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Chronic Obstructive Pulmonary Disease (COPD)

Michael Jay Katz, MD, PhD

Our courses fulfill continuing nursing education requirements in all 50 states. For more accreditation information, click here. Nurse practitioners may apply these contact hours to pharmacy continuing education and prescriptive authorization.

This course includes straightforward answers to basic questions about COPD and smoking for nurses and other health professionals who advise patients over the telephone (see the last section of the course: Telephone Counseling).

Chronic obstructive pulmonary disease (COPD) is a disease that makes moving air into and out of the lungs increasingly difficult. Difficulty moving air in the lungs is called airflow obstruction or airflow resistance, and COPD is characterized by a progressively increasing airflow obstruction that cannot be reversed, although it can sometimes be temporarily improved by medications (Wise, 2007).

Most COPD is caused by the long-term inhalation of pollutants, especially cigarette smoke. The specific form that the disease takes can range along a spectrum. At one end of the spectrum, some people get emphysema, the destruction of small respiratory units (alveoli and respiratory bronchioles) and the formation of large, useless air spaces in the lung. At the other end of the spectrum, some people get chronic bronchitis, narrowed inflamed airways filled with mucus, accompanied by a chronic phlegmy cough. Many people with COPD have some combination of emphysema and chronic bronchitis.

The critical symptom of COPD is dyspnea, difficulty breathing. At first, this shortness of breath occurs only during vigorous exercise. Over the years, though, the dyspnea begins to happen with mild exercise. Later, normal activities of living cause dyspnea, and finally, the person is short of breath even when sitting quietly. The relentless increase of dyspnea gradually limits a person's activities, and at some point it becomes hard for a person with COPD to do anything but sit or lie down (Reilly et al., 2005).

No currently available treatments can stop the gradual decline in lung function produced by COPD. However, people who stop smoking before they have developed clinical COPD can often avoid the significant worsening of airflow obstruction brought on by the disease. After COPD has become symptomatic the disease is treated with bronchodilators, which can ease the patient's dyspnea so that a wider range of activities remains tolerable.

Patients with COPD have little or no reserve capacity in their lungs. Respiratory infections, increases in inhaled pollution, and the occurrence of other medical problems will further reduce their ability to absorb oxygen and to expel carbon dioxide, and these problems can send COPD patients into hypoxemia. Unfortunately, respiratory stresses are unavoidable, so COPD patients suffer repeated episodes of significantly worsened symptoms, or acute exacerbations. Acute exacerbations resolve slowly, over weeks or months even with medical treatment, and sometimes acute exacerbations must be managed in a hospital.

COPD follows a relentless downward course. Supplemental oxygen therapy can prolong some patients' lives, and a few select patients can benefit temporarily from lung surgery. Acute exacerbations continue, however, and most patients eventually succumb to an acute exacerbation that cannot be reversed (Shapiro et al., 2005). Asthma is another common lung disease that causes obstruction of the pulmonary airways; however, episodes of asthma are reversible, while COPD is not.

COPD is caused by inhaled pollutants. In the developed world, cigarette smoke is the direct cause of most COPD. Persistent smoke in the lungs leads to chronic, excessive, and destructive inflammation of the bronchial tree. In some patients, this inflammation causes significant emphysema; in other patients, it causes significant chronic bronchitis. Regardless of the form of the disease, however, all patients with COPD have continually worsening and irreversible airflow obstruction. In COPD, the main resistance to airflow is at the level of the small airways (Reynolds, 2005).

MAJOR FORMS OF COPD

The specific form that COPD takes varies from person to person. The predominant forms of COPD are emphysema and chronic bronchitis.

Emphysema

In some people, COPD causes significant destruction of the terminal airways and air sacs (alveoli); this form of COPD is called emphysema. In emphysema, the structure of the lung is altered dramatically. The lung becomes honeycombed with useless spaces. These air spaces are created when the walls of small respiratory airways and their alveoli are torn and the neighboring airways and alveoli merge. In the process, the surrounding capillaries are damaged, making the new air spaces useless for gas exchange. In addition to reducing the lung area available for gas exchange, emphysema leads to hyperinflated lungs and obstructed airflow (Anthonisen, 2008).

Chronic Bronchitis

In another manifestation of COPD, inflamed airways become clogged with mucus, and patients develop a chronic cough that brings up sputum. This form of COPD is called chronic bronchitis.

Chronic bronchitis can occur without COPD. The term chronic bronchitis describes a persistent mucus-filled cough that has occurred frequently for at least two years and is not caused by another disease such as an infection, cancer, or congestive heart failure. All chronic bronchitis is characterized by an increase in the number and size of the mucus glands in the airways of the lung. More than one-third of smokers have chronic bronchitis, but the disorder is only considered to be a form of COPD when there is also significant airflow obstruction in the lungs (Sharma, 2006).

In the past, COPD patients with emphysema were said to have type A and were sometimes called "pink puffers." At the other end of the spectrum, COPD patients with chronic bronchitis were said to have type B and were sometimes called "blue bloaters." Although these names are still used, the division of COPD into two alternative types is too simple because many patients present with a mix of emphysema and chronic bronchitis. Currently, the emphasis is on the common feature of all COPD patients: Whether it appears as emphysema, as chronic bronchitis, or as a mixture, COPD is characterized by chronic, worsening, and irreversible airflow obstruction.

INCIDENCE OF COPD

Chronic obstructive pulmonary disease is the most common major lung disease in the United States. Over the last few decades there has been an increase in the percent of Americans with COPD. Currently, between 10 and 14 million adults in the United States are diagnosed with COPD—and an equal number of Americans with COPD may still be undiagnosed. Among people with COPD, significantly more have the chronic bronchitis form than the emphysema form (Shapiro et al., 2005).

In 2004 a comparison of the two major heart/lung diseases in the United States revealed 24 million cases of COPD (estimated, half still undiagnosed) and 79.4 million cases of cardiovascular disease (NHLBI, 2007). Most people who get COPD have been long-term smokers, and the characteristics of the smoking population define the characteristics of the population of people with COPD (Wise, 2007).

Age of Onset

A person's smoking intensity is measured in pack-years. "One pack-year" means that a person has smoked approximately one pack (20 cigarettes) per day for a year. Thus, smoking a half-pack a day for 2 years is equivalent to 1 pack-year; smoking 2 packs a day for 1 year is equivalent to 2 pack-years.

Symptomatic COPD usually takes more than 20 pack-years of smoking to develop, and the typical COPD patient has a smoking history of more than 40 pack-years. Therefore, COPD is most common in older people.

In the United States, 1 out of every 7 people between the ages of 55 and 64 has moderate COPD, and 1 out of every 4 people older than 75 years has moderate COPD. This is the highest rate of COPD in history, because the current generation of older adults has done a record-breaking amount of cigarette smoking. Although many elder Americans have stopped smoking, even those who quit can develop symptoms of COPD and suffer a greater-than-normal decline in their breathing ability late in life (Hall & Ahmed, 2007).

Gender

More men than women have COPD. Among white Americans, for example, approximately 5% of all men have COPD, while approximately 2% of all women have the disease (Swadron & Mandavia, 2006). The difference between men and women reflects the historical tendency for men to have smoked more heavily than women. However, the increased level of smoking by women over the past 30 years is causing the women's death rate from COPD to rise. Today, more American women than men die from COPD (Anthonisen, 2008).

COPD Mortality by Gender — United States 1980-2000

The number of Americans dying from COPD has been rising for decades. Earlier, more men than women died of the disease. Recently the women's mortality rate has surpassed the rate for men. (The y-axis is the number of thousands of deaths; i.e., "20" means 20,000 deaths.)

Race

The prevalence of COPD follows the history of the level of smoking in a population. In the United States, higher rates of COPD are found among white people, blue-collar workers, and people with less formal education. More Caucasians in the United States die from COPD than people of other races (ALA, 2007; ALAESU, 2007; Wise, 2007).

Mortality Rates

COPD is the fourth leading cause of death in the United States Between the years 2000 and 2004, there was an average of 120,000 deaths a year, a frequency of 42 deaths per 100,000 people. Approximately half of COPD patients die within 10 years of their initial diagnosis (ALA, 2007; ALAESU, 2007).

Ten leading causes of death: Death Rates, United States, 2004 (NHLBI, 2007).

EFFECT OF COPD ON LUNG TISSUE

COPD is a reactive disease: it is a disease in which the body is turned against itself. The body's reaction to inhaled pollutants, mainly smoke from burning plant material such as tobacco, results in chronic inflammation of the bronchial tree. The inflammation is a natural protective reaction, but it is useless against air pollutants. Instead of helping, the persistent inflammatory reactions begin to damage the lungs.

The Normal Lung

Before exploring the details of inflammatory damage, we must first look at the structure and function of the normal lung. The following illustration depicts normal lung function.

The lower airway. (Illustration by Jason M. McAlexander, MFA. Copyright © 2007 Wild Iris Medical Education.)

STRUCTURE

The two lungs comprise millions of microscopic alveoli clustered at the ends of the branches of a "tree" of airways. The airways of the lung are branching tubes that become successively narrower, shorter, and more numerous from the center of the lung to the periphery. The central airways are the bronchi and bronchioles; the peripheral airways are respiratory bronchioles, which are tiny tubes lined with alveoli. It is through the walls of the alveoli that gases are exchanged from the blood in the surrounding capillaries.

