Alterations of Pulmonary Function

• Alterations in pulmonary function and related signs and symptoms are essential for understanding pulmonary diseases.

Signs and Symptoms of Pulmonary Disease

• Dyspnea is the subjective experience of breathing discomfort.
• Orthopnea is dyspnea that occurs when a person is lying down.
• Paroxysmal nocturnal dyspnea (PND) occurs suddenly during sleep.
• Coughs can be acute or chronic.
• Abnormal sputum can indicate infection or disease.
• Hemoptysis is coughing up blood.
• Kussmaul respiration (hyperpnea) and Cheyne-Stokes respiration are abnormal breathing patterns.
• Hypoventilation leads to hypercapnia.
• Hyperventilation leads to hypocapnia.
• Cyanosis is a bluish discoloration of the skin due to poor oxygenation.
• Clubbing is the bulbous enlargement of the distal segments of the fingers or toes.
• Pain is a common symptom of pulmonary disease

Conditions Caused by Pulmonary Disease or Injury

• Hypercapnia is increased carbon dioxide in arterial blood.
• Hypoxemia is reduced oxygenation of arterial blood, while hypoxia refers to reduced oxygen at the tissue level.
• Ventilation-perfusion abnormalities, including shunting, can result in hypoxemia.
• Acute respiratory failure is inadequate gas exchange

Chest Wall Disorders

• Chest wall restriction indicates compromised chest wall movement
• This can be caused by deformation, immobilization, and/or obesity.
• Flail chest is instability of a portion of the chest wall which is caused by the fracture of several ribs +/- sternum

Pleural Abnormalities

• Pneumothorax: Refers to air in the pleural space, which can be open, tension, spontaneous (primary), or secondary.
• Pleural effusion: The presence of fluid in the pleural space.
  • Transudative effusion is watery fluid that diffuses out of the capillaries.
  • Exudative effusion is fluid with high concentrations of white blood cells and proteins.
  • Hemothorax is blood in the pleural space.
  • Empyema is infected pleural effusion containing pus.
  • Chylothorax is the presence of chyle in the pleural space.

Pulmonary Disorders

• Restrictive Lung Diseases: These diseases limit lung expansion.
  • Aspiration is the passage of fluid and solid particles into the lungs.
  • Atelectasis is the collapse of lung tissue.
    • This can occur due to compression, absorption, or surfactant impairment.
  • Bronchiectasis is persistent abnormal dilation of the bronchi.
  • Bronchiolitis is inflammatory obstruction of the small airways that's common in children, or adults with chronic bronchitis and viral infection.
  • Pulmonary fibrosis leads to Idiopathic Pulmonary Fibrosis (IPF).
• Inhalation Disorders: Caused by inhalation of harmful substances.
  • Toxic gases can lead to lung damage.
  • Pneumoconiosis is caused by inhalation of dusts like silica, asbestos, and coal.
  • Allergic alveolitis (hypersensitivity pneumonitis) results from an allergic reaction to inhaled particles or fumes and can be extrinsic.
• Pulmonary edema is excess fluid in the lungs
• Acute Lung Injury (ALI)/Acute Respiratory Distress Syndrome (ARDS) is characterized by acute lung inflammation and diffuse alveolocapillary injury.
  • Injury and inflammation to the alveocapillary membrane can cause pulmonary edema.
  • Its phases are exudative, proliferative, fibrotic.
  • Manifestations include dyspnea, hypoxemia, hyperventilation, respiratory alkalosis, decreased tissue perfusion and tidal volume, metabolic acidosis, organ dysfunction, hypercapnia, respiratory acidosis, respiratory failure, decreased cardiac output, hypotension, and death.
  • Diagnosis is based on history of lung injury, physical examination, analysis of blood gases, and radiological examination; supportive therapy is used.
• ARDS and COVID-19: Severe COVID-19 can manifest as viral pneumonia-induced ARDS, with advanced age as a significant risk factor.
  • Postmortem studies reveal that COVID-induced ARDS cases exhibit undetectable viral loads.
  • Cytotoxic effects of virus are not the main cause of death; it is the host's failure to deactivate/modulate inflammation for lung tissue repair.
• Vaping and Lung Injury: Electronic cigarettes were promoted as a safer alternative to tobacco, but recent evidence has associated it with lung injury

