Pathophysiological Concepts Chapter 27: Alterations of the Pulmonary System

General Respiratory Disorders

• Cyanosis: A bluish discoloration indicating severe hypoxemia; typically not present in adults until significant hypoxemia arises.
• Clubbing of the Fingers: Enlarged tips of digits often associated with conditions like cystic fibrosis, lung abscesses, and congenital heart disease.
• Localized Chest Pain: Pain can originate from chest wall infections or inflammation affecting the pleura, which can present as pleural friction rub; assess for cardiac events when patients present with chest pain.

Hypercapnia

• Definition: Increased CO2 levels in arterial blood due to hypoventilation, leading to respiratory acidosis.
• Causes:
  • Prescription medications depressing the respiratory center.
  • Central nervous system changes and thoracic cage abnormalities.
  • Airway obstructions or decreased ability to ventilate, prevalent in emphysema.
• Treatment: Address underlying causes of hypoventilation.

Hypoxemia

• Definition: Decreased oxygenation in arterial blood, distinct from hypoxia which refers to less oxygen in tissues.
• Causes: Issues with oxygen delivery, diffusion from alveoli into blood, or pulmonary capillary perfusion.
• Ventilation/Perfusion (V/Q) Mismatch:
  • Very low V/Q indicates shunting caused by atelectasis or pneumonia.
  • High V/Q results in inadequate perfusion in well-ventilated areas, known as dead space linked with pulmonary embolism.

Respiratory Failure

• Definition: Inadequate gas exchange in respiratory system.
• Causes: Direct lung injury, spinal or brain injuries, surgical complications, or opioid overdoses.
• Treatment Options:
  • Ventilatory support for hypercapnia.
  • Supplemental oxygen for hypoxemia.
  • Narcan/Naloxone for opioid overdose management.

Postoperative Complications

• Potential Issues:
  • Atelectasis, pneumonia, pulmonary edema, and pulmonary emboli.
• Prevention Strategies:
  • Frequent repositioning, deep-breathing exercises with incentive spirometry, and early mobilization.

Chest Wall Restriction

• Causes: Deformities, trauma, immobilization, or obesity affecting breathing mechanics.
• Consequences: Increased work of breathing (WOB) and decreased tidal volume leading to hypoventilation.
• Flail Chest: A severe condition from multiple rib fractures causing unstable chest wall movement during respiration.

Pneumothorax

• Definition: Air in the pleural space, causing lung collapse due to loss of negative pressure.
• Types:
  • Primary (spontaneous) occurs without an apparent cause.
  • Secondary arises from an underlying lung condition.

Pulmonary Fibrosis

• Definition: Excessive fibrous tissue formation in lungs leading to scarring.
• Idiopathic Pulmonary Fibrosis (IPF): A type with no known cause.
• Symptoms: Dyspnea on exertion and inspiratory crackles.
• Treatment Options: Use of oxygen, corticosteroids, cytotoxic medications, and potential lung transplant.

Pulmonary Edema

• Definition: Excess fluid in lungs, typically due to left-sided heart disease.
• Symptoms: Dyspnea, hypoxemia, increased WOB, and frothy sputum in severe cases.
• Treatment: Depends on the cause; potential use of diuretics and supplemental oxygen.

Acute Lung Injury/Acute Respiratory Distress Syndrome (ALI/ARDS)

• Origin: Caused by sepsis, trauma, or other injuries leading to alveolocapillary damage.
• Clinical Manifestations: Progressive symptoms from dyspnea and hypoxia to respiratory failure and metabolic acidosis.
• Diagnosis: Via patient history, physical exam, ABG analysis, and chest X-ray.
• Treatment: Supportive care focusing on oxygenation, ventilation, and complication prevention.

Restrictive Lung Diseases

• Bronchiectasis: Characterized by chronic inflammation and dilation of bronchi, leading to productive cough.
• Bronchiolitis: Inflammation of small airways, primarily affecting children; symptoms include fever and increased respiratory rate.
• Pneumoconiosis: Lung damage from inhaling inorganic particles, typically requiring palliative care.

Obstructive Lung Disease

• Characteristics: Airway obstruction more pronounced during expiration, requiring more effort for expiration, leading to dyspnea and wheezing.
• Common Disorders: Include asthma and COPD, which encompasses both chronic bronchitis and emphysema.

Asthma

• Definition: Chronic inflammatory disorder causing airway constriction and reversible airflow obstruction.
• Pathophysiology: Inflammation leads to bronchoconstriction, impaired expiration, and respiratory complications like hypoxemia.
• Symptoms: Include wheezing and dyspnea, with a focus on avoidance of allergens and use of inhalers for management.

Chronic Obstructive Pulmonary Disease (COPD)

• Definition: A progressive condition characterized by airflow limitation caused by chronic inflammation, including bronchitis and emphysema.
• Manifestations: Symptoms include productive cough, dyspnea, and chronic hypoventilation.
• Management: Use of bronchodilators, corticosteroids, and education about disease progression and symptom management.

Respiratory Tract Infections

• Divisions: Upper respiratory tract infections (e.g., common cold) and lower respiratory tract infections (e.g., pneumonia).
• Acute Bronchitis: Inflammation of airways, typically viral, presenting with symptoms likened to pneumonia, but without pulmonary consolidation.
• Pneumonia: Bacterial or viral infection of lower lungs, distinguished by various classifications and commonly arises from aspiration. Symptoms include cough, fever, and crackles.