American Thoracic Society
MEDICAL SECTION OF THE AMERICAN LUNG ASSOCIATION
Am J Respir Crit Care Med Vol 159. pp 1666–1682, 1999 Internet address: www.atsjournals.org
Pulmonary Rehabilitation—1999
This Official Statement of The American Thoracic Society was Adopted by The ATS Board of Directors, November 1998
CONTENTS
Introduction
The Scope of Pulmonary Rehabilitation Benefits of Pulmonary Rehabilitation
Impairment Disability Handicap Survival Economics
Patient Selection and Assessment
Benefits Across Settings: Inpatient, Outpatient, and Home-based Pulmonary Rehabilitation
The Essential Components of Pulmonary Rehabilitation Exercise Training
Education
Psychosocial and Behavioral Intervention Outcome Assessment
Future Directions for Pulmonary Rehabilitation
INTRODUCTION
Since the last Statement by the American Thoracic Society on Pulmonary Rehabilitation in 1981 (1), the efficacy and scien-tific foundation of pulmonary rehabilitation have been firmly established. The belief that there is little hope for improve-ment in patients with advanced chronic respiratory disease has been refuted, and pulmonary rehabilitation is no longer viewed as a last-ditch effort to manage patients with severe respiratory impairment. Strategies employed by pulmonary rehabilitation programs are now an integral part of the clinical management and health maintenance of patients with chronic respiratory disease who remain symptomatic or continue to have decreased function despite standard medical manage-ment.
The principal goals of pulmonary rehabilitation are to re-duce symptoms, decrease disability, increase participation in physical and social activities, and improve the overall quality of life for individuals with chronic respiratory disease (2). These goals are achieved through several processes, including exercise training, patient and family education, psychosocial and behavioral intervention, and outcome assessment. The re-habilitation intervention is geared toward the unique prob-lems and needs of each patient and is implemented by a multi-disciplinary team of health care professionals. On the basis of these concepts, the American Thoracic Society has adopted the following definition: Pulmonary rehabilitation is a multi-disciplinary program of care for patients with chronic
respira-tory impairment that is individually tailored and designed to optimize physical and social performance and autonomy.
The purposes of this Statement are to define the scope of pulmonary rehabilitation, outline the essential components in the rehabilitation process, and make recommendations for fu-ture investigation.
THE SCOPE OF PULMONARY REHABILITATION
Pulmonary rehabilitation reduces symptoms, increases func-tional ability, and improves quality of life in individuals with chronic respiratory disease, even in the face of irreversible ab-normalities of lung architecture. These benefits are possible since often much of the disability and handicap result not from the respiratory disorder per se, but from secondary morbidi-ties that are often treatable if recognized (Table 1). For exam-ple, although the degree of airway obstruction or hyperinfla-tion of chronic obstructive pulmonary disease does not change appreciably with pulmonary rehabilitation, reversal of muscle deconditioning and better pacing enable patients to walk far-ther with less breathlessness. Although pulmonary rehabili-tation should be beneficial in the pediatric population, con-trolled studies have not been performed in this group. Benefits of Pulmonary Rehabilitation
Since the previous American Thoracic Statement in 1981, the clinical effectiveness of comprehensive pulmonary rehabilita-tion has been established. A summary of the scientific basis for the individual components of pulmonary rehabilitation have been recently outlined in a combined American College of Chest Physicians and American Association of Cardiovas-cular and Pulmonary Rehabilitation panel report (3). In view of this, and since pulmonary rehabilitation involves a compre-hensive approach to care, only those trials involving the entire rehabilitation process are highlighted in this document (Table 2) (4–11).
Patient-specific outcomes are described according to the International Classification of Impairments, Disabilities, and Handicaps developed by the World Health Organization (12). Under this classification, respiratory impairment is a loss or abnormality of psychologic, physiologic, or anatomic structure or function resulting from respiratory disease. Impairment is the exteriorization of a pathologic state, and is usually deter-mined by a laboratory measurement. For respiratory disease, impairment is reflected in a decreased FEV1 and airtrapping
on pulmonary function testing or decreased quadriceps force on peripheral muscle function testing. Respiratory disability
refers to the inability to perform an activity in the manner within the normally expected range because of lung disease. This would include reductions in dynamic function, task limi-tation, and physical performance. For pulmonary rehabilita-tion, this is often determined by field tests such as the timed
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walk test or questionnaire such as the Baseline and Transi-tional Dyspnea Indexes (13). Respiratory handicap represents the disadvantage resulting from an impairment or disability within the context of the patient’s ability to perform in society or fill expected roles. For example, a reduced exercise perfor-mance during a timed walk test is disability, but the resultant inability to maintain employment is handicap. A reduction in functional performance (which focuses on activities of daily living) may be considered midway between disability and handicap.
The World Health Organization classification of impair-ment, disability, and handicap is suitable for categorizing
much of the morbidity arising from respiratory disease. How-ever, dyspnea, the overriding symptom of most patients re-ferred for pulmonary rehabilitation, does not fit neatly into this schema. Because exertional dyspnea is usually rated dur-ing exercise testdur-ing and overall dyspnea is commonly assessed through its impact on daily activities, it is included under dis-ability. Other outcomes such as survival and cost-benefit anal-ysis will be discussed separately.
Impairment. Airflow obstruction, an impairment that is in-tegral to the diagnosis of chronic obstructive pulmonary dis-ease, is generally considered to be irreversible with either standard medical therapy or with pulmonary rehabilitation.
TABLE 1
CONSEQUENCES OF RESPIRATORY DISEASE
Types of Secondary Morbidity Mechanism(s)
Peripheral muscle dysfunction Deconditioning, steroid myopathy, ICU neuropathy, malnutrition, decreased lean body mass, fatigue, effects of hypoxemia, acid-base disturbance, electrolyte abnormalities
Respiratory muscle dysfunction Mechanical disadvantage secondary to hyperinflation, malnutrition, diaphragmatic fatigue, steroid myopathy, electrolyte abnormalities
Nutritional abnormality Obesity, cachexia, decreased lean body mass Cardiac impairment Deconditioning, cor pulmonale
Skeletal disease Osteoporosis, kyphoscoliosis Sensory deficits (impaired vision,
hearing, etc.)
Medications (e.g., steroids, diuretics, antibiotics)
Psychosocial Anxiety, depression, guilt, panic, dependency, cognitive deficit, sleep disturbance, sexual dysfunction
TABLE 2
RANDOMIZED CONTROLLED TRIALS OF PULMONARY REHABILITATION
Investigator Study Design
Patients
(n) Patient Characteristics Outcomes Goldstein,
1994 (4)
8 wk. Inpatient rehabilitation followed by 16 wk partially supervised home training versus control group given conventional care
89 Treatment group mean age, 66 yr; FEV1, 35% pred
Treatment group had significant increase (37.9 m) in 6MWD and submaximal cycle endurance time (4.7 min), and significant improvements in dyspnea, emotion, and mastery components of the CRQ or CRDQ, and dyspnea as measured by the TDI (12.7 units).
Reardon, 1994 (5)
6 wk. Comprehensive outpatient rehabilitation versus untreated control group
20 Treatment group mean age, 66 yr; FEV1, 35% pred
No significant change in maximal exercise testing in either group. Rehabilitation patients had significantly lower exertional dyspnea during exercise testing and lower overall dypsnea measured by the TDI.