The medium and large bronchi are wrapped with smooth muscle, which tightens to narrow the airways and relaxes to widen the airways. The walls of all the airways are lined by ciliated epithelial cells with interspersed secretory cells. The secretory cells coat the inner walls of the airways with mucus. All the cilia of the epithelial cells beat in the direction of the trachea and throat. In this way, mucus and trapped particles are continuously moved up and out of the lungs.

Healthy lungs are lightweight, soft, spongy, and elastic. Normally, the chest walls stretch the lungs and keep them expanded to three times their normal relaxed size. When the chest is surgically opened, however, the lungs recoil, as the innate elasticity of the lungs pulls them back to their resting size. When an adult takes a full breath, the volume of air in the lungs is about 6 liters. After a complete exhalation, there are about 2.5 liters of air left (Albertine et al., 2005).

FUNCTION

Lungs are the organs through which oxygen is absorbed into, and carbon dioxide is expelled from, the bloodstream. These gas exchanges occur through the walls of the alveoli and terminal respiratory airways, which make up the distal-most air spaces inside the lungs. Maintaining healthy levels of blood gases are the lungs' primary function, and the blood vessels of the lungs are extensive. In a normal, functioning lung, most of the volume is air, but the lung tissue itself is very thin and delicate and most of the weight is blood.

People with healthy lungs rarely use all the gas-exchange potential of their lungs. Even during the most strenuous activity, a healthy person will use only 60% to 70% of maximal ventilatory capacity. Strenuous exercise will cause temporary dyspnea, but due to the 30% to 40% ventilatory reserve, the dyspnea of a healthy person passes in a short time, and it is never as debilitating as the dyspnea of a person with severe COPD.

Healthy lungs function less efficiently as they age. As people get older, their chest walls stiffen and their respiratory muscles diminish. Both changes make breathing almost twice as much work for a 70-year-old than a 20-year-old. The vital capacity (VC or FVC) and the amount of air that can be exhaled in a second (FEV1) gradually and progressively decline. In a healthy person, none of the natural lung changes approach the dramatic declines caused by COPD; on the other hand, the natural decline in lung function imposes a further burden on elders who have COPD (Prendergast & Russo, 2006).

Lungs with COPD

COPD slowly destroys the lungs and makes it increasingly difficult for a patient to breathe. The most serious effect is a progressive obstruction of airflow that is the result of inhaling pollutants.

Healthy alveoli and one showing COPD. The airways leading into the alveoli are narrowed, less flexible, and often clogged with mucus. Eventually, many alveoli coalesce into larger, useless airspaces because the walls separating them have been damaged or destroyed by the disease process (CDC, n.d.; NIH, n.d.).

CAUSES OF COPD

In the industrialized world, cigarette smoking is the main cause of COPD. In underdeveloped countries, smoke from plant products that are burned for indoor cooking and heating is as much a cause of COPD as cigarette smoking (Shapiro et al., 2005).

In the United States, more than a quarter of all people who have smoked for 25 years or more develop COPD and another 10% to 20% of smokers have measurably decreased lung function for their age (Lokke et al., 2007). The longer and more intensely people smoke, the more likely they are to develop COPD.

Long-term smokers are likely to develop COPD, but the severity of the disease varies from person to person, even among heavy smokers. People living in the same environment and smoking the same amount can, nonetheless, differ in their propensity for developing COPD. Two main factors have been suggested as the basis for this difference: airway sensitivity and genetic factors (Swadron & Mandavia, 2006).

People differ in airway sensitivity, that is, how readily their airways constrict when exposed to a variety of irritants such as pollen, dust, and chemicals. Asthma is the most common disease of people who have abnormally sensitive bronchial trees. Many people with COPD also have excessively reactive airways. Although asthma and COPD are different diseases, studies have shown that smokers with asthma or with the tendency to develop asthma are more likely to develop COPD and are more likely to have COPD that worsens quickly (Reilly et al., 2005).

Certain families carry genetic factors that make them more susceptible to developing COPD than others, and one specific genetic propensity has been identified: alpha1-antitrypsin (AAT) deficiency. AAT is a protein that slows or stops elastase, an inflammatory enzyme that chews up elastin, which is a supportive extracellular protein.

An inflammatory reaction in the lung such as is caused by COPD produces elastase. Normally, AAT circulating in the blood restrains this elastase from doing significant lung damage. A deficiency in AAT, however, means there is little or no AAT to keep the elastase enzyme in check, so a persistent inflammatory reaction ends up destroying the walls of alveoli and terminal airways. This destruction then leads to emphysema, a condition in which empty air spaces are formed by the merger of damaged alveoli.

Smokers typically develop COPD in their fifties. In contrast, smokers with AAT deficiency develop emphysema at an average age of 40 years. Even nonsmokers with severe AAT deficiency can develop emphysema; in nonsmokers with severe ATT deficiency, emphysema shows up at an average age of 53 years. AAT deficiency also causes other problems, most notably, liver disease. In the United States, AAT deficiency is the basis of only 1% to 2% of cases of COPD, because fewer than 1 in 3000 people are born with severe AAT deficiency (Hellewell & Fairman, 2006).

Cellular Responses to Smoking

Cigarette smoking causes COPD by inciting a chronic inflammatory response to the pollutants in the smoke. Over time, the persistent inflammation leads to destruction of lung tissue, accumulation of mucus, and thickening of small airways (Reilly et al., 2005).

THE INFLAMMATORY RESPONSE

Inhaling cigarette smoke triggers inflammation throughout the airways of the lung. The inflammatory response is a stereotyped cascade of events; in COPD, it begins with the activation of local macrophages in the lung tissue; in fact, the gradual and progressive accumulation of macrophages throughout the lungs is a characteristic feature of COPD. These macrophages secrete proteases—destructive enzymes such as elastase. Macrophages also attract neutrophils (polymorphonuclear leukocytes) from the bloodstream. The greater the number of neutrophils that invade the lung tissue, the faster the lung function declines.

ENZYMATIC DESTRUCTION OF TERMINAL AIRWAYS

When responding to irritants, both macrophages and neutrophils secrete a variety of active molecules, including proteases. Normally, the destructive action of the proteases is held in check by balancing molecules, the antiproteases (eg, alpha1-antitrypsin), which circulate in the bloodstream and are also released by neighboring epithelial cells. In this way, local tissues are largely protected from the damage of normal short-term inflammation.

Smoking, however, causes an imbalance in the inflammatory process. On the one hand, cigarette smoke is a strong and continuous stimulant of inflammation, and in the lungs of a chronic smoker proteases are constantly being released. On the other hand, in people who develop COPD the activity level of antiproteases is low. A lack of proteases may be an innate feature of those people who develop COPD. Much of the problem, however, seems to be an unfortunate result of long-term inflammation. A byproduct of persistent inflammation is the accumulation of free radicals, superoxide anions, and hydrogen peroxide, and all of these molecules inhibit the action of antiproteases.

In COPD, the imbalance of proteases and antiproteases allows the proteases to begin to destroy local tissues. Elastin and other structural molecules in the walls of the airways and the alveoli are degraded. The walls first become perforated and are later obliterated, with the natural forces of breathing helping to rip them apart. The small, distinct alveoli coalesce into larger, poorly demarcated, useless air spaces. When these empty spaces become >1 cm in diameter, they are called bullae (singular, bulla). It is this creation of empty air spaces in the lung that is called emphysema.

In the emphysematous form of COPD, lung parenchyma is progressively destroyed, usually in a pattern called centrilobular emphysema. This pattern consists of destruction of alveoli, loss of lung elasticity, and the collapse of small airways that rely on the support of surrounding connective tissues to stay open when a person exhales.

FIBROSIS AND NARROWING OF SMALL AIRWAYS

A hallmark of COPD is the increased resistance to airflow in the lungs. In the chronic bronchitis form of COPD, much of the obstruction comes from a progressive thickening and stiffening of small airways. The pathologic process is fibrosis, the accumulation of excess collagen, which makes the airways walls fatter and more rigid. This extra collagen is secreted as a natural repair response to tissue damage. In COPD, lung damage from inflammation is a chronic process, and it is accompanied by continuing fibrosis.

The chronic bronchitis aspect of COPD causes other changes in the small airways, reducing their internal volume still farther:

• Mucus cells proliferate and become larger, thus generating excess mucus.
• Smooth muscle thickens.
• The airway walls bulge with invading inflammatory cells.

Functional Effects

Normally, air is blown out of the lungs partly by the natural elastic recoil of the lung tissue. The narrowed airways of COPD carry smaller volumes of air and fibrotic airways lose their elasticity; therefore, an exhalation of breath takes more effort and more time than normal. Using spirometry, the airway obstruction can be quantified by measuring the patient's FEV1, the volume of air that can be pushed out of the lungs during the first second after a full inhalation. COPD is characterized by a low FEV1, and the persistent and irreversible low level of forced expiratory flow rates is the most characteristic objective finding.

In COPD, difficulty in breathing is worsened by excessively expanded (hyperinflated) lungs. People with COPD usually have some degree of emphysema, which means there is wasted air space. At the same time, COPD patients do not have the energy to fully empty their lungs. Therefore, each new breath of air has to be packed into a lung that is already partly inflated.

