II. Epidemiology: Incidence (United States)

  1. Medical Encounters: 20,000/year
  2. Men: Up to 28 per 100,000/year
  3. Women: Up to 6 per 100,000/year

III. Pathophysiology

  1. Pressure gradient from intraalveolar space to intrapleural space
    1. Intrapleural pressure is negative
      1. Chest wall springs outward and alveoli recoil inward
      2. Inspiration: -12 mmHg
      3. Expiration: -4 mmHg
    2. Alveolar pressures become positive on expiration (3 mmHg)
  2. Defect in alveolar wall and visceral pleura allows air to enter the pleural space
    1. Pleural air accumulates and decreases pressure gradient if defect does not close
    2. Eventually, if pleural pressure increases to alveolar pressure, lung collapses
    3. Tension Pneumothorax mechanism
      1. Air enters pleural space during inspiration, BUT
      2. Air is trapped from exiting during expiration

IV. Types

  1. Primary Spontaneous Pneumothorax (66%)
    1. No underlying lung disease
    2. Typical patient is a tall, thin male
    3. Age typically 10 to 30 years old (uncommon after age 40 years)
    4. Subpleural blebs are responsible for most cases (forming at apices in tall, thin patients)
    5. Occurs most often with the patient at rest
  2. Secondary Spontaneous Pneumothorax (33%)
    1. Chronic Obstructive Pulmonary Disease or COPD (70% of secondary causes)
      1. Related to Pulmonary Blebs
    2. Asthma
      1. Related to marked thoracic pressure changes
    3. Tuberculosis and abscess (most common cause world-wide)
    4. Cystic Fibrosis
      1. Lifetime risk of 8-20%
    5. AIDS
      1. Risk: 2-6%
      2. Typically associated with comorbid Pneumocystis jiroveci Pneumonia
    6. Menstruation (Catamenial Pneumothorax, thoracic endometrial syndrome)
      1. Occurs within first 3 days of Menses onset
      2. Endometrial implants on diaphragm or lung
      3. High risk of recurrence with Menses (cyclical)
    7. Pneumonia
    8. Bronchitis
    9. Connective Tissue Disease
      1. Marfan Syndrome
      2. Ehlers-Danlos
    10. Valsalva or Muller Maneuver
      1. Drug smokers
      2. Vaping

V. Risk Factors

  1. See Primary Spontaneous Pneumothorax regarding body habitus
    1. Tall Stature
    2. Low BMI
  2. See Secondary causes above
  3. Tobacco Abuse
    1. Increases the risk of both Primary Spontaneous Pneumothorax (20 fold in males, 10 fold in females)
    2. Also increases the risk of Secondary Spontaneous Pneumothorax
    3. May increase lifetime risk from 0.1% in non-smokers to 12% in smokers
  4. Prior Pneumothorax
    1. See recurrence rates below
  5. Other contributing factors
    1. Malnutrition
    2. Connective Tissue Disease
    3. Cold Weather
  6. Factors that appear unrelated
    1. Exercise does not appear to predispose to Pneumothorax
    2. Most Spontaneous Pneumothorax events take place at rest

VI. Symptoms

  1. Presentation within 24 hours of onset in 70% of cases
  2. Chest Pain
    1. Sudden sharp pain
    2. Radiates to back or Shoulders
    3. Pleuritic Chest Pain initially transitions into a steady ache-type Chest Pain
    4. Chest Pain improves after the first 24 hours despite persistence of Pneumothorax
  3. Dyspnea
    1. Variably present
    2. Typically not severe in Primary Spontaneous Pneumothorax
  4. Variable cardiopulmonary symptoms
    1. Symptoms severity is increased with Secondary Spontaneous Pneumothorax
    2. Severe Dyspnea with Hypoxia, Hypotension, Tachycardia is Tension Pneumothorax until proven otherwise

VII. Signs

  1. Examination may be unremarkable
    1. Tachycardia may be the only clinical finding (single most common finding)
  2. Keep high index of suspicion
    1. COPD patients
    2. Tall, thin males
  3. Changes on affected side
    1. Unilateral absent or decreased breath sounds
    2. Hyperresonance to percussion
    3. Decreased tactile fremitus
    4. Decreased chest wall movement
    5. Coin Test

VIII. Signs: Red Flags - Signs of Tension Pneumothorax

X. Precautions

  1. Secondary Spontaneous Pneumothorax is significantly higher risk than Primary Spontaneous Pneumothorax
    1. Secondary Spontaneous Pneumothorax has potential for life threatening presentation due to underlying lung disease
    2. Treat Secondary Spontaneous Pneumothorax aggressively
    3. Mortality approaches 10% even after reexpansion of Pneumothorax
  2. Delayed presentation in >50% of patients
    1. Higher risk of complication (e.g. reexpansion Pulmonary Edema)

