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 othe
r 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. T
he 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 pulmon
ary 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 f
orms 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. Ven
tilatory 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 d
ecreasing 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 exer
cise. 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.
posted by Dr.Mohamed rizk - د محمد رزق @ 2:16 PM
2 comments
