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Chronic Obstructive Pulmonary Disease (COPD), the third leading cause of mortality in the United States, is defined as a progressive disease characterized by chronic airflow limitation that is not fully reversible. Approximately 24 million people in the US are affected by COPD, but only 12 million have been diagnosed. New Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommendations were introduced in January 2012 and highlighting the need for Spirometry to diagnose COPD and defining the role of individualized medical care to alleviate the symptoms of COPD. The primary treatment for COPD is pharmacologic with use of bronchodilators to mitigate the cardinal symptoms of COPD: fatigue and shortness of breath. Many non-pharmacologic interventions, such as smoking cessation, long term use of oxygen, and Pulmonary Rehabilitation, beneficially affect the symptoms of COPD and return patients to their highest level of function.Pulmonary Rehabilitation is an evidence- based, multidisciplinary intervention using exercise training to improve exercise capacity, improve independent activity, and improve quality of life. In 1952, Dr. Alvan Barach first touted the benefits of exercise for symptom management in patients with COPD and, in 1969, led to landmark work by Dr. Thomas Petty which demonstrated the benefits of exercise training on exercise tolerance, hospitalization rate, and work productivity. After a period of decline in the 1980’s, due to doubts about the efficacy of exercise in ventilatory limited patients, research in the 1990’s demonstrated an improvement in exercise capacity by using higher exercise intensities to improve the aerobic function of muscles. Better aerobic function leads to a decreased lactic acid production minimizing its effect on production of muscle fatigue and shortness of breath. Based on clinically significant longitudinal studies, Pulmonary Rehabilitation is now integral to the management of patients with disabling symptoms due to advanced lung disease.
Exercise training is the key component of any rehabilitation program. The measurable training effect of rehabilitation improves gas exchange, skeletal muscle dysfunction, cardiac dysfunction, and temporizes dynamic hyperinflation’s effect on lung function. Dynamic hyperinflation is an important limiting factor in patients with COPD as it leads to early cessation of activity due to increased work of breathing and increased perception of shortness of breath. During rehabilitation, patients learn energy conservation techniques and breathing retraining to counter the negative effects of dynamic hyperinflation on shortness of breath. The typical exercise prescription mirrors the recommendations of the American College of Sports Medicine’s (ACSM) recommendations for activity. The suggested program involves 20 to 30 minutes of aerobic activity, 3 to 5 days per week, for a minimum of 8 weeks, with exercise intensities ranging from 40 to 85% of peak workload. The longer the rehabilitation intervention, the better effect at one year after treatment.
Patient selection for rehabilitation involves an assessment of all patients with shortness of breath and reduced exercise tolerance, regardless of lung function measured by Spirometry. Any patient with a desire to improve their overall physical condition and symptoms, should be considered for treatment. New evidence suggests patients can safely undergo rehabilitation at the time of discharge from a hospital because the risk of re-hospitalization is greatest within the 8 weeks after discharge for exacerbation of COPD. Early referral to Pulmonary Rehabilitation is crucial toward preserving independent function and allowing preventive strategies such as depression screening, smoking cessation, and nutritional therapy to be instituted. Two important factors delay referral to rehab and should be considered before initiation of any exercise program. First, disability due to osteoarthritis may limit mobility and hamper aerobic activity. Second, patients with heart disease should be pre-screened by cardiopulmonary exercise testing (CPET) prior to initiation of exercise training.
In conclusion, Pulmonary Rehabilitation is a comprehensive, multidisciplinary, exercise based intervention demonstrated to improve exercise capacity, improve quality of life, and decrease hospitalizations in patients with advanced lung disease. All symptomatic patients, with lung disease, should be encouraged to attend rehabilitation.