Ries, 1995 (6)
8 wk. Comprehensive outpatient rehabilitation versus educational control group
119 Treatment group mean age, 61.5 yr; FEV1, 1.21 L
Significant postrehabilitation improvement in O2max and treadmill endurance time, and decreased exertional and overall dyspnea. No significant postrehabilitation change in HRQL (Quality of Well-Being score), number of hospital days, or survival.
Wijkstra, 1996 (7, 8)
12 wk. Home-based multi- disciplinary rehabilitation versus untreated control group
43 Treatment group mean age, 64 yr; mean FEV1, 44% pred
Treatment group showed a significant increase in work rate, o2max, and 6MWD (438 to 447 m), and decreases in exertional dyspnea and inspiratory muscle workrate during incremental cycle exercise testing. HRQL (CRDQ) increased significantly in treatment group. Strijbos,
1996 (9)
12 wk. Hospital-based outpatient versus 12 wk home rehabilita- tion versus untreated control group. Follow-up, 18 mo
45 Treatment group mean ages, 61.2 and 60.0 yr; FEV1, 40.4 and 45.5% pred in outpatient and home rehab groups
Both outpatient and home-based rehabilitation had increases in maximal cycle work level, 4MWD, and decreases in exertional dyspnea compared with the control group. Gains made in the outpatient group tended to peak after formal rehabilitation then gradually decline. Those in home-based rehabilitation tended to gradually increase during the 18-mo obervation period. Bendstrup,
1997 (10)
12 wk. Hospital-based outpatient rehabilitation versus untreated control group
32 Treatment group mean age, 64 yr; mean FEV1, 1.02 L
At 12 and 24 wk, the treatment group had a significant increase in 6MWD (113 m versus 21 m) and activities of daily living than the control group. CRDQ scores were significantly higher at 24 wk. Wedzicha,
1998 (11)
8 wk. Exercise and education versus education alone. Hospital-based or home-based depending on level of dyspnea
126 Mean ages ranged from 69 to 73 yr; FEV1 from 36 to 38% pred
In the group with moderate dyspnea (n 5 66), exercise training and education led to improvement in the shuttle walking distance and health status compared with education alone. Exercise ability and health status did not significantly change in either group with severe dyspnea.
Definition of abbreviations: 6MWD 5 6 minute walk distance; CRQ or CRDQ 5 Chronic Respiratory Disease Questionnaire; TDI 5 Transitional Dyspnea Index; O2max 5 maximal
minute ventilation.
V·
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1668 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 159 1999 Therefore, most studies evaluating the effectiveness of
pulmo-nary rehabilitation use the FEV1 and other measures of
pul-monary impairment as descriptors of the patient population rather than as outcome measures. Other impairments com-mon to chronic respiratory disease such as weakness and dys-function of peripheral and respiratory muscles, anxiety and depression, and abnormalities of nutrition and body composi-tion are more responsive to treatment. These will be discussed in later sections.
Disability. Studies using exercise as an outcome measure have shown either an increase in the exercise performed or a decrease in dyspnea for a given level of exercise or both. A meta-analysis of 11 studies found a positive effect size for ex-ercise with training (Figure 1) (14). This positive effect size for exercise is noteworthy since the course of COPD is progres-sively downhill.
Significant increases in maximal exercise capacity mea-sured during incremental exercise testing have been observed after pulmonary rehabilitation. For example, a 1.5 metabolic equivalent increase (33% increase over baseline) in maximal treadmill work rate and a 0.11 L/min increase (9% increase over baseline) in maximal oxygen consumption was demon-strated in a clinical trial at the completion of 8 wk of outpa-tient pulmonary rehabilitation (6). Similarly, an eight watt in-crease in maximal workrate on cycle ergometry (11% inin-crease over baseline) resulted after 12 wk of home-based pulmonary rehabilitation (8). In a study comparing outpatient, hospital-based rehabilitation and home-hospital-based rehabilitation with a control group receiving standard medical therapy, the outpa-tient program showed an initial 20% increase in maximal work rate after rehabilitation, but this improvement gradually decreased in the 18-mo follow-up period (9). The home-based
rehabilitation program, on the other hand, showed a gradual increase in maximal work rate, peaking at 21% above baseline at 18 mo.
Steady-state exercise endurance also improves substan-tially after pulmonary rehabilitation. In an 8-wk study of in-patient pulmonary rehabilitation followed by 16 wk of outpa-tient supervision, stationary cycle ergometer endurance time at 60% of the symptom-limited maximal power output in-creased 4.7 min over that in a control group (4). This repre-sented a 38% increase over the baseline measurement of the treatment group. Even more impressively, the controlled study evaluating outpatient rehabilitation described earlier (6) demonstrated a 10.5-min increase in treadmill endurance time in the treatment group, an 85% increase over baseline.
The 6-min walk distance as a measure of exercise perfor-mance has shown increases of 38 m in pulmonary rehabilita-tion patients (inpatient) compared with control subjects (4). This distance exceeds the minimum 30 m for a clinically im-portant change for the 6-min walk test estimated by one method (15), but is below the 54-m estimate of clinical signifi-cance determined by another (16). In a more recent, con-trolled 12-wk study of outpatient pulmonary rehabilitation (10), the 6-min walk distance increased by 80 m at 6 wk (half-way into the program), 113 m at the end of the program, and 96 m 12 wk after the program ended. These changes were all significantly greater than those of a control group. Using a 4-min walk test, an approximately 40-m increase has been shown with outpatient hospital-based and a 30-m increase with home-care pulmonary rehabilitation (9).
Dyspnea has also been frequently included as an outcome measure for pulmonary rehabilitation. The recent Statement on Dyspnea by the American Thoracic Society summarizes the effects of exercise training on decreasing dyspnea (Figure 2) (17). The beneficial effects from exercise training affects not only dyspnea, but this effect on dyspnea appears to exceed that from bronchodilator or oxygen therapy.
Improvements in overall and exertional dyspnea have been demonstrated in controlled trials of comprehensive pulmo-nary rehabilitation. A clinically meaningful decrease in dys-pnea was found after inpatient pulmonary rehabilitation using the Transitional Dyspnea Index (TDI). A 2.3-unit increase in the TDI (possible range, 212 to 112 units) indicated de-creased dyspnea associated with day-to-day functioning in a controlled study of outpatient pulmonary rehabilitation (5). In that same study, rehabilitation was also associated with de-creased exertional dyspnea measured by the visual analog scale (74 to 51% of line length) recorded at maximal work rate during incremental testing. Other studies have shown signifi-cant postrehabilitation decreases in questionnaire-rated dys-pnea associated with activities of daily living (6) and decreased levels of perceived breathlessness during stationary cycle exer-cise at work loads similar to baseline levels (9).
Handicap. Improvements in health status (health-related quality of life) after pulmonary rehabilitation have been docu-mented in several studies (4, 7, 10, 11). Inpatient pulmonary rehabilitation led to statistically significant improvements in the dyspnea, mastery, and emotional functioning components of the Chronic Respiratory Disease Questionnaire (CRDQ), a respiratory-specific health status instrument (4). Other studies have also demonstrated improvements in health status (mea-sured by the CRDQ) after comprehensive outpatient (10, 11) and home-based (7) pulmonary rehabilitation.
