CHAPTER 43—RESPIRATORY DISEASES AND DISORDERS
AGE-RELATED PULMONARY ALTERATIONS
COMMON RESPIRATORY SYMPTOMS AND COMPLAINTS
MAJOR PULMONARY DISEASES IN OLDER PERSONS
INTENSIVE CARE OF THE CRITICALLY ILL
Studies of age-specific alterations in pulmonary function are limited by common and important comorbidities experienced by older persons, including smoking-related diseases, occupational and industrial exposures, and other significant organ dysfunction such as heart failure or deconditioning. These limitations notwithstanding, decrements in various aspects of pulmonary function occur with aging.
Because of alterations in connective tissue, the size of the airways is reduced and the alveolar sacs become shallow. Chest wall compliance is reduced as a consequence of kyphoscoliosis, calcification of the costal cartilage, and arthritic changes in the costovertebral joints. Sarcopenia results in intercostal muscle atrophy and a reduction in diaphragmatic strength by 25%. These processes result in a decline of forced vital capacity and forced expiratory volume in 1 second of 25 to 30 mL per year in nonsmokers and approximately double that (60 to 70 mL per year) in smokers aged 65 years and over. The normal A-a gradient increases with age and can be approximated by the following formula: (Age / 4) + 4. The Pao2 decreases with age and can be approximated by the following equation: Pao2 = 110 − (0.4 × age).
There is a common misperception that older persons tend to overestimate or exaggerate respiratory symptoms; however, the opposite is more often true. For example, many older persons and their physicians tend to underestimate the importance of dyspnea, which may go undiagnosed until advanced disease is evident. This is partly due to the fact that dyspnea is blamed on deconditioning and age. Older persons will often adjust their activity level to compensate for insidiously shrinking lung function and disabling dyspnea. Such changes in life style often go unnoticed by family, the patient’s physician, and even the patient. Pulmonary or cardiac disorders, or both, may underlie such modifications in life style, and testing (eg, pulmonary function tests or chest radiography) may reveal major abnormalities such as asthma, emphysema, or pulmonary fibrosis. Another complicating feature of symptom recognition in older persons is that older persons often have more than one explanation for their problems. A patient may have overlapping symptoms of dyspnea, cough, and wheezing because of a combination of diseases such as asthma or emphysema, obstructive sleep apnea, heart failure, and gastroesophageal reflux.
Dyspnea becomes prominent in end-stage lung diseases such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis. Importantly, the level of dyspnea is the best predictor of quality of life, yet it does not correlate with either oxygenation or pulmonary function tests. A thorough history and physical examination can help tailor both testing and empirical treatment choices. For example, in an older person presenting with dyspnea and associated nocturnal cough, one would first consider common diseases such as asthma, emphysema, allergic rhinitis with postnasal drip, and gastroesophageal reflux disease. Minimal testing (eg, pulmonary function tests only) followed by an empiric trial directed toward the most likely cause would be a reasonable approach. In the same patient, the presence of significant weight loss or constitutional symptoms (fever, night sweats) could suggest other diseases, such as malignancy or tuberculosis. At times, the particular language the patient choses to describe the dyspnea can be revealing, such as “heavy” for cardiac dysfunction or deconditioning or “tight” for angina or asthma. The common causes of dyspnea in older persons to consider include COPD, cardiac disease, asthma, interstitial lung disease, and deconditioning.
Fortunately, most patients can be reassured that chronic cough, though particularly annoying, usually has a benign cause. By far, the most common causes of chronic cough are postnasal drip, asthma, and gastroesophageal reflux. These three diagnoses account for over 90% of the causes identified in most series, and a reasonable approach to the treatment of chronic cough, then, is empiric treatment for these conditions. Not infrequently, a combination of these conditions may contribute, so treatment for multiple causes may be warranted when single therapies are ineffective. Less common yet important differential diagnostic considerations of cough in older persons would include drug effects (eg, angiotensin-converting enzyme inhibitors), heart failure, laryngeal dysfunction, Bordetella pertussis infection, chronic cough after viral upper respiratory tract infection or secondary bacterial infections, recurrent aspiration, or respiratory tract abnormalities such as bronchiectasis or airway tumors.
Though asthma is a common cause of wheezing in all age groups, it is not the most common cause, particularly if the wheezing is not associated with cough or dyspnea. Postnasal drip is another common cause to consider; also, the rates of heart failure rise in the older age groups, and associated pulmonary edema may present as “cardiac asthma.” Finally, airway hyperresponsiveness from chronic bronchitis is not uncommon in older patients with a history of wheezing and sputum and tobacco use.
