Introduction
Patients with advanced chronic respiratory disease frequently have distressing symptoms, limitations in exercise ability, and reductions in health and functional status that persist despite optimal pharmacologic management. Pulmonary rehabilitation complements standard medical therapy and can lead to improved exercise and functional capacity, decreased dyspnea, improved health status, and (perhaps) reduced risk of premature morbidity and mortality. Pulmonary rehabilitation is now accepted as the standard of care for patients with chronic obstructive pulmonary disease (COPD), and it has been incorporated into international guidelines for this disease. Although pulmonary rehabilitation was designed and is applied primarily to symptomatic patients who are limited due to the burden of COPD, the same fundamental principles appear applicable to other chronic respiratory disease states.
Definition and Goals
The American Thoracic Society and European Respiratory Society define pulmonary rehabilitation as “a comprehensive intervention based on a thorough patient assessment followed by patient-tailored therapies that include, but are not limited to, exercise training, education, and behavior change, designed to improve the physical and psychological condition of people with chronic respiratory disease and to promote the long-term adherence to health-enhancing behaviors. As this definition indicates, there is now a strong evidence base demonstrating the effectiveness of pulmonary rehabilitation, and it should be considered in the general care of patients with chronic respiratory disease.
Pulmonary rehabilitation and exercise training have been erroneously considered to be equivalent. Although exercise training is a necessary component of pulmonary rehabilitation, other interventions are integral to a rehabilitation program. These include patient assessment, education (especially involving collaborative self-management strategies), nutritional intervention, psychosocial support, and a discussion of advance directives. Promotion of activity in the home and community settings is becoming recognized as an essential component in pulmonary rehabilitation. Smoking cessation, breathing retraining, chest physical therapy, oxygen therapy, and adjunctive therapies are also provided for selected individuals.
It may appear paradoxical that pulmonary rehabilitation does not have a significant, direct effect on pulmonary function, yet it provides the greatest improvements in dyspnea, exercise tolerance, and health status of any therapy for COPD. Emerging data suggest that it may also be beneficial for other chronic respiratory diseases. This apparent paradox is explained by the fact that COPD can be considered to be a systemic disease, and comorbidity (such as decreased oxidative capacity of the muscles of ambulation, physical deconditioning, fear of dyspnea-producing activities, improper pacing) contributes to patients’ symptoms and disability. The 6-minute walk distance, which reflects the systemic nature of the disease, is therefore a stronger predictor of survival in COPD patients than measurements of airflow limitation such as the forced expiratory volume in 1 second (FEV 1 ). Similarly, the midthigh cross-sectional and midarm cross-sectional areas, measures of muscle mass, are better predictors of survival than lung function.
Pulmonary rehabilitation is effective in reducing the negative impact of comorbidities. For example, exercise tolerance in COPD is limited by multiple factors, including increased resistive work of breathing (due to breathing through narrowed airways), increased elastic work of breathing (due to static and dynamic hyperinflation), and abnormalities in the muscles of ambulation (leading to lactate production and fatigue at low exercise intensities). Exercise training leads to a decreased ventilatory requirement at a given level of exercise due in part to physiologic changes in the leg muscles. This decrease in ventilatory requirement allows the patient to breathe at a lower respiratory rate during exercise, thereby reducing the effects of dynamic hyperinflation. Thus, pulmonary rehabilitation exercise training leads to increased exercise capacity by its direct effects on the leg muscles that reduce the ventilatory requirement and its direct effects on dynamic hyperinflation and cardiac output —despite the fact there is no measurable change in FEV 1 .
Comprehensive pulmonary rehabilitation requires contributions from different health care professionals. Physicians, nurses, nurse practitioners, physical therapists, respiratory therapists, nutritionists, and occupational therapists may be involved in a particular program, depending on availability and resources. A physician medical director and a professional pulmonary rehabilitation coordinator are necessary for program certification in the United States. The goals of pulmonary rehabilitation are to reduce symptoms, improve functional status, and reduce health care costs.
History
Pulmonary rehabilitation and its components have been recognized by clinicians as an effective intervention since at least the middle of the 20th century. Since the mid-1990s, it has risen to prominence as a state-of-the-art, scientifically proven intervention for individuals with chronic lung disease. Its current importance as a therapeutic option is underscored by four events:
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Its incorporation as the “best therapy” to which lung volume reduction surgery was compared in the National Emphysema Treatment Trial (NETT).