Pulmonary Disorders - Obstructive Lung Diseases

• Obstructive lung diseases involve airway obstruction that worsens with expiration.
• Common signs and symptoms include dyspnea and wheezing.
• Common obstructive disorders are asthma, COPD, emphysema, and chronic bronchitis.
• Asthma is a chronic inflammatory disorder of the airways with hyper-responsiveness
  • It can lead to obstruction and status asthmaticus.
  • Symptoms include expiratory wheezing, dyspnea, and tachypnea.
  • The disorder is treated using peak flow meters, corticosteroids, beta-agonists, and anti-inflammatories.
• COPD stands for chronic obstructive pulmonary disease.
  • It is characterized by persistent airflow limitation that is usually progressive.
  • It is the most common chronic lung disease in the world
  • It's risk factors include tobacco smoke, occupational dusts/chemicals, air pollution, and factors affecting lung growth during gestation/childhood
• Obstructive Lung Diseases: Chronic Bronchitis
  • Hypersecretion of mucus and chronic productive cough must last for at least 3 months of the year and for at least 2 consecutive years to classify as chronic.
  • Inspired irritants will increase mucus production and both the size and number of mucous glands.
    • Mucus is thicker than normal.
  • Bronchodilators, expectorants, and chest physiotherapy are used to treat the disease.
• Obstructive Lung Diseases: Emphysema
  • There is abnormal permanent enlargement of the gas-exchange airways accompanied by destruction of alveolar walls without obvious fibrosis.
  • An inherited deficit of a₁-antitrypsin will result in the reduction of any elastic recoil from the alveoli.
• Respiratory tract infections: acute bronchitis.
  • It commonly follows a viral illness.
  • Acute bronchitis causes symptoms similar to those of pneumonia, but does not demonstrate pulmonary consolidation and chest infiltrates
• Respiratory tract infections: pneumonia
  • Types of pneumonia include health care-acquired (HCAP), community-acquired (CAP), hospital-acquired (HAP), and ventilator-associated (VAP).
  • It is caused by bacteria, viruses, fungi, protozoa, or parasites.
  • Pneumococcal pneumonia is most common and most lethal, causing an intense inflammatory response.
  • Viral pneumonia is seasonal, usually self-limiting, and often preceded by a viral URI
• Respiratory tract infections: tuberculosis
  • Mycobacterium tuberculosis is an acid-fast bacillus transmitted through the air that can cause tubercle formation and caseous necrosis
  • Diagnosis via positive tuberculin skin test (PPD).
• Abscess formation and cavitation:
  • It causes consolidation and the forming of abscesses.
• Pulmonary vascular disorders: pulmonary embolus.
  • Emboli commonly arise from the deep veins in the lower leg.
• Pulmonary embolus occludes a portion of the pulmonary vascular bed which can be attributed to many things.
  • This includes a thrombus, embolus, tissue fragment, or lipids. Virchow triad is comprised of venous stasis, hypercoagulability, and injuries to the endothelial cells that line the vessels.
• Pulmonary vascular disorders: pulmonary artery hypertension (PAH)
  • Mean pulmonary artery pressure is >25 mm Hg at rest
  • Idiopathic pulmonary arterial hypertension (IPAH) has unclear multifactorial mechanisms. Diseases of the respiratory system and hypoxemia are more common causes
• PAH classifications have no known cause or are associated with inheritance, medications, or toxins.
  • This includes any connective tissue disease or infection. Attributable to left ventricular disease Caused by chronic lung disease or hypoxia, or both Includes chronic thromboembolic pulmonary hypertension It can be caused by other multifactorial mechanisms including blood, metabolic, and systemic disorders
• Pulmonary vascular disorders: cor pulmonale
  • It is of pulmonary heart disease.
  • This involves right ventricular enlargement secondary to pulmonary hypertension.
• Pulmonary hypertension creates chronic pressure overload in the right ventricle.
• Malignancies of the respiratory tract include laryngeal cancers
  • There are different forms including carcinoma of the true vocal cords (most common), supraglottic, and subglottic(rare).
• The lung (bronchogenic) is a leading cause of cancer death in Canada. Environment and occupational risk factors can be environmental. The most common cause being cigarette smoking
• Lung - Types:
  • Non-small cell cancer, Squamous cell carcinoma, Adenocarcinoma large cell carcinoma, Large cell carcinoma
  • Small cell (oat cell) carcinoma-from neuroendocrine tissue