When the lungs become hyperinflated, the chest wall stretches, causing extra resistance for each inhalation. Meanwhile, the shape of the expanded chest changes the mechanics of the diaphragm and the chest muscles so that they do not work efficiently.

The obstructed airflow and hyperinflated lungs of COPD make breathing hard work. When the disease is severe, simply walking slowly on a level surface can use a third of the body's normal oxygen intake. For a person with COPD, the increased work of breathing can be exhausting. Patients may not have enough energy to pull in all the oxygen they need or to expel all the carbon dioxide they produce. As a result, people with severe COPD become chronically hypoxemic (too little circulating oxygen) and hypercapnic (too much circulating carbon dioxide).

COPD puts yet another obstacle in the way of maintaining appropriate levels of oxygen and carbon dioxide in the circulation. As the disease progresses, COPD leads to destruction of alveoli and the small capillaries that surround them, and the surface area available for gas exchange diminishes. Moreover, the remaining blood vessels become less responsive to the demands of exercise: they cannot expand when in response to an increased need for absorbing oxygen and releasing carbon dioxide. People with COPD easily become hypoxemic, and over time they can become unable to exercise at all (Gold, 2005b).

Other Chronic Damage

Patients with COPD have problems with systems other than their lungs. COPD eventually leads to hypoxemia, it drains energy reserves, and it is a source of chronic inflammation. These problems can cause muscle weakness and weight loss. In addition, people with COPD have a high incidence of clinical depression, which seems to be, in part, a result of the systemic metabolic and inflammatory changes caused by the lung disease.

The greatest effect of COPD outside the lungs is on the heart, and cardiovascular diseases are often the immediate causes of death for COPD patients. The inflammatory reaction that causes much of the lung damage in COPD also initiates a generalized prothrombotic condition in the circulation, making blood clots more likely to form. The prothrombotic state makes it more likely for patients to get small clots, strokes, deep-vein thromboses, and pulmonary emboli.

Chronic hypoxemia by itself is a strain on the heart. Low blood oxygenation reduces the ability of the heart's ventricles to increase the speed and strength of their contractions in response to exercise. Worse still, in COPD the heart often has to contend with pulmonary hypertension. The hypoxia and acidemia that come from poor gas exchange make the lung arteries constrict. Pressure from the hyperinflated lungs also constricts the pulmonary arteries. In addition, COPD causes destruction of many lung capillaries and the thickening of the walls of many small pulmonary blood vessels. All of these changes reduce the size of the pulmonary vasculature and increase its resistance to blood flow, leading to pulmonary hypertension.

Pulmonary hypertension is especially hard on the right ventricle, which hypertrophies in response. As the strain on the right ventricle persists, the heart can fail, leading to cor pulmonale, which is heart failure secondary to lung problems (Gal, 2005).

RESTRICTED FUNCTION

Over the years, patients with COPD become less and less able to do even modest exercise without developing dyspnea. Dyspnea, the feeling of breathlessness, is a common symptom. It comes from a mix of three sensations:

• The urge to breath. This urge is triggered by exercise or by the metabolic results of exercise, namely, hypoxemia, hypercapnia, and metabolic acidosis.
• Difficulty breathing. This feeling is produced by excess amounts of chest movement and by unusual amounts of effort of the muscles of respiration during breathing.
• Anxiety. This sensation can be caused by a fear of suffocating or by a memory of past discomfort with breathlessness. Anxiety can also come from entirely different sources of stress. (Stulbarg & Adams, 2005)

Breathlessness is very uncomfortable. It stops people from exercising, and it is the major symptom that severely limits the activities of people with COPD. The inability to exercise without developing shortness of breath gets worse as COPD progresses. Patients begin to spend all their time either sitting in a chair or lying in bed. After months of inactivity, COPD patients become deconditioned as their muscles and circulatory system settle into sedentary states.

It is a spiraling problem: dyspnea causes lack of exercise, lack of exercise causes deconditioning, and deconditioning makes exercise even harder. As they become deconditioned, COPD patients get severe leg tiredness and leg discomfort when they try to exercise. Soon these patients find leg problems to be another limiting factor when they exercise—and, of course, the lack of exercise makes the leg problems worse. Part of the long-term treatment of COPD is exercise rehabilitation. Supervised training regimens can reverse the muscle weakness and pain, and these programs can improve the patient's overall ability to exercise (Gold, 2005b).

CLINICAL PRESENTATION OF COPD

The typical COPD patient is an elderly white male with a history of smoking at least one pack of cigarettes per day for more than 40 years. He complains of general tiredness and he becomes short of breath when exercising. His legs bother him when walking, so he spends most of his time sitting. If you ask him to breathe out quickly, it takes him an inordinate amount of time.

Other aspects of the clinical picture range along a spectrum. If this person is on the emphysematous end of the spectrum, he will tend to be thin and have a wide, barrel-shaped chest. He will always be "out of breath." When he coughs he does not produce much sputum. On chest examination, this person's breath sounds are distant and relatively clear.

In contrast, if this person is on the chronic bronchitis end of the spectrum, he will tend to be of normal weight or overweight. He will cough frequently and will bring up sputum. On chest examination, his breath sounds will include rales (dry crackles), rhonchi (wet crackles), and wheezes. A COPD patient with chronic bronchitis will tend to get many respiratory infections (Reynolds, 2005).

Chief Complaints

Smokers generally have COPD for many years before the symptoms become serious enough to induce them to see a doctor. At this first visit, breathlessness (dyspnea) is usually the chief complaint.

DYSPNEA

Breathlessness during mild exercise is the most common reason that people with COPD first seek out a doctor. Their breathing difficult stems from two problems. First, the chests of many COPD patients remain overly expanded in the resting state (after exhaling); this makes it difficult for the respiratory muscles to expand the chest farther when attempting to take a new breath. Second, COPD patients have airway obstruction, and they cannot fully empty their lungs before they need to take another breath. The residual air, which keeps the lungs hyperinflated, dilutes the oxygen content of the newly inhaled air.

The dyspnea of COPD comes on gradually over a period of years and it takes a while to be noticed. However, dyspnea worsens and becomes more apparent after an illness. Many patients report that a recent illness triggered their dyspnea. If the patient has COPD, a careful review of the history of exercise tolerance usually elicits evidence of increasing dyspnea before the illness (Reilly et al., 2005).

COUGH

Dyspnea is the symptom that most often brings COPD patients to a doctor, but coughing is the most common symptom reported by patients with COPD. The cough of COPD is usually worse in the mornings, and early in the disease it produces only a small amount of colorless sputum (mucus and lung secretions that are expelled into the throat by coughing). Coughing, which typically appears earlier in the course of the disease than dyspnea, is annoying but usually does not limit the patient's daily activities.

Medical History

As a rule, the health system first sees COPD patients when they are in their late forties to mid-fifties. These people come with chief complaints of dyspnea and excessive coughing. In retrospect, their symptoms have been going on for at least a decade, with coughing having shown up first. At one time, the dyspnea was noticed only during heavy exertion, but eventually dyspnea began to interfere with even mild activities.

Many COPD patients will report that typical respiratory infections have become more frequent, more severe, and longer lasting. These illnesses have included increased breathlessness, wheezing, coughing, and sometimes the production of colored (yellow, green, or blood-tinged) sputum (Sharma, 2006).

A key element in the history of a COPD patient is smoking. The first symptoms of COPD appear after about 20 pack-years of smoking, and the disease usually becomes clinically significant after 40 pack-years of smoking.

In addition to asking about chronic diseases and heart conditions, a few other specific problems should be explicitly investigated when taking the history of a patient with COPD:

• Allergy history. Asthma and other allergic syndromes that affect the respiratory system can worsen (or mimic) COPD.
• Symptoms of GERD. Gastroesophageal reflux disease (GERD) can cause chronic cough and can sometimes be confused with chronic bronchitis.
• Symptoms of clinical depression. Depression is more common in people with chronic illnesses such as COPD. (Anthonisen, 2008)

Physical Exam

A patient with mild COPD may have few signs of the disease, especially when sitting quietly. In contrast, the physical exam of a person with severe COPD can be diagnostic (Shapiro et al., 2005; Swadron & Mandavia, 2006).

GENERAL APPEARANCE

COPD patients with significant emphysema are typically thin with a barrel-shaped chest. They tend to breathe through pursed lips, and they sit leaning forward in a "tripod position"; this is a posture that widens the chest as much as possible by supporting the upper body on the elbows or the extended arms.

The tripod position. Patient leans forward, resting on elbows orhands, in an effort to expand the chest and ease breathing. (Illustration by Jason M. McAlexander, MFA. Copyright © 2007 Wild Iris Medical Education.)

In contrast, patients with significant chronic bronchitis are typically of normal weight or overweight. They have a productive cough and may be cyanotic. At rest, their rate of respirations is high, often more than 20 breaths per minute. Patients with the chronic bronchitis form of COPD who are hypoxemic may have a clouded consciousness, making them dull and irritable.

WEIGHT

Obesity can worsen the symptoms of COPD. On the other hand, many COPD patients—especially patients with the emphysematous form of COPD—are cachectic and underweight, with muscle wasting. In these cases, nutritional therapy is an important part of their treatment.

