Summary

11.1 Concepts of Oxygenation and Perfusion

• The respiratory system allows the body to breathe air and oxygenate blood. It is made up of the conducting zone and the respiratory zone.
• The lungs are protected by the ribs and sternum and are covered in protective membranes called pleurae.
• The bronchi branch off into tiny airways called bronchioles, ending in a terminal bronchiole. Terminal bronchioles meet a respiratory bronchiole, then connect to an alveolar duct. Gas exchange occurs in the alveolar sacs, at the end of the alveolar duct.
• Ventilation refers to the movement of air into and out of the lungs. During inhalation, air passes through the conducting zone and travels to the respiratory bronchiole and the alveolar sac. Carbon dioxide in the blood diffuses across the capillaries into the alveoli, leaving the body during exhalation.
• Oxygen molecules from inhaled air pass into the capillaries by diffusion. Most of the oxygen attaches itself to hemoglobin in the red blood cells so it can travel throughout the body, delivering oxygen to tissues.
• Physiologic factors that negatively affect oxygenation include hypoventilation related to decreased respiratory rate, limitations in chest wall/diaphragmatic expansion, and narrowed airways. Additionally, damaged alveoli and pulmonary capillaries, unventilated alveoli, and alveolar filling disorders can also cause inadequate oxygenation.
• Perfusion, as it relates to the respiratory system, means blood is flowing through the pulmonary capillaries. To receive oxygen, blood must be able to flow toward the alveoli, and oxygenated blood must be able to flow into the pulmonary vein so it can travel to the left side of the heart.
• When blood vessels are narrowed or blocked, blood flow decreases, and the lungs are less able to oxygenate blood.

11.2 Upper and Lower Respiratory Assessment

• Subjective assessment obtains information about the patient’s history and current symptoms.
• Initial assessment looks at the patient’s overall affect and appearance, observing for anxiety, distress, confusion, pallor, cyanosis, sweating, and ability to speak.
• Look at the patient’s posture and observe accessory muscle usage, pursed lips, and nasal flaring.
• Before using a stethoscope, note if the patient’s breathing is audible.
• Auscultation can identify adventitious lung sounds.
• A normal respiratory rate is twelve to twenty breaths per minute.
• Normal oxygen saturation (SpO₂) is 94 to 100 percent.
• Even with normal vital signs, respiratory problems can be present.
• Both hypoxemia (low blood levels of oxygen) and hypercapnia (high blood levels of carbon dioxide) can cause changes in level of consciousness, irritability, and distress.

11.3 Disorders of the Upper Respiratory System: Bronchiectasis

• Bronchiectasis is a chronic lung disease that leads to widened, damaged airways.
• The supportive structures of the bronchial wall lose elasticity and the bronchi dilates abnormally. The damage and dilation make it harder to clear mucus from the lower airways.
• Bacteria can flourish, causing a recurrent cycle of infection, inflammation, and airway damage.
• Almost all patients with bronchiectasis will have a cough.
• Bronchiectasis is diagnosed by CT scan.
• Crackles are the most common adventitious lung sound.
• Patients with bronchiectasis need to avoid environmental irritants, including smoking, secondhand smoke, and air pollution.
• Antibiotic therapy is often needed to treat an infection.
• Airway clearance therapies are necessary to help patients raise and clear phlegm.

11.4 Disorders of the Lower Respiratory System: Asthma

• Asthma is one of the most prevalent diseases in the United States.
• There are significant sex-, race-, and socioeconomic-based disparities in asthma care and outcomes.
• An asthma attack (or exacerbation) occurs when a trigger causes inflammation; this narrows the airway, causing bronchoconstriction.
• In a patient with asthma, the airways are considered hyperresponsive, meaning they narrow more than usual in response to stimuli.
• Asthma is classified into four stages (intermittent, mild, moderate, severe) based on how often symptoms occur.
• Shortness of breath, cough that is often worse at night, wheezing, and chest tightness are classic asthma symptoms.
• Pulmonary function testing confirms an asthma diagnosis.
• Bronchodilators are used to treat asthma; they work by opening narrowed airways.
• Environmental irritants can trigger asthma exacerbations.
• Patient education includes using an inhaler and peak flow meter, implementing an asthma action plan, and strategies to avoid triggers.
• Medication management may include both short- and long-acting medications.

11.5 Disorders of the Lower Respiratory System: Chronic Obstructive Pulmonary Disease

• COPD is a common chronic disease in the United States.
• Smoking is the primary risk factor for COPD.
• In patients with COPD, inflammation causes airway changes, including narrowing, smooth muscle hypertrophy, and increased mucous production.
• Problems with exhalation develop due to emphysema; alveolar walls become damaged and lose elasticity.
• Patient-reported symptoms include cough, progressive shortness of breath, and mucous production.
• Spirometry testing is used to diagnose COPD.
• Spirometry testing is also used to stage COPD; the disease can be mild, moderate, severe, or very severe.
• Medication management includes both short- and long-acting medications.
• Many patients with COPD will need to use long-term oxygen therapy.
• Vaccinations for preventable respiratory diseases are an important part of COPD management.
• Signs of an acute exacerbation include worsening cough, increased wheezing, fever with no other cause, recent upper respiratory infection, increased respiratory rate, or increased heart rate.

