16-Pulmonary rehabilitation for COPD

Patient selection:

Any patient with symptoms of
respiratory disease is a candidate for rehabilitation. Programs are best
instituted when disease is moderate so that disabling end-stage respiratory
failure can be prevented. While patients with minimal impairment may show
little obvious change in function, benefits are, in fact, significant.
Patients with advanced lung disease also benefit. Even critically ill
patients awaiting lung transplantation or lung volume reduction surgery
often have significant functional improvement and increased exercise
endurance after pulmonary rehabilitation (12,13).

Lack of motivation is often a problem, and patients with moderate disease
may not be eager to invest the effort needed to maintain a viable program.
Other factors that hinder the success of rehabilitation are the presence of
disabling diseases, such as severe heart failure or arthritis; low education
levels; occupation; and lack of family and socioeconomic support (14,15).


Although patients with cancer were previously considered poor candidates for
rehabilitation, this assumption is changing. Many patients with limited
exercise capacity who are otherwise good surgical candidates do, in fact,
benefit from pulmonary rehabilitation. This fact is particularly important
as new surgical procedures broaden the chances of restoring function.



Program organization:


The key player in building a pulmonary rehabilitation program is the coordinator, whose job is to organize the different components into a functioning unit. Decisions about whether to provide inpatient or outpatient services depend on the methods of reimbursement, patient population, available personnel, and hospital policy.

The ideal system is one that provides both an inhospital arm for patients
recovering from acute exacerbations and an outpatient arm (including home therapy) for long-term follow-up.

Patient education:
The education component
includes respiratory anatomy and physiology as well as simplified
explanations of the disease process and therapy. Resource personnel are
needed to teach and supervise respiratory therapy techniques (eg, use of
supplemental oxygen, inhalers, nebulizers), physical therapy (breathing
techniques, chest physical therapy, postural drainage), exercise
conditioning (upper and lower extremity), and activities of daily living
(work simplification, energy conservation). Services that can provide
evaluation of and advice on nutritional needs, psychological status, and
vocational counseling also are desirable (14).



Therapeutic components:


Rehabilitation therapy basically consists of exercise, ventilatory therapy,
ventilatory muscle training, and respiratory muscle resting. Nutritional and
psychological support round out the program.



Exercise:


Exercise training is the most important component of a pulmonary
rehabilitation program. Casaburi (16) reviewed 36 uncontrolled studies that
evaluated the effect of exercise training on exercise performance in over
900 patients with chronic obstructive pulmonary disease (COPD). Training
improved exercise endurance in all of these patients. This finding has been
corroborated by controlled trials showing that a rehabilitation program with
lower extremity exercise is better than other forms of therapy, such as
optimization of medication, education, breathing retraining, and group
therapy (5-10,17).

Lower extremity exercise: Two recent controlled trials support the theory
that pulmonary rehabilitation is better than conventional treatment in
symptomatic COPD patients. The first one, reported by Goldstein and
associates (9), involved 89 patients randomly assigned to participate in
either 8 weeks of inpatient rehabilitation followed by 16 weeks of
outpatient treatment or conventional care as provided by their physician.


At the end of the study, the 45 patients in the rehabilitation group had
significantly improved exercise endurance and submaximal cycle time,
compared with the 44 controls, as well as a decrease in dyspnea and
improvement in emotional function and mastery.

In the second study, Wijkstra and coworkers (11) reported the results of 12
weeks of rehabilitation in 28 patients with COPD compared with 15 untreated
controls. This study is unique in that the rehabilitation was conducted at
home and the program was supervised by nonspecialists. After rehabilitation,
patients showed a greater increase in distance walked, maximal work, and
oxygen uptake and a decrease in lactate production and perception of dyspnea
when compared with controls.

Perhaps the most complete report is that of Ries and coworkers (7), who
studied 119 patients. A total of 62 patients received educational support,
and 57 were provided with both education and exercise training. After 6
months, the exercise group showed significantly improved exercise endurance
and peak oxygen uptake and reported less dyspnea and greater comfort when
walking than did the patients who received education alone.

In a unique investigation, O'Hara and associates (17) enrolled 14 patients
with COPD in a home program that included weight lifting. After training,
the weight lifters had a reduction in minute ventilation and a 16% increase
in ergometric endurance compared with pretraining levels. This finding
suggests that for some patients, strength training may be an appropriate
alternative to more traditional training.

The suggestion that patients with COPD who exercise may become desensitized
to the dyspnea induced by the ventilatory load was supported by the work of
Belman and Kendregan (18). The investigators randomly assigned patients to
receive either upper extremity or lower extremity exercise and obtained
muscle biopsies of the trained limbs before and after training. In spite of
a significant increase in exercise endurance, no changes occurred in the
oxidative enzyme content of the trained muscle.