CHEST

A COPD patient with chronic bronchitis but little emphysema may have a normal-sized chest. Significant emphysema, on the other hand, leads to a wide, barrel-shaped chest with a flattened diaphragm. In a patient with emphysema, the chest remains perpetually in the position of inhalation. To take a new breath, therefore, emphysematous patients must expand their chests beyond the normal position of inhalation, and this requires using accessory respiratory muscles of the shoulder, neck, and back.

LUNGS

The chest of an emphysematous patient is unusually resonant to percussion and the breath sounds are distant. At the other end of the spectrum, the chest of a chronic bronchitis patient can have dull spots when percussed and it will be noisy with rales, rhonchi, and wheezing.

The common feature of all forms of COPD is airway obstruction, which worsens as the disease becomes more severe. A simple, direct measure of airway obstruction is the time it takes a patient to blow out an entire lungful of air. A normal person has a forced expiratory time (FET) of <3 seconds. An FET of >4 seconds suggests obstruction. An FET of >6 seconds indicates considerable airway obstruction, at the level of moderate-to-severe COPD.

HEART

COPD can injure the heart in two major ways. First, the chronic inflammatory state of COPD predisposes a person to develop coronary artery disease; therefore, a heart history and physical examination should probe for evidence of ischemic heart problems. Second, COPD can cause pulmonary hypertension, which strains the right ventricle of the heart. Pulmonary hypertension makes the pulmonary component of the second heart-sound louder. In addition, it can cause tricuspid valve insufficiency, which will be heard as a holosystolic murmur loudest along the left sternal border. Pulmonary hypertension can cause right-sided heart failure (cor pulmonale), and this will lead to jugular venous distension and edema of the legs and ankles.

Laboratory Findings

The key chemistry values for a person with COPD are the levels of blood gases—oxygen and carbon dioxide—and the pH of the blood.

BLOOD OXYGEN LEVELS

The severity of a patient's COPD can be estimated by the degree that the blood gases deviate from normal. In the early stages of the disease the amount of oxygen in arterial blood is usually within normal limits. Oxygen concentration in arterial blood is measured as its partial pressure (PaO₂), and a normal oxygen partial pressure (or oxygen tension) is 80 to 100 mm Hg. As COPD worsens, the PaO₂ can drop below 60 mm Hg; this level signals respiratory distress to the brain, and it strongly activates the respiratory centers. When the PaO₂ is below 60 mm Hg, a person hyperventilates in an attempt to reverse the hypoxemia by breathing in more oxygen. Unfortunately, hyperventilation due to hypoxemia expels too much carbon dioxide from the bloodstream, and this causes respiratory alkalosis, a pH imbalance.

In later stages of COPD, even with a PaO₂ <60 mm Hg, the patient does not have the energy to hyperventilate and carbon dioxide builds up in the blood. Now the hypoxemia is accompanied by hypercapnia (excess blood carbon dioxide) and the patient develops chronic respiratory acidosis, an ominous sign (Sharma, 2006; Swadron & Mandavia, 2006).

Arterial Blood Gases

Early in the course of COPD, arterial blood gases do not need to be checked regularly. However, an early set of baselines values can be a used as a comparison to measure the degree of change brought on during acute exacerbations, such as when the patient gets a serious respiratory infection.

Pulse Oximetry

Accurately measuring a person's blood oxygen tension requires drawing arterial blood and testing it in a laboratory. Pulse oximetry is a quick and noninvasive alternative tool. A pulse oximeter has a small probe that can be clipped onto a patient's finger or earlobe. Using measurements of transmitted light, the oximeter determines the percent of the patient's hemoglobin (Hb) that is saturated with oxygen.

Pulse oximeters are not as accurate as direct oxygen tension measurements from arterial blood gases, and the percent of hemoglobin saturation measured by an oximeter is not the same as a person's PaO₂. Nonetheless, the two values are related. A person with a normal PaO₂ (80–100 mm Hg) will have an Hb saturation of ≥96%; a person with hypoxemia of 60 mm Hg will have an Hb saturation of about 86%.

RED BLOOD CELLS

Routine blood analyses are not needed to manage most cases of COPD. Some people with severe COPD produce excess red blood cells (polycythemia), apparently in response to their chronic hypoxia. This leads to hematocrit readings of >52% in men (normal is 43–52%) and >48% in women (normal is 37–48%).

ALPHA1-ANTITRYPSIN LEVELS

Patients who develop emphysema at an early age (younger than 40 years old) and nonsmokers of any age who develop emphysema are usually tested for their blood levels of the enzyme alpha1-antitrypsin (AAT). Deficiency of this enzyme makes a person unusually susceptible to emphysematous COPD, and the patient and family should be educated about this genetic disease. It is sometimes possible to treat AAT-deficiency with replacement doses of the enzyme.

Imaging Studies

The most commonly used images for evaluating and managing COPD are chest x-rays and computed tomography (CT) scans.

CHEST X-RAYS

COPD is a disease defined by functional problems, specifically, the restriction or obstruction of airflow in the lungs. Breathing measurements are better diagnostic indicators of the disease than are chest x-rays. Chest x-rays are important, however, for ruling out other causes of airway obstruction, such as mechanical obstruction, tumors, infections, effusions, or interstitial lung diseases. In acute exacerbations of COPD, chest x-rays are used to look for pneumothorax, pneumonia, and atelectasis (collapse of part of a lung) (Wise, 2007).

At the severe stage, COPD produces a number of changes visible in chest x-rays. When the disease includes significant emphysema, the chest is widened, the diaphragm flattened, and the lung fields have fainter and fewer vascular markings. The heart may appear long, narrow, and vertical and the airspace behind the heart can be enlarged.

When severe COPD includes significant chronic bronchitis, chest x-rays have a "dirty" look. There are more vascular markings, more nonspecific bronchial markings, and the walls of the bronchi look thicker than normal when viewed end-on. Often, the heart appears enlarged (Swadron & Mandavia, 2006).

COMPUTED TOMOGRAPHY (CT) SCANS

Computed tomography scans, especially high-resolution scans, are better than chest x-rays at resolving the details of lung abnormalities caused by COPD. These scans are also used to more definitive identification of diseases such as tumors or infections that may be complicating a patient's COPD. Late in the disease, CT scans are used to evaluate COPD patients who are to be treated surgically.

Lung Function Tests

Pulmonary function tests can quantify the severity of airway obstruction in COPD. When COPD is diagnosed, baseline pulmonary function values should be recorded. Later tests can then be used objectively to follow the progression of the disease and the effectiveness of treatments (Gold, 2005a). For COPD, the two general classes of breathing tests are (1) measurements of effective lung volumes, and (2) measurements of airflow rates and airflow volumes.

LUNG VOLUMES

In COPD, airway obstruction makes it difficult to empty the lungs fully. The residual air merely takes up space. The air that remains behind keeps the lungs hyperinflated even after a complete exhalation, making it more difficult for a patient to pull in sufficient air for the next full breath. As a result, the total air volume of the lungs often increases while the volume of air actually breathed in and out decreases.

The effective volume of air is called the vital capacity (VC), which is the largest volume of air that can be exhaled after a full inhalation. The vital capacity is measured by having a patient take as large a breath as possible and then exhale as quickly and forcefully as possible. The volume of exhaled air is the vital capacity. When measuring vital capacity this way, the result is also called the forced vital capacity (FVC) (Wanger & West, 2005).

AIRFLOW RATES

The airway obstruction of COPD slows the movement of air in the lungs. This slowing can be measured directly. Measurements of the rate of air movement during breathing are called spirometric measurements. Specifically, spirometry records the volume of air exhaled in a defined period of time (Miller et al., 2005).

A small, handheld spirometry device can be used for quick office or clinic tests (NIH, n.d.b).

A full-function laboratory spirometry apparatus gives detailed reports on a range of characteristics of a patient's lung ventilation (NIH, n.d.c).

The most common spirometric measurement used to characterize a patient's COPD is the one-second forced expiratory volume (FEV1). This is the maximum amount of air that a patient can breathe out in the first second of a forced exhalation after having taken a full breath.

Evaluating Airway Obstruction

People with normal lungs can expel most of the air in their lungs within 1 to 2 seconds. The amount of air forcefully exhaled in the first second (the FEV1) is about 3/4 of the vital capacity (the FVC) of a normal person.

If someone could exhale their entire vital capacity in 1 second, their FEV1/FVC would be 1.00. A normal person has an FEV1/FVC between 0.70 and 0.80; in other words, a person with normal lungs can exhale between 70% and 80% of their vital capacity in the first second. This ratio, FEV1/FVC (the percent of the vital capacity that can be exhaled in one second), declines as a person ages, but even elderly people will have FEV1/FVC >0.70 if their lungs are normal.

In COPD, airway obstruction restricts the rate of exhaling and people with COPD cannot get a normal amount of air out of their lungs in one second. People with COPD have FEV1/FVC <0.70. When a person has an FEV1/FVC <0.70 and a history of >20 pack-years of smoking, they can be given a presumptive diagnosis of COPD (Wagner & West, 2005).

