Pulmonary rehabilitation (PR) for patients with primary pulmonary disease can have a great effect on quality of life, functional capacity, and activities of daily living as well as a potential effect on hospitalizations and mortality. It is a comprehensive program of exercise, education, and lifestyle modification that aims to help improve the physical and psychological condition of patients with chronic pulmonary disease while promoting a program of long-term adherence to health-enhancing behaviors. PR can be done in the acute hospital setting, on inpatient rehabilitation services, and in outpatient rehabilitation settings. The role of the rehabilitation professional is to promote appropriate activity while monitoring medical compliance and enhancing education about the disease process and physiology of patients’ exercise limitations. PR is appropriate for patients with all types of lung disease and for those who will undergo lung surgery or transplantation.
The definition of pulmonary rehabilitation (PR) by the Joint American Thoracic Society European Respiratory Society task force is as follows:
“ Pulmonary rehabilitation is 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. ”
Chronic obstructive pulmonary disease (COPD) had an age-adjusted death rate of 41.2 per 100,000 population in 2009, when it became the third leading cause of death in the United States. In 2014, this figure had increased to 46.1 per 100,000 population (or 5.6% of total deaths). Other lung diseases in the top 10 for mortality include influenza and pneumonia, which can leave residual pulmonary disability in survivors. Emphysema has continued to be the only major disease with rates that are continuing to increase. The most common lung disease seen by prevalence is asthma, followed by bronchitis, COPD, and then interstitial lung diseases (ILDs). With the widespread prevalence and mortality from lung disease, there is a great deal of morbidity, leading patients with conditions amenable to rehabilitation interventions to seek PR services.
Patients with primary pulmonary disease present with three primary symptoms: Dyspnea or a sense of shortness of breath; exercise intolerance, often as a result of dyspnea; and fatigue ( Fig. 150.1 ). Fatigue in patients with pulmonary disease usually manifests as a state of continuous exhaustion with complaints of generalized weakness and lack of energy. Associated complaints can also be anxiety and depression as well as cough and secretions, whereas pain is usually not present in most patients.
Abnormal physical findings on auscultation in COPD include wheezing, hyperresonant lung sounds, decreased breath sounds, a prolonged expiratory phase, and rales. Chest percussion may reveal hyperresonance, hyperinflation, barrel chest, use of auxiliary respiratory muscles, and pursed-lip breathing. In pulmonary fibrosis there may be inspiratory “Velcro-like” crackles in the lower lung fields, tachypnea, and shallow breaths. In advanced lung disease, 50% of patients have clubbing and may have a loud pulmonic second heart sound with peripheral edema when there is pulmonary hypertension. Associated signs of collagen vascular disease may be seen in ILD.
Patients with pulmonary disease have decreased peak exercise capacity and endurance. This, combined with weakness and fatigue, often makes the performance of occupational activities difficult. Many patients become disabled from their occupation due to a combination of shortness of breath, and their low exercise capacity does not allow them to perform normally. This fatigue and breathlessness also limits ADLs, making even washing or dressing difficult for the most severely impaired individuals. Adding to the respiratory limitations there is often muscle weakness from chronic steroid use and inactivity compounded by anxiety and depression, which can further inhibit activity.
In addition to the patient evaluation in Table 150.1 , medical, physical, financial, or psychological factors that may interfere with rehabilitation must be addressed. Therefore multiple diagnostic studies are in order. These may include the diagnosis of anemia due to erythropoietin resistance or increased serum inflammatory proteins.