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A Cochrane report demonstrating the effectiveness of pulmonary rehabilitation in meta-analyses.
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Its endorsement by the Global Initiative for Obstructive Lung Disease (GOLD) and its prominent position in the current treatment algorithm for COPD.
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Its acceptance as an approved medical benefit in the United States under the Centers for Medicare and Medicaid Services (CMS) beginning in January 2010.
Over time, what was considered a form of therapy reserved only for patients with the most severe impairment is now recommended for all patients with symptoms that limit their performance and a moderate severity of disease. Before 1991, much of the literature supporting pulmonary rehabilitation consisted of descriptions of comprehensive pulmonary rehabilitation and presentations of uncontrolled, pre-intervention/post-intervention studies showing its effectiveness primarily in reducing hospital utilization. However, in 1991 Casaburi and colleagues reported on a study of 19 COPD patients who were randomized to either higher or lower levels of exercise training on a cycle ergometer. Training was 5 days per week for a total of 8 weeks. The patients who trained at lower levels exercised longer, so the total amount of work was roughly equivalent in the two groups. Both levels of training led to significant physiologic benefits manifested by reduced lactic acidosis and ventilatory requirement at the same work rate. However, those who trained at higher intensity had more physiologic benefit than those who trained at lower intensity. Before this study, many believed that patients with advanced COPD, often being ventilatory limited during exercise, could not derive true physiologic benefit from this type of intervention. This was the first randomized, controlled trial to demonstrate that a training effect could result from exercise training, the cornerstone of pulmonary rehabilitation.
In 1994, Goldstein and associates reported a prospective, randomized, controlled trial of pulmonary rehabilitation. Eighty-nine patients with COPD were randomized to either pulmonary rehabilitation, initially given in an inpatient setting, or conventional medical care. The group that participated in pulmonary rehabilitation had significantly greater increases in the 6-minute walk distance, submaximal cycle endurance time, and health status compared with the group given standard medical care. This was the first of several randomized, controlled trials of pulmonary rehabilitation that established the effectiveness of pulmonary rehabilitation as a treatment option for chronic lung disease.
That same year, Reardon and coworkers reported on 20 COPD patients who were randomized either to comprehensive outpatient pulmonary rehabilitation or to a waiting period during which they were given conventional medical care. Rehabilitation led to significant improvements in exertional dyspnea, measured by incremental treadmill exercise testing and by questionnaire-rated dyspnea with daily activities. Exertional dyspnea was reduced at levels of exercise common to activities of daily living, underscoring its clinical meaningfulness. This was the first study to demonstrate the effectiveness of pulmonary rehabilitation on dyspnea, the most important symptom in advanced lung disease. Subsequent studies by O’Donnell and colleagues showed that the reduction in postexercise training dyspnea was associated with decreased ventilatory demand, probably due to physiologic changes in the leg muscles.
In 1995, Ries and associates reported on 119 patients with COPD who were randomized either to comprehensive outpatient pulmonary rehabilitation with exercise training or to education alone. Compared with education alone, rehabilitation led to significant relief of dyspnea, maximal exercise capacity, exercise endurance, and self-efficacy for walking. “Self-efficacy” refers to the patient’s confidence in successfully managing respiratory symptoms associated with an activity. Positive results declined over time, approaching those of the control group by 18 to 24 months. This was the first large randomized, controlled study showing the effectiveness of outpatient pulmonary rehabilitation on multiple outcomes. The decline in gains made over time underscored the importance of strategies to improve long-term adherence with rehabilitation.
In 1996, Maltais and coworkers reported on 11 patients with COPD who were evaluated before and after 36 sessions of high-intensity endurance training. In addition to the expected physiologic training effect including reduced exercise-induced lactic acidosis, exercise training led to increased levels of oxidative enzymes in muscle biopsy specimens. Of additional importance, the improvement in biochemical markers correlated with reduced lactic acid production during exercise. Along with other work, this study showed that exercise training improves skeletal muscle oxidative capacity in COPD patients and that this improvement has clinical value.
