Pneumothorax Study Notes

PNEUMOTHORAX

Anatomic Alterations of the Lung

  • Lung Collapse: Refers to the condition where part or all of the lung has shut down and is not capable of gas exchange.

  • Visceral and Parietal Pleura Separation: The visceral pleura covers the lungs, while the parietal pleura lines the chest cavity. In pneumothorax, space or air accumulates between these two layers, leading to separation.

  • Atelectasis: The complete or partial collapse of a lung or lobe of a lung. This can occur due to pneumothorax as air in the pleural space prevents the lung from expanding fully.

  • Chest Wall Expansion: Refers to the ability of the thoracic cage to expand during inhalation. The presence of air in the pleural cavity compromises this process.

  • Compression of the Great Veins and Decreased Cardiac Venous Return: The build-up of pressure from air in the pleural space can compress the major veins returning blood to the heart, decreasing cardiac output.

Definition

  • Pneumothorax: A collection of air or gas in the chest or pleural space that causes part or all of the lung to collapse.
      - Mechanics: Normally, the pressure in the lungs is greater than in the pleural space. When pneumothorax occurs, this pressure dynamic is reversed, leading to lung collapse.

Pathology

  • Typically, a pneumothorax causes only partial lung collapse.

  • If the collapse is sufficient, it can lead to:
      - Decreased oxygen levels in the blood, causing dyspnea.
      - Potentially rapid progression to severe cardiovascular impairment.

Etiology

  • Gas Entry into Pleural Space: There are three primary ways that gas can enter:
      - From the Lungs: Through perforation of the visceral pleura.
      - From the Atmosphere: Through perforation of the chest wall and parietal pleura or, in rare cases, via esophageal fistula or perforation of an abdominal viscus.
      - From Gas-forming Microorganisms: This can occur in an empyema within the pleural space, though it is considered rare.

Fist-and-Balloon Analogy

  • This analogy illustrates the relationship between the two pleura and the pleural space.
      - Outer Balloon Wall: Represents the parietal serous membrane.
      - Inner Balloon Wall: Represents the visceral serous membrane.
      - Cavity (Fist): Represents the pleural cavity where air can accumulate in pneumothorax.

Classifications of Pneumothorax

  • Closed Pneumothorax: Gas in the pleural space is not in direct contact with the atmosphere.

  • Open Pneumothorax: The pleural space is in direct contact with the atmosphere, allowing gas to move freely (also called a sucking chest).

  • Tension Pneumothorax: The intrapleural pressure exceeds intraalveolar pressure or atmospheric pressure, resulting in severe physiological changes.

Pneumothorax Classifications Based on Origin

  • Causes:
      - Ruptured Blebs: Common in patients with COPD leading to air leaks.
      - Thoracentesis: A procedure that can inadvertently introduce air into the pleural space.
      - Trauma: Can cause both spontaneous and traumatic pneumothorax.
      - Secondary Infection: Pneumothorax can arise from infections such as pneumonia or tuberculosis (TB).

  • Types:
      - Spontaneous Pneumothorax: Occurs without an external cause, often in young, thin individuals aged 15-40.
      - Traumatic Pneumothorax: Due to penetrating wounds or accidents where the chest wall is breached.
      - Iatrogenic Pneumothorax: Associated with medical procedures like lung biopsies or mechanical ventilation.

Signs and Symptoms/Diagnosing

  • Common signs and symptoms include:
      - Dyspnea: Shortness of breath.
      - Anxiety: Psychological impact due to difficulty breathing.
      - Tachycardia: Increased heart rate as a compensatory mechanism.
      - Pleural Pain: Sharp pain on the affected side.
      - Asymmetrical Chest Wall Expansion: Observed during physical examination.
      - Breath Sounds: Diminished or absent on the affected side.

Diagnosis Procedures

  • Chest X-Ray: Used to visualize the presence of air in the pleural space.

  • Arterial Blood Gases (ABG): To assess oxygenation and carbon dioxide levels in the blood.

Spontaneous Pneumothorax

  • Can occur due to ruptured congenital blebs on the visceral pleura acting as a check valve.

  • Associated with lung diseases like COPD, pneumonia, and TB.

  • Frequently occurs in tall, thin individuals aged 15-35 or 20-40 years old.

Traumatic Pneumothorax

  • Result from penetrating wounds, automobile, or industrial accidents.

  • Characterized by a one-way ball valve effect where air enters but does not exit the pleural space on exhalation.

  • This increases pressure in the pleural cavity, making it dangerous.

Tension Pneumothorax

  • A severe situation where air cannot escape the pleural cavity.

  • Results in increased intrathoracic pressure leading to:
      - Compression of the lungs and trachea, pushing them towards the unaffected side (mediastinal shift).
      - Can become life-threatening without prompt intervention.

Iatrogenic Pneumothorax

  • Often occurs due to medical procedures, including:
      - Pleural Biopsy and Thoracentesis: Procedures that intentionally penetrate the chest wall.
      - Intercostal Nerve Blocks and Cannulation of the Subclavian Vein. Also a risk during Tracheostomy.

  • Particularly dangerous in patients on mechanical ventilation.