Dyspnea can be assessed with surveys. Symptoms and conditions such as coughing, wheezing, chest pain, neurologic or psychological disturbances, allergies, previous communicable diseases, injuries, and nutritional status should be evaluated. Complete social, educational, vocational histories with relevant environmental factors should be obtained. Spirometry, along with an assessment of oxygenation and diffusion capacity for carbon monoxide, can be helpful. Exercise capacity can be assessed with either a laboratory or field exercise test before the initiation of PR. For severely ill patients, cardiopulmonary exercise testing (CPET) is recommended; for those with milder impairments, a 6-minute walk test (6-MWT) or shuttle walk test (SWT) may be appropriate. CPET can determine whether a patient’s disability is pulmonary, cardiac, or related to exercise-induced bronchospasm and can document progress with rehabilitation. The most important CPET results are oxygen consumption, minute ventilation, and metabolic rate. Oxygen consumption is reported in metabolic equivalents (METs) (1 MET = 3.5 mL O 2 /kg/min). Peak ventilation can help to allow assessment of ventilatory reserve and exercise hypoxemia can help identify patients who may need supplemental oxygen with exercise. When CPET is not available, maximum exercise tolerance can be estimated from field tests such as the 6-MWT and SWT in combination with pulmonary function data. The patient is instructed to gradually increase walking speed and duration on subsequent walking tests.
COPD is the best-studied condition for PR.
By the GOLD recommendations, any patient with grade 2 to 4 COPD should have a PR program. All patients with pulmonary disease and decreases in exercise tolerance or who have recently begun to require ongoing medical attention for pulmonary symptoms or complications are ideal candidates.
Organization of a Comprehensive Rehabilitation Program
A comprehensive PR program involves an interdisciplinary team that includes a supervising physician, exercise physiologists, respiratory therapists, and nurses to administer therapeutic exercise as well as nutritional, social, and psychological support. In many ways PR is similar to cardiac rehabilitation, and often the resources for treating the patients can be shared while meeting the regulatory requirement that the therapy sessions for these programs be separated. Evidence of beneficial outcomes of PR is very strong for COPD patients. Other than for smoking cessation, there is no evidence that inpatient programs are more effective than outpatient PR programs. Recent evidence points to a variety of exercise programs and interventions including home-based interventions, telemedicine, and improved self-efficacy, all of which have been shown to be effective. Table 150.2 presents a sample therapeutic prescription for an ambulatory, moderately affected COPD patient.
The optimization of medical treatment is important as a part of a PR program. Inhaler bronchodilator teaching should include training in the use of “spacers” and nebulizers. Appropriate medication such as anticholinergics and short-acting β-2 mimetics can improve exercise tolerance by up to 33%. Early medical attention is important during intercurrent respiratory tract infections, with appropriate use of antibiotics, glucocorticoids, and adjustment of bronchodilators and mucolytic agents.
Counseling and General Medical Care
Dyspnea can cause fear and panic while also worsening tachypnea and increasing dead-space ventilation, work of breathing, hyperinflation, and air trapping. Relaxation exercises, biofeedback, yoga, and diaphragmatic and pursed-lip breathing can decrease tension and anxiety. Low quality of life and depression are seen in up to 50% of patients, along with a severe reduction in social interactions. Integrating psychosocial support with multimodal PR optimizes outcomes and can help address loss of employment and independence.
Self-efficacy can be used to improve adherence to prescribed medication regimens and help with avoidance of atmospheric or vocational pollutants. Yearly flu vaccinations along with the administration of 5- to 10-year pneumococcal vaccine are also important. Appropriate oxygen use with the addition of 0.5 L/min for high-altitude travel and self-monitoring of O 2 saturation are also beneficial. Modern portable oxygen concentrators allow for ease of use during travel and can be employed on airplanes. Good hydration should always be maintained.
Some 19% to 71% of COPD patients have weight loss and up to 40% to 50% of patients with chronic hypoxemia or normoxemic patients with an FEV 1 below 35% are malnourished, with impaired nutritional status more prevalent in those requiring mechanical ventilation (74% vs. 43%). Undernutrition is associated with increased susceptibility to infection and higher colonization with Pseudomonas species. Malnutrition also adversely affects lung repair, surfactant synthesis, respiratory muscle function, lung mechanics, and water homeostasis; it also increases difficulty in weaning from a ventilator. Likewise, inappropriate nutrition, such as increased carbohydrate intake, can exacerbate hypercapnia. Short-term refeeding can improve respiratory muscle endurance and increase respiratory muscle strength. Because of bloating, patients should take smaller and more frequent meals. For hypercapnia, the consumption of more calories derived from fat is helpful. Growth hormone has not been shown to be useful, but there may be a role for anabolic steroids over several weeks to a month to help increase lean body mass and promote weight gain.