11.6 Disorders of the Lower Respiratory System: Pneumothorax

• COPD and smoking increase the risk of pneumothorax.
• Pneumothorax occurs when air accumulates in the pleural space, causing the lung to collapse and deflate, limiting the area available for oxygenation and ventilation.
• Patient-reported symptoms commonly include a rapid onset of dyspnea, cough, and intense chest pain that is worse with movement.
• Vital sign changes can include an increased respiratory rate, decreased oxygen saturation, and increased heart rate.
• Physical assessment findings can include unequal chest expansion and decreased or absent breath sounds.
• Pneumothorax is diagnosed with imaging, most commonly chest x-ray.
• A small pneumothorax may be asymptomatic and not require treatment.
• More substantial pneumothoraxes will require chest tube placement with connection to a specialized drainage device.
• Surgery is used to treat pneumothorax in certain patient populations.
• If there is an open chest wound from a penetrating trauma, the nurse must be prepared to apply a three-sided occlusive dressing.
• A tension pneumothorax occurs when a large volume of air enters the pleural space, causing a major amount of lung collapse and forcing the heart and trachea to shift.
• Tension pneumothorax is treated with immediate needle decompression.
• Treatment of pneumothorax is often painful; pain assessment and management are necessary.
• Patient education includes information about the treatment plan, mobility restrictions related to procedures or inserted tubes, and pain management.

11.7 Disorders of the Lower Respiratory System: Pneumonia and Aspiration

• Pneumonia occurs when infection occurs in the lungs and tissues become inflamed.
• Pneumonia can be caused by bacteria, a virus, or a fungus.
• Community-acquired pneumonia is common; hospital-acquired and ventilator-acquired pneumonia can also occur.
• Typical symptoms include cough, fever, and fatigue.
• Patients with COPD have the highest risk of hospitalization for pneumonia.
• Other high-risk diagnoses include heart disease, diabetes, smoking, alcohol and opioid use, and immunosuppression.
• Imaging, usually chest x-ray, is used for conclusive diagnosis.
• Sputum cultures and viral testing can identify the responsible organism.
• Treatment may involve antibiotics, antivirals, or antifungal medications.
• Ongoing assessment of a patient’s respiratory effort, observing for signs of labored breathing, is a key nursing task.
• In serious cases, supplemental oxygen, including noninvasive ventilation or a ventilator, may be necessary.
• Patient education topics may include medication management, oxygen therapy, vaccines, and ventilatory support.
• In cases of aspiration pneumonia, patient education will often center around safe swallowing techniques.

11.8 Disorders of the Lower Respiratory System: Tuberculosis

• While TB is relatively rare in the United States, the global burden of disease is immense.
• TB is a highly contagious airborne illness.
• Immunocompromise increases the risk of infection and serious disease.
• Common symptoms include fever, cough, night sweats, weight loss, fatigue, chills, decreased appetite, shortness of breath, and pleuritic chest pain.
• Diagnostic evaluation of a patient with suspected TB may include a blood or skin test and imaging. A conclusive diagnosis can only be made, however, by examining a sputum sample for the presence of tubercle bacilli.
• Because TB is an airborne illness, infection prevention is a high priority.
• Patients should ideally be placed in a private, negative airflow room. Staff PPE should include a respirator that has been fit tested for everyone.
• TB generally requires a six-month treatment course of antibiotics. Incomplete treatment can result in ongoing infection and antibiotic resistance.

11.9 Disorders of the Lower Respiratory System: Cystic Fibrosis

• CF is an inherited genetic disorder that affects about one in 3,500 births in the United States.
• Most patients are diagnosed in infancy; virtually all are diagnosed prior to age two.
• The gene mutation impairs the movement of sodium and chloride ions across cell membranes, causing thick mucus to build up in the lungs and throughout the body.
• CF is conclusively diagnosed using a sweat test; it will show elevated levels of sodium and chloride.
• Because of treatment advances, the average life expectancy of a person with CF has increased to the age of forty.
• Antibiotics are commonly used to treat exacerbations; some patients will require prophylactic antibiotics.
• Inhaled medications and airway clearance techniques are used to help patients raise thick mucus.
• Many patients with CF will have pancreatic insufficiency, so supplementation with pancreatic enzymes is necessary.

11.10 Effects of Smoking, Vaping, and Environmental Triggers of the Respiratory System

• Cigarette smoking is a major cause of preventable morbidity and mortality worldwide.
• Vaping, or e-cigarette usage, involves heating a liquid to a high temperature; particles become a fine vapor, which is inhaled. Many of the inhaled components are damaging to lung tissue.
• There are many environmental and occupational triggers for respiratory disease.
• Most environmentally triggered respiratory diseases are not curable.
• Personal protective equipment can mitigate the risk of occupationally triggered respiratory diseases if available and used properly.
• Coaching and patient education around smoking cessation is a complex, challenging, high-priority intervention.