XI. Management: Small Pneumothorax options

  1. Observation for small Pneumothorax
    1. Indications
      1. Volume: <20%
      2. Apical depth: <1-3 cm (from apex to lung cupola)
      3. Low risk patients (no significant impacted comorbidity)
      4. Reassuring Vital Signs
        1. Respiratory Rate <24
        2. Heart Rate <120 bpm
        3. Normal Blood Pressure
        4. Oxygen Saturation >90%
    2. Observe for 3-6 hours in emergency department and disposition home
      1. Repeat Chest XRay before ED discharge (e.g. 4 hours)
      2. Repeat Chest XRay in 1 to 2 days
      3. Careful precautions for return (e.g. increasing Shortness of Breath)
    3. Efficacy
      1. More than 94% resolve uncomplicated Spontaneous Pneumothorax without Chest Tube
      2. Brown (2020) N Engl J Med 382(5):405-15 [PubMed]
  2. Supplemental Oxygen
    1. Successful in 70% of cases
    2. However slow resolution
      1. Room air: 1.25% per day (25% Pneumothorax would resolve in 20 days)
      2. High Flow Oxygen (10 L/min): 5% per day (25% Pneumothorax would resolve in 5 days)
    3. Kelly (2008) Chest 134(5): 1033-6 [PubMed]
  3. Simple Needle aspiration
    1. See Simple Needle Aspiration of Pneumothorax
    2. Similar technique as with Small Calibre Chest Tube (Heimlich Valve, Pigtail Chest Catheter)
    3. Insert 16 to 18 gauge catheter with 3-way stop cock
      1. Place into the second intercostal space mid-clavicular line (or lateral 4-5th intercostal anterior axillary line)
    4. Remove catheter after full evacuation of air
  4. Small Caliber Chest Tube (Heimlich Valve, Pigtail Chest Catheter)
    1. Allows patient to go home with catheter
  5. Chest Tube (large bore standard Chest Tube)
    1. See Indications below

XII. Management: Large or complicated Pneumothorax (Chest Tube)

  1. Chest Tube Indications
    1. Large Pneumothorax
    2. Decompensating patient status
    3. Positive Pressure Ventilations used
    4. Hemothorax
    5. Persistent air leak despite cook catheter (Heimlich Valve) described above
    6. Signs of infection
    7. Failure to reexpand lung
  2. Technique
    1. See Chest Tube
    2. See Small Caliber Chest Tube (Heimlich Valve, Pigtail Chest Catheter)
    3. Chest Tube size
      1. Uncomplicated Spontaneous Pneumothorax: 16F to 22 F (small bore)
      2. Unstable, Bronchopleural Fistula or Mechanical Ventilation: 24-28 F
      3. Hemothorax: 32 F (large bore)
        1. Some Trauma surgeons recommend 36 or 40 F
    4. Suction
      1. Start with water seal or Heimlich Valve
      2. Low intermittent suction (-10 to -20 cm H2O) indicated in persistent air leak despite Chest Tube >24 hours
    5. Prophylactic Antibiotics
      1. Not indicated in non-Traumatic Pneumothorax with Chest Tube

XIII. Management: Refractory Pneumothorax (Surgery)

  1. Surgical Indications
    1. Recurrent ipsilateral Pneumothorax (after second event)
    2. Bilateral Spontaneous Pneumothorax
    3. Persistent air leak or failed re-expansion (>5-7 days)
      1. Despite well placed large Chest Tube to low intermittent suction
    4. Spontaneous Hemothorax
    5. Tension Pneumothorax
    6. High risk profession (e.g. pilot, scuba diver)
  2. Methods
    1. Pleurodesis with talc or other sclerosing agent
      1. Decreases Spontaneous Pneumothorax recurrence rate from 20-60% to less than 5-8%
      2. Talc appears more effective than Tetracycline
      3. Guo (2005) Respirology 10(3): 378-84 [PubMed]
    2. Cautery to visceral pleura
    3. Application of mesh to pleura
    4. Bleb resection
    5. Thoracotomy with bullectomy and pleurectomy
  3. References
    1. Kurihara (2010) Gen Thorac Cardiovasc Surg 58(3): 113-9 [PubMed]

XIV. Management: Disposition

  1. Hospitalization indications
    1. Moderate to large Spontaneous Pneumothorax
    2. Secondary Spontaneous Pneumothorax
    3. Delayed presentation of large Spontaneous Pneumothorax (risk of reexpansion Pulmonary Edema)
    4. Unreliable or difficult follow-up (e.g. patient lives far from emergency department)
    5. Air transport anticipated
  2. Hospital Observation Chest Tube discontinuation protocol
    1. Indications to clamp Chest Tube
      1. No air leaks after 12 hours of continuous suction or water seal AND
      2. Patient stable with improved lung expansion on serial Chest XRay
    2. Indications for Chest Tube removal
      1. Chest Tube clamped AND
      2. Patient stable with no Pneumothorax reaccumulation
  3. Discharge indications
    1. No hospitalization indications above AND
    2. Observation for 3-6 hours without Pneumothorax reexpansion (see protocol below)
  4. Protocol: Observation prior to discharge
    1. Admit all patients with Secondary Spontaneous Pneumothorax
      1. Observe for at least 24 hours
    2. Hgh flow oxygen (10 Liters) is typical (see above for details)
    3. Observation for small to moderate Primary Spontaneous Pneumothorax following air evacuation or Chest Tube placement
      1. British Thoracic Society: 6 hours
      2. American College of Chest Physicians: 3-6 hours
    4. Repeat imaging
      1. Prior to discharge at 3-6 hours
      2. Follow-up: 24 to 48 hours

