 2.2 times increased risk of mortality from follicular carcinoma per 20 years of increasing age. Therefore, prognosis for elderly patients with differentiated thyroid carcinomas is worse when compared to younger counterparts. The higher prevalence of vascular invasion and extracapsular extension among older patients is, in part, responsible for the poorer prognosis in geriatric patients. (See Schwartz 9th ed., p 1723.)
11. Indications for surgical treatment of primary hyperparathyroidism in elderly patients include
A. 10% decrease in creatinine clearance
B. Urinary calcium excretion >100 mg
C. Serum calcium >12.0
D. Altered mental status
Approximately 2% of the geriatric population, including 3% of women 75 years of age or older, will develop primary hyperparathyroidism. Specific indications for operative intervention regardless of age include a 30% decrease in creatinine clearance, 24-hour urinary calcium excretion >400 mg, and decreased bone density. Elderly patients are especially prone to developing mental manifestations of hyperparathyroidism that may be severe enough to produce a dementia-like state. There often is a significant improvement in mental status after parathyroidectomy. (See Schwartz 9th ed., p 1724.)