Survival. In the only randomized, controlled trial of pul-monary rehabilitation that included survival as an outcome measure, 67% of the rehabilitation versus 56% of education-treated control patients were alive at 6 yr (Figure 3) (6). This
Figure 1. Effect of respiratory rehabilitation on functional exercise capacity. Reprinted with permission from Reference 14.
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difference, however, was not statistically significant (p 5 0.3), possibly because of the lack of power to detect a survival ad-vantage.
Economics. Controlled trials have shown a trend toward a decrease in the use of health care resources after rehabilita-tion (18, 19), including a reducrehabilita-tion in the number of hospital-izations and the number of hospital days for pulmonary-related illness (6, 20–22). For example, rehabilitation groups tended to have fewer hospital days after rehabilitation (22.4 6 15.4 versus 11.3 6 10.7 d at 12 mo, compared with education-only treatment (6.4 6 12.6 versus 3.6 6 6.6 d, p 5 0.2) (6).
Patients with chronic obstructive pulmonary disease (COPD) are frequent utilizers of health care resources, and a reduction in the number of hospitalization days per patient after reha-bilitation has been noted in uncontrolled studies (23, 24). Pul-monary rehabilitation may also lead to reductions in the util-ization of other health care resources such as visits to the emergency department or a physician’s office and phone calls to the physician’s office (25, 26). Preliminary evidence sug-gests that these benefits may result in an ongoing decrease in the number of hospitalization days required for COPD-related causes (27).
One concern regarding these studies is that each was con-ducted prior to the institution of managed care. More recent evidence suggests that resource utilization for patients
under-going rehabilitation in a health maintenance organization is significantly decreased during the year after completion of the program (28). Thus, the beneficial effects of pulmonary reha-bilitation, from a health care utilization viewpoint in both the inpatient and the outpatient settings, are becoming recognized in an era of managed health care. More clinical trials are nec-essary, however, to evaluate these benefits.
Patient Selection and Assessment
Selection criteria. Pulmonary rehabilitation is indicated for pa-tients with chronic respiratory impairment who, despite op-timal medical management, are dyspneic, have reduced exercise tolerance, or experience a restriction in activities. It should be emphasized that symptoms, disability, and handicap, not the severity of physiologic impairment of the lungs, dictate the need for pulmonary rehabilitation. Thus, there are no specific pulmonary function criteria indicating the need for pulmonary rehabilitation. Unfortunately, in the United States, referral to pulmonary rehabilitation is too often reserved for those with far-advanced lung disease. Although these patients still stand to benefit considerably from pulmonary rehabilitation (29), referral at an earlier stage would allow for earlier preventative strategies such as smoking cessation, greater latitude in the exercise prescription, and, perhaps, better long-term adher-ence with maintenance exercise. Common indications for pul-monary rehabilitation relate to the handicap resulting from chronic respiratory disease (Table 3).
Because pulmonary rehabilitation has traditionally dealt with patients with COPD, the effectiveness of this therapy for pulmonary conditions other than COPD has received less at-tention (30). Although COPD remains the major referral base, patients with other conditions (Table 4) may be appro-priate candidates for pulmonary rehabilitation because the same principles of ameliorating secondary morbidity also ap-ply. By necessity, programs for patients without COPD may differ in educational focus and exercise prescription from tra-ditional rehabilitation for those with COPD. For instance, ed-ucation for the asthmatic patient emphasizes environmental issues such as recognizing and avoiding triggers and the need for use of controller medication, whereas exercise training in-tensity of patients with interstitial lung disease may require modification because of exercise-induced hypoxemia.
Exclusion criteria for pulmonary rehabilitation fall into two broad categories: (1) conditions that might interfere with the patient undergoing the rehabilitative process and (2) condi-tions that might place the patient at undue risk during exercise training. Co-morbidities such as advanced arthritis, the inabil-ity to learn, or disruptive behavior are examples of the former, whereas severe pulmonary hypertension, unstable angina, or recent myocardial infarction are examples of the latter. How-ever, even in those unable to fully participate in an exercise training program, education, psychosocial, and/or nutritional
Figure 2. Effect of exercise training on dyspnea compared with bronchodilators and oxygen. Reprinted with permission from Ref-erence 17.
Figure 3. Kaplan-Meier survival curves for patients in the rehabili-tation and education groups during 6 yr of follow-up (5). At 6 yr of follow-up, 38 of 57 patients survived in the rehabilitation group (67%) and 35 of 62 in the education group (56%). These differ-ences were not statistically significant (p 5 0.3). Reprinted with permission from Reference 6.
TABLE 3
COMMON INDICATIONS FOR REFERRAL FOR PULMONARY REHABILITATION
Respiratory disease resulting in: • Anxiety engaging in activities • Breathlessness with activities • Limitations with:
– Social activities – Leisure activities
– Indoor and/or outdoor chores
– Basic or instrumental activities of daily living • Loss of independence
1670 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 159 1999
interventions alone may be of benefit. Patients who are poorly motivated are not ideal candidates for pulmonary rehabilita-tion; however, their level of motivation may change if they at-tend rehabilitation sessions. Finally, although including cur-rent cigarette smokers in a pulmonary rehabilitation program remains a subject of debate, it is reasonable to consider enroll-ing these individuals, particularly if they are participatenroll-ing ac-tively in a smoking cessation program.
Assessment. Comprehensive assessment of the rehabilita-tion candidate is necessary for the development of an ap-propriate, individualized plan of care. The clinical history, physical examination, and review of pertinent records (e.g., spirometry) are necessary to determine the severity of respira-tory impairment and to assess for other significant morbidity. An educational assessment by the rehabilitation staff deter-mines the patient’s knowledge base and learning needs and helps focus the educational intervention. A determination of baseline exercise capacity using incremental exercise testing is important in formulating the initial exercise training prescrip-tion, in detecting cardiac abnormalities associated with exer-cise, and in evaluating for hypoxemia during exercise. Other assessments that may be performed include: measurements of respiratory muscle strength such as maximum inspiratory and expiratory pressures, measures of peripheral muscle strength, assessments of activities of daily living, health status, cognitive function, emotional and mood state, and nutritional status/ body composition.
Assessment of cognitive function should be considered in patients with suspected memory problems since a limitation might impede rehabilitation efforts by interfering with the pa-tient’s ability to follow instructions or articulate his or her health status. Cognitive deficits, which may result from aging, dementia, hypoxemia (31, 32), or substance abuse, can be evaluated using one of several easy to administer instruments (33) such as the Mini-Mental State Exam (MMSE) (34) or the Neurobehavioral Cognitive Status Examination (NCSE) (35). These questionnaires screen for general factors such as mem-ory, alertness, attention, orientation, and reasoning. Norma-tive values for patients with COPD are available for the MMSE (36).
Because of the prevalence of symptoms related to anxiety and depression in patients with advanced lung disease (34, 37– 40), questionnaires may be used to screen for potential pathol-ogy. Alternatively, anxiety and depression can be assessed prerehabilitation and postrehabilitation as an outcome mea-sure. Evaluation for the presence of emotional disturbances may be included as an integral part of the program or may be implemented on a case-by-case basis. High levels of anxiety or clinically significant depression may lead to difficulty in assim-ilating the educational components of rehabilitation since memory and attention are affected by these disorders (41).