In 2000, Griffiths and colleagues presented data on 200 patients with chronic lung disease who were randomized to either 6 weeks of multidisciplinary pulmonary rehabilitation or standard medical management. In addition to showing substantial improvements in exercise performance and health-related quality of life, the pulmonary rehabilitation intervention led to fewer days in the hospital and fewer primary care home visits in the 1-year follow-up period. Thus, this large randomized trial demonstrated that pulmonary rehabilitation led to a substantial reduction in health care utilization, confirming conclusions from earlier uncontrolled studies. A subsequent study from this group provided evidence supporting the cost-effectiveness of pulmonary rehabilitation.
A study by Bourbeau and associates suggested that a self-management program in the home led to fewer hospital admissions and other health utilization variables and improvement in health status. Subsequent trials have been less consistent, but a recent meta-analysis of 17 studies supports benefits in quality of life, fewer hospital admissions, but no differences in visits to the emergency department or survival.
In 2005, Casaburi and coworkers showed that increasing bronchodilation in patients with COPD led to enhanced outcomes from pulmonary rehabilitation. Patients with optimized lung function could exercise at higher intensities and achieve greater increases in exercise capacity. Thus, not only does pulmonary rehabilitation add to the positive outcomes from pharmacologic therapy, pharmacologic therapy also adds to the benefits from pulmonary rehabilitation.
In 2007, joint guidelines from the American College of Chest Physicians (ACCP) and the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) summarized the evidence base underlying pulmonary rehabilitation. The document cited strong evidence supporting the effectiveness of pulmonary rehabilitation on improvements in dyspnea and quality of life. There was also substantial evidence supporting its effectiveness in reducing health care utilization and improving psychological outcomes.
Pulmonary rehabilitation is the most effective therapy available for increasing the exercise capacity of patients with chronic respiratory disease. However, its effectiveness in promoting increased activity in the home and community setting was not proved until fairly recently. Increased physical activity is an important outcome because patients with COPD are often sedentary, and lower levels of physical activity are associated with poorer long-term outcomes. In 2008, Walker and colleagues demonstrated that directly measured activity (from activity monitors) was increased following 8 weeks of pulmonary rehabilitation. This study corroborated results from two other studies that also demonstrated similar positive effects. These studies, therefore, provide strong support for the idea that the increased exercise capacity attained in the pulmonary rehabilitation center translates into increased activity in other settings.
Rationale
Pulmonary rehabilitation has a minimal, if any, effect on the abnormal lung function or respiratory physiology of individuals with chronic lung disease. The apparent paradox is explained by the fact that a considerable portion of the dyspnea and the health status limitations from chronic lung disease results from extrapulmonary effects of the disease, which can respond to treatment. Some of the associated systemic manifestations of chronic lung disease include nutritional depletion, a decrease in lower extremity muscle mass and peripheral muscle weakness and fatigability, alterations in peripheral muscle fiber type, and a reduction in peripheral muscle oxidative enzymes. In addition, poor pacing techniques, maladaptive coping skills, and fear of dyspnea-producing activities result in a vicious circle of further deconditioning and debilitation. Pulmonary rehabilitation is effective in interrupting this cycle, usually resulting in clinically meaningful improvement in multiple areas of importance to the patient, including a reduction in exertional dyspnea and the dyspnea associated with daily activities, improvement in exercise performance and in health status, and reduction in health care utilization.
Indications
Pulmonary rehabilitation is indicated for individuals with chronic respiratory disease who have persistent symptoms or disability despite standard medical therapy. Figure 105-1 represents the course of patients with lung function limitation over time and the role of pulmonary rehabilitation. Patients are usually referred for one or more of the following symptoms or conditions :
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Severe dyspnea and/or fatigue
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Decreased exercise ability
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Interference with performing activities of daily living
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Impaired health status
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Decreased occupational performance
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Nutritional depletion
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Increased medical resource utilization
It should be noted that persistent symptoms and/or limitation in these clinical areas—not just the specific physiologic impairment of the lungs (such as a low FEV 1 or hypoxemia)—dictate the need for intervention. Furthermore, symptoms, exercise performance, functional status, and health status correlate relatively poorly with pulmonary function abnormalities. Because of this, there are no specific threshold pulmonary function inclusion criteria for pulmonary rehabilitation.