XV. Management: Restrictions

  1. Exercise
    1. Exertion or Exercise is not a risk for recurrence of Pneumothorax
    2. No restriction of activity after Spontaneous Pneumothorax has resolved
    3. Athletes with Traumatic Pneumothorax typically return within 4 weeks of Pneumothorax resolution
  2. Scuba Diving Contraindications
    1. History of Spontaneous Pneumothorax
      1. In some cases, may be permitted following definitive surgical management
    2. History of Pulmonary Blebs or bullae
    3. Emphysema

XVI. Management: Air travel after Pneumothorax

  1. Precautions
    1. Gas (including that in a Pneumothorax) expands up to 30% at 8000 feet of elevation (maximal pressurization of an airplane cabin)
    2. Partial Pressure of oxygen decreases from FIO2 of 21% to 15% at typical flight altitude
      1. Results in hypobaric Hypoxia
      2. Healthy patients may decrease Oxygen Saturation from 99 to 92%
      3. COPD patients with Oxygen Saturation of 92% may drop to 80%
  2. Air transport to a medical facility for Pneumothorax management
    1. Risk of Tension Pneumothorax
    2. Requires Chest Tube placement and drain to water seal or Heimlich Valve prior to transport
  3. Guidelines for return to air travel
    1. Current Pneumothorax is a contraindication to commerical airline flight
    2. Criteria to allow return to air travel following Pneumothorax in otherwise healthy patients
      1. End-expiratory Chest XRay demonstrates Pneumothorax resolution AND
      2. Patient waits additional time beyond resolution on XRay prior to travel
        1. Spontaneous Pneumothorax: 1 week after Chest XRay shows resolution
        2. Traumatic Pneumothorax: 2 weeks after Chest XRay shows resolution
    3. Criteria to allow return to air travel with underlying lung disease (e.g. COPD)
      1. Above criteria AND
      2. Pulmonology assessment (may include hypoxic chamber test) to determine safety for flight
  4. Commercial aircraft travel following Pneumothorax resolution
    1. Commerical air travel does not increase Pneumothorax recurrence risk
    2. Commercial regulations following Pneumothorax resolution (by Chest XRay) varies by guideline
      1. U.S. safety regulations: 3 week waiting period prior to air travel
      2. British Thoracic society: 6 week waiting period prior to air travel
  5. Management of suspected in flight Pneumothorax
    1. May present as Pleuritic Chest Pain and Dyspnea
    2. Apply Supplemental Oxygen
    3. Discuss with flight crew regarding descending to lower altitude and possible diversion
  6. References
    1. Jhun and Herbert in Herbert (2014) EM:Rap 14(6): 15
    2. British Thoracic Society Pneumothorax Guidelines
      1. MacDuff (2010) Thorax 65(Suppl 2):ii18-ii31 [PubMed]

XVII. Complications

  1. Tension Pneumothorax
  2. Spontaneous hemopneumothorax
    1. Hemothorax accompanies penumothorax in up to 2.6% of cases
    2. Hemopneumothorax is >400 ml of air and blood within the pleural cavity
    3. Significant blood loss may occur
  3. Pneumomediastinum and subcutaneous Emphysema
    1. May occur with Valsalva Maneuver or other similar exertional activity
  4. Re-Expansion Pulmonary Edema
    1. Massive Pulmonary Edema onset following re-expansion of Pneumothorax
      1. Severe, life threatening event
    2. Risk Factors
      1. Young patients
      2. Large Pneumothorax
      3. Pneumothorax present longer than 72 hours
      4. Hemothorax (or pus)
      5. Rapid re-expansion with suction
    3. Management
      1. Admit to Intensive Care unit
      2. Intubation
      3. IV Fluids
      4. Supportive care

XVIII. Prognosis: Recurrence

  1. Recurrent Spontaneous Pneumothorax will typically occur within 2 years of prior episode
  2. Overall recurrence rate: 20-60% (with similar rates on the contralateral side)
  3. Secondary Spontaneous Pneumothorax recurrence rate: 40-80%
  4. Third Spontaneous Pneumothorax recurrence rate: >80%
  5. Recurrence rate after definitive surgical management (e.g. pleurodesis): <5%

XIX. References

  1. Foster (2021) Crit Dec Emerg Med 35(3): 10-1
  2. Majoewsky (2012) EM:RAPC3 2(2): 3-4
  3. Tranchell (2013) Crit Dec Emerg Med 27(7): 11-8
  4. Noppen (2003) Respiration 70(4): 431-8 [PubMed]

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