Emotional disturbances may also limit motivation or interfere with the ability to perform exercise training. Just as physiolog-ically unstable patients must be stabilized prior to entering the rehabilitation program, so too should those with significant emotional disorders be treated and stabilized.
Many mood questionnaires are heavily biased toward as-sessing activity levels and other somatic factors such as sleep, eating patterns, and energy levels—areas also affected by physiologic changes from respiratory disease (42). Therefore, questionnaires relying primarily on cognitive changes may be more appropriate for pulmonary patients. The following ques-tionnaires are commonly used in pulmonary patients, but they vary in the degree to which they measure cognitive changes. Questionnaires commonly used to measure coping and mood include the Psychosocial Adjustment to Illness Scale-Self Re-port (43, 44) and the Profile of Mood States (45). Question-naires more specific to symptoms of depression and/or anxiety include the Geriatric Depression Scale (46), the Center for Epidemiological Studies–Depression Scale (47), the Hospital Anxiety and Depression Scale (48), the Self-Rating Depres-sion Scale (49), the Beck DepresDepres-sion Inventory (50), and the State and Trait Anxiety Inventory (51).
Nutritional assessment is important since disturbances in body weight, body composition, and changes in eating habits are common in patients with advanced COPD (52, 53). Body weight can be assessed as a percentage of ideal body weight (the latter often obtained from insurance tables) or as the body-mass index (in units of kilograms per meters squared). Decreased weight is associated with decreased exercise per-formance (54), reduced muscle aerobic capacity (55), and in-creased mortality, independent of lung function in patients with advanced COPD (56). Body composition can be evalu-ated using anthropometry or bioelectrical impedance analysis, which estimate fat-free mass, or dual energy X-ray absorpti-ometry (DEXA), which estimates lean mass. Substantial re-ductions in fat-free or lean body mass, which, in part, reflect the impact of advanced pulmonary disease on peripheral mus-culature, may be present in patients of normal weight (52, 57). Alterations in body composition are correlated with impaired performance on timed walk testing and poorer health status, independent of body weight (54, 57).
Benefits Across Settings: Inpatient, Outpatient, and Home-based Pulmonary Rehabilitation
Despite substantial variability in program structure, pulmo-nary rehabilitation performed in inpatient (4), outpatient (5, 6, 10, 11), or home settings (8, 9) has documented clinical effi-cacy. Although little data exist directly comparing patient out-comes in different settings, it is probably the structure and components of the program rather than the setting itself that determine the effectiveness of pulmonary rehabilitation (9).
Pulmonary rehabilitation by setting may vary considerably in staff availability, program duration, structure, and individ-ual components. The choice of setting often depends on the prerehabilitation physical, functional and psychosocial status of the patient, the availability and distance to the program, in-surance payer stipulations, and patient preference. The advan-tages and disadvanadvan-tages of pulmonary rehabilitation in outpa-tient, inpaoutpa-tient, and home-based settings are listed in Table 5. Inpatient rehabilitation is generally best-suited for the sickest patients, reflecting its intensive rehabilitative services and spe-cialized training of the patient and/or family. Outpatient reha-bilitation, which can be hospital-based or community-based, is currently the most widely available and, as such, has the po-tential to benefit the most patients. A certain level of
func-TABLE 4
NON-COPD INDICATIONS FOR PULMONARY REHABILITATION
• Asthma (193, 194) • Chest wall disease (20, 195) • Cystic fibrosis (196, 197)
• Interstitial lung disease, including post-ARDS pulmonary fibrosis (30, 152) • Lung cancer (198, 199)
• Selected neuromuscular diseases (152, 200, 201) • Perioperative states (e.g., thoracic, abdominal surgery) • Postpolio syndrome (202, 203, 204)
• Prelung and postlung transplantation (205, 206) • Prelung and postlung volume reduction surgery (207, 208)
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tional ability, however, must already be present for patients to physically attend outpatient sessions two to three times a week (11).
The concept of home-based pulmonary rehabilitation may vary considerably among programs. For example, a home-based program may provide regular supervised home exercise and education given by physiotherapists for patients too dys-pneic to attend outpatient rehabilitation (11). Alternatively, a program may include daily stationary bicycle exercise at home taught by a physical therapist, combined with twice-weekly visits to a local physiotherapist for additional training, regular home visits by a nurse, and monthly visits to a general practi-tioner (8). Patients attending the latter type of program would be considered as candidates for outpatient pulmonary rehabil-itation programs elsewhere. The principal advantages of home-based rehabilitation are convenience for the patient and fam-ily members and a familiar environment for training and the acquisition of techniques. Although not well studied, the latter may promote sustained motivation with continued exercise training after completion of the formal program (9). Despite its convenience, home-based pulmonary rehabilitation may not be the ideal site for severely disabled patients since one re-cent study was unable to demonstrate significant improve-ments in exercise ability or quality of life in patients with se-vere dyspnea who were given rehabilitation at home (11).
THE ESSENTIAL COMPONENTS OF PULMONARY REHABILITATION
Comprehensive pulmonary rehabilitation programs generally have four major components: exercise training, education, psychosocial/behavioral intervention, and outcome assessment.
These interventions are generally provided by a multidisci-plinary team that varies among programs but often includes physicians, nurses, respiratory therapists, physical therapists, occupational therapists, psychologists, and social workers. Al-though exercise training is the only component demonstrated in controlled clinical trials to enhance outcomes, the pervasive nature of the functional deficits in the typical patient suggests that a comprehensive approach would be optimal.
Exercise Training
Exercise training is the foundation of pulmonary rehabilita-tion. Although exercise has to date not resulted in measurable effects on the underlying respiratory impairment, its positive effects on dyspnea (Figure 1) underscores the importance of physical deconditioning as a co-morbid factor in advanced lung disease. Exercise training is based on general principles of exercise physiology: intensity, specificity, and reversibility (58).
Training intensity. In healthy subjects, aerobic training is usually targeted at 60 to 90% of the predicted maximal heart rate or 50 to 80% of the maximal oxygen uptake. This level is sustained for 20 to 45 min and repeated three to four times a week. Training at this intensity, which is usually well above the anaerobic threshold, increases maximal exercise perfor-mance, causes physiologic adaptations in peripheral muscles, and improves cardiac function in healthy subjects (59).
Until recently, the prevailing thought has been that pa-tients with advanced lung disease (such as COPD) have a ven-tilatory limitation that precludes the aerobic training levels necessary for beneficial physiologic adaptations (60). The training intensity in earlier studies, however, was often well below the level of maximal work rate. Recent studies have demonstrated that anaerobic metabolism and an early onset
TABLE 5
ADVANTAGES AND DISADVANTAGES OF PULMONARY REHABILITATION IN DIFFERENT SETTINGS
Advantages Disadvantages
Inpatient Closer medical monitoring makes it ideal for sickest patients with the greatest functional deficits
Cost and potential difficulty with insurance coverage
Intensive nursing care available 24 h/d Not suitable for patients with less severe respiratory or comorbid disease
Transportation to and from the program is not an issue for patient
Transportation potentially difficult for family members
Allows participation and observation of family members in therapies Ideal setting for patients requiring
assistive devices, tracheostomy care, or ventilator weaning
Outpatient Widely available Potential transportation issues Least costly No opportunity to observe home
activities Efficient use of staff resources
Least intrusive to the family
Home-based Convenience to the patient Cost and potential difficulty with insurance coverage
Transportation not an issue for patient unless frequent trips to a health-care provider are part of the program
Lack of group support
Adaptation of exercise to a familiar environment may lead to better adherence with long-term treatment goals
Potential lack of full spectrum of multidisciplinary health personnel
1672 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 159 1999 of lactic acidosis can be observed in exercise training of
pa-tients with COPD (61, 62). Furthermore, greater improve-ments in maximal and submaximal exercise responses can be obtained after exercise training at high (60% of maximal work rate, above the anaerobic threshold) compared with low (30% of maximal work rate) exercise levels (61). Increases in oxida-tive enzymes in the peripheral muscles have been found after strenuous (63), but not low intensity, training (60). The reduc-tion in ventilareduc-tion and lactate levels at identical submaximal work rates after high-intensity exercise training strongly sug-gests that aerobic metabolism is indeed attainable in many pa-tients with COPD (61). Training respiratory papa-tients at 60 to 75% of maximal work rate results in substantial increases in maximal exercise capacity and reductions in ventilation and lactate levels at identical exercise work rates (63, 64).