Often the referral to pulmonary rehabilitation has been reserved for advanced lung disease. Although patients in this category can still benefit from the intervention, referral at an earlier stage would allow more emphasis on preventive strategies such as smoking cessation and would permit exercise training at higher levels of intensity.
Traditionally, pulmonary rehabilitation has dealt primarily with COPD, whereas its effectiveness for other pulmonary conditions has received less attention. Nonetheless, patients with chronic asthma and airways remodeling, bronchiectasis, cystic fibrosis, chest wall disease, or interstitial lung disease may be appropriate candidates. Pulmonary rehabilitation is the standard of care before and after lung transplantation and lung volume reduction surgery. On the basis of these accepted indications, pulmonary rehabilitation should also be useful to recondition patients for other major surgical procedures.
There are two primary exclusion criteria for pulmonary rehabilitation:
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An associated condition that might interfere with the rehabilitative process. Examples include disabling arthritis and severe neurologic, cognitive, or psychiatric disease.
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A comorbid condition that might place the patient at undue risk during exercise training. Examples include severe pulmonary hypertension or unstable cardiovascular disease.
It should be noted that many patients with pulmonary hypertension have safely (and successfully) participated in pulmonary rehabilitation programs, often while awaiting lung transplantation. The exercise training component has to be modified in this situation and patients require close monitoring. In addition, poor motivation is a relative contraindication to pulmonary rehabilitation. However, the level of motivation might change during therapy, especially if patients perceive demonstrable benefit from the sessions.
Smoking Cessation
Cigarette smoking is the cause of COPD in more than 90% of affected patients. Furthermore, there is no doubt that smoking cessation is the single most important therapy that can retard the progression of airflow limitation and positively influence survival. The various pharmacologic and behavior modification techniques that are available to assist persons to stop smoking are reviewed in Chapter 46 . Although controversy still exists, active cigarette smokers are reasonable candidates for pulmonary rehabilitation provided smoking cessation interventions become an important component of the process. Indeed, frequent contact and reinforcement during the rehabilitation program can influence a patient to adopt a proactive role in cessation.
Components of a Comprehensive Pulmonary Rehabilitation Program
Exercise Training
Exercise training, including upper and lower extremity endurance training and strength training, is an essential component of comprehensive pulmonary rehabilitation. This follows the current knowledge that the peripheral muscles in patients with chronic lung disease are not only wasted but also appear to have alterations in fiber type distribution and decreased metabolic capacity. Exercise training improves endurance, increases the level of functioning, aids in performance of activities of daily living, helps reduce systemic blood pressure, improves lipid profiles, tends to counteract depression, reduces anxiety associated with dyspnea-producing activities, and facilitates sleep.
Exercise training for individuals with chronic lung disease, similar to that in healthy individuals, is based on general principles of intensity (higher levels of training produce more results), specificity (only those muscles trained show an effect), and reversibility (cessation of regular exercise training leads to loss of training effect).
Ventilatory or gas-exchange limitations are common in advanced chronic lung disease and limit the intensity of exercise training. However, exercise capacity in many patients is also limited by peripheral muscle and cardiovascular deconditioning, with an early onset of anaerobic metabolism and the production of lactic acidosis during exercise. Peripheral muscle dysfunction is responsive to the exercise training intervention. Many respiratory patients are capable of exercising for prolonged periods of time at levels close to capacity, and the higher level of exercise training results in greater improvement in exercise performance. The demonstrated reduction in ventilation and lactate levels at identical submaximal work rates following high-intensity exercise training strongly suggests that a training effect is attainable in many patients with advanced lung disease. A dose-related increase in oxidative enzymes in the peripheral muscles accompanies these physiologic adaptations to training. A reduction in lactic acid production has been demonstrated to be associated with improvement in oxidative capacity of the peripheral muscles.