RANKING THE SEVERITY OF COPD

The basic stages of COPD are termed mild, moderate, severe, and very severe. All stages of COPD have an abnormally low one-second exhaled percent of vital capacity (FEV1/FVC <0.70). The specific stage of COPD is then determined by how much the disease has reduced the maximal airflow below normal; this is measured by comparing the patient's FEV1 to the predicted value for their age, gender, height, and weight (Swadron & Mandavia, 2006; Wise, 2007):

STAGING OF COPD

Stage	Severity	FEV1/FVC
Stage I	Mild	FEV1/FVC <0.70 and FEV1 ≥80% predicted value*
Stage II	Moderate	FEV1/FVC <0.70 and 50% ≤FEV1 <80% predicted value*
Stage III	Severe	FEV1/FVC <0.70 and 30% ≤FEV1 <50% predicted value*
Stage IV	Very Severe	FEV1/FVC <0.70 and FEV1 <30% predicted value*
*Predicted FEV1 values adjusted for a person's age, gender, height, and weight can be calculated from published equations (Pellegrino et al., 2005). Source: Modified from Rabe et al., 2007.

DIFFERENTIAL DIAGNOSIS

What other diseases might present with symptoms similar to COPD? Cough and dyspnea are the two main symptoms of the early stages of COPD. Measurable lung destruction begins before these symptoms become a significant problem to most COPD patients, and, for most patients, increasing dyspnea is typically the complaint that pushes them to see a doctor. When a patient comes with a complaint of dyspnea or cough, however, there are a host of possible causes (Gonzales, 2008). Sudden onset of severe dyspnea can be a medical emergency, but the persistence of gradually worsening dyspnea over a period of many months or years can usually be evaluated in an outpatient setting.

Coughing is stimulated by irritation of the bronchial tree. Acute coughing is usually from a respiratory infection and is accompanied by fever, tachycardia, and tachypnea. This type of cough typically lasts less than three weeks, although in some people, coughs can hang on as long as two months after a respiratory illness. The coughing of COPD, however, occurs intermittently for years.

COPD is usually diagnosed on the basis of history, physical exam, and breathing tests. Many other causes of worsening dyspnea or chronic cough, however, can be recognized from imaging studies (often simply chest x-rays) and clinical signs. These causes include pneumothorax, pulmonary emboli, pneumonia, lung infections, atelectasis, interstitial lung disease, sarcoidosis, effusions, lung masses, upper-airway or foreign-body obstructions, or congestive heart failure. Anemia or metabolic acidosis can cause chronic dyspnea, and both of these can be identified by blood studies.

Asthma is high on the list of differential diagnoses for dyspnea and cough, but it cannot usually be distinguished from COPD by chest x-rays, clinical signs, or blood studies. Asthma is an obstructive airway disease that causes dyspnea and coughing, but asthma involves different cellular mechanisms and has a different natural history than COPD.

Patients with asthma have hypersensitive airways that are always slightly inflamed, edematous, and filled with immune cells (characteristically, eosinophils). Certain inhaled allergens and a variety of stresses trigger these primed immune cells, causing the disorder to flare up with more edema, mucus, and narrowed airways. Like COPD, asthma obstructs airways and impedes airflow, but unlike COPD, the airway restrictions of asthma can be, at least in young people, quickly and almost entirely reversed by bronchodilators.

As some people with asthma age, however, their airway obstruction becomes more fixed and less reversible. Clinically, these people's disease begins to share many features with COPD and the two may be hard to distinguish. The distinction between diseases can be important for their treatment. For example, the dyspnea of asthmatic patients tends to improve markedly when the patient is given steroids, but the dyspnea of most COPD patients does not improve following steroids (Jeffery, 2003).

A patient's medical history can often distinguish asthma from COPD. Asthma usually appears in people younger than 30 years of age, while COPD typically appears in people older than 40. Episodes of symptomatic asthma are reversed quickly and completely by medications. In contrast, symptoms of COPD are reversed only modestly and temporarily by medications.

Asthma often runs in families, while COPD usually does not. Finally, only 20% to 30% of asthmatic patients have been smokers, and those who smoke have less than a 20 pack-year history. On the other hand, 90% to 95% of COPD patients have been smokers, and most have greater than a 20 pack-year history of smoking (McFadden, 2005).

ACUTE EXACERBATIONS

Patients with COPD have little or no ventilatory reserve and any further compromise of their respiratory system can send them into hypoxemia. The normal wear and tear of daily life puts respiratory compromises in everyone's path periodically. Therefore, people with COPD suffer repeated acute exacerbations (episodes of suddenly worsened symptoms) (Reynolds, 2005).

During an acute exacerbation, patients become more breathless than usual, have chest tightness, and may begin to wheeze and find it hard to talk. These episodes can include increased sputum, which may be yellowish or greenish and filled with white cells. The sudden decrease in ability to breath efficiently makes patients tachycardic and sweaty, and their percent of oxygenated hemoglobin (measured by pulse oximetry) decreases. In serious cases, patients cannot get rid of sufficient carbon dioxide (hypercapnia), and they become acidotic and lethargic.

A typical patient with mild to severe COPD is likely to have three acute exacerbations a year. The sudden decompensation seen in acute exacerbations of COPD can be caused by a variety of factors. Infections, especially respiratory infections, from colds to pneumonias, will trigger a sudden worsening of COPD, and acute exacerbations occur more often in the winter, the season with the most viral infections. Increases in air pollution can also bring on an acute exacerbation.

The occurrence or the worsening of other medical conditions can trigger exacerbations of COPD, especially when these conditions relate to the respiratory system. Pneumothorax, pulmonary emboli, congestive heart failures, heart arrhythmias, chest trauma, lung atelectasis, and pleural effusions all significantly worsen COPD. However, many acute exacerbations cannot be easily explained. No cause can be identified in approximately one-third of the episodes of suddenly worsening COPD.

A patient's normal daily medication will not reverse an acute exacerbation. "Rescue" medicines—typically, additional doses of short-acting bronchodilators—are first-line treatments. Often further medical assistance, including hospitalization, is required to treat the cause of the episode and to prevent the ventilatory decompensation from continuing to worsen.

Unlike attacks of asthma, acute exacerbations of COPD improve slowly even with prompt medical attention. On average, it will take a week for a person to recover from an exacerbation of COPD, and in 25% of cases recovery takes more than a month. For patients with severe COPD, an acute exacerbation can be fatal.

TREATMENT

COPD is a life-long disease. It requires daily medications and permanent adjustments to a patient's lifestyle. It also needs special medical treatment during acute exacerbations.

Long-Term Treatment

The goals of long-term COPD treatments are:

• Slow or stop the disease from progressing
• Ease the symptoms
• Increase the patient's ability to be mobile and to do activities of daily living
• Prevent acute exacerbations (Rabe et al., 2007)

All COPD patients should learn about their disease, and especially come to understand that smoking and air pollution will further damage their lungs. They need to make a special effort to avoid respiratory infections and to get yearly influenza vaccinations (Rich & McLaughlin, 2005; Shapiro et al., 2005).

At each stage of the disease, there are some characteristic medical therapies. Mild COPD is usually treated with short-acting bronchodilators, which are used as needed for dyspnea. Moderate COPD requires regular treatments with bronchodilators, sometimes with the addition of inhaled corticosteroids; at this stage, many patients are enrolled in a pulmonary rehabilitation program. When COPD becomes severe, the patient may need to take two or more bronchodilators regularly, and inhaled corticosteroids are added to the regimen to prevent repeated acute exacerbations. Very severe COPD usually needs the addition of long-term oxygen therapy; surgical treatments can be appropriate at this stage. Rabe and colleagues (2007) have written an excellent guide to the diagnosis and management of COPD.

The range of treatments for COPD runs from bronchodilator therapy to surgery (NIH, n.d. d).

LIFESTYLE ADDITIONS AND INTERVENTIONS

Medications are the fundamental day-to-day tools for controlling the symptoms of COPD, but there are also four key nonpharmaceutical steps in the treatment of COPD (Shapiro et al., 2005; Stulbarg & Adams, 2005).

Patient Education

Teach your patients about COPD. Explain that the disease causes irreversible and progressive problems. Warn patients that they will have episodes in which the symptoms—difficulty breathing, wheezing, productive cough and tiredness—get worse for days or even weeks.

Assure patients that you will help them by ordering medications that make breathing easier. Tell them there are a number of things they themselves can do to slow the progression of the disease and to lessen the number of acute exacerbations. The most important of these things is to stop smoking; although smoking has already damaged their lungs, continued smoking will increase the damage and will make their COPD worsen more quickly.

Explain to patients the importance of staying active. In addition, give them practical suggestions that will help them to cope with the inevitable limitations posed by COPD. For example, tell them:

• Slow the speed at which you do things, and stop and rest when you are tired. Don't push yourself.
• Pace yourself and plan your activities for times when you have the most energy. You will feel best soon after you take your bronchodilator medicines. Wait an hour after meals before you do activities.
• Sit on a chair or stool in the shower—don't stand. Likewise, sit while you shave, comb your hair, and brush your teeth.
• Don't use products that are hard on the lungs; for example, hair sprays, spray-on deodorants, or strong perfumes.
• Use the exhaust fan in your kitchen to make it less likely that you will breathe smoke and cooking vapors.
• Wear slip-on shoes so you don't have to bend over to tie laces.
• Make sure your occupation does not require more physical exercise than you can actually do. Consider setting smaller goals at work and allowing more time to finish tasks.
• Find out how to get a daily air pollution report, and don't go out on days with moderate or severe pollution.
• Ask people not to smoke in your home or work area. (ALA, 2007)

Stop Smoking

In the United States, smoking starts in the teenage years: 90% of adult smokers began smoking before the age of 18. More than a quarter of high school students and 1 in 10 middle school students smoke (Ranney et al., 2006).

