Chapter 18 Clinical Exemplar

CLINICAL EXEMPLARS

There are multiple conditions that contribute to impaired gas exchange—more than are described in this text. Box 18.3 lists common conditions associated with impaired gas exchange across the lifespan; further details about these conditions can be found in medical–surgical and pediatric nursing textbooks.

Featured Exemplars

Asthma

Asthma is a chronic disorder characterized by periods of reversible airflow obstruction. These asthma attacks are caused by hyperreactive airways leading to contraction of the muscles surrounding the airways and inflamed airways. Patients experience wheezing, coughing, dyspnea, and chest tightness. Factors involved in the development of asthma include genetics, inhalation of airborne allergens or pollutants, airway infections, exercise, or emotional stress. Asthma can be controlled with medications and avoidance of triggers for asthma attacks. Prevalence for adults is higher among females, people 20 to 24 years old, and multirace and American Indian or Alaska Native persons. Among children, prevalence is higher among males, children 5 to 14 years old, and multirace and Black persons.12

Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease is characterized by chronic airflow limitation that is not fully reversible. Chronic obstructive pulmonary disease includes two obstructive airway diseases: chronic bronchitis and emphysema. Chronic bronchitis develops when hypersecretion of mucus obstructs the trachea and bronchi, caused by irritants such as cigarette smoke, air pollution, or respiratory infection. Symptoms are productive cough and dyspnea on exertion.2 Emphysema develops when the alveolar walls are destroyed leading to permanent abnormal enlargement. The most common cause is cigarette smoking. Patients with emphysema are often underweight, with a barrel chest, and become short of breath with minimal exertion.5 Chronic obstructive pulmonary disease is typically diagnosed in adults approximately 50 years of age after a long history of smoking. It is the third leading cause of death by disease in the United States.13

Lung Cancer

Lung cancer is an uncontrolled growth of anaplastic cells in the lung tissue. Common causes include cigarette smoke, pipe and cigar smoke, exposure to radon gas, and occupational and environmental exposures such as secondhand smoke, asbestos, radiation, and air pollution. Cigarette smoking is by far the most important risk factor for lung cancer. The most common initial symptom is persistent cough, but other complaints include chest pain, productive cough, dyspnea, and recurrent lung infections. Lung cancer remains the leading cause of cancer-related deaths in the United States. Incidence and mortality rates have steadily declined since 2000, attributed to reductions in smoking.14

Pneumonia

An inflammation of terminal bronchioles and alveoli results in pneumonia. Microorganisms are the most frequent causes. Viral pneumonia tends to produce a nonproductive cough or clear sputum, whereas bacterial pneumonia causes a productive cough of white, yellow, or green sputum. Other manifestations include fever, chills, dyspnea, fatigue, and sharp or stabbing chest pain upon inspiration.15 Rhonchi or crackles may be heard on auscultation. Children may experience retractions and nasal flaring. Viral pneumonias occur more frequently than bacterial pneumonia in children of all ages.3 Older adults with pneumonia may experience confusion.15

Coronavirus (COVID-19)

Most individuals afflicted with COVID-19, a viral infection, will experience mild to moderate effects on the respiratory system. Individuals with COVID-19 may experience a cough, fatigue, and shortness of breath or difficulty breathing, all of which can impede gas exchange.16 Most individuals recover without specialized treatments. Those with chronic respiratory disease are vulnerable to develop serious illness potentially leading to coronavirus pneumonia and acute respiratory distress syndrome, associated with a high mortality rate.17 Long-term effects of COVID-19 (known as Long Covid) can cause gas exchange impairment lasting for months or even years. Specifically, many of individuals with Long Covid have less exercise capacity and more radiologic abnormalities, even after their recovery from COVID-19 pneumonia.18

Anemia

Oxygen moves from the alveoli to the cells attached to erythrocytes. When erythrocytes are in short supply, which occurs in anemia, oxygenation is less than optimal. Anemia is caused by disorders that interfere with the formation of erythrocytes (aplastic anemia, folic acid deficiency, iron deficiency, pernicious anemia, and thalassemia), premature destruction of erythrocytes (sickle cell anemia), and loss of erythrocytes (hemolytic anemia). Despite the cause, common manifestations that occur in all anemias include weakness, fatigue, pallor, exertional dyspnea, dizziness, and lethargy.1 Vitamin B12 deficiency may occur in 12% of older people because of inadequate dietary intake or malabsorption from low stomach acid.5

Pulmonary Emboli

A blockage of pulmonary arteries by a thrombus, fat or air embolism, or tumor tissue creates a pulmonary embolism. The embolus travels with blood flow through smaller blood vessels until it obstructs perfusion of alveoli. Manifestations are nonspecific, making diagnosis difficult. The classic triad of dyspnea, chest pain, and hemoptysis occurs in approximately 20% of patients. Hypoxemia with low arterial carbon dioxide is a common finding. Most emboli arise from deep vein thromboses in the legs. Venous thromboembolism is the preferred terminology to describe the spectrum of pathology from deep vein thrombosis to pulmonary embolism. The highest rate of deep vein thrombosis is seen in patients with prolonged bed rest.