Most pulmonary rehabilitation programs emphasize endurance training of the lower extremities, often advocating sustained exercise for about 20 to 30 minutes two to five times a week. This may include exercise on a stationary cycle ergometer or motorized treadmill, climbing stairs, or walking on a flat surface such as a corridor or auditorium. Training is usually performed at levels at or greater than 50% or 60% of the maximal work rate. For those unable to maintain this intensity for the recommended duration, interval training, consisting of 2 to 3 minutes of high-intensity training (60% to 80% maximal exercise capacity), alternating with equal periods of rest, has similar results with less dyspnea. Optimization of bronchodilator therapy is desirable because it will allow patients to exercise at higher intensities. Similarly, supplemental oxygen therapy for hypoxemic patients, in addition to increasing safety, will allow patients to train at higher work rates. Oxygen supplementation may even promote exercise training at higher intensities in nonhypoxemic COPD patients, but further studies will be necessary to confirm that this approach is effective. If patients cannot achieve high work rates during exercise training, lower work rates have also been demonstrated to produce positive outcomes.
Although the strength of the upper extremity muscles is relatively preserved compared with that of the lower extremities in COPD, the former are important to many activities of daily living. The use of upper extremity muscles is often associated with considerable dyspnea, probably because the arm muscles are also accessory muscles of respiration. Endurance training of the upper extremities is thus an important component of pulmonary rehabilitation. Its effectiveness has recently been demonstrated in a randomized clinical trial. Training can be accomplished using supported arm exercises, such as with arm ergometry, or unsupported arm exercises, such as by lifting free weights or dowels or by stretching elastic bands.
Because peripheral muscle weakness and/or atrophy contributes to exercise limitation in patients with lung disease, strength training is a rational component of exercise training during pulmonary rehabilitation. Training in weight-lifting exercises alone, involving the upper and lower extremities, increases muscle strength and endurance performance on a cycle ergometer. In the current practice of pulmonary rehabilitation, strength training is usually added to standard aerobic training. This combination increases muscle strength and mass, but its additive effect on health status has not been proved.
The total duration of exercise training in pulmonary rehabilitation should reflect the patient’s underlying respiratory disease, his or her level of physical and cardiovascular conditioning, and the progress made during the exercise training sessions. The GOLD guidelines report that the optimum length of exercise training has not been determined in randomized, controlled trials but suggests there is evidence that programs of longer duration provide greater benefit. Ideally, the optimal length of an exercise training program should depend on whether the patient continues to progress toward goals. However, in reality, the program length is generally set by resources, reimbursement, and continued patient motivation. Longer programs may provide more sustained benefits in outcomes.
Exercise training is typically given in the pulmonary rehabilitation facility under supervision. Generally, this is supplemented with patient-specific instructions for additional exercise training at home or in the community. Early incorporation of home exercise into the routine of daily life may promote long-term adherence with the exercise prescription. Carrying this concept one step further, a randomized trial demonstrated that, after 4 weeks of standardized education, 8 weeks of exercise training in the home was as effective in its primary outcome as 8 weeks of supervised training in the pulmonary rehabilitation center. The primary outcome in this study was questionnaire-rated dyspnea at 1 year following rehabilitation. Similar improvements were noted in exercise capacity, although the mean changes in the 6-minute walk distance were well below the established minimum clinically important difference of 54 m. Of importance, there were no significant differences in adverse events in the two groups, and the treating physicians and the study steering committee did not identify any serious adverse events attributable to the exercise training. It remains to be determined whether this home exercise approach to pulmonary rehabilitation will become a practical alternative to the traditional approach.
Education
Education is an important component of pulmonary rehabilitation programs, and its incorporation alongside exercise training provides a good setting to promote the health behavior change necessary to optimize disease control. Educational needs are determined as part of the initial patient assessment and then are reassessed over the course of the program. Education provides important information to the patient and family about the disease process, its comorbidity, and its treatment. This information encourages active participation in health care, thereby promoting adherence to therapy and important self-management skills. Education also helps the patient and family find ways to cope with chronic illness and its comorbidities. Some standard educational topics are listed in Table 105-1 . In pulmonary rehabilitation, education is usually provided both in small-group settings and in a one-to-one format.