Most pulmonary rehabilitation programs emphasize endur-ance training, utilizing periods of sustained exercise for about 20 to 30 min two to five times a week. Although training at levels of 60% of the maximal work load for prolonged periods of time is possible for a considerable proportion of patients with severe airway obstruction (6, 61), some cannot tolerate training at this intensity (63, 64). In these patients, interval training, consisting of two to three min of high-intensity (60 to 80% maximal exercise capacity) training alternating with equal periods of rest, might be an alternative. In healthy sub-jects, interval training elicits training effects similar to those of endurance training (65, 66), but to date, its role in patients with lung disease is unclear (67).
On the basis of available research, the target level of exer-cise training intensity should be a percentage of the maximum work capacity, e.g., 60% of the maximal oxygen consumption. In many centers, a percentage of the maximum heart rate is used to estimate this training intensity. Additionally, changes in heart rate can be used to study cardiac adaptations after ex-ercise training in patients with COPD (61, 63, 68). The rela-tionship between heart rate and work rate, however, varies widely among subjects (69) and may be affected by cardiac and lung disease or their therapy (70). Despite these limita-tions, heart rate measured at a given percentage of peak work rate is a reasonable parameter to set future training intensity. Alternatively, dyspnea ratings during maximal graded exer-cise testing may reliably predict specific exerexer-cise intensities during training (71), making symptom-guided exercise train-ing a possible alternative to heart rate–guided traintrain-ing (72, 73).
Training specificity. Training specificity refers to the obser-vation that benefit is gained only in those activities involving the muscle groups that are specifically trained. For instance, an increase in the 6-min walk distance (6MWD) occurs with lower extremity training but not with upper extremity training (74). There is, however, some transfer effect to other activities since cycle ergometer training improves walking distance (75) and vice versa. Because of training specificity, exercise pro-grams should provide training that parallels the desired out-come(s) as closely as possible.
Upper extremity endurance training. Endurance training of
the upper extremities to improve arm function is particularly important since many activities of daily living involve use of the arms. Training can be accomplished using supported arm exercises with ergometry or unsupported arm exercises by lift-ing free weights, dowels and stretchlift-ing elastic bands. Both methods can effectively improve arm endurance (76).
Lower extremity endurance training. Most pulmonary
re-habilitation programs emphasize training of lower extremities using singly or in combination stationary cycle exercise, tread-mill walking, or ground-based walking. As stated earlier, not only is there a considerable increase in submaximal endurance
time with lower extremity training of patients with COPD, there is also a dose-response effect: higher intensity exercise (60 to 80% of the maximal work rate) increases endurance time more than does lower intensity exercise (30% of the maximal work rate) (61). Other studies of cycle ergometer training (77, 78), treadmill walking (4, 6, 65), or combined walking and cycling (72) have also shown improvements in maximal work rate and endurance time.
Strength training. Because peripheral muscle weakness
contributes to exercise limitation in patients with lung disease (79), strength training is a rational component of exercise training during pulmonary rehabilitation. To date, relatively few studies have evaluated the effectiveness of strength train-ing in patients with lung disease, so its role in pulmonary reha-bilitation remains to be defined. However, two randomized controlled studies suggest it may be an important component to exercise training. A trial of weight lifting as an exercise for respiratory patients showed that the group that exercised with loads ranging from 50 to 85% of the one-repetition maximum had a greater increase in peripheral muscle function than did an untreated control group (80). Although there was no con-comitant increase in maximal endurance exercise capacity, there was a measured improvement in quality of life.
In a trial of a low-intensity (i.e., no additional loads) leg and arm muscle conditioning compared with an untreated control group (81), the treatment group increased their walk distance and had physiologic adaptation to exercise mani-fested by a reduced ventilatory equivalent for oxygen and car-bon dioxide. No changes in maximal exercise performance were present. These positive results are somewhat surprising since in other studies low intensity exercise was not very effec-tive (61).
Respiratory muscle training. Inspiratory muscle function
may be compromised in COPD, an impairment that may con-tribute to dyspnea (82), exercise limitation (83), and hyper-capnia (84). Respiratory muscle strength is commonly esti-mated by measuring maximal negative inspiratory pressure (PImax) (85), although this is a highly effort-dependent test.
Inspiratory muscle training is generally initiated at low inten-sities then gradually increased to achieve 60 to 70% of PImax.
The minimal load required to achieve a training effect is 30% of the PImax (86). Two methods of inspiratory muscle training
most commonly used are threshold loading and resistive load-ing. With threshold loading the training load is independent of flow (87, 88), requiring the build up of negative pressure be-fore flow occurs, and hence is inertive in nature. Threshold and resistive training effects have not been adequately com-pared.
Although inspiratory muscle training using adequate loads undoubtedly improves strength of the inspiratory muscles in patients with COPD (89–93), it remains unclear whether this results in decreases in symptoms, disability, or handicap. There is some evidence that improvement in inspiratory muscle strength in COPD is accompanied by decreased breathless-ness and increased respiratory muscle endurance (79, 94), but the benefits of inspiratory muscle strength training are not well established (95). Further research is needed to identify optimal candidates and diseases for respiratory muscle train-ing and clarify its benefits and role in pulmonary rehabilita-tion programs.
Training reversibility. The reversibility of training effects is well known (58, 96, 97). As with normal persons, the training effects in patients with chronic lung disease are maintained only so long as exercise is continued. A reduction in adher-ence with the maintenance exercise prescription given at the completion of the formal pulmonary rehabilitation probably
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explains to some degree the reductions in timed walk distance (98) and exercise endurance time (6) occurring months to years later.
In a trial evaluating the long-term effects of home rehabili-tation (99), patients were randomized into three groups: a treatment group given 12 wk of pulmonary rehabilitation fol-lowed by visits to a physical therapist once a week for a total of 18 mo, another treatment group given the same formal re-habilitation but visited the physical therapist once a month for 18 mo, and a control group that received no rehabilitation at all but was followed for 18 mo. Although both rehabilitation groups showed significant increases in maximal cycle work rate and 6MWD postrehabilitation, this improvement was not sustained at 18 mo with either maintenance training fre-quency. There was an overall tendency for a decline in the 6MWD after 18 mo, but there were no significant differences between the two training frequencies. In another trial where patients completing formal rehabilitation were instructed to continue exercise training at home and to visit the program once a month, the gains made in treadmill exercise endurance diminished considerably by 12 mo (6).
