Should continuous positive airway pressure (CPAP) be avoided in patients with pulmonary bullae or blebs?

CPAP Should Generally Be Avoided in Patients with Active Pneumothorax, But Pulmonary Bullae/Blebs Alone Are NOT an Absolute Contraindication

BiPAP/CPAP should be withheld from patients with an active pneumothorax as long as the pneumothorax is present 1. However, the presence of asymptomatic pulmonary bullae or blebs without pneumothorax does not automatically preclude CPAP use.

Key Clinical Distