PULMONARY REHABILITATION
Pulmonary rehabilitation is an integral part of the clinical management and health maintenance of those patients with chronic respiratory disease who remain symptomatic or continue to have decreased function despite standard medical treatment.
CONSEQUENCES OF RESPIRATORY DISEASE
Peripheral muscle dysfunction
Respiratory muscle dysfunction
Nutritional abnormalities
Cardiac impairment
Skeletal disease
Sensory deficits
Psychosocial dysfunction
MECHANISMS FOR THESE MORBIDITIES
Deconditioning
Malnutrition
Effects of hypoxemia
Steroid myopathy or intensive care unit (ICU) neuropathy
Hyperinflation
Diaphragmatic fatigue
Frequent hospitalizations
Effects of various medications
Psychosocial dysfunction resulting from anxiety, depression, guilt, dependency, and sleep disturbance
DEFINITION OF PULMONARY REHABILITATION
Pulmonary rehabilitation has been defined in the following terms:
A multidimensional continuum of services directed to persons with pulmonary disease and their families, usually by an interdisciplinary team of specialists, with the goal of achieving and maintaining the individual's maximum level of independence and functioning in the community.
PRINCIPAL GOALS OF PULMONARY REHABILITATION
Pulmonary rehabilitation aims to reduce symptoms, decrease disability, increase participation in physical and social activities, and improve the overall quality of life (QOL) for patients with chronic respiratory disease.
These goals are achieved through patient and family education, exercise training, psychosocial and behavioral intervention, and outcome assessment.
The rehabilitation intervention is geared toward the unique problems and needs of each patient and is implemented by a multidisciplinary team of health care professionals.
BENEFITS OF PULMONARY REHABILITATION
The benefits of pulmonary rehabilitation are seen even in irreversible pulmonary disorders, because much of the disability and handicap results not from the respiratory disorder per se but from secondary morbidities that often are treatable if recognized.
Although the degree of airway obstruction or hyperinflation of chronic obstructive pulmonary disease (COPD) does not change appreciably with pulmonary rehabilitation, reversal of muscle deconditioning and better pacing enables patients to walk farther and with less dyspnea.
Pulmonary rehabilitation programs include prevention, early recognition and treatment of morbidities, and inpatient, outpatient, and extended care of patients with chronic respiratory illness. The anticipated patient outcomes of a comprehensive pulmonary rehabilitation program include increased independence and improved QOL, as well as fewer hospitalizations or shorter hospitalization time.
DISEASE, IMPAIRMENT, DISABILITY, AND HANDICAP
According to the international classification of impairments, disabilities, and handicaps developed by the World Health Organization, a patient's specific outcomes are described as follows:
Ø Disease is a pathologic condition of the body with a unique set of symptoms and signs, often resulting in impairment. The impairment may lead to functional deficit.
Ø Impairment is any loss or abnormality of psychological, physical, or anatomic structure or function.
Ø Disability is any restriction or lack of ability (as a result of impairment) with regard to the performance of an activity in the manner or within the range that is considered normal for a human being. Impairment of activities of daily living (ADL) has an impact on the capacity of the individual to live independently.
Ø A handicap is a disadvantage for a given individual, resulting from impairment or a disability that limits or prevents the fulfillment of a role that is normal for that individual.
For patients with pulmonary impairment, disability can be due to muscle dysfunction, primary skeletal or cardiopulmonary pathology, poor endurance, or some combination of impairments. The patient can be handicapped further by inadequate finances, inadequate family support or education, and various public policies.
BENEFITS
A successful rehabilitation program identifies and differentiates the disease process (ie, impairments, disabilities, handicaps) so that remedial strategies can be determined.
The functional consequences of these impairments are addressed so that the person with chronic respiratory impairment is returned to the fullest possible physical, mental, social, and economic independence. The effectiveness of a comprehensive pulmonary rehabilitation program has been established by controlled clinical trials.
Several impairments, such as weakness, dysfunction of peripheral and respiratory muscles, anxiety and depression, and abnormalities of nutrition, have responded to treatment.Improvements in overall and exertional dyspnea, as well as health-related QOL, have been documented. Significant increases in maximal exercise capacity, as measured during exercise testing, have been observed.
In the only randomized study that has been conducted, survival benefit was not demonstrated, possibly because of the inability to detect the difference. Controlled trials have shown a decrease in health care resource use after rehabilitation, indicated by reduction in the number of hospitalizations and emergency department or physician office visits.
Although not conclusively proven, the effect of pulmonary rehabilitation on outcomes in patients without COPD may be substantial. Retrospective study has shown no significant difference in improvement in exercise tolerance or QOL following pulmonary rehabilitation in COPD versus non-COPD patients. Therefore, pulmonary rehabilitation is effective for patients with disability due to any chronic respiratory disease, not just COPD.
Respiratory rehabilitation may improve prognosis in patients who develop COPD exacerbation. Evidence from 6 trials suggests that respiratory rehabilitation is effective in COPD patients after acute exacerbation.
PATIENT SELECTION AND ASSESSMENT
Pulmonary rehabilitation is indicated for patients with chronic respiratory impairment who, despite optimal medical management, are dyspnoeic, have reduced exercise tolerance, or experience a restriction in activities. Indication for pulmonary rehabilitation is based not on the severity of physiologic impairment of the lungs but on the persistence of symptoms, disability, and handicap.
Although chronic obstructive pulmonary disease (COPD) remains the major disease involved in referral for rehabilitation services, patients with other conditions may be appropriate candidates for pulmonary rehabilitation, because the same principles of ameliorating secondary morbidity apply.
