Pneumothorax

Overview of Pneumothorax and Hemothorax

• A pneumothorax is defined as the collection of air within the pleural cavity.

• It occurs when air leaks from the lung into the space between the parietal and visceral pleura in the chest.

• The resulting accumulation of air exerts pressure on the lung, leading to lung collapse.

• A pneumothorax is a potentially life-threatening condition requiring immediate medical intervention.

• A hemothorax, often discussed alongside pneumothorax, involves the accumulation of blood within the pleural space.

Pathophysiology

• The development of a pneumothorax alters the pressure gradient within the thorax.

• In a normal physiological state, the pressure gradient within the pleural space is negative relative to the atmospheric pressure.

• As the chest wall expands outward, the surface tension between the parietal and visceral pleura causes the lungs to also expand.

• Maintaining this negative pressure in the pleural space is essential for lung inflation.

• When the pleura is breached, air enters the pleural space, cause the lung to decrease in size, a process commonly referred to as collapsing.

• The collapse leads to a decrease in oxygen partial pressure.

• Air can enter the pleural space through two primary routes:

  • Trauma to the chest wall.

  • Rupture of the visceral pleura, allowing air to leak from the lung.

Classifications of Pneumothorax

• Traumatic Pneumothorax: This results from blunt or penetrating trauma, such as a rib fracture, a stab wound, or a gunshot wound. The trauma creates a one-way valve in the pleural space, allowing air to flow in while trapping it so it cannot flow out.

• Open Pneumothorax: A subset of traumatic pneumothorax where a chest wound is large enough to allow air to pass freely into the thoracic cavity. This is often accompanied by a "sucking" sound as air moves through the chest wall, leading to the term "sucking chest wound."

• Iatrogenic Pneumothorax: A type of traumatic pneumothorax caused by medical diagnostic or therapeutic procedures. Examples include:

  • Thoracentesis.

  • Pleural biopsy.

  • Central line placement.

  • Mechanical ventilation.

  • Thoracoscopy.

• Primary Spontaneous Pneumothorax (PSP): Occurs automatically without any contributory conditions or clinically apparent underlying lung disease.

  • It typically occurs due to the rupture of asymptomatic blebs or bullae (blister-like structures) on the lung surface.

  • When a bleb ruptures, it creates an opening for air to move from the lung into the pleural space.

  • Lung inflammation and oxidative stress are common findings in PSP.

• Secondary Spontaneous Pneumothorax (SSP): Occurs as a complication of an underlying pulmonary disease.

• Tension Pneumothorax: A life-threatening condition characterized by air entering the chest cavity and becoming trapped with no means of escape.

  • Positive pressure (tension) increases with every breath.

  • This leads to total lung collapse and a mediastinal shift, where the heart and great vessels are pushed toward the unaffected side.

  • The increased intrathoracic pressure decreases cardiac output and peripheral circulation, compromising both respiration and circulation.

Etiology and Risk Factors

• Risk Factors for Primary Spontaneous Pneumothorax (PSP):

  • Smoking (both tobacco and cannabis).

  • Body Type: Being taller and thinner than average. The height factor is associated with more significant negative pressure occurring at the apex of the lung.

  • Gender: More common in males.

  • Family history of pneumothorax.

  • Other conditions: Pregnancy and Marfan syndrome.

  • Genetic predisposition.

• Risk Factors for Secondary Spontaneous Pneumothorax (SSP):

  • Smoking: Smokers are $102$ times more likely to experience SSP than non-smokers.

  • Underlying diseases: Chronic Obstructive Pulmonary Disease (COPD), Tuberculosis (TB), sarcoidosis, cystic fibrosis, or malignancy.

  • Atmospheric pressure: Drops in pressure, such as those experienced during mountain climbing or moving between different pressure areas without proper acclimatization.

• Specific Causes of Traumatic Pneumothorax:

  • Rib fractures.

  • Blunt trauma to the chest.

  • Flying or diving (changes in pressure).

• Specific Causes of Tension Pneumothorax:

  • Blunt trauma to the chest.

  • Barotrauma.

  • Positive pressure ventilation.

  • Tracheostomy injury.

  • Occlusive dressings on an open pneumothorax that act as a one-way valve.

Comorbidities and Associated Conditions

• COPD: The most frequent underlying cause of SSP, often involving the rupture of apical blebs or bullae.

• Cystic Fibrosis: Associated with low Forced Expiratory Volume ($FEV$), increasing the risk for SSP.

• Lung Cancer: Potential causes include underlying COPD or necrotizing cysts/pneumonia.

• COVID-19: Spontaneous pneumothorax often occurs as a complication of severe infection, particularly in those on mechanical ventilation, though it has been reported as a late manifestation in mild, non-ventilated clients.

• Other Comorbidities for SSP:

  • Asthma.

  • HIV with Pneumocystis pneumonia.

  • Necrotizing pneumonia.

  • Sarcoidosis.

  • Idiopathic pulmonary fibrosis.

  • Severe Acute Respiratory Distress Syndrome (ARDS).

  • Bronchogenic carcinoma.

Epidemiology

• PSP Statistics:

  • Common age range: $20$ to $30$ years old.

  • Incidence in the United States: $7$ in $100,000$ males and $1$ in $100,000$ females per year.

  • Recurrence risk is highest within the first $30$ days after resolution.