After childhood, there is a second peak in the prevalence of asthma beyond the age of 65; 5% to 10% of older persons meet criteria for obstruction and bronchial hyperreactivity. The rate of death from asthma has increased most significantly in those aged 65 and over, accounting for up to 45% of all asthma deaths. This is likely due to reduced awareness of bronchial constriction on the part of the patient (with delays in seeking medical attention), as well as under-recognition and undertreatment on the part of clinicians. Therapy of asthma in older and younger persons differs in several ways. Paramount to the care of the elderly asthmatic patient is adequate instruction in the proper use of peak expiratory flow monitoring (because of the older person’s decreased perception of bronchoconstriction) and in the correct activation of the metered-dose inhaler. Neurologic, muscular, and arthritic diseases in older persons can lead to suboptimal timing and discoordination in the actuation of the inhaler device. The clinician should observe the patient actually using the inhaler. Inhaled corticosteroids (or other controller drugs such as leukotriene receptor antagonists) represent the mainstay of therapy in both older and younger persons. Use the lowest effective dose, and counsel regarding rinsing of the oropharynx to avoid thrush. In older people, theophylline is fraught with adverse effects and drug interactions, and should be considered a third-line drug to be used only as a once-daily medication in the evening for severe asthma or COPD, targeting a serum level of 10 to 12 mg/dL if tolerated. Oral corticosteroids are discussed in the next section on COPD. Although controversy persists as to whether the response to relievers such as β-agonists varies with age, these drugs remain a mainstay as an as-needed reliever medication. The potential for adverse effects of β-agonists—for example, hypokalemia or possible QT prolongation in cardiac patients on digoxin or other medications—warrants adequate controller use by asthmatic patients to minimize their overreliance on the β-agonist. The use of long-acting β-agonists is controversial and should be considered with caution and only in those patients who are reliably able to manage medications. (See Table 43.1 for commonly used medications taken with metered-dose inhalers.)
COPD affects approximately 15 million people in the United States and is the fourth most common cause of death after heart disease, cancer, and stroke. The prevalence and mortality rate from COPD is increasing, especially in older persons. Episodes of acute respiratory failure that require mechanical ventilation are associated with mortality rates ranging from 11% to 46%. The National Lung Health Education Program Executive Committee has noted that the morbidity and mortality from COPD accounts for more than $15 billion per year in U.S. medical care expenditures. Hospitalization continues to represent the largest component of cost for COPD patients.
The diagnosis of airflow limitation is challenging in that no single item or combination of items from the history and clinical examination excludes airflow limitation. The finding most strongly associated with a decreased likelihood of airflow limitation is a history of never having smoked cigarettes (especially in patients without a history of wheezing and without wheezing on examination). Wheezing noted on physical examination is the most potent predictor of airflow limitation, and patients with obstructive airflow limitation are 36 times more likely to have wheezing than are patients without this problem. Other findings associated with an increased likelihood of airflow limitation include a barrel-shaped chest, hyperresonance on percussion, and a forced expiratory time of greater than 9 seconds measured during the clinical bedside examination.
Smoking cessation at any age has been shown to slow the decline in lung function, and aggressive cessation efforts are appropriate even in the oldest-old patient. The basic elements of the approach are the “Five As” from the Agency for Health Care Policy and Research:
The chief components of daily drug therapy in emphysema consist of a β-agonist, ipratropium bromide or tiotropium, or both drugs in combination. For more severe disease, the use of long-acting β-agonists such as salmeterol along with a combined albuterol and ipratropium bromide metered-dose inhaler can achieve improved adherence and long-term control by reducing the number of inhalers by one (ie, the patient will have only the long-acting inhaler and the combination short-acting inhaler rather than three inhalers). Inhaled corticosteroids have now been tested in several multicenter randomized controlled trials in COPD with negative results overall; however, there does appears to be a benefit in subgroup analyses of patients with “asthmatic COPD” as defined by spirometry testing with documented bronchodilator responsiveness. A landmark investigation documented that the use of systemic corticosteroids (intravenous followed by oral) reduces the duration and recurrence of acute exacerbations of COPD for up to 6 months. Importantly, there is no benefit to a course of steroids longer than 14 days. For the few patients (5% to 10%) who do benefit or who require prolonged use of corticosteroids, the risks should be considered, discussed, and documented in the patient’s chart. These risks include peptic ulcer disease, hypertension, cataracts, diabetes mellitus, osteoporosis, psychosis, seizures, poor wound healing, infections, and aseptic necrosis of the hip. Appropriate preventive measures should also be taken in these circumstances of prolonged use, such as using the lowest possible dose of corticosteroids and using supplemental vitamin D, calcium, and perhaps a bisphosphonate for those at risk for osteoporosis. Other possible beneficial interventions in older emphysema patients include pulmonary rehabilitation via exercise training and respiratory therapy and education. Both major depression and anxiety have been shown to be present in up to 40% of COPD patients, and their treatment must be considered. In fact, unprovoked anxiety attacks often result in patients’ seeking help in emergency departments, being admitted to the hospital, and being treated with potentially avoidable courses of oral corticosteroids when the anxiety is not diagnosed and treated.