Retraining of Breathing
Patients with pulmonary disease often have shallow, rapid breathing and altered ventilatory muscle recruitment, using excessive auxiliary inspiratory muscles rather than the diaphragm. Instruction in diaphragmatic breathing and pursed-lip exhalation (DPLB) can help to reverse these tendencies by decreasing respiratory rate, coordinating the breathing pattern, and improving blood gases. DPLB involves breathing deeply through the nose, using abdominal muscles, and exhalating via pursed lips. DPLB is used during routine ADLs and exercise to improve exercise performance and decrease dyspnea.
Elimination of Airway Secretions
Clearance of airway secretions is crucial to decrease air trapping and help sputum clearance when a cough may be weak and ineffective due to obstructed airflow. “Huffing,” or frequent short expulsive bursts following a deep breath, is often an effective and more comfortable alternative to coughing. Chest percussion and postural drainage can be useful for patients with chronic bronchitis, bronchiectasis, or greater than 30 mL of sputum production per day. Autogenic drainage involves breathing small but gradually increasing tidal volumes starting between residual volume and the functional residual capacity (FRC) and gradually surpassing the FRC to deeper lung volumes then coughing or huffing to expulse secretions. Flutter breathing is a combination of PEP and oscillation applied at the mouth by having the patient expire through a device that has a vibrating ball. The mucus-mobilizing effect is due to percussion oscillations by the oscillating ball, but the results of clinical trials have been conflicting. Mechanical vibration/oscillation applied to the thorax or directly to the airway facilitates the elimination of airway secretions and is frequently dependent for efficacy with frequencies between 10 and 15 Hz being most effective for mucus transport. For patients with cystic fibrosis (CF), manual high-frequency chest-wall compression can improve pulmonary function and gas exchange while also decreasing dyspnea. Side effects can include increasing obstruction to airflow or possible atelectasis. The mobilization of CF airway secretions is associated with a slower rate of loss of pulmonary function, but compliance is often poor.
Inspiratory Resistive Exercises
Inspiratory resistive exercises can improve the strength and endurance of respiratory muscles. Typically patients breathe through these devices for a total of 30 minutes daily for 8 to 10 weeks. The settings of the devices are adjusted to increase difficulty as patients improve and the program advances. Although isocapnic hyperpnea may not be better than other techniques, some studies have shown that an isocapnic hyperventilation training program improves the maximum rate of O 2 consumption (VO 2max ), while walking exercises improved lower limb exercise endurance but not ventilatory muscle endurance.
Respiratory Muscle Rest
Application of the rehabilitation principle of interspersing periods of exercise and rest can help to reduce respiratory muscle fatigue and failure, which can cause hypercapnia before overt fatigue manifests. Diaphragm rest can be achieved by noninvasive positive pressure ventilation (NIV) using bilevel positive airway pressure. Home NIV can be administered during sleep to medically stable individuals who need ventilatory assistance around the clock or to patients who can benefit from nocturnal NIV alone. NIV can normalize arterial blood gases, improve sleep quality, increase quality of life, 12-minute walking distance, respiratory muscle endurance, and decrease dyspnea while also opening the airway to prevent sleep apnea and airway collapse.
Supplemental Oxygen Therapy
Supplemental oxygen therapy is indicated for patients with pO 2 continuously less than 55 to 60 mm Hg and can decrease pulmonary artery hypertension (PAH), polycythemia, perception of effort during exercise; it can also prolong life. The increased sympathetic modulation and reduced baroreflex sensitivity in COPD can be modulated with supplemental O 2 , thus decreasing blood pressure and pulse rate. Additionally, cognitive function can be improved and hospital needs reduced. The international consensus on long-term oxygen treatment suggests that O 2 prescription should be based on:
An appropriately documented diagnosis
Concurrent optimal use of other rehabilitative approaches, such as pharmacotherapy, smoking abstinence, and exercise training
Properly documented chronic hypoxemia.