Examples include asthma, chest wall disease, cystic fibrosis, bronchiectasis, interstitial lung disease, lung cancer, selected neuromuscular diseases, postpolio syndrome, and perioperative conditions (thoracic or abdominal surgery, lung transplantation, lung volume reduction surgery).
Exclusion criteria include conditions interfering with rehabilitative processes or that could cause risk during exercise training (eg, cognitive dysfunction, severe pulmonary hypertension, unstable angina, recent myocardial infarction).
ASSESSMENT
Comprehensive assessment of the candidate for pulmonary rehabilitation is necessary for developing an appropriate, individualized plan of care.
The clinical history, physical examination, and review of pertinent investigations (eg, pulmonary function tests) are necessary to determine the severity of respiratory impairment.
The determination of baseline exercise capacity is essential in formulating the exercise training prescription and in evaluating for hypoxemia during exercise. The assessment of exercise capacity may be performed using either incremental exercise testing or a timed, 6-minute walk test.
Other assessments that may be performed include measurements of respiratory muscle strength (eg, maximum inspiratory and expiratory pressures), measurement of peripheral muscle strength, assessment of performance of ADL, health status, cognitive function, emotional and mood state, and nutritional status, as well as body composition.
Questionnaires may be used to screen for anxiety and depression. Several such instruments (eg, the Beck depression inventory [BDI], the geriatric depression scale [GDS]) are available.
Nutritional assessment is important, because changes in body weight, body composition, or eating habits are common in patients with advanced respiratory disease. Body composition can be evaluated using anthropometry, bioelectrical impedance analysis, or dual-energy radiographic absorptiometry (DRA), which estimates lean body mass.
SETTING FOR PULMONARY REHABILITATION
Despite a substantial variability in program structure, the efficacy of pulmonary rehabilitation performed in inpatient, outpatient, or home settings has been documented. The structure and components of the program, rather than the setting itself, determine the effectiveness of pulmonary rehabilitation.
The choice of setting often depends on the variability and distance to the program, insurance payer coverage, patient preference, and the physical, functional, and psychosocial status of the patient. Inpatient rehabilitation generally is recommended for patients affected to the greatest degree, because intensive rehabilitative services and specialized training for the patient and/or family will be available.
Outpatient rehabilitation, which can be hospital or community based, has the potential to benefit most patients but nonetheless requires a certain level of functional ability. Although outcomes have not been well studied, home-based pulmonary rehabilitation is convenient for the patient and family members and may provide sustained motivation for continued exercise training.
REHABILITATION TEAM
Because rehabilitation offers a holistic and comprehensive approach to medical care, the combined expertise of an interdisciplinary team is necessary. The rehabilitation team is led by a physician specialist skilled in evaluating the neuromuscular, musculoskeletal, cognitive, and cardiopulmonary systems.
The physician should be trained in cardiopulmonary and exercise fitness, ventilator management, and treatment of functional deficits. The physician should be skilled in working with a team of professionals, because he/she is responsible for the medical treatment and rehabilitation program.
The other members of the rehabilitation team include a physical therapist, occupational therapist, rehabilitation nurse, social worker, respiratory therapist, vocational counselor, and psychologist. A successful team maintains coordination, cooperation, and open communication. Each member also needs to have knowledge of the general principles of other members' approaches.
FUTURE DIRECTIONS OF PULMONARY REHABILITATION
Despite the progress made in understanding pulmonary rehabilitation, more information is needed to ensure appropriate treatment for the increasing number of patients with chronic respiratory disease. Pulmonary rehabilitation remains an art of medical practice, but one that is built increasingly on a foundation of scientific research.
The research embraces traditional outcome measures (eg, mortality and physiologic indices of lung and exercise function), as well as psychosocial measures (eg, symptoms, health-related QOL, economic analysis of costs and benefits).
The following are several areas where further study or research is needed as the field of pulmonary rehabilitation continues to grow:
Ø Few data have been published on the impact of pulmonary rehabilitation on health care costs and survival; controlled studies in both areas are needed.
Ø Exercise training is an important component of pulmonary rehabilitation. Little is known about the additional benefit of education, breathing strategies, psychosocial support, and group therapy. Knowledge of the effectiveness of these components would be beneficial for other patients who cannot exercise.
Ø More remains to be learned regarding the intensity, duration, and optimum form of exercise training. The benefits of strength training and the best exercises for upper extremity training are unknown.
Ø The benefits of respiratory muscle rest with noninvasive, positive-pressure mechanical ventilation need to be further explored. Perhaps for selected patients with stable but advanced chronic obstructive pulmonary disease (COPD), noninvasive positive pressure ventilation could be used to help patients exercise more.
Ø The gains of pulmonary rehabilitation decline over time. It remains to be seen whether this progression can be slowed with a maintenance exercise program.
Ø The optimal frequency of a pulmonary rehabilitation program is not well established. Whether more frequently repeated pulmonary rehabilitation in patients with COPD leads to physiological gains and decreases the hospitalization rate is not known. Data suggest that in severe and disabling COPD, frequently repeated inpatient pulmonary rehabilitation may lead to some additional physiological and clinical benefits over 1 year.
Ø Too often, the questionnaires for outcome assessment are long, difficult to administer, and complex to score. Simplifying or minimizing the current instruments without sacrificing their discriminative capability or their ability to detect change with intervention would be beneficial.
Ø Not much scientific information is available on the effectiveness of pulmonary rehabilitation in diseases other than COPD and asthma. Do patients with pulmonary fibrosis or chest wall disease improve with pulmonary rehabilitation? Do pediatric patients improve with pulmonary rehabilitation?
These questions should be assessed in future investigations. As an established preventive health care strategy for patients with chronic lung disease that is effective, noninvasive, and low in cost, pulmonary rehabilitation is an ideal subject for logical scientific inquiry.