[L. emphysema, fr Gr. emphysēma, inflation]
1. Pathological distention of interstitial tissues by gas or air. The distention can be palpated or seen radiographically. Causes include leaking tracheostomy tubes or open pneumothoraces.
2. A chronic obstructive pulmonary disease marked by an abnormal increase in the size of air spaces distal to the terminal bronchiole, with destruction of the alveolar walls. These changes result in a loss of the normal elastic properties of the lungs and difficulty exhaling air. Alveolar septa are destroyed, and portions of the capillary bed are eliminated. Residual volume increases.
More than 12 million people in the U.S. have been diagnosed with emphysema, but underdiagnosis is common, and the illness may affect twice that number. Women have a slightly higher rate of emphysema than men.
Tobacco smoking is the most common cause of the tissue destruction found in emphysema. Exposure to environmental dust, smoke, or particulate pollution may also contribute to the disease. A small number of people with emphysema may have developed it as a result of alpha-1-antitrypsin deficiencies, a group of genetic illnesses in which there is inadequate protection against destructive enzyme activity in the lung. Complications include cor pulmonale, recurrent respiratory infections, and respiratory failure.
SYMPTOMS AND SIGNS
Symptoms include difficulty breathing, esp. during exertion. Weight loss, chronic cough, and wheezing are also characteristic. Physical findings include prolongation of expiration, diminished breath sounds, a decrease in the measured distance between the thyroid cartilage and the chin, and heart tones that are audible only in the subxiphoid region of the chest.
Emphysema is diagnosed based on the clinical history (usually a long history of smoking), the results of a chest x-ray or CT scan of the lung, and pulmonary function testing.
Smoking cessation helps preserve the remaining alveoli. Inhaled bronchodilators and anticholinergics, such as ipratropium, tiotropium, albuterol, or salmeterol may improve respiratory function. Aerosolized corticosteroids reduce inflammation, and mucolytics thin inspissated secretions and aid mucus expectoration. Antibiotics are only used when bacterial infections are identified. Oxygen therapy prevents right-sided heart failure. The respiratory therapist administers oxygen at low-flow settings to maintain adequate oxygenation (Pao2 60 to 80 mm/Hg). Lung volume reduction surgery can eliminate hyperinflated (nonfunctional) portions of the lungs, allowing the healthier lung tissue that is left behind to expand and contract with improved efficiency. The patient is protected from environmental bronchial irritants, such as smoke, automobile exhaust, aerosol sprays, and industrial pollutants.
SEE: chronic obstructive pulmonary disease for further treatment recommendations.
In 2009, according to the American Lung Association, approx. 134,000 people in the U.S. died of complications of emphysema.
The patient's oxygenation, weight, and the results of electrolyte and complete blood count measurements are monitored. The patient is evaluated for infection and other complications and for the effects of the disease on functional capabilities. Prescribed medications are administered by parenteral or oral route or by inhalation.
The patient is encouraged to intersperse normal activities with rest periods. Respiratory infections may be devastating to the emphysema patient; some of them can be prevented by avoiding crowds and contact with infectious persons; by using correct pulmonary hygiene procedures, including thorough hand hygiene; and by obtaining influenza and pneumococcal immunizations. Patients are taught breathing techniques to control dyspnea. Frequent small meals of easy-to-chew, easy-to-digest, high-calorie, high-protein foods and food supplements are encouraged. Small meals conserve patient energy, prevent fatigue, and also reduce intra-abdominal pressure on the diaphragm and reduce dyspnea.
When patients with emphysema are hospitalized, the respiratory therapist and physician monitor the results of arterial blood gas assays, pulmonary function studies, and breath sounds. Once stabilized, the patient often benefits from participation in a pulmonary rehabilitation program to promote improved lung function and more efficient breathing techniques.
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