Supplemental O 2 improves exercise tolerance, including that which occurs during submaximal exercise. In patients with primary pulmonary disease, it is safe and effective to give as much O 2 as needed with activity to maintain the O 2 sat uration above 90%. Even in patients with COPD, this can be safe as long as the supplemental O 2 is returned to resting-level supplementation (usually no more than 2 L/min) at the end of exercise.
In severe COPD, supplemental oxygen can double exercise performance and decrease the ventilatory requirement in exercise by chemoreceptor inhibition. This increases exercise tolerance without improving oxygen consumption and possibly prevents exercise-induced oxidative stress. Supplemental oxygen should be prescribed for individuals who have an O 2 saturation below 90% at rest and with activity. Inspiratory phase (pulsed) O 2 therapy avoids wasting oxygen and decreases discomfort and the drying of mucous membranes.
The hallmark of PR programs is exercise training to improve function and decrease dyspnea by allowing the patient to take “more steps per breath.” Benefits of exercise training in COPD include improving muscle function as well as improvements in exercise capacity. In COPD, improved exercise capacity reduces hyperinflation and ameliorates dyspnea. Other benefits include improved mood, improved cardiovascular function, and reduced symptom burden.
Exercise limitations in COPD result from any combination of ventilatory constraints, pulmonary gas exchange abnormalities, peripheral muscle dysfunction, cardiac dysfunction, anxiety, depression, poor motivation, and deconditioning. Ventilatory limitation and hypoxemia are the major limitations for patients with both obstructive and restrictive lung disease. Hypoxemia can be relieved using supplemental O 2 , whereas the relief of ventilatory dysfunction is implemented by medication and the treatment of deconditioning. Muscle dysfunction includes both respiratory and limb muscles. Fortunately, exercise programs have been shown to ameliorate both forms of muscle weakness.
In COPD the maximal exercise ventilation (VE max ) can be close to or may exceed maximal voluntary ventilation (MVV). Although cardiac output rises normally with exercise, peak cardiac output and heart rate are often limited because of the ventilatory limitations. Hypoxia—and in severely limited patients, hypercapnia—can occur with exercise. Thus many moderately to severely affected patients cannot attain the classic target range of 60% to 70% of maximal heart rate for cardiac or aerobic exercise training. Because of this, pulmonary patients need a modified exercise prescription.
Exercise training programs have evolved from simple endurance training to incorporate multiple exercise modalities. Endurance training, the mainstay of most PR programs, involves continuous aerobic training (CAT) with increasingly longer periods of progressively intensive exercise in order to achieve endurance. For patients with profound dyspnea, low-intensity CAT or interval training (IT) may be used. Although the benefits of low-intensity CAT may not be as robust as IT, it still makes a difference for COPD patients, while IT may be more beneficial than CAT for many others. For postexercise training, maintenance of a minimal number of steps per day shows promise. The most common CAT modalities are walking and cycle ergometry, but increasing leisure and community walking for patients with pulmonary disease may be superior to cycle ergometry. When a patient has a higher level of function, more traditional techniques of exercise prescription can be used, basing the intensity of the CAT program on a CPET and using the ventilatory anerobic threshold (VAT) for a target intensity. The ventilatory threshold being the point at which there is onset of accumulation of lactic acid is a good target for efficient exercise. In patients with severe lung disease who cannot reach VAT, a target intensity set at 60% to 70% of peak intensity can be effective. Thus moderate to severely affected COPD patients can perform exercise training successfully at intensity levels that represent higher percentages of their maximal physiologic capacities than typically recommended for unaffected individuals. With training, patients can exceed the levels attained during initial exercise testing. For patients who can sustain it, training above the VAT leads to a reduced ventilatory requirement during exercise and therefore improved maximal exercise tolerance. At-home walking programs should include a 5-minute warmup and cool down with 20 to 40 minutes of exercise at target intensities. The Borg rating of perceived exertion, heart rate, and walking speed can used to monitor intensity and progress.
Innovation in exercise in PR has started to include IT, which has been shown to be more effective than CAT over the same time period when used by athletes. Benefits of IT have also been reported in COPD on quality of life, dyspnea, exercise capacity, and skeletal muscle adaptation to exercise. However, most studies have not included high-intensity interval training (HIIT) for patient populations. If programs of HIIT were to be applied to patients with pulmonary conditions, they might also achieve the greater benefits than with CAT, as has been seen in heart failure populations.