In contrast, Maltais and coworkers (19) documented a true training effect.
In their study, the muscle biopsies in trained patients showed significant
increases in all enzymes responsible for oxidative muscle function. Reduced
exercise lactic acidosis and minute ventilation after training support
speculation that these biochemical changes are associated with important
physiologic outcomes.

Zu Wallack and associates (20) evaluated pulmonary function in 50 patients
with severe COPD before and after exercise training. They observed an
inverse relationship between the degree of improvement and the baseline
12-minute walking distance. In other words, the more limited the patient at
baseline, the greater the magnitude of improvement.

Results in patients selected for lung transplantation show that
rehabilitation improves performance to a degree not achieved with any other
form of therapy. The data support exercise as a crucial component in the
rehabilitation of patients with severe lung disease. This is illustrated in
figure 1 (not shown), which documents improvement in 6-minute walking
distance in patients with severe COPD who underwent pulmonary rehabilitation
before lung volume reduction surgery at our institution.

Upper extremity exercise: Most of our knowledge about exercise conditioning
comes from programs emphasizing leg training. This is unfortunate, because
the performance of many everyday tasks requires use of not only the hands,
but also other muscle groups used in upper torso and arm positioning. Some
of these muscle groups serve respiratory as well as postural functions, and
arm exercise can improve ventilation (21). If the arms are trained to
perform more work, or if the ventilatory requirement for the same work is
decreased, the capacity to perform activities of daily living could improve.


In general, arm training improves task-specific performance. Ries and
associates (22) studied the effect of two forms of arm exercise (resistance
and modified proprioceptive neuromuscular facilitation) and compared
outcomes with those in patients who did not use arm exercise. In the
patients who completed the program, performance on tests specific for the
training improved. The patients also reported a decrease in fatigue for all
tests performed.

Martinez and coworkers (23) showed that unsupported arm training (against
gravity) decreases oxygen uptake at the same workload when compared with
arm-cranking training. They concluded that unsupported arm exercise may be
effective for pulmonary rehabilitation because such exercises condition
muscles used in activities of daily living.



Ventilatory therapy:


This includes controlled breathing techniques (diaphragmatic breathing,
pursed-lip breathing,
and forward-bending exercises) and chest physical therapy (postural
drainage, chest percussion, and vibration). The controlled breathing
exercises help decrease dyspnea, and chest drainage enhances removal of
secretions. Benefits include less dyspnea and anxiety, fewer panic attacks,
and improved sense of well-being.

Ventilatory therapy requires careful instruction by specialists familiar
with the techniques. Treatment should be started early in the rehabilitation
process and repeated often under close supervision until the patient shows a
thorough understanding of the technique. Relatives or friends should be
involved, since procedures (eg, chest percussion) often require the help of
another person.

Breathing training: This helps control respiratory rate and breathing
patterns, thus decreasing air trapping. It also attempts to decrease the
work of breathing and improve the position and function of the respiratory
muscles (24). The easiest of these maneuvers is pursed-lip breathing.
Patients inhale through the nose and exhale for 4 and 6 seconds through lips
pursed in a whistling or kissing position. The exact mechanism by which this
decreases dyspnea is unknown. It does not seem to change functional residual
capacity or oxygen uptake, but it does decrease respiratory frequency and
increase tidal volume (24).

Forward-bending posture has been shown to decrease dyspnea in some patients
with severe COPD, both at rest and during exercise. The best explanation is
that increased gastric pressure during forward bending allows better
diaphragmatic contraction. These changes can also be seen in the supine and
Trendelenburg positions.

Diaphragmatic breathing changes the breathing pattern from one where the rib
cage muscles are the predominant pressure generators to a more normal one,
where the pressures are generated with the diaphragm.

The technique can be taught by having the supine patient place a hand on the
abdomen and breathe in. With proper diaphragmatic breathing, the hand moves
up on inspiration. The patient then exhales with pursed lips and is
encouraged to use the abdominal muscles to return the diaphragm to a more
lengthened, resting position. After using diaphragmatic breathing in the
supine position, the patient is encouraged to try it while standing.
Diaphragmatic breathing is most helpful when used for at least 20 minutes
two or three times daily.

Although most patients report improvement in dyspnea and clinical perception
of symptoms with diaphragmatic breathing, little or no change occurs in
oxygen uptake and resting lung volume (24). Respiratory rate and minute
ventilation usually fall and tidal volume increases.

Chest physical therapy: This approach includes postural drainage, chest
percussion, vibration, and directed cough. The goal is to remove airway
secretions and decrease airflow resistance and bronchopulmonary infection.
The single most important criterion for chest physical therapy is the
presence of sputum production.