• SSP Statistics:

  • Common age range: $60$ to $65$ years old.

  • Incidence: $6.3$ per $100,000$ for men; $2$ per $100,000$ for women.

  • Incidence among COPD patients: $26$ per $100,000$.

Impact on the Aging Adult

• Physiological respiratory changes occur with age, including reduced oxygen delivery and lower baseline blood oxygen saturations.

• Ideal oxygen saturation range for an aging adult: $93\%$ to $94\%$.

• Ideal oxygen saturation range for a younger client: $94\%$ to $96\%$.

• Older adults face higher energy expenditure for breathing due to a rigid chest wall, reduced rib cage volume, and decreased lung capacity.

Clinical Presentation and Examination Findings

• General Manifestations:

  • Shortness of breath (dyspnea).

  • Tachypnea (increased respiratory rate).

  • Tachycardia (increased heart rate).

  • Hypoxia.

  • Chest pain (pleuritic, often radiating to the shoulder).

• PSP Presentation: Manifestations may be minimal but typically include severe pleuritic chest pain and shortness of breath.

• SSP Presentation: Likely to involve severe dyspnea due to the underlying disease.

• Physical Examination Findings:

  • Respiratory discomfort.

  • Asymmetrical lung expansion.

  • Decreased tactile fremitus.

  • Hyper-resonant percussion notes.

  • Decreased or absent breath sounds on the affected side.

• Tension Pneumothorax Specific Findings:

  • Severe hypotension (due to decreased cardiac output or increased central venous pressure).

  • Tachycardia exceeding $134\,bpm$.

  • Tracheal deviation (late manifestation).

  • Jugular Venous Distension (JVD).

  • Cyanosis.

Laboratory and Diagnostic Studies

• Chest X-ray: The most common method for diagnosing a pneumothorax.

• Ultrasonography: Useful, particularly in trauma situations (Extended Focused Abdominal Sonography, or EFAST).

• CT Scan: Used for detailed diagnosis.

Management and Emergency Interventions

• Initial Assessment: Prioritize Airway, Breathing, and Circulation (ABCs). Oxygenation and perfusion must be stabilized immediately to prevent respiratory or cardiac arrest.

• Positioning: Place the client in Semi-Fowler's position ($35^{\circ}$ to $45^{\circ}$ angle) to enhance lung expansion and comfort.

• Needle Decompression: Required for unstable clients to evacuate air. A $14$ to $16$ gauge angiocatheter is inserted into the second intercostal space at the midclavicular line. This location is chosen because it is the thinnest part of the chest wall, has a low risk of hitting the thoracic nerve, and results in minimal scarring.

• Thoracostomy (Chest Tube): Typically placed in the fifth intercostal space at the midclavicular line to remove air or fluid.

• Chest Drainage Systems:

  • Must be placed below the level of the catheter to prevent fluid suction back into the pleural space.

  • Wet or dry suction control may be used.

  • Continuous suction is typically set between $-10$ and $-20\,cm\,H_2O$.

  • A pressure release valve helps equilibrate collection chamber pressure with atmospheric pressure.

  • Air leak severity can be quantitatively measured by the number of bubbling columns in the air leak gauge of a wet suction system.

• Specific Clinical Management Protocols:

  • Asymptomatic PSP ($< 2\,cm$ deep): Discharged with follow-up instructions for $2$ to $4$ weeks.

  • SSP ($< 1\,cm$ deep, no dyspnea): Admitted, provided high-flow oxygen (to facilitate air reabsorption), and observed for $24$ hours.

  • SSP ($1$ to $2\,cm$ deep): Needle aspiration is performed. If the resulting size is $< 1\,cm$, manage with high-flow oxygen. If $> 2\,cm$, a thoracostomy tube is placed.

• Surgical Intervention: Candidates for surgery (such as Video-Assisted Thoracic Surgery, or VATS) include those with:

  • Continuous air leaks lasting more than $7$ days.

  • Bilateral pneumothoraces.

  • High-incidence professions (pilots, divers).

  • A diagnosis of AIDS.

• Pleurodesis: A procedure used to occlude the pleural space and prevent recurrence (reducing risk to less than $5\%$).

  • Mechanical Pleurodesis: Uses an irritant like a scratch pad or dry gauze in the pleural space.

  • Chemical Pleurodesis: Involves instilling a sclerosing agent (talc, doxycycline, or minocycline) to create adhesions between pleural membranes.

Roles and Considerations in Care

• Nursing Role:

  • Monitor oxygenation, perfusion, vital signs, and pulse oximetry.

  • Auscultate lung and heart sounds.

  • Assess for subcutaneous emphysema and tracheal deviation.

  • Manage chest tube drainage systems and analgesics.

  • Provide emotional support, calm reassurance, and clear communication to address client anxiety and fear.

  • Educate on environmental risks: Air pollution, carbon monoxide, second-hand smoke, and chemical irritants that exacerbate COPD or interstitial lung disease.

  • Counsel on smoking cessation.

• Mobility: Early mobility is encouraged as part of therapy to promote airway clearance and prevent deconditioning, muscle weakness, and microvascular dysfunction. Temporary bed rest may be necessary for stabilization.

• Pharmacotherapy: primarily focuses on pain control, particularly during and after procedures like needle thoracostomy and chest tube insertion.