Most patients with COPD have a long smoking history and many will still be smoking when they are under medical care. Currently, the only way to change the course of COPD is for the patient to stop smoking. No matter how old they are and no matter how long they have been smoking, COPD patients benefit from quitting.

COPD is an insidious disease, and it develops over many years before it compromises people enough that they go to a doctor. The disease is already active and destructive by the time that it is diagnosed, and treatment should be aggressive from the beginning. From day one, strongly urge your patients to stop smoking.

Nicotine is powerfully addictive. In addition, the smoking ritual fills many basic psychological needs. When doctors merely tell patients to stop smoking, their patients succeed over the long-term only 5% of the time.

Although simply advising smokers to quit is rarely effective, healthcare professionals are less likely to offer smoking cessation assistance with their advice (CDC, 2007).

Long-term success rates of greater than 20% to 40% can be achieved by comprehensive programs that include behavioral therapy and medications. Successful smoking intervention programs begin by setting a quitting date with the patient. They then maintain continued contact with the patient to provide medication, counseling, support, advice, and a modicum of social pressure. For specific recommendations, the report Treating Tobacco Use and Dependence: Clinical Practice Guidelines can be downloaded from the United States Surgeon General's website at http://www.surgeongeneral.gov/tobacco.

The pharmacologic aspect of smoking cessation programs attempts to ease the effects of nicotine withdrawal. Smokers who need their first cigarette within a half-hour of getting up in the morning are likely to be highly addicted to nicotine. When these people stop smoking they become anxious, irritable, easily angered, easily tired, and depressed. Their sleep is disrupted and they have difficulty concentrating. Withdrawal effects happen during the first 2 to 3 weeks after quitting.

To lessen withdrawal symptoms, nicotine can be taken directly. Nicotine replacements are available as gum, lozenges, transdermal patches, inhalers, and nasal sprays. These should be used on a regular schedule and also prn (as needed for cigarette cravings) for about two weeks, and then the doses reduced gradually.

Antidepressants (notably, bupropion and nortriptyline) have been shown to help patients for whom nicotine replacement therapy has not worked. In 2006 a nicotine agonist, varenicline (Chantix), was approved by the FDA for anti-smoking therapy. Varenicline binds to nicotine receptors and prevents nicotine from activating the receptors while producing a smaller stimulant effect than nicotine.

Pulmonary Rehabilitation

Pulmonary rehabilitation is the term for a group of techniques used to improve patients' conditioning and ease their breathing difficulties. Pulmonary rehabilitation is done as outpatient therapy. Some programs continue for an extended time, but most run for a few weeks and then give patients individualized instructions for continuing at home. Education sessions are important parts of rehabilitation programs; in these sessions, patients and their families learn details about COPD and its treatment (Chesnutt et al., 2008).

Pulmonary rehabilitation programs are tailored to the needs of each individual. Typically, they include graded aerobic exercise programs such as regular sessions of walking or stationary bicycling three times weekly. A walking exercise program, for example, might begin with slow treadmill walking for only a few minutes. The length and speed of the walking would then be increased gradually over 4 to 6 weeks. The goal would be for the patient to walk for 20 to 30 minutes without needing to stop because of shortness of breath. At that point, the patient would be assigned a maintenance exercise program to be done at home.

Rehabilitation sessions also include exercise routines to condition the upper body and exercises aimed at strengthening respiratory muscles. Breathing instruction teaches patients how to slow their rate of breathing by pursing their lips. Patients also learn how to give their upper respiratory muscles a rest by using abdominal breathing techniques instead of chest breathing.

Comprehensive pulmonary rehabilitation can reduce COPD patients' symptoms and increase the amount of exercise that patients can do without being stopped by dyspnea. It can also reduce the number of hospitalizations for acute exacerbations, and improve the quality of patients' lives, both subjectively and objectively (Stulbarg & Adams, 2005).

Physiotherapy

It is important that COPD patients with significant chronic bronchitis keep their airways clear. Coughing up sputum should be encouraged, and cough suppressants or sedatives should not be used routinely. When patients cannot clear their secretions by coughing, postural drainage may help (Stulbarg & Adams, 2005).

Most people's lungs secrete extra mucus in response to inhaled irritants. To avoid stimulating excess secretion, COPD patients need to avoid smoke-filled rooms and stay indoors during air pollution alerts. Home air conditioners and air filters are effective and helpful.

Improved Diet

Overweight COPD patients find improvement when they slim down. Some COPD patients, however, have the opposite problem: they become thin and malnourished. In part, cachexia results from the high-energy cost of breathing with COPD. In addition, the chronic inflammatory state underlying COPD tends to put the body's metabolism into a catabolic state. To help them maintain a healthy body weight, thin COPD patients should be given dietary counseling that includes specific recommendations of meals that are nutritionally balanced and that contain sufficient calories to make up for the work of breathing (Stulbarg & Adams, 2005; Wise, 2007).

The American Lung Association has produced a brochure that explains nutrition for COPD patients and that includes a variety of recipes. The brochure is printed on their website at http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=3529631, and it can be downloaded in PDF format.

DRUG TREATMENTS

The medicines currently available for COPD do not significantly change the progressive decline in lung function that is caused by the disease. Instead, drug therapy is used to reduce the debilitating dyspnea of COPD so patients can be more active. Most drugs work by keeping airways as wide open as possible (Hall & Ahmed, 2007).

COPD Medications for Long-Term Control

Type of medication	Generic name	Brand name	Possible side effects
Long-acting beta2-agonists: inhaled and oral Bronchodilators used daily to keep symptoms controlled	Salmeterol	Serevent	Headaches Shaking (tremors) Higher blood pressure Faster heart beat Stomach upset, nausea Trouble sleeping Muscle cramps
	Formoterol	Foradil
Combined inhaled Bronchodilators that combine a controller inhaler and a quick relief inhaler, or combine 2 controller inhalers into one	Albuterol + Ipratropium	Combivent	Refer to side effects of each individual medicine
	Albuterol + Ipratropium	DuoNeb
	Salmeterol + Fluticasone	Advair
Long-acting or maintenance Methylxanthine: Oral Bronchodilator that relaxes the muscles around the airways	Theophylline	Slo-Bid	Stomach upset Nausea Faster heartbeat Trouble sleeping
		Theochron
		Theo-Dur
		Theo-24
		Uniphyl
Corticosteroids: inhaled Potent anti-inflammatory that may help to reduce swelling and inflammation	Beclomethasone	Beclovent QVAR Vanceril	Hoarseness Thrush, yeast infection in the mouth
	Budesonide	Pulmicort Turbuhaler
	Flunisolide	Aerobid
	Fluticasone	Flovent
	Triamcinolone	Azmacort
Anticholinergics: inhaled Bronchodilator that relieves the tightening of the airways, or bronchospasm	Ipratropium Short-Acting	Atrovent	Dry mouth Bitter taste
	Tiotropium bromide Long-Acting	Spiriva	Dry mouth Constipation Faster heartbeat
Source: ALA, 2005a.

Bronchodilators

Spirometry shows that bronchodilators only modestly reduce airway obstruction in most COPD patients. Nonetheless, patients with moderate or worse COPD have less dyspnea and can be more active when taking regular doses of bronchodilators. Bronchodilators work by relaxing the muscles in the walls of the lung's airways. This relaxation widens the airways, allowing air to move through them more easily. Airway muscles are smooth muscles that are involuntary and are controlled by the autonomic nervous system.

The autonomic nervous system has two divisions: parasympathetic and sympathetic. The major parasympathetic neurotransmitter is acetylcholine. The major sympathetic neurotransmitter is norepinephrine. Stimulation of the parasympathetic division of the autonomic nervous system tightens airway muscles and narrows the airways, while stimulation of the sympathetic division of the autonomic nervous system relaxes airway muscles and widens the airways. Bronchodilators are available to work at either parasympathetic receptors or sympathetic receptors.

The parasympathetic bronchodilators are anticholinergic drugs, which relax airway muscles by blocking the effect of acetylcholine. The classic anticholinergic drug is atropine, but atropine gets through the blood-brain barrier and into the central nervous system where it can cause serious side effects. The anticholinergic drugs used for peripheral problems, such as COPD, are those that cannot get into the brain and thus cause fewer systemic side effects. Typical adverse effects of anticholinergic bronchodilators are pupillary dilation, blurred vision, and dry mouth (Hall & Ahmed, 2007).

Short-acting anticholinergics include ipratropium (Atrovent), the most commonly prescribed parasympathetic bronchodilator. It is relatively inexpensive and widely available. Ipratropium is usually administered via a metered-dose inhaler (MDI), although there are other formulations. Ipratropium takes effect in 15 to30 minutes, has its peak action in 1 to 2 hours, and lasts 4 to 6 hours.

Tiotropium (Spiriva) is a longer-acting anticholinergic bronchodilator. It is more expensive than ipratropium, but a typical dose lasts an entire day and studies show that it is more effective than ipratropium. Tiotropium is inhaled as a powder via a dry powder inhaler (DPI).