Postural drainage uses gravity to help clear the individual lung segments.
Chest percussion also assists drainage but should be used with care in
patients with osteoporosis or bone problems. Although cough is effective for
removing excess mucus from the larger airways, patients with COPD often have
impaired cough mechanisms. Maximum expiratory flow is reduced, ciliary beat
is impaired, and the mucus itself has abnormal viscoelastic properties.
Directed cough is preferred, and cough spasms should be avoided because of
risks of dyspnea, fatigue, and increased obstruction.

With controlled coughs, patients are instructed to inhale deeply, hold their
breath for a few seconds, and then cough two or three times with the mouth
open. They are also taught to tighten the upper abdominal muscles to assist
in the cough.

Pulmonary function does not improve with any of these techniques.
Nonetheless, studies (24) show that programs using postural drainage,
percussion, vibration, and cough increase the clearance of inhaled
radiotracers and increase sputum volume and weight.

Ventilatory muscle training: Specific respiratory muscle training can
improve strength and endurance. Because inspiratory muscles tend to be
weakened in patients with COPD, the role of respiratory muscle training in
these patients has been viewed with great interest. Strength training has
limited clinical significance.

In controlled trials, endurance training has increased the time that
ventilatory muscles can tolerate a known load (25). Some data show a
significant increase in strength and a decrease in dyspnea during
inspiratory load and exercise. In studies where exercise performance was
evaluated, the increase in walking distance proved to be minimal (25).

While ventilatory muscle training with resistive breathing improves muscle
strength and endurance, it has marginal effects on overall exercise
performance. Whether this effort results in decreased morbidity or mortality
or offers any other clinical advantage is not clear (26).



Respiratory muscle resting:


When the respiratory muscles have to work against a large load, they may
tire. Experiments show that this occurs in healthy volunteers as well as in
patients with COPD. Clinically, respiratory muscle fatigue seems to play an
important role in acute respiratory failure in patients with COPD.
Therefore, it seems logical that noninvasive ventilation may be helpful in
cases of acute or chronic respiratory failure with impending respiratory
muscle fatigue.

Three randomized trials have confirmed this assumption (27-29). Each
evaluated various outcomes, including number of intubations, length of time
in an intensive care unit, length of total hospital stay, incidence of
dyspnea, and number of deaths. All investigators agreed that noninvasive
positive-pressure ventilation effectively reversed acute respiratory
failure. Results were best in patients with elevated PaCO2 and no other
major problems (ie, sepsis, pneumonia) who were able to cooperate with the
caregivers.

Because positive-pressure noninvasive ventilation is potentially dangerous,
patients must be closely monitored by professionals thoroughly trained in
ventilatory techniques.

The possibility that respiratory muscles of patients with stable, severe
COPD function at close to the fatigue threshold has led many investigators
to explore the role of resting the muscles through noninvasive
negative-pressure and positive-pressure ventilation. However, only one of
the controlled trials using both forms of ventilation showed benefit in most
of the outcomes studied. Therefore, the routine use of noninvasive
ventilation in stable COPD is not justified.



Evaluation of nutrition:


Many patients with emphysema are thin, emaciated and, in fact, malnourished.
Although evidence is lacking as to unequivocal benefits of improved
nutrition on the respiratory system, most authorities agree that
deficiencies should be corrected whenever possible. Treatment of anemia
could improve oxygen-carrying capacity, and adjusting electrolyte imbalances
could improve cardiopulmonary performance. Similarly, simple measures, such
as encouraging the patient to take small amounts of food at frequent
intervals, may alleviate abdominal distention and dyspnea after meals.
Oxygen saturation during meals should also be evaluated and can be corrected
by using supplemental oxygen while eating.



Psychological support:


Most patients with advanced lung disease have minor but frequent
psychological problems, especially reactive depression and anxiety.
Fortunately, these are likely to improve with rehabilitation that encourages
activity. Simple measures, such as being able to exercise under the
supervision of supportive specialists, often alleviate symptoms, including
dyspnea and fear. Evidence shows that 15 to 20 rehabilitation sessions that
include education, exercise, physical therapy, and breathing and relaxation
techniques are more effective in reducing anxiety than a similar number of
psychotherapy sessions. Nonetheless, a patient with major psychological
problems occasionally requires primary psychiatric evaluation and treatment.




Conclusions:


Many patients with chronic lung diseases benefit from pulmonary
rehabilitation, and any patient with moderate to severe symptoms should be
considered a candidate. Even the most severely ill patients, including those
awaiting lung transplantation and those about to undergo lung volume
reduction surgery, show improvements in pulmonary function with
individualized training and support.

The most effective programs include patient education, exercise, nutrition
guidance, psychological support, and a number of therapeutic options, such
as breathing training and chest physical therapy. Primary care physicians
can provide an important service by incorporating pulmonary rehabilitation
in the care of patients with breathing disorders.