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The educational process includes the promotion of a healthy lifestyle, the incorporation of adaptive techniques (such as self-pacing) into the home setting, and the promotion of long-term adherence with the postrehabilitative instructions. Education about self-management is an essential component of pulmonary rehabilitation. It emphasizes “learning through doing,” enhances patient self-confidence, and encourages a “take-charge” attitude (in collaboration with the health care providers) toward managing the disease. Some strategies in collaborative self-management include interventions for smoking cessation, encouragement of regular exercise at home, incorporation of increased levels of physical activity into the home setting, and early recognition and treatment of respiratory exacerbations. The development of a patient-specific, collaborative self-management plan for COPD exacerbations is an important goal of pulmonary rehabilitation; this includes education about the symptoms and signs associated with exacerbations to foster early recognition followed by the implementation of an action plan, which often includes using filled prescriptions for a short course of systemic steroids and an antibiotic. Ongoing collaboration among the patient and the medical team members is the key to effective self-management. Advance directive discussions are also an important component of pulmonary rehabilitation (see later).
Because education is a component of virtually all pulmonary rehabilitation programs, there are few studies evaluating its individual contribution to the overall effectiveness of the comprehensive program. However, self-management strategies applied to the home setting have been shown to be effective in improving health status and reducing utilization of medical resources.
Psychosocial Training and Support
Psychosocial problems, such as anxiety, depression, problems coping, and decreased self-efficacy, contribute to the burden of advanced respiratory disease. Psychosocial and behavioral interventions vary widely among comprehensive pulmonary rehabilitation programs but often involve educational sessions or support groups, focusing on areas such as coping strategies or stress management techniques. Techniques of progressive muscle relaxation, stress reduction, and panic control may reduce not only anxiety but dyspnea as well. Educational efforts may also improve coping skills. Participation by family members or friends in pulmonary rehabilitation support groups is encouraged. Informal discussions of the common symptoms and concerns of patients with chronic lung disease may provide emotional support to patients and their families. Because of these interventions, it should come as no surprise that a randomized clinical trial has demonstrated that comprehensive pulmonary rehabilitation can decrease psychosocial morbidity in patients with severe COPD even when no specific psychological intervention is provided. Individuals with substantial psychiatric disease should, of course, be referred for appropriate professional care.
Nutritional Support
Nutritional depletion, including abnormalities in body composition such as decreased lean body mass, is present in 20% to 35% of patients with stable COPD. Depletions in lean body mass undoubtedly contribute to the morbidity of patients with chronic respiratory disease by leading to decreased respiratory muscle strength, handgrip strength, exercise tolerance, and health status. Nutritional depletion and alteration in body composition are also significant predictors of the mortality of COPD, independent of FEV 1 . Because of this, nutritional intervention is a recommended component of comprehensive pulmonary rehabilitation.
However, the benefit from simple nutritional supplementation to underweight patients with chronic lung disease has not been substantial, with one meta-analysis of nutritional intervention for COPD reporting only a 1.65-kg increase in weight following intervention. In view of these disappointing results with calorie supplementation alone, consideration is being given to hormonal supplementation with anabolic steroids. This has led to increases in weight, lean body mass, respiratory muscle strength, and arm and thigh muscle circumference. In addition, one study has demonstrated that the combination of testosterone and weight training in men with COPD and low testosterone levels leads to greater increases in muscle mass and strength than either alone. Whether these preliminary findings in this select group can be applied with safety and efficacy to a more generalized population remains unknown. The Joint ACCP/AACVPR Guidelines on Pulmonary Rehabilitation do not recommend routine use of anabolic steroids for COPD patients.
Breathing Training, Inspiratory Muscle Training, and Chest Physical Therapy
These modalities have been part of pulmonary rehabilitation over the years, but conclusive evidence supporting their effectiveness in pulmonary rehabilitation is for the most part lacking. Breathing training is aimed at controlling the respiratory rate and breathing pattern, with a goal of decreasing air trapping. Pursed-lip breathing takes place when the patient inhales through the nose and exhales over 4 and 6 seconds through lips pursed in a whistling/kissing position. This technique facilitates the recruitment of abdominal muscles during exhalation and has a favorable effect on the breathing pattern, thereby increasing tidal volume and reducing end-expiratory lung volumes. The result is less hypoxemia and decreased dyspnea. In selected patients, pursed-lip breathing has also been shown to reduce the oxygen cost of breathing. Patients with COPD can usually be readily trained in pursed-lip breathing; in fact, they often spontaneously adopt this breathing pattern when dyspneic. Breathing while bending forward has been shown to decrease dyspnea in some patients with severe COPD, both at rest and during exercise. Similar improvements can be achieved by breathing in the supine and Trendelenburg positions. The best explanation for the reduction in dyspnea is that the increased abdominal pressure caused by bending overstretches the diaphragm, moving it into a better contracting position and leading to improved diaphragmatic function. Diaphragmatic breathing has not been shown to be beneficial; in fact, this technique may actually decrease breathing efficiency.