Neither of the above studies reported details of adherence with the postrehabilitation exercise training. Thus, the optimal frequency and intensity of regular post-rehabilitation mainte-nance exercise training remains to be determined. Addition-ally, the role of short periods of supervised exercise training after exacerbations of respiratory disease with a goal of re-turning the patient to baseline performance is an untested al-ternative. Thus, although it is clear that efforts at improving long-term adherence with exercise training at home will be necessary for long-term effectiveness of pulmonary rehabilita-tion, further information from controlled trials is needed. Education
Although the benefits directly attributable to the educational component of pulmonary rehabilitation have not been fully documented, education is now so integral to virtually all com-prehensive pulmonary rehabilitation programs that its effect in isolation cannot be readily determined. Education encour-ages active participation in health care (100, 101), leads to a better understanding of the physical and psychologic changes that occur with chronic illness, and helps patients and their families explore ways to cope with those changes (102, 103). Through the educational process, patients can become more skilled at collaborative self-management and more adherent to their treatment plan (104).
Education can be provided in small groups or on an indi-vidual basis, depending on needs of the patient, the site, the resources, and the design of the rehabilitation program (105). In general, the educational needs of pulmonary rehabilitation participants are determined at the initial evaluation and are reassessed during the program. A number of standard topics are addressed in the educational sessions (Table 6) (106). Three topics frequently incorporated into pulmonary rehabili-tation programs are breathing retraining, energy conservation, and proper use of medications (and treatments) will be de-scribed in further detail. The utility of including education on end-of-life planning will also be discussed because of the emerg-ing recognition of its importance for patients with chronic lung disease.
Breathing strategies. Some patients may benefit from the breathing strategies of pursed-lip and diaphragmatic breath-ing. Pursed-lip breathing involves a nasal inspiration followed by expiratory blowing against partially closed lips, avoiding forceful exhalation. This strategy is often unconsciously used by patients with COPD to enhance exercise tolerance during
periods of dyspnea and increased ventilatory demand. Pursed-lip breathing does reduce respiratory rate, minute ventilation, and carbon dioxide level, and increases tidal volume, arterial oxygen pressure, and oxygen saturation (107–109). Despite these physiologic actions, the effectiveness of pursed-lip breathing in reducing dyspnea in COPD is controversial, with some studies actually demonstrating an increase in breathless-ness at rest (110) and during exercise (111).
The strategy of diaphragmatic breathing is to consciously expand the abdominal wall during inspiratory diaphragm de-scent (112). In theory, this would increase the efficiency of the diaphragm while reducing the ineffective movements of the upper rib cage during ventilation of patients with COPD (113, 114). Despite an early study reporting an increase in dia-phragm excursion with diadia-phragmatic breathing (115), later studies showed increases in overall chest wall motion asyn-chrony, abdominal paradox, reduced mechanical efficiency of the chest wall, and increased work of breathing with this ma-neuver (116–118) without improvement in the distribution of ventilation to the lung bases (119). Finally, diaphragmatic breathing was found to increase rather than decrease the level of dyspnea (118). In view of these results, the routine use of diaphragmatic breathing training in pulmonary rehabilitation is not recommended.
Energy conservation and work simplification. Principles of energy conservation and work simplification assist patients in maintaining activities of daily living such as self-care, home management, shopping, and performance of job-related tasks. Methods include paced breathing, which is based on principles of reducing breathholding and timing the respiratory cycle with physical activities, optimizing body mechanics, advanced planning, prioritization of activities, and the use of assistive devices. These techniques might help the patient conserve en-ergy from basic daily activities to be used for leisure activities and socialization. In combination with exercise training, en-ergy conservation techniques may make it possible for some patients with advanced disease to continue or even resume em-ployment.
Medication and other therapies. Education in the types of medications, action, side effects, dosage, frequency, and proper use of all oral and inhaled respiratory medications should be provided in a comprehensive pulmonary rehabilita-tion program. Instrucrehabilita-tion in metered dose inhaler technique and spacer devices are particularly important since new modes
TABLE 6
COMMON TOPICS ADDRESSED IN EDUCATIONAL COMPONENT
• Anatomy and physiology of the lung • Pathophysiology of lung disease • Airway management
• Breathing training strategies
• Energy conservation and work simplification techniques • Medications
• Self-management skills
• Benefits of exercise and safety guidelines • Oxygen therapy
• Environmental irritant avoidance • Respiratory and chest therapy techniques • Symptom management
• Psychological factors—coping, anxiety, panic control • Stress management
• End of life planning • Smoking cessation • Travel/leisure/sexuality • Nutrition
1674 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 159 1999 of administration such as dry-powder inhalers evolve and
defi-ciencies in technique are common in patients with chronic lung disease (120, 121). Not uncommonly, supplemental oxy-gen therapy is instituted at about the time patients are re-ferred for pulmonary rehabilitation. Instruction on the indica-tions and appropriate use of oxygen is often invaluable for both patients requiring oxygen as well as in preparation for those who may eventually require its use.
End-of-life education. The progressive nature of airflow limitation in patients with COPD presents a risk for respira-tory failure that increases over time. Patients faced with an ep-isode of respiratory failure need to decide (along with their families and clinician) if intubation and mechanical ventilation will provide life-saving support for a remedial episode of respiratory failure or will only delay the dying process at the terminal phase of their disease. Unfortunately, clinical factors assessable at the onset of respiratory failure caused by COPD are poor predictors of outcome from mechanical ventilation (122–125). The decision to initiate life-support, therefore, is not purely medical in nature. It requires patients to determine the acceptability of life-sustaining care by blending their phy-sician’s uncertain estimates of a meaningful recovery with their own personal values and life goals (126, 127). Unfortu-nately, most patients with chronic lung disease are poorly pre-pared to participate in this decision-making process because they have not discussed these issues with their health care pro-vider during periods of stable health (129). Delaying these dis-cussions until the terminal hospitalization provides a limited opportunity for patients to make informed decisions (129).
End-life education during pulmonary rehabilitation of-fers an opportunity to provide patients with an understanding of life-sustaining interventions and the importance of advance planning. Recent data indicate that 99% of patients enrolled in pulmonary rehabilitation desire a greater understanding of end-of-life care and they consider nonphysician educators within pulmonary rehabilitation to be as acceptable as physi-cians as sources for this information (129). Also, most patients prefer to receive advance planning information during periods of stable health in outpatient settings when their decision-making capacity is not impaired by acute complications of their disease (129). No investigations have examined the effec-tiveness of different curricular techniques within pulmonary rehabilitation for advance planning education, but one study indicates that video presentations, brochures, and group dis-cussions that require minimal educator time can promote the adoption of advance directives and more frequent patient-physician communication on end-of-life care (130). Consider-ing the high interest among pulmonary patients for advance planning information, greater incorporation of this topic within pulmonary rehabilitation curricula is needed consider-ing that only 8% of programs in the United States now pro-vide end-of-life education to their patients (131).
