What is the management of pneumothorax in patients on mechanical ventilation (MV)?

Management of Pneumothorax in Patients on Mechanical Ventilation

Patients with pneumothorax on mechanical ventilation should be treated with chest tube drainage as positive pressure ventilation maintains the air leak and prevents spontaneous resolution. 1

Initial Assessment and Management

Tension Pneumothorax Recognition

• Clinical presentation may include:
  • Sudden deterioration in cardiopulmonary status
  • Rapid labored respiration, cyanosis, sweating, tachycardia
  • Hypoxemia, reduced cardiac output, impaired venous return
  • May progress to electromechanical dissociation (EMD) arrest
  • Often missed in ICU settings 1

Emergency Management of Tension Pneumothorax

1. Administer high-concentration oxygen
2. Perform immediate needle decompression:
   • Insert cannula into second anterior intercostal space, mid-clavicular line
   • Use cannula of at least 4.5 cm length (chest wall thickness exceeds 3 cm in 57% of patients) 1
   • Remove air until patient is no longer hemodynamically compromised
3. Leave cannula in place until chest tube is functioning properly 1

Definitive Management

Chest Tube Placement

• Tube size selection:
  • For most patients: 16F to 22F chest tube (good consensus) 1
  • For patients with anticipated large air leaks or requiring positive pressure ventilation: 24F to 28F chest tube 1, 2
  • Large-bore tubes (≥20F) are associated with fewer tube-related complications than small-bore tubes (≤14F) in ventilated patients 2

Drainage System Options

1. Water seal device:

   • Can be used initially without suction (good consensus) 1
   • Apply suction if lung fails to re-expand with water seal alone 1
   • Some experts recommend immediate application of suction after tube placement 1

2. Heimlich valve:

   • May be used in select cases 1
   • Should be replaced with water seal device and suction if lung fails to re-expand 1

Ongoing Management

Ventilator Adjustments

• Modify ventilator settings to reduce barotrauma risk:
  • Decrease respiratory rate
  • Use smaller tidal volumes (6-8 mL/kg)
  • Shorter inspiratory time (inspiratory flow rate 80-100 L/min)
  • Longer expiratory time (I:E ratio 1:4 or 1:5) 1
  • Consider permissive hypercapnia to reduce barotrauma risk 1

Monitoring for Auto-PEEP

• Monitor for auto-PEEP (breath stacking), which can lead to:
  • Hyperinflation
  • Tension pneumothorax
  • Hypotension 1
• If auto-PEEP is suspected:
  • Temporarily disconnect patient from ventilator to allow passive exhalation
  • Assist exhalation by pressing on chest wall if hypotension is present 1

Chest Tube Management

• Maintain chest tube until:
  • Complete resolution of pneumothorax on chest radiograph
  • No clinical evidence of ongoing air leak 1
• Staged removal process:
  1. Discontinue any suction
  2. Observe for recurrence (repeat chest radiograph 5-12 hours after last evidence of air leak)
  3. Remove tube if no recurrence 1

Special Considerations

Loculated Pneumothoraces

• May require image-guided drainage with catheters (16F-24F)
• Can improve oxygenation and reduce risk of further pulmonary compromise 3

Persistent Air Leaks

• For persistent air leaks despite appropriate chest tube placement:
  • Consider surgical intervention if patient remains stable enough for procedure
  • Chemical pleurodesis may be considered in patients with contraindications to surgery 1

COVID-19 Associated Pneumothorax

• Higher incidence (7.4%) and mortality (58%) in COVID-19 patients on mechanical ventilation
• More likely to require prolonged drainage (median 12 days) 2

Pitfalls and Caveats

1. Delayed recognition: Tension pneumothorax may be missed in ICU settings; maintain high index of suspicion with sudden deterioration in ventilated patients 1

2. Inadequate decompression: Ensure needle length of at least 4.5 cm for emergency decompression 1

3. DOPE mnemonic for acute deterioration in intubated patients:

   • Tube Displacement
   • Tube Obstruction
   • Pneumothorax
   • Equipment failure 1

4. Occult pneumothorax: Small pneumothoraces identified on CT but not visible on chest X-ray may sometimes be managed conservatively even in ventilated patients, but require close monitoring 4

5. Chest tube size matters: Large-bore tubes (≥20F) are associated with fewer complications in ventilated patients with pneumothorax 2