Sleep-related breathing disorders are very common in older persons, and obstructive sleep apnea is the most common type of sleep-related breathing disorder. Obstructive sleep apnea has been associated with cerebrovascular accidents, myocardial infarctions, and a threefold increase in mortality. Most patients with obstructive sleep apnea remain undiagnosed and therefore without treatment of this life-threatening, yet potentially correctable disease. Treatment options include addressing upper-airway obstruction via weight loss, avoidance of alcohol and sedatives, sleeping on one’s side or upright, correction of metabolic disorders such as hypothyroidism, and continuous positive airway pressure (CPAP) via a nasal mask. To increase adherence with the use of CPAP, one might order the treatment with “nasal pillows” to increase comfort and “ramping technique” to give a delayed rise in the applied pressure after the patient has fallen asleep. Treatment issues are generally the same for the young and the old, and the major consideration for the clinician is a high index of suspicion and clinical recognition of this disease.
There are more than 100 causes of restrictive lung diseases; however, the history, examination, serologic testing, and biopsy often leave the patient with the diagnosis of idiopathic pulmonary fibrosis. This disease is increasing in prevalence with the aging of our population. Rarely is it an inherited disorder. Pulmonary fibrosis is extremely frustrating for all involved because of its relentless progression. The median survival is 3 to 5 years. The presentation is normally one of insidious dyspnea (often unrecognized because of a decrease in the activity level on the part of the patient) and cough. Clubbing is often a prominent finding on physical examination in pulmonary fibrosis, as opposed to emphysema, which rarely causes clubbing (prompting a search for another disease such as occult lung cancer). Oral corticosteroids (0.5 mg/kg/day) for 3 to 6 months is the initial therapeutic maneuver most commonly taken, yet only 10% to 20% of patients respond and adverse effects are often prominent. Early referral to a subspecialist is warranted if the patient wishes to consider further therapeutic attempts so that steroid-sparing agents such as azathioprineOL or enrollment in a randomized controlled trial of newer pharmacologic agents (eg, interleukin-10 or interferon gamma) can be considered.
The incidence of pulmonary thromboembolism triples between the ages of 65 and 90 years and has a reported 10% recurrence rate within 1 year. Age above 70 years has been independently associated with missed antemortem diagnosis. Importantly, 10% to 20% of patients with documented pulmonary embolism have an entirely normal blood gas (ie, normal Pao2 and normal A-a gradient for age). Age-specific risk factors for pulmonary thromboembolism include hypercoagulability due to increases in fibrinogen, activated protein-C resistance due to factor-V Leiden gene mutation, malignancy, stasis (decreased mobility due to stroke, heart failure, or arthritis), or vessel injury (due to trauma or varicosities). The diagnostic work-up is not different for young and older patients. Anticoagulants are central to therapy and generally guided by the same principles in younger and older patients. Because of lessened cardiopulmonary reserve, it may be even more important to achieve therapeutic levels of heparinization quickly to avoid major adverse hemodynamic or oxygenation defects in older patients. The trend toward increased utilization of outpatient low-molecular-weight heparin preparations, while achieving anticoagulation with warfarin, is supported by large and appropriately designed randomized controlled trials. There should be an overlap of approximately 1 to 3 days between heparinization and adequate warfarin therapy with an INR target of 2 to 3. Warfarin interacts with many drugs that are commonly used in the older age group (for lists of drugs that increase or decrease INR with warfarin, see the section on anticoagulation in the Appendix). Studies have inconsistently shown that age itself is a risk factor for bleeding risk with use of warfarin. Duration of therapy for at least 6 months has been shown to be superior to 3 months, and the shorter duration should be used only for those patients with either a specific risk factor that is now removed or for those in whom the risk of prolonged anticoagulant therapy clearly outweighs that of completing 6 months of therapy. Indeed, patients with multiple ongoing risk factors for pulmonary thromboembolic disease are to be considered for anticoagulation therapy for up to 2 years or longer. Recurrent pulmonary thromboembolism is usually treated with lifelong anticoagulation.