Psychosocial and Behavioral Intervention
Psychologic and behavioral problems such as anxiety, depres-sion, difficulties in coping with chronic lung disease, and re-ductions in self-efficacy (the ability to cope with illness) con-tribute to the handicap of advanced respiratory disease (6, 132–134). Dyspnea has a prominent affective component (135), and fear of dyspnea-producing activities may further limit the patient’s ability to participate in activities of daily living. Fur-thermore, the anxiety and decreased energy levels associated with chronic lung disease may affect the patient’s self-efficacy. Reduced self-efficacy of the patient may also burden the spouse or caregivers with new or increased responsibility for bathing, dressing, and meal preparation (136).
Psychosocial and behavioral intervention in comprehensive pulmonary rehabilitation programs can be in the form of regu-lar patient educational sessions or support groups focusing on specific problems such as stress management. Instruction in progressive muscle relaxation, stress reduction, and panic con-trol may help reduce dyspnea and anxiety (137). Because of the effects of chronic respiratory disease on the family, partici-pation of family members or friends in pulmonary rehabili-tation support groups is encouraged. Informal discussions of common symptoms, concerns, and problems during rehabilita-tion sessions may lend emorehabilita-tional support to patients. Group therapy, which is occasionally offered in pulmonary rehabilita-tion programs, integrates many of the principles of coping and role transition. The usefulness of group therapy in pulmonary rehabilitation, however, is not established (138).
The effect of pulmonary rehabilitation on psychologic out-comes has not been clearly defined. Significant reductions in symptoms of depression and anxiety one month after pulmo-nary rehabilitation were observed in one noncontrolled study of pulmonary rehabilitation that, in addition to exercise train-ing and educational topics five days a week, included group psychologic counseling and stress management sessions twice-weekly (139). On the other hand, no significant changes in de-pression were noted in a controlled, randomized trial of out-patient pulmonary rehabilitation (6). These studies, however, used different measures for evaluating depressive symptoms. Self-efficacy, which can be measured before and after pulmo-nary rehabilitation as an outcome variable (140–143), may in-crease with exercise training (144). Inin-creases in self-efficacy for walking have been demonstrated after pulmonary rehabili-tation (6).
Outcome Assessment
Outcome assessment has become an important component of comprehensive pulmonary rehabilitation both for determining individual patient responses and for evaluating the overall ef-fectiveness of the program. Measurement of the individual’s change in performance serves to reinforce the importance and magnitude of the gains made through the hard work of the pa-tient, family, and staff. Evaluation of the program through standardized outcome measures determines the overall effec-tiveness of the program and serves as a tool for quality im-provement. A variety of tests exist for measuring the disability and handicap (Table 7). Questionnaire measures of functional status, which fall somewhere between disability and handicap, are listed under handicap. Not listed are measures of psycho-logical status, which are described earlier in this paper.
Measures of disability
Incremental exercise tests. Incremental exercise testing on a stationary bicycle or treadmill involves increasing work rate at regular intervals to maximal tolerance or to a heart rate of 85% of predicted maximum. Routine measurements include heart rate, respiratory rate, blood pressure, electrocardio-gram, and oxygen saturation. Analysis of exhaled gases, avail-able in some exercise laboratories, allows for the determina-tion or calculadetermina-tion of minute ventiladetermina-tion, oxygen consumpdetermina-tion, carbon dioxide production, anaerobic threshold, and dead space. Dyspnea or leg fatigue during exertion can be rated us-ing a category scale or a visual analog scale. The effect of training on physiologic variables can be determined by mea-sures such as the E at maximum work rate or at identical
submaximal levels before and after intervention. Incremental exercise testing, although often symptom-limited in chronic lung disease, is reproducible (145–148) and sensitive to im-provements from pulmonary rehabilitation.
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Submaximal exercise tests. Stationary cycle or treadmill ex-ercise testing at a constant fraction of maximal work rate is frequently used to measure exercise endurance capacity in pulmonary rehabilitation (1, 3, 149). A longer exercise time on the cycle ergometer or treadmill indicates greater exercise en-durance. This test, which is more effort-dependent than incre-mental exercise testing, is often extraordinarily responsive to pulmonary rehabilitation intervention, with postrehabilitation exercise endurance times considerably longer than correspond-ing baseline values (6). Endurance testcorrespond-ing can also be used to show a reduction in ventilatory requirements for exercise after a period of exercise conditioning by demonstrating a decrease in minute ventilation at a given work rate (150).
Walking tests. Physical tests of disability may assess the pa-tient’s ability to perform specific activities of daily living such as walking. In the pulmonary rehabilitation setting, the six-and 12-min walking tests six-and the Shuttle Walking Test are conducted for this purpose. The timed walk tests are typically conducted under field testing conditions and are less repro-ducible than tests conducted under more highly controlled conditions (151). For the timed walk tests, patients are in-structed to walk as far as possible in a corridor or large room at his/her own pace during the allotted period of time. These tests are simple to perform, well-tolerated, and relevant to many daily activities. Patients with COPD demonstrate signif-icant learning effects for both of the timed walk tests, espe-cially when they are repeated over relatively short intervals (152–157). Timed walk tests correlate with peak exercise per-formance on graded exercise tests (119, 158, 159) and self-reported data on functional status questionnaires (124, 160). One study has suggested that the minimal clinically meaning-ful increase in the 6MWD is about 54 m (16). As with other tests of physical performance, the testing conditions must be standardized. Encouragement and coaching strategies can sig-nificantly influence performance and should be standardized from test to test (155).
The progressive 10-m Shuttle Walking Test is an externally paced measure of exercise capacity designed for individuals with COPD. The patient must walk up and down a 10-m
dis-tance (shuttle) at gradually increasing speeds. Walking speed, dictated by a beeping signal, is increased after every minute of walking by shortening the time between signals. The Shuttle Walking test is similar to the timed walk test in that it is a field test where distance walked is the outcome measure (161); however, it differs in two aspects. First, it is incremental in na-ture and therefore more a measure of exercise capacity than of endurance. Second, since the external signal sets the pace, self-pacing (which is of considerable importance to the timed walk) is eliminated. The shuttle walk is reproducible (162) and correlates well with maximum oxygen consumption during in-cremental treadmill exercise (r 5 0.88) (163). However, it has not yet been extensively used as an outcome measure for pul-monary rehabilitation. A recent study has suggested it is highly responsive to therapeutic intervention (11).
Exertional and overall dyspnea. Dyspnea is the most com-mon symptom of individuals with chronic pulcom-monary disease, and is frequently the major reason for seeking emergent care (164). Exertional dyspnea can be directly rated during a spe-cific activity such as treadmill exercise or timed walking tests. Overall, dyspnea can be assessed by determining its effects on day-to-day activities.