The rationale behind inspiratory muscle training is that COPD patients have weak inspiratory muscles and that training them may improve outcomes. The Joint ACCP/AACVPR Evidence-Based Clinical Practice Guidelines reviewed the relatively numerous studies on inspiratory muscle training and concluded that this treatment increases inspiratory muscle strength, increases exercise performance, and decreases dyspnea. Their recommendation is to consider inspiratory muscle training in selected COPD patients with decreased inspiratory muscle strength and breathlessness despite optimal medical therapy.
Chest physical therapy is used in an attempt to remove airway secretions. The techniques include postural drainage, chest percussion and vibration, and directed cough. Postural drainage uses gravity to help drain the individual lung segments. Chest percussion should be performed with care in patients with osteoporosis or bone problems. Cough would be an effective technique for removing excess mucus from the larger airways; unfortunately, patients with COPD have impaired cough mechanisms (maximum expiratory flow is reduced, ciliary beat is impaired), and the mucus itself has altered viscoelastic properties. Because spasms of coughing may lead to dyspnea, fatigue, and worsened obstruction, directed cough might be helpful by enhancing the beneficial effect and preventing the untoward ones. With directed coughs, patients are instructed to inhale deeply, hold their breath for a few seconds, and then cough two or three times with the mouth open. They are also instructed to compress the upper abdomen to assist in the cough. These techniques are probably useful in selected patients with difficulty mobilizing secretions.
Vaccination
The causes of exacerbations of COPD are poorly understood and probably multifactorial. Both influenza virus and Streptococcus pneumoniae may play a role, and there is no doubt that, with either of these infections, patients with chronic lung disease are at increased risk for serious complications, including death. One of the national health objectives in the United States has been to increase influenza and pneumococcal vaccination levels to higher than 60% in persons at high risk for complications and for everyone 65 years of age or older. As stated, this includes all patients with COPD and other forms of chronic lung disease, regardless of age. Because the influenza vaccine is type specific and serotypes are constantly changing, vaccination must be repeated every year, preferably at the beginning of the season in the fall. In contrast, the pneumococcal vaccine is polyvalent and its benefits should last a lifetime. One of the responsibilities of a rehabilitation program is to educate enrollees about the importance of vaccination against influenza and pneumococcal infections and to ensure that it is carried out and (for influenza) repeated annually.
Oxygen Assessment and Therapy
Background
Although not in itself a unique component of pulmonary rehabilitation, testing for oxygen needs and/or adjusting the oxygen to achieve its full benefits is part of all rehabilitation programs. Two landmark studies clearly showed improved survival in patients with COPD and hypoxemia (arterial oxygen pressure P o 2 < 55 mm Hg) who breathed supplementary oxygen at night compared with those who received no supplemental oxygen; there was even better survival in those who breathed oxygen for longer periods through the aid of an ambulatory delivery system. Contemporary guidelines for prescribing home oxygen for patients with COPD, based in part on these trials, are shown in Table 105-2 . The chief criterion is significant hypoxemia, defined as an arterial P o 2 of 55 mm Hg or less for 3 weeks or more when the patient is in a clinically stable state (i.e., has been free from exacerbation of bronchitis, heart failure, or other intercurrent complications). Additional criteria were also used in the North American multicenter trial to enroll stable patients with COPD whose arterial P o 2 values were between 55 and 59 mm Hg. They included evidence of pulmonary hypertension as judged by radiographic abnormalities (an enlarged pulmonary outflow tract); electrocardiographic findings of elevated right-sided intracardiac pressures (P waves in standard leads II, III, and aVF > 2-mm amplitude); clinical evidence of cor pulmonale with heart failure; or secondary polycythemia from chronic hypoxemia. Patients with COPD who have echocardiographic evidence of right ventricular hypertrophy and/or pulmonary hypertension also qualify.