Signs and Symptoms of Tension Pneumothorax

  • Severe manifestations relative to standard pneumothorax:
      - Deviation of the trachea towards the unaffected side.
      - On chest X-ray: one side shows complete radiolucency while the opposite side shows compression of lung and heart.

Clinical Data

  • Due to decreased alveolar ventilation, the V/Q (ventilation/perfusion) ratio decreases:
      - Atelectasis results in pulmonary shunting.
      - Increased central venous pressure (CVP) and pulmonary artery pressure (PAP).
      - Decreased pulmonary capillary wedge pressure (PCWP) and cardiac output (CO).

Diagnosis Procedures

  • Chest Assessment:
      - Hyperresonant percussion note over the pneumothorax area.
      - Decreased breath sounds noted.
      - Displaced heart sounds towards the unaffected side.
      - Increased thoracic volume on affected side detected upon physical examination.

  • Pulmonary Function Test (PFT): Indicate restrictive lung pathology with decreased values.

  • Chest X-ray: Exhibits increased translucency on the affected side, decreased vascular markings, and potential atelectasis.

  • ABG Analysis: Demonstrate acute alveolar hyperventilation with associated hypoxemia.

Radiological Findings

  • Chest Radiograph Specifics:
      - Increased translucency on the pneumothorax side.
      - Mediastinal shift towards the unaffected side in cases of tension pneumothorax.
      - Depressed diaphragm is also present.

Clinical Questions

  1. Pneumothorax occurs when free air accumulates in the:
       - A. pericardial space
       - B. mediastinal space
       - C. peritoneal space
       - D. pleural space

  2. The significant pathologic structural changes associated with a pneumothorax include:
       - A. pulmonary edema
       - B. atelectasis
       - C. lung collapse
       - D. chest wall expansion

  3. The most serious type of pneumothorax is:
       - A. spontaneous
       - B. tension
       - C. open
       - D. closed

  4. When a patient suffers from a gunshot to the chest with a hole in the chest wall, this condition is classified as:
       - A. closed
       - B. iatrogenic
       - C. tension
       - D. open

Signs and Symptoms

  • Common symptoms include:
      - Chest Pain: Sharp or stabbing sensation.
      - Shortness of Breath: Difficulty breathing.
      - Cyanosis: Bluish discoloration due to oxygen deprivation.
      - Chest Tightness: Sensation of pressure.
      - Easy Fatigue: Increased tiredness due to compromised gas exchange.
      - Rapid Heart Rate: Heart compensates for reduced oxygen levels.
      - Nasal Flaring: Enhanced respiratory effort.
      - Hyperresonant Percussion: Due to trapped gas in the pleural space.
      - Diminished Breath Sounds: Indicative of affected lung.
      - Possible Tracheal Shift: Movement of the trachea to the unaffected side.

Percussion Sounds

  • The accumulation of gas in a pneumothorax leads to a hyperresonant percussion note during examination due to the increased ratio of extrapulmonary gas to solid tissue.

Management and Treatment

  • Small pneumothorax (less than 15-20%) may resolve with:
      - Rest or Limited Activity: May require observation as spontaneous resolution can occur within 30 days.

  • Larger pneumothorax should be managed with:
      - Chest Tube Insertion: To evacuate air and allow lung re-expansion.
      - Needle Aspiration: May be necessary if the patient is unstable.

Procedure Specifics

  • To Drain Air from Pleural Space:
      - Insert large bore needle at the second intercostal space along the midclavicular line.

  • To Drain Fluid:
      - Tube is inserted in the fifth to seventh intercostal space along the mid axillary line.

Chest Tube Management

  • Suction:
      - Typically does not require more than -12 cm H2O; -5 cm H2O is usually sufficient.

  • Post Lung Re-expansion:
      - Once lung inflation is achieved, keep the chest tube in without suction for 24-48 hours.

Pleurodesis

  • Definition: A procedure involving the injection of chemicals or medications into the chest cavity to produce an inflammatory reaction that causes the lung to adhere to the chest wall.

  • Agents Used:
      - Talc
      - Tetracycline
      - Bleomycin sulfate

Preventive Measures

  • While no definitive prevention exists for pneumothorax, risk can be minimized by:
      - Avoiding Smoking: Smoking cessation helps improve overall lung health.
      - Use of Seatbelts: To prevent trauma-related pneumothorax in accidents.
      - Awareness of Lung Diseases: Those with lung conditions should be monitored closely.
      - Avoiding Extreme Pressure Changes: Particularly important for individuals at risk (e.g., divers, aviators).

RT Treatment Protocols

  • Treatment Approaches Includes:
      - Oxygen Therapy Protocol.
      - Lung Expansion Therapy Protocol.
      - Mechanical Ventilation Protocol.

More Practice Questions

  1. Management options for a patient with a pneumothorax may include:
       - A. 1, 2
       - B. 3, 4
       - C. 2, 3, 4
       - D. 1, 2, 3, 4

  2. A patient has a chest x-ray showing a 25% pneumothorax of the left lung. Recommended action is:
       - A. Remove air via needle in right pleural space
       - B. Provide supplemental oxygen and hyperinflation therapy
       - C. Remove air through chest tube in left pleural space
       - D. Place bilateral pleural chest tubes to equalize lung pressures