See Infectious Diseases.
See Oncology.
There is widespread belief that many patients do not want aggressive care at the end of life. Moreover, eight of ten health care professionals believe that the treatments they offer to patients are often overly burdensome. More consistency in our attempts to obtain patients’ preferences for do-not-resuscitate orders might reduce the extent and burden of aggressive medical care for the elderly age group. Clinicians receive little training regarding this topic. Data from the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT) showed that physician error rates in approximating patients’ preferences for mechanical ventilation increased from 36% for patients younger than 50 up to 79% for patients older than 80. Furthermore, SUPPORT data also showed that age was a predictor of less aggressive care in the intensive care unit (ICU) even after adjusting for severity of illness, gender, race, and diagnosis.
A report from a cohort of mechanically ventilated patients in a medical ICU, on the other hand, showed that persons older than 75 years spent the same amount of time on the ventilator as did younger patients but had a lower cost of ICU and in-hospital care. These outcomes were not explained by differences in mortality, since both groups had similar survival rates. Accordingly, the decision to use mechanical ventilation should not be based on age alone, and the appropriate use of ventilatory support in the elderly patient requires further prospective evaluation.
When ICU care and mechanical ventilation are chosen to treat an older person with respiratory failure, special issues related to liberation from the ventilator may be important. In contrast to the general medical ICU population, acute lung injury and acute respiratory distress syndrome patients do appear to have a higher mortality with advancing age. Interestingly, three separate studies of more than 1500 patients have shown that older persons recover from their pulmonary physiologic abnormalities such as hypoxemia and ventilatory disturbances at a rate equal to their younger counterparts after acute lung injury. These patients do, however, have a particularly difficult time during the latter stages of ventilatory support and require nearly twice as long to be successfully liberated from the ventilator and discharged from the ICU. Often comorbid conditions contribute to these patients’ deaths despite the apparent correction of their acute lung injury-induced physiologic disturbances. Sedative and analgesic medications must be used judiciously, and delirium, heart failure, hypothyroidism, electrolyte disturbances, oropharyngeal dysfunction, and aspiration should be considered in patients with difficulty liberating from the ventilator. For many older people in good physical condition who succumb to an acute illness, cognitive decline is the main threat to their ability to recover their former functional abilities. For those whose physical activities were already limited, cognitive decline may dramatically worsen after an ICU stay and become the major additional threat to quality of life.
Establishing end-of-life care in critically ill patients is treacherous. Numerous studies have documented the tremendous inaccuracy in formulating the prognosis for patients with serious illnesses. At times, in caring for critically ill patients, it may become apparent to the patient, family, and clinician that further intervention would not likely be of substantial benefit, depending on the individual patient’s goals, values, and hopes. Thus, a strict definition of futility is impossible. The American Medical Association recommends a standardized “fair process” rather than a strict definition of futility. As much as possible, physicians should base futility decisions on factors such as clinical efficacy of treatment, likelihood of mortality, and subsequent quality-of-life considerations rather than on chronologic age alone.
A recent analysis of 6303 ICU-related deaths found that 26% of these deaths occurred in patients receiving full ICU care, including failed cardiopulmonary resuscitation; 24% received full ICU care without cardiopulmonary resuscitation; 14% had life support withheld; and 36% (the single largest group) had life support actively withdrawn. Although there was a wide variation in the practice pattern of different ICUs, the authors concluded that the limitation of life support prior to death is a common practice in teaching ICUs across the country.
In another study of 851 patients receiving mechanical ventilation, 63% were successfully liberated, 17% died while receiving mechanical ventilation, and 20% had mechanical ventilation withdrawn. The top four reasons given for withdrawing the ventilator were 1) physicians’ perception that the patient did not want life support, 2) physicians’ prediction that ICU survival was lower than 10%, 3) physicians’ prediction that future cognitive function would be severely impaired, and 4) the ongoing need for an inotrope or vasopressors. The inability for physicians to accurately prognosticate beyond hours of impending death must again be acknowledged as challenging such decisions and should temper concerns about the application of technology in critically ill older patients.