Resistance training (RT) is another important component of PR programs. RT appears to be beneficial for patients with COPD and other lung conditions as well. The addition of RT to the exercise program of patients with pulmonary disease can increase muscle mass, which CAT fails to do. RT can reverse the effects of deconditioning, inactivity, and glucocorticoid therapy. Since the optimal dosage of resistance exercise for patients with lung disease is not clear, the recommendation of the American Academy of Sports Medicine for one to three sets of 8 to 12 repetitions undertaken 2 to 3 days each week is used. 36 Initial loads in RT are at 60% to 70% of a one-repetition maximum and can be gradually increased as the patient becomes stronger. The addition of RT to CAT for patients with COPD has been demonstrated to increase muscle mass and strength but not add additional endurance capacity. However, the additional strength can assist patients with their ADLs, including stair and hill climbing, with decreased fatigue.
Upper limb training is also an important component of PR programs. Upper limb training includes a combination of CAT using upper body ergometry and RT. The muscle groups that are focused on include the biceps, triceps, deltoids, latissimus dorsi, and pectorals. These training programs improve arm function and strength. Unsupported upper extremity activities include athletic and personal daily care activities. Unsupported arm exercise appears to provide greater benefit than other forms of arm exercise.
Another component of the PR exercise program is the inclusion of flexibility training. There are no clear studies demonstrating functional improvement from flexibility; however, there may be some benefit in increasing pulmonary compliance and vital capacity. Flexibility training may also help to lessen the risk of musculoskeletal injuries in this sedentary population, which has often been on corticosteroids and thus may be at increased risk of musculotendinous injuries.
For very disabled patients with COPD, there may be a benefit to the use of neuromuscular electrical stimulation (NMES), as it can provide training that does not increase dyspnea and may preserve and increase muscular function. In patients with severe COPD, NMES can increase limb muscle strength and exercise capacity while decreasing dyspnea; it can be done even during acute exacerbations. NMES can also be used in addition to traditional mobilization and CAT for additional benefits in mobility and may decrease the risk of critical illness myopathy for critical care patients. For patients with severe debility in a hospital setting or with severe limitations, NMES may prove beneficial in addition to traditional exercise modalities. It is unclear if there are any additional benefits for more mobile or only moderately impaired individuals.
PR also has benefit for patients with ILD and may have benefit for PAH. Benefits include improvement in peripheral muscle dysfunction, fatigue, exercise tolerance, dyspnea, and quality of life. Similarly, CF patients have been reported to benefit from PR, including demonstrating improved pulmonary toilet and secretion management. In CF, higher levels of physical activity, exercise capacity, and quality of life correlated with improved long-term outcomes.
For PAH, the role of PR has increased as the survival of patients has improved with the advent of vasodilator therapy. The primary limitation to exercise in patients with PAH is pulmonary vascular resistance and right heart failure. Patients also develop peripheral muscle dysfunction as well as deconditioning. Recent studies have demonstrated that patients with PAH can benefit from PR programs, showing increases in exercise capacity and symptom relief. The optimal dosage for training programs is not yet established, but CAT is better than high-level RT and IT to avoid increased pulmonary pressures.
PR is also an integral component of the preparation of patients for lung volume reduction surgery (LVRS) or lung transplantation, as noted from outcomes of the National Emphysema Treatment Trial. PR was shown to be safe and effective in improving exercise tolerance, quality of life, and dyspnea for this population of severely impaired COPD patients. The PR program prior to LVRS is a classical COPD program with the addition of education about LVRS surgery. After LVRS, PR restores function and improves exercise capacity since the mechanics of breathing are improved. In lung transplantation, PR has a similar role, with education about posttransplant medication and lifestyle changes being essential. Pretransplant rehabilitation also maintains muscle strength and function and helps to keep patients viable while waiting for an acceptable donor organ. Aggressive perioperative PR can help to improve function and alleviate muscle weakness due to transplant medications, allowing PR to benefit patients before and after lung transplantation.
