What is the management of pneumothorax (collapsed lung) secondary to asthma exacerbation?

Management of Pneumothorax Secondary to Asthma Exacerbation

Pneumothorax complicating asthma exacerbation should be treated as a secondary pneumothorax with immediate chest tube drainage (16F-22F) connected to a water seal device, with hospitalization required in virtually all cases, as these patients have underlying lung disease and are at high risk for clinical deterioration. 1

Initial Recognition and Assessment

Clinical Stability Determination

Assess whether the patient meets stability criteria, which include all of the following: 1

• Respiratory rate <24 breaths/min 1
• Heart rate >60 and <120 beats/min 1
• Normal blood pressure 1
• Room air oxygen saturation >90% 1
• Ability to speak in complete sentences between breaths 1

Any patient not meeting all these criteria is clinically unstable and requires more aggressive intervention. 1

Pneumothorax Size Classification

Determine pneumothorax size by measuring the distance from lung apex to ipsilateral thoracic cupola on upright chest radiograph: 1

• Small pneumothorax: <3 cm apex-to-cupola distance 1
• Large pneumothorax: ≥3 cm apex-to-cupola distance 1

Critical Diagnostic Consideration

Obtain chest radiography urgently in any asthma patient who deteriorates despite appropriate bronchodilator and steroid therapy, as pneumothorax may be the cause of clinical worsening. 1, 2

Management Algorithm

For Clinically Stable Patients with Large Pneumothorax (≥3 cm)

Insert a small-bore catheter (≤14F) or 16F-22F chest tube and hospitalize the patient. 1 The British Thoracic Society acknowledges that aspiration has significant limitations in secondary pneumothorax, and initial chest drain insertion is recommended for patients where aspiration is unlikely to succeed. 1

The catheter or tube should be: 1

• Attached to either a Heimlich valve or water seal device 1
• Left in place until lung expands against chest wall and air leaks resolve 1
• Connected to suction if lung fails to reexpand quickly with water seal alone 1

Do not discharge these patients home—hospitalization is required. 1

For Clinically Unstable Patients with Large Pneumothorax

Immediately insert a 16F-22F chest tube connected to a water seal device and hospitalize. 1 The degree of clinical instability guides tube size selection. 1

Use a larger 24F-28F chest tube if: 1

• The patient requires or will require positive-pressure ventilation 1
• There is anticipated bronchopleural fistula with large air leak 1

Apply suction immediately or if the lung fails to reexpand with water seal drainage alone. 1

For Small Pneumothorax (<3 cm) in Stable Patients

While the American College of Chest Physicians guidelines suggest observation for small secondary pneumothoraces in stable patients 1, extreme caution is warranted in asthma patients given their underlying airway disease and potential for rapid deterioration. 1

Consider chest tube drainage even for small pneumothoraces in asthma patients, particularly if: 1

• The patient has severe underlying asthma 1
• There is any concern about clinical stability 1
• The patient requires ongoing bronchodilator therapy that may worsen air leak 3

Critical Management Pitfalls to Avoid

Positive-Pressure Ventilation

If the asthma patient requires intubation and mechanical ventilation, a chest tube MUST be inserted before initiating positive-pressure ventilation to prevent tension pneumothorax. 1, 4 Use a 24F-28F large-bore tube in this scenario. 1

Tension Pneumothorax Recognition

Immediately decompress if tension pneumothorax develops, characterized by: 1, 3

• Severe respiratory distress 3
• Hemodynamic instability 3
• Tracheal deviation 3
• Absent breath sounds on affected side 3

Perform immediate needle decompression followed by chest tube insertion. 3, 5

Simple Aspiration Limitations

Do not rely on simple aspiration as primary treatment in asthma-related pneumothorax. 1 The British Thoracic Society explicitly states that aspiration has significant limitations in secondary pneumothorax, and the American College of Chest Physicians found simple aspiration appropriate rarely in secondary pneumothorax. 1

Ongoing Asthma Management During Pneumothorax Treatment

Continue aggressive asthma treatment concurrently: 1

• High-dose nebulized β-agonists (salbutamol 5 mg or terbutaline 10 mg) 1
• Systemic corticosteroids (prednisolone 30-60 mg or IV hydrocortisone 200 mg) 1
• Ipratropium 0.5 mg nebulized if life-threatening features present 1
• Supplemental oxygen to maintain saturation >90% 1

Avoid sedation, which is contraindicated in acute asthma. 1

Monitoring and Follow-Up

Monitor continuously for: 1

• Respiratory rate, heart rate, blood pressure, oxygen saturation 1
• Peak expiratory flow measurements 1
• Serial chest radiographs to assess lung re-expansion 1

Do not remove the chest tube until: 1

• The lung has fully re-expanded 1
• Air leak has completely resolved 1
• The patient's asthma is adequately controlled 1