What is the purpose and use of a Heimlich valve in patients with pneumothorax?

Heimlich Valve in Pneumothorax Management

The Heimlich valve is a one-way flutter valve that connects to a small-bore chest tube (typically 8-14F) to drain air from the pleural space while preventing backflow, enabling outpatient management of stable pneumothorax patients without the need for bulky underwater seal systems. 1

Mechanism and Basic Function

The Heimlich valve is a compact one-way drainage system (less than 13 cm long) that allows air and fluid to exit the pleural cavity in one direction only, preventing return of gases or fluids back into the pleural space. 2, 3 The valve:

• Functions in any position and never requires clamping (except when an active air leak is present, which would be contraindicated). 3
• Drains into a flexible plastic collection bag that can be held at any level, allowing complete patient ambulation. 2, 3
• Can have regulated suction attached if necessary, though this is typically not required for stable patients. 3

Optimal Patient Selection

The Heimlich valve works best for stable patients with primary spontaneous pneumothorax without large air leaks. 1 Specifically:

• Ideal candidates: First episode, unilateral primary spontaneous pneumothorax with at least 2-cm rim of air and minimal or no pleural effusion. 4
• Patients requiring larger bore tubes and water seal: Those with COPD, on positive pressure ventilation, mechanically ventilated patients with suspected bronchopleural fistula, or those with large air leaks. 1, 5
• Absolute contraindications: Unstable patients, tension pneumothorax, or those requiring mechanical ventilation with large air leaks should receive larger bore tubes (24F-28F) with water seal and suction instead. 1, 5

Technical Implementation

Connect the Heimlich valve to a small-bore chest tube (8-14F) or catheter-over-guidewire system inserted using the Seldinger technique. 1 Implementation details:

• Small lumen catheters (as small as 2 mm/7F) can be used successfully, with studies showing success in 27 of 28 patients with mean drainage time of 48 hours. 1
• The 8F chest drain with Heimlich valve achieved a 65.5% success rate for outpatient management of primary spontaneous pneumothorax. 1, 4
• Recent technical developments allow Heimlich valves to be attached to tubes ranging from 7F to larger bore sizes. 1

Expected Outcomes and Timeline

• Complete lung re-expansion typically occurs within 2-5 days, with 66% showing full expansion within one hour and 94.4% achieving complete expansion by five days. 6
• For interventional procedure-induced pneumothorax, pneumothorax resolution occurs within 2-3 days with good lung re-expansion. 7

Critical Safety Considerations and When to Escalate

Never clamp a chest tube with an active air leak (bubbling), whether connected to a Heimlich valve or underwater seal, as this can convert a simple pneumothorax into life-threatening tension pneumothorax. 1

Escalation Criteria:

• If pneumothorax fails to resolve or air leak persists beyond 48 hours: Switch from Heimlich valve to water seal with suction and refer to respiratory physician for consideration of repositioning or surgical intervention. 1
• If air leak persists beyond 4 days: Consider surgical intervention (thoracoscopy with bullectomy and pleurodesis) or chemical pleurodesis with doxycycline or talc slurry, as chronic pneumothorax carries significant morbidity risk. 1, 5
• Valve blockage: If blockage occurs due to exudative fluid or associated pleural effusion, switch to standard underwater seal drainage immediately. 6

Complications and Management

• Tube blockage by hemoserous discharge: Occurs in approximately 1.8% of cases; requires switching to underwater seal system. 6, 4
• Tube dislodgement: Occurs in approximately 5.5% of cases; requires reinsertion or alternative management. 4
• Surgical pleurodesis rate: Approximately 23.6% of patients ultimately require surgical intervention despite initial Heimlich valve placement. 4

Advantages Over Traditional Water Seal Systems

• Enables outpatient management for stable patients, avoiding hospitalization and its associated costs. 1, 7, 4
• Immediate patient mobility without cumbersome apparatus, allowing patients to carry a simple drainage bag. 3, 6
• Eliminates well-known dangers of connecting intrapleural catheters to water trap systems. 6
• Micro-invasive, easy to perform, and safe for appropriate patient populations. 7

Evidence Quality Note

The American College of Chest Physicians notes "good consensus" for Heimlich valve use but still considers water seal devices the better option for most hospitalized patients. 1 However, the British Thoracic Society acknowledges Heimlich valves are gaining popularity and may replace simple aspiration in certain scenarios. 1