Dyspnea during exercise is usually measured with a cate-gory scale such as the Borg scale (165) of perceived exertion or a visual analog scale (VAS) (166). Using the Borg scale, breathlessness is rated by selecting a number corresponding to a verbal descriptor. Descriptors usually range from no breath-lessness (zero) to maximal breathbreath-lessness (10). The VAS mea-sures breathlessness by having the patient point along a verti-cal line, which is 100 mm in length and anchored at either end with descriptors such as “greatest breathlessness” and “no breathlessness.” The distance from the beginning of the line to the point noted by the patient represents the level of dyspnea. The effect of dyspnea on functional status or daily activities can be measured with instruments such as the Medical Re-search Council (MRC) dyspnea questionnaire, the University of California San Diego Shortness of Breath Questionnaire (UCSD-SOBQ) (167, 168), the dyspnea component of the Chronic Respiratory Disease Questionnaire (4, 169), the
Base-TABLE 7
COMMONLY USED OUTCOME MEASURES IN PULMONARY REHABILITATION
Outcome Measures Impairment Disability Handicap Symptoms* Exercise ability
Incremental exercise tests √
Submaximal exercise tests √
Walking tests √
General health status
Sickness Impact Profile (SIP) √ √
Quality of Well Being Scale (QWB) √ √
Medical Outcomes Study, Short-Form 36 (SF-36) √ √ P Respiratory-specific health status
St. George’s Respiratory Questionnaire (SGRQ) √ √ D Chronic Respiratory Disease Questionnaire (CRQ or CRDQ) √ √ F Respiratory-specific functional status
Pulmonary Functional Status and Dyspnea Questionnaire (PFSDQ) or √ √ D
modified version (PFSDQ-M) √ √ D/F
Pulmonary Functional Status Scale (PFSS) √ √
Exertional dyspnea
Visual analog scale rating during exercise testing (VAS) D/F/P Category rating (Borg) during exercise testing D/F/P Overall dyspnea
Medical Research Council Scale (MRC) √
Baseline and Transitional Dyspnea Indexes (BDI and TDI) √
1676 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 159 1999 line and Transitional Dyspnea Indexes (BDI and TDI) (13),
and the Pulmonary Functional Status and Dyspnea Question-naire (PFSDQ) (170) and its modified version (PFSDQ-M) (171). The dyspnea component of the Chronic Respiratory Disease Questionnaire evaluates the impact of dyspnea on five activities chosen by the patient to be important. The BDI mea-sures disturbances in function, effort, and task resulting from dyspnea, whereas the TDI measures changes in these areas over time. The PFSDQ and PFSDQ-M evaluate general dysp-nea as well as dyspdysp-nea related to specific functional activities.
A study evaluating the impact of exercise training on dys-pnea of individuals with COPD illustrates the usefulness of ex-ertional and general dyspnea ratings as outcome measures (72). Thirty patients given 6 wk of supervised multimodality exercise training were compared with an equal number of un-treated control subjects. Dyspnea and fatigue, measured with a Borg scale during graded cycle exercise, decreased signifi-cantly in the treatment group. The relief in dyspnea correlated with a fall in ventilatory demand during exercise, indicating a training effect from the exercise. The exercise training group also had decreased chronic dyspnea, with the TDI increasing by 2.8 units compared with no change in the untreated control group.
Measures of handicap
Health status (health-related quality of life). Pulmonary re-habilitation incorporates a variety of interventions to produce improvements in symptoms, disability, and handicap. Al-though it is possible to make specific measurements of each of these domains, there is a need for an overall summary mea-sure of benefit. Health status instruments can provide such a measure (172). There is evidence that the correlation between improved physiologic functioning and the patient’s perception of improved overall health is very weak (173), thus gains in health must be measured directly and not inferred from other measures. After rehabilitation, the improvement in the pa-tients’ sense of mastery is equal to the improvement in their dyspnea associated with daily activities (14). It is necessary, therefore, to quantify the psychologic improvement as well as the physical function gains after rehabilitation.
Quality of life has been described as a person’s satisfaction or happiness with life in domains he or she considers impor-tant (174, 175). Given this framework, quality of life may be thought of as a balance between that which is desired in life and that which is achieved or achievable. This applies very well to an individual, but valid measurements of an individ-ual’s quality of life are difficult to make and have limited util-ity since, by definition, measures cannot be standardized and applied to all populations of patients. Despite difficulties in measurement, the concept of quality of life is very useful be-cause it fits with an approach to rehabilitation in which areas of impaired life may be identified for each patient.
Health status, or health-related quality of life, has a more restricted measurement focus than quality of life. It pertains only to the domains of life insofar as they affect (or are af-fected) by “health.” Three main types of health status mea-surement have been used in pulmonary rehabilitation: utility scales such as the Quality of Well Being Scale (176), general health questionnaires such as the Sickness Impact Profile and the Medical Outcomes Study Short Form-36 (SF-36) (177, 178), and disease-specific scales such as the Chronic Respi-ratory Disease Questionnaire (CRDQ) (169) and the St. George’s Respiratory Questionnaire (SGRQ) (172). The reader is referred to the American Thoracic Society’s Web page for a description of these instruments in greater detail (175). There is evidence that all three types of measures have
the ability to discriminate between different levels of impaired health among patients. However, the disease-specific mea-sures have better evaluative properties, i.e., demonstrate greater sensitivity to change from baseline after rehabilitation intervention (3, 7, 11).
Health status measures have two major applications in the context of pulmonary rehabilitation: quantifying the benefit of programs (4) and measuring the effectiveness of new method-ologies in clinical trials (179). Currently, there is little experi-ence in the use of such measures to assess the benefits in indi-vidual patients.
Respiratory-specific functional status. Functional status can be described as having four dimensions: capacity, performance, reserve, and capacity utilization (180). Functional capacity is what the patient is capable of doing, whereas functional per-formance is what the patient actually does on a day-to-day basis. Functional reserve is the difference between capacity and performance, called upon in time of need. Treatment of pulmonary patients (including rehabilitation) serves to in-crease this reserve, allowing patients greater ability to engage in daily activities. Whether the patient takes advantage of this “reserve” is an individual choice, which may account for the variability in performance among patients postrehabilitation. Functional capacity utilization refers to how closely perfor-mance approaches the patient’s functional capacity.
Functional performance evaluation in respiratory disease focuses on the individual’s ability to perform activities of daily living (181). Activities of daily living can be divided into basic activities such as eating, bathing, or dressing, and instrumental (higher level) activities, which are needed to adapt indepen-dently to the environment such as walking outdoors, or shop-ping (182). The impact of respiratory disease on these activi-ties varies. Dyspnea may be associated with otherwise normal levels of activities, the activity may be limited because of dys-pnea or fatigue, or the activity may be eliminated altogether because of these symptoms.
Functional status is usually measured by a questionnaire and, thus, is a self-report of functional performance. Several questionnaires have been used successfully in pulmonary re-habilitation (Table 7) (170, 171, 183). These provide an esti-mate of the impact of the program on various activities, recog-nizing that the results are limited by patient motivation, recall, and perception of improvement.
Which outcome measures to choose and when to measure them. Measurement of outcomes should be incorporated into every comprehensive pulmonary rehabilitation program. The extent of assessment will depend on the purpose of the mea-surement, the goals of the program, and the resources and level of clinician expertise. Minimal requirements include prereha-bilitation and postrehaprereha-bilitation assessment of: (1) dyspnea, (2) exercise ability, (3) health status, and (4) activity levels (if this is not sufficiently evaluated by the health status questionnaire). The zeal to capture all outcome areas must be tempered by the realization that these assessments require considerable staff time and can be burdensome to the patient. Although prereha-bilitation to immediately postrehaprereha-bilitation changes are of im-portance, the long-term maintenance of the gains in the vari-ous outcome areas should also be a concern. Accordingly, consideration should be given to follow-up measurements at longer periods of time such as 6 and/or 12 mo, if feasible.
FUTURE DIRECTIONS FOR PULMONARY REHABILITATION
Despite the progress made in understanding pulmonary reha-bilitation as outlined in this document, more information is