Role of Behavioral Management in Pulmonary Rehabilitation
Although it is beyond the scope of this chapter to discuss the full range of behavioral modifications for patients with pulmonary disease, it is important to address psychosocial issues, self-efficacy, and lifestyle changes. In particular, smoking cessation is essential for any PR program, since, as one of my favorite senior pulmonologists, Byron Thomashow, likes to say, “Treating a patient with COPD who continues to smoke is like bailing water on the Titanic.” The goals are to control adverse behaviors and establish better health behaviors to allow patients to regain control over their condition and disease management. Education in PR includes patients understanding their disease, medications, health behaviors, and adaptive techniques. Self-management has four components: (1) changing cognitions, (2) enhancing self-efficacy, (3) addressing motivation, and (4) collaborative self-management. Changing cognitions means helping patients learn how to control emotional responses to their disease through understanding. Enhanced self-efficacy teaches patients that they play the most important role for optimizing and maintaining their health. Addressing motivational issues determines the goals that are meaningful in order to help a patient participate through an exacerbation or other challenge. Finally, collaborative self-management trains a patient self-management through goal setting, problem solving, decision-making, and developing action plans. Collaborative self-management plans are custom-tailored to each patient and his or her needs while taking into account available support systems and clinical resources. The benefits of self-efficacy can be seen in reduced health care utilization and decreased hospitalizations.
Because of fatigue and dyspnea, certain aids like motorized scooters and rollators with seats can greatly improve function and quality of life for pulmonary patients. Walking aids improve functional exercise capacity by reducing dyspnea and permitting rest periods. ADL aids such as reachers and sock aides can also decrease effort and improve quality of life.
The Results of Pulmonary Rehabilitation
In evaluating the efficacy of PR for patients with primary pulmonary disease, patient-centered outcomes, survival, and exercise capacity are the key items to track. PR has been shown to improve symptoms, quality of life, and exercise performance. All improvements are above the minimal clinically important differences as compared with before PR and are maintained over the long term. Many questionnaires and scales are currently used and are either generic (e.g., the 36-item Short Form Health Survey [SF-36]) or disease-specific (e.g., the Chronic Respiratory Questionnaire [CRQ]), being intended to follow the efficacy of treatments and interventions.
Quality of life is improved by PR in the commonly used questionnaires including the St. George’s Respiratory Questionnaire (SGRQ) and the Chronic Respiratory Disease Questionnaire (CRQ). Dyspnea is improved in the short term (Borg scale), in situational measures (Baseline Dyspnea Index), or impact measures (CRQ). Depression and anxiety are also improved in commonly employed instruments (e.g., components of the SGRQ).
Functional assessments done by self-rating or by observation use functional measures including the Manchester Respiratory Activities of Daily Living Scale and the pulmonary Functional Status and Dyspnea Questionnaire. Such assessments are improved by PR. The 6-MWT and CPET show regular improvements with PR. Field tests as with the 6-MWT are inexpensive and easily applied for populations, whereas CPET may be more helpful with more complex patients or for studies including physiologic parameters. Physical activity assessed with subjective reporting, measures of energy expenditure, or through activity monitors is also helpful. Finally, self-efficacy in management is a patient-centered outcome that assesses the effectiveness of the educational and psychological portions of the PR program. The latest trend in the assessment of patients with lung disease has been the creation of composite indices, the best known of which is the BODE Index for COPD. The benefits of the composite index are the combination of reported self-function, airflow obstruction, body mass index, and the functional measure in the form of the 6-MWT. It has been shown to have predictive validity for both clinical outcomes and mortality.
Virtually all studies indicate that PR with exercise training results in significant increases in ambulation capacity and exercise endurance as well as a reduction in symptoms of COPD and other lung diseases. A recent Cochrane meta-analysis of PR in COPD concluded as follows:
“Rehabilitation relieves dyspnea and fatigue, improves emotional function, and enhances patients’ control over their condition. These improvements are moderately large and clinically significant. Rehabilitation forms an important component of the management of COPD.”
The principles of PR for COPD are being increasingly applied to patients with asthma, with similar outcomes, and PR is now recommended for other pulmonary conditions as well.