For preoperative pulmonary evaluation in elderly patients, see Perioperative Care. For other aspects of end-of-life care, see Palliative Care and Legal and Ethical Issues.
■ Chan ED, Welsh CH. Geriatric respiratory medicine. Chest. 1998;114(6):1704–1733.
This review article has an extensive reference list (376) and a thorough discussion of issues related to pulmonary medicine in the aging patient (including pneumonia, tuberculosis, and lung cancer, not covered in this chapter). It would be an excellent resource for geriatric fellows during their training, as well as for practitioners.
■ Cook D, Rocker G, Marshall J, et al. Withdrawal of mechanical ventilation in anticipation of death in the intensive care unit. N Engl J Med. 2003;349(12):1123–1132.
Rather than age or the severity of the illness and organ dysfunction, the strongest determinants of the withdrawal of ventilation in critically ill patients were found to be the physician’s perception that the patient preferred not to use life support, the physician’s predictions of a low likelihood of survival in the intensive care unit, a high likelihood of poor cognitive function, and the use of an inotrope or vasopressors.
■ Ely EW, Evans GW, Haponik EF. Mechanical ventilation in a cohort of elderly patients admitted to an intensive care unit. Ann Intern Med. 1999;131(2):96–104.
This prospective analysis of 63 patients aged 75 years or older compared with 237 patients younger than 75 years treated with mechanical ventilation demonstrated that older patients remained on the mechanical ventilator a median of 4 days whereas younger patients remained a median of 6 days (P = .14). Older patients recovered from the pulmonary physiologic perspective at least as quickly as did the younger patients. Using multivariate logistic regression analysis to adjust for race, gender, and severity of illness, the researchers found advanced patient age to be predictive of approximately 3 days less on the ventilator, and ICU and hospital costs were lower for the older group. In-hospital mortality in the two groups was not different. These results indicate that the current system of triaging certain elderly patients to the ICU when critically ill appears to be appropriate and that age alone does not portend lesser physiologic recovery of lung function.
■ Lynn J, Ely EW, Zhong Z, et al. Living and dying with chronic obstructive pulmonary disease. J Am Geriatr Soc. 2000;48(5 Suppl):S91–S100.
This report was derived from the 1016 chronic obstructive pulmonary disease (COPD) patients enrolled in the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT) trial, and it is the most in-depth investigation into the dying process of COPD patients to date. One-year survival was 60%; 40% had more than three comorbidities; and 20% of the last 6 months were spent in hospitals. The burden of dyspnea was often under-recognized, and 2 of 3 patients had serious dyspnea throughout their last 6 months of life; 1 in 4 had serious pain. Patients’ illnesses had a major impact on over 25% of families. Patients’ preferences for do-not-resuscitate orders increased from 40% at 3 to 6 months before death to 80% within 1 month of death; their decisions not to use mechanical ventilation increased from 10% to 30%; and their preferences for resuscitation decreased from 50% to 25%. Patients with advanced COPD often died within a year and had substantial comorbidities and symptoms.
■ Niewoehner DE, Erbland ML, Deupree RH, et al. Effect of systemic glucocorticoids on exacerbations of chronic obstructive pulmonary disease. Department of Veterans Affairs cooperative study group. N Engl J Med. 1999;340(25):1941–1947.
This landmark article represented the first adequately performed, randomized, double-blind, placebo-controlled trial to document that systemic corticosteroids reduce the duration and recurrence rate of acute exacerbations of chronic obstructive pulmonary disease (COPD). From 25 Veterans Affairs medical centers, 271 patients hospitalized with an acute exacerbation of COPD were enrolled; 80 received an 8-week course of glucocorticoids, 80 received a 2-week course of glucocorticoids, and 111 received placebo. Rates of treatment failure were significantly higher in the placebo group than in the two treatment groups at 30 days and at 90 days. Systemic glucocorticoids were associated with a shorter hospital stay and a higher FEV1 by about 100 mL within 24 hours of enrollment in the study. The 8-week regimen was not superior to the 2-week regimen, and neither treatment group showed significant benefit beyond 6 months.
E. Wesley Ely, MD, MPH