Summary

The term chronic obstructive pulmonary disease, (COPD), refers to a group of respiratory disorders, including chronic bronchitis, pulmonary emphysema, and asthmatic bronchitis, that nearly always coexist to varying degrees. COPD causes clinically significant progressive obstruction to expiratory airflow.

COPD is a common and important disorder. It is the fourth most common cause of death in the United States. In fact, 30 to 35 million Americans are believed to be afflicted, about half of whom are symptomatic.

The pathogenesis of COPD is becoming better understood. Currently accepted concepts include a progressive inflammatory response, possibly associated with unrestrained proteolytic enzyme release and toxic oxygen radicle production, induced by cigarette smoke and other inhaled pollutants. Why only 15% to 20% of cigarette smokers are predisposed to develop COPD remains an important unanswered question.

Many details about the natural history of COPD are lacking. But it is clear that susceptible smokers have an accelerated rate of deterioration of expiratory airflow compared with other persons, and that smoking cessation restores the rate of decline to normal.

Patients who are symptomatic or who have chest x-ray abnormalities resulting from COPD generally have moderately severe or advanced disease. In other words, the typical symptoms and signs of COPD occur late in its evolution. Patients with early COPD are often asymptomatic or nearly so, and diagnosis can be made only by documenting the presence of expiratory airflow obstruction. Simple spirometry is all that is required, and should be available in the office to screen all heavy smokers and other persons at risk for COPD.

The management of COPD is not difficult, but it requires a thorough evaluation of all aspects of the patient’s illness and the thoughtful implementation of a treatment program that can be revised as needs change. The goals of therapy are to improve symptoms, to minimize deterioration of lung function, and to prevent hospitalization. These can be attained by a four-phase management strategy:

1. Smoking cessation and patient and family education about COPD.
2. Treatment of all reversible components of airflow obstruction using drugs selected from a hierarchy of available agents. Oxygen therapy and exercise are important adjuncts in advanced disease.
3. Early treatment of the precipitating causes of acute exacerbations in the outpatient setting.
4. Prevention of non-COPD complications of therapy.

Among the intercurrent complications of COPD, infections are the most frequent and important. These usually present as acute purulent bronchitis, manifested chiefly by increased cough, sputum production, and dyspnea often without fever, leukocytosis, and new chest x-ray abnormalities. Empirical antimicrobial therapy with amoxicillin or trimethoprim sulfamethoxazole is usually successful. Pneumonia is apt to be clinically more severe. A search should be made for the causative microorganism and specific therapy administered. Otherwise, broad-spectrum antimicrobial treatment is indicated.

Patients with COPD are at increased risk for postoperative respiratory complications. These can be minimized by preoperative preparation, careful perioperative management, and most importantly postoperative care, including particular attention to maneuvers aimed at restoring the patient's ability to cough and take deep breaths.

Transient nocturnal oxygen desaturation is common in patients with COPD. Usually it is caused by sleep-induced respiratory physiologic abnormalities and not by classic sleep apnea; the mechanism can be identified by physiologic monitoring during sleep. Treatment with supplementary oxygen appears to be warranted, but definitive indications will depend on the results of future studies.

Acute respiratory failure represents a life-threatening deterioration in the course of COPD that is caused by an intercurrent complication, usually acute purulent bronchitis or another pulmonary infection, but possibly oversedation, surgery, or congestive heart failure. Confirmation of the diagnosis requires arterial blood gas analysis. Oxygen therapy is essential while all other aspects of treatment, including administration of corticosteroids, are intensified. Intubation and mechanical ventilation are needed in only a minority of patients (10 %), but are lifesaving when indicated. The prognosis is better than customarily believed, and the patient's lung function generally returns to its previous baseline level.

Cor pulmonale, also known as right ventricular dilation or hypertrophy secondary to lung disease, is a late complication of COPD. It occurs earlier in patients whose airflow obstruction is caused predominantly by chronic obstructive bronchitis than in those who suffer chiefly from emphysema. Depending on its severity, right-sided heart failure in patients with COPD-associated cor pulmonale is treated with a progressive regimen of salt restriction and diuretics, followed by continuous oxygen administration.

Pulmonary rehabilitation is a method of integrated multidisciplinary care that offers improved well-being and quality of life to many patients with advanced COPD. The components of pulmonary rehabilitation, which are added to routine medical therapy, are:

a. Patient and family education.
b. Smoking cessation.
c. Systemic exercise.
d. Breathing training and respiratory muscle exercise.
e. Oxygen therapy in selected patients.
f. Patient support groups.

These strategies are now also being offered to patients with early COPD who may also benefit from them.

Most cases of COPD are caused by tobacco smoking. Smoking cessation is the only tactic guaranteed to slow the progressive decline of expiratory airflow that culminates in COPD. It also minimizes the risks of acquiring many other deadly smoking-related diseases that kill nearly half a million persons in the United States each year. Primary care physicians play an important role in ensuring that their patients stop smoking. Always ask if patients smoke. If they do, advise them to quit. Suggest that they take advantage of the many available community resources to quit smoking. Arrange follow-up for reinforcement. It is difficult to stop smoking, but with the proper advice and encouragement, it can be done.