One class of sympathetic bronchodilators, the beta2 agonists, acts by mimicking the effect of norepinephrine on airway muscles. Beta2 agonists stimulate the beta2-adrenergic neuroreceptors and cause smooth muscles to relax; this widens airways in the lung. Muscle tremors and heart palpitations are the most common side effects of beta2 agonists, but when the medicines are inhaled (as opposed to taken in oral formulations), the side effects are usually mild.

What are beta2 adrenergic agonists? The natural hormones epinephrine and norepinephrine are secreted by the nerve endings of the sympathetic nervous system. Under sympathetic activation (fight or flight response) the heart beats faster and harder, the lung's airways widen, sugar is released into the bloodstream, and peripheral blood vessels narrow, sending more blood to central organs and muscles (Westfall & Westfall, 2006).

Chemicals other than epinephrine and norepinephrine that also mimic the actions of the sympathetic nervous system are called sympathomimetic agonists. The receptors stimulated by epinephrine and norepinephrine are called adrenergic receptors, so sympathomimetic agonists are also called adrenergic agonists. Adrenergic agonists are used primarily to treat asthma and COPD (Westfall & Westfall, 2006).

There are two types of adrenergic receptors, alpha and beta; lung airways have mainly beta2 receptors while the heart has mainly beta1 receptors. Originally, epinephrine and ephedrine were the two adrenergic agonists used as bronchodilators. Epinephrine, however, is a nonselective agonist that stimulates all adrenergic receptors; albuterol is an example of a selective beta2 adrenergic agonist. Albuterol is preferred for COPD because the bronchodilatory effect of albuterol comes with little excess stimulation of the heart (Westfall & Westfall, 2006).

Short-acting beta2 agonists include Albuterol (Accuneb, Proair, Proventil, Ventolin) and metaproterenol (Alupent); they are the most commonly prescribed sympathetic bronchodilators. These drugs are usually administered either via MDI or DPI. Short-acting beta2 agonists such as albuterol and metaproterenol take effect in 5 to 15 minutes and last for 2 to 4 hours.

Short-acting beta2 agonists are typically administered on a regular schedule to prevent dyspnea, but they are also used prn, when patients need immediate relief, or "rescue," from sudden episodes of increased dyspnea.

Long-acting beta2 agonists bronchodilators include formoterol (Foradil) and salmeterol (Serevent). These drugs are more expensive than albuterol or metaproterenol, but a typical dose lasts for at least 12 hours. Inhalation is the recommended route for administering the long-acting beta2 agonists.

Another class of sympathetic bronchodilators, the phosphodiesterase inhibitors, acts by stimulating the release of norepinephrine, which then relaxes smooth muscles in the airways of the lung. Theophylline (Elixophyllin, Theo-Dur), a relative of caffeine, is a phosphodiesterase inhibitor that will dilate airways, stimulate the respiratory centers of the brain, and improve the function of respiratory muscles.

Theophylline is taken orally and side effects are common; among them are sleeplessness and gastrointestinal upset, including nausea and vomiting. Occasionally, theophylline causes serious cardiac arrhythmias or seizures, especially when liver disease has decreased the body's ability to metabolize theophylline. Older people are more likely to get theophylline toxicity. Two newer phosphodiesterase inhibitors, cilomilast (Ariflo) and roflumilast (Daxas), appear to be safer drugs than theophylline.

Patients vary in their response to bronchodilators, and individually tailored drug regimens will be the most effective. Finding the right drug or set of drugs is empirical. When drug combinations are being tried, it is best to introduce the drugs one at a time to learn the patient's response.

Ipratropium is often the first drug tried because it lasts longer than short-acting beta2 agonists and, as an anticholinergic drug, it does not have the sympathetic drugs' side effects. Ipratropium is used on a regular schedule as a preventive measure. Patients are given short-acting beta2 agonists, however, for quick rescue from sudden episodes of increased dyspnea.

If this regimen is insufficient, combined doses of ipratropium and a short-acting beta2 agonist are a typical second-step therapy. Combined formulations of these drugs are available commercially.

As COPD progresses, most patients do better with combinations of two or three bronchodilators. In the United States and Europe theophylline (or another phosphodiesterase inhibitor) is usually the last bronchodilator to be added, but in Japan it is frequently the first drug tried.

If they are to be followed faithfully, drug regimens must be realistic. Bronchodilator therapy with two or three drugs is expensive. In addition, using inhalers can be difficult for some people, especially the elderly. Therefore, physicians may need to modify an optimal pharmacologic therapy so that it is practical for a particular patient.

Corticosteroids

Corticosteroids are two-edged swords. On the one hand, they are effective anti-inflammatory medicines and can be used to tone down the inflammatory response that underlies or exacerbates many diseases. On the other hand, the continued use of corticosteroids causes Cushing's syndrome, glaucoma, cataracts, myopathy, ulcers, osteoporosis, hyperglycemia, poor healing, and the inability to overcome infections.

In stable COPD, the problems that come from long-term use of oral (ie, systemic) corticosteroids usually outweigh the drugs' benefits. Inhaled steroids—such as fluticasone (Flovent), beclomethasone (Beclovent, Beconase) and budesonide (Pulmicort Turbuhaler)— have fewer adverse effects than oral formulations, and approximately 10% of people with COPD find that inhaled steroids reduce their airway obstruction. For this population of patients, inhaled steroids can be a useful addition to a regimen of bronchodilators.

Unfortunately, the usefulness of corticosteroid therapy cannot be predicted in advance for any one patient. At the moment, spirometrically testing a patient's response is the only way to identify those COPD patients who are helped by adding inhaled steroids to their regular regimen of bronchodilators.

In people with severe COPD, high doses of inhaled steroids can reduce the number of exacerbations and the rate of mortality. For people with severe COPD, inhaled corticosteroids are typically combined with a long-acting beta2 agonist in a regular treatment regimen (Hall & Ahmed, 2007).

Vaccinations

As protection against serious respiratory illnesses, people with COPD should get an influenza vaccination each year. During outbreaks of strains of flu not covered by the annual vaccination, people with COPD should probably receive prophylactic antiviral treatment such as amantadine (Symmetrel), rimantadine (Flumadine), oseltamivir (Tamiflu), or zanamivir (Relenza). Pneumococcal vaccinations are also recommended (Hall & Ahmed, 2007).

OXYGEN THERAPY

Supplemental oxygen improves the oxygenation of the blood and reduces the rate at which patients need to breathe. For people with COPD, supplemental oxygen also slows the rate at which muscles fatigue. These effects make it easier for patients to breathe more deeply and to exercise for longer periods of time.

On the other hand, oxygen therapy is expensive and involves special equipment. Therefore, when people with COPD can maintain a blood oxygenation level of PaO₂ >60 mm Hg (an oxygenation saturation of more than 86%), supplemental oxygen therapy is not routinely prescribed (Rich & McLaughlin, 2005; Chesnutt et al., 2008).

Continuous Oxygen

Eventually, oxygen can be a necessity. Some COPD patients cannot participate in regular exercise programs without taking extra oxygen. For other patients, the typical activities of daily living excessively deplete their blood of oxygen, and taking supplemental oxygen is necessary for these patients to carry out the basic tasks of life.

If they live long enough, all patients with COPD lose sufficient lung function that they will be hypoxemic at rest, even on an optimal regimen of regular bronchodilator treatments. For these people, continuous oxygen therapy can prolong their lives and reduce hospitalizations. When a patient's blood PaO₂ <55 mm Hg (an oxygen saturation of less than 84%) at rest, it is recommended that supplemental oxygen should be given continuously—which means, in practical terms, more than 19 hours per day.

Low-flow (2–3 liter/min) oxygen inhaled through nasal cannulas is usually sufficient to raise a COPD patient's blood PaO₂ to 65–80 mm Hg (an oxygen saturation of 88–94%). In addition to increasing survival rates by about 50%, this level of supplemental oxygen lowers the person's hematocrit toward a normal range, makes sleep easier, and improves exercise tolerance.

Home oxygen therapy is also recommended for COPD patients with heart failure, pulmonary hypertension, or erythrocytosis (ie, a hematocrit >56 %), even when their PaO₂ is >55 mm Hg. Some patients who maintain a higher level of arterial oxygen during the day drop to a PaO₂ <55 mm Hg when they sleep; for people whose hemoglobin desaturates at night, nocturnal oxygen therapy is helpful.

Home Oxygen Delivery Systems

Home oxygen can be purchased as liquid O₂ or as compressed gas, or it can be "manufactured" directly by home oxygen concentrators. The cost of continuous home oxygen therapy can currently be $500 or more per month; in many cases, Medicare will cover 80% of the cost.

A home system is usually adjusted to deliver 2 to 3 liters of oxygen per minute, and in most cases this will maintain a patient's oxygen saturation at 90% or greater. For patients who continue to have dyspnea at night, the flow rate is raised by 1 liter/min during sleep.

One goal of oxygen therapy is to allow patients to remain active. Inside the home, long tubes can connect the nasal cannulas to stationary oxygen delivery units, so patients can move around. For more freedom, and to go outdoors, patients can carry portable tanks of compressed oxygen or liquid oxygen.

Hazards

Concentrated oxygen is flammable. Patients and their families cannot smoke or use open flames near the oxygen equipment.

Air Travel

Commercial planes maintain an internal air pressure equivalent to 5000–8000 feet above sea level. For those COPD patients whose resting arterial blood oxygen concentration is low (PaO₂ <69 mm Hg) at sea level, the cabin concentration of oxygen will usually not be high enough to avoid hypoxemia. Airlines can provide supplemental oxygen, and some airlines will allow patients to bring small oxygen delivery systems with them. However, patients must make arrangements with the airline in advance.

SURGERY FOR COPD

Surgery is risky in people with severe COPD. Postoperatively, many normal patients temporarily have reduced lung volumes, rapid shallow breathing, and an impaired ability to take in oxygen and expel carbon dioxide. These routine postoperative problems add additional stress to the already compromised respiratory systems of patients with COPD. One result is that patients with severe COPD develop postoperative pneumonia 13 times more often than patients with normal lung function. (Preoperative antibiotics can reduce the high rate of postoperative pneumonia.)

Nonetheless, the lack of alternative treatments for severe COPD has led to the development of three surgical procedures that attempt to improve and prolong the lives of COPD patients. The techniques are lung transplantation, lung volume reduction surgery, and bullectomy (Gold, 2005a).

Lung Transplantation

People with severe COPD are the most common recipients of lung transplants. Candidates for lung transplantation are patients with severe COPD who have exhausted medical therapies and have life expectancies of ≤2 years. Three-quarters of COPD patients who receive lung transplants live for ≥2 years after the operation, and many of the survivors have substantially improved abilities to exercise.

Lung Volume Reduction

As noted earlier, the lungs of an emphysematous patient become hyperinflated with air spaces that contribute little to gas exchange and the resulting widened chest is difficult for the patient to expand further when attempting to inhale. By removing lung tissue around dead air space, surgery can sometimes reduce the patient's work of breathing.

In lung volume reduction surgery, 20% to 30% of the lung volume is removed from both sides of the chest. As a result, survivors can usually exercise more than they could before the surgery. Those patients who have mainly upper-lung emphysema also have an increased lifespan after this surgery. For other COPD patients, however, longevity is not increased and it may even be shortened.

The major postoperative complication of lung volume reduction surgery is significant continuing air leakage from the lungs into the chest. Operative mortality rates are from 4% to 10% in hospitals providing the procedure.

Bullectomy

Selective removal of individual large empty air spaces (bullae) can sometimes be carried out using a thoracoscope. In patients with emphysema, bullae are usually a few centimeters in diameter. Occasionally, however, bullae can be huge, taking up as much as a third of the chest space. These giant bullae squeeze the healthier lung tissue and compress the adjacent blood vessels. By removing giant bullae, the remaining lung tissue can re-expand and some of the circulation will be restored. As with lung volume reduction surgery, a major postsurgical complication of bullectomy is persistent air leakage.

Treating Acute Exacerbations

A variety of insults can cause an acute exacerbation of a patient's COPD. As a first step in counteracting the sudden worsening of their lung functions, patients are usually advised to take a pre-determined "rescue dose" of short-acting bronchodilators.

Quick Relief Medicines

Type of medicine	Generic name	Brand name	Possible side effects
Short-acting beta2-agonists: inhaled or oral Bronchodilators relax and open airways to increase the flow of air	Albuterol	ProAir HFA Proventil Proventil HFA Ventolin Volmax VoSpire ER	Faster heartbeat Headache Shaking (tremors)
	Metaproterenol	Alupent
	Pirbuterol	Maxair
	Terbutaline	Brethaire Brethine
	Bitolterol	Tornalate
	Levalbuterol	Xopenex
Note: Patients should keep their quick relief inhaler with them at all times.
Source: ALA, 2005b).

Some triggers of an acute exacerbation are emergencies. When a sudden worsening of the ability of a COPD patient to breathe is not improved by rescue therapy, the patient needs to be seen quickly by a doctor. The treating physician will check for pneumothorax, pulmonary embolism, anaphylaxis, airway obstruction, myocardial infarction, worsening congestive heart failure, or a respiratory infection such as pneumonia.

Inappropriate drugs can also trigger an acute exacerbation of COPD. For example, beta-blockers and cholinergic drugs prescribed for other reasons can produce bronchospasms, and sedatives can reduce a person's respiratory drive, which may bring on hypoxemia in COPD patients (Braithwaite & Perina, 2006).

EMERGENCY TREATMENT

Patients with the sudden onset of severe dyspnea should be evaluated as a medical emergency. They must be assured of a clear airway and they need to be checked for trauma, bleeding, shock, cardiac failure, and the inability autonomously to move air into and out of their lungs. Any of these problems need immediate treatment. An intravenous (IV) line should be established and a cardiac monitor connected. If the patient's pulse oximetry shows an oxygen saturation of <98 %, supplemental oxygen should be given. Blood chemistries, blood gases, and a chest x-ray are obtained.

ONGOING MEDICAL MANAGEMENT

When patients experiencing acute exacerbations of COPD have been stabilized, the next step is to find what triggered it. Patients with serious instabilities or decompensations are admitted to an intensive care unit and the workup takes place there. Mental confusion, cyanosis, lethargy, extreme muscle fatigue, worsening hypoxemia, respiratory acidosis, or the need for mechanical ventilation are all conditions best treated in intensive care.

While looking for the cause of an episode of decompensation, an adequate level of blood oxygen and an appropriate blood pH need to be maintained in the patient. Some patients are in good enough condition, and the cause of the episode was mild enough, that, after bronchodilators, steroids, and oxygen, the patient will improve rapidly. These patients often receive further treatment as outpatients.

Other patients' lung functioning has deteriorated sufficiently that the person needs to be supported in a hospital. For COPD patients, hospital therapy includes bronchodilator treatments, steroids, and intravenous antibiotics; if a specific infection has not been identified, antibiotics are given prophylactically. The patient's blood gases and blood chemistries are monitored and supplemental oxygen is given to maintain the PaO₂ >60 mm Hg (oxygen saturation >90 %). In severe cases, noninvasive positive pressure mechanical ventilation (also called, noninvasive ventilatory support, or NIVS) with a facemask or nasal cannulas will often improve gas exchange without having to intubate the patient.

Recovery from an acute exacerbation can take weeks to months. For those COPD patients who need to be hospitalized during an acute exacerbation, there is a 10% mortality rate.

End-Stage Care

Severe difficulty in breathing is an uncomfortable and upsetting problem to both patients and their families. Near the end of a COPD patient's life, dyspnea must be eased:

Although patients with chronic lung disease are normally encouraged to exercise to maintain their state of fitness, there comes a time when a different approach is required and the focus shifts from prolongation of life to relief of distress. When dyspnea with exertion is extreme, it may be more appropriate to restrict activity and to focus on modifying treatments such as oxygen, opiates, and anxiolytics. Palliative treatment may include partial ventilatory support or, under rare circumstances, a tracheostomy with mechanical ventilation. Such dramatic steps to relieve dyspnea must be taken with full understanding of the ramifications and complications. Some patients may choose a morphine drip to allow a comfortable death, whereas others might choose an aggressive approach focused on prolongation of life as well as relief of discomfort. It is up to the healthcare provider to help the individual patient understand these choices. (Stulbarg & Adams, 2005, p. 824)

PROGNOSIS

COPD develops quietly. Early in their disease, patients have measurable declines in their lung function before they develop symptoms. The first symptoms are usually an intermittent cough and some shortness of breath during exercise. Patients often dismiss these as temporary lung irritations or a lack of physical conditioning.

After many years, the cough becomes chronic or the spells of breathlessness become more frequent. Typically, this is the stage at which people first seek medical help. As time progresses, even with bronchodilator therapy, the patient's lung function continues to decline gradually. Occasional episodes of debilitating exacerbations become more frequent. Patients admitted to intensive care units with acute exacerbations of COPD have a mortality rate of >20 %, and when the patient is older than 65 years, the mortality rate doubles; 40% of the COPD deaths in an ICU are from pulmonary emboli.

Eventually, the dyspnea limits a COPD patient to only minimal activity. Patients are continually fatigued, they lose weight, and at some point, they succumb to a respiratory illness, pulmonary embolism, heart failure, acute respiratory failure, or lung cancer.

When the patient's FEV1 has dropped to <0.75 liters/sec (very severe COPD), there is a 30% chance that they will die within a year and a 95% chance that they will die within 10 years (Roizen & Fleisher, 2005).

PREVENTION

COPD can be almost entirely prevented by avoiding long-term inhalation of pollutants, mainly cigarette smoke. As they age, all people suffer a decline in their lung functions. Smokers who quit before developing symptoms of COPD can often reduce the decline in their lung functions to nearly normal levels within a few years of remaining smoke free (Lokke et al., 2007).

TELEPHONE COUNSELING

Health professionals who advise patients over the telephone should know straightforward answers to basic questions. Here are a few important questions and answers about COPD and smoking.

Advice and Triage Questions

ABOUT COPD

ABOUT SMOKING

Informational Questions

ABOUT COPD

ABOUT SMOKING

Posted February 18, 2008

Expires February 1, 2010

Copyright © 2008 Wild Iris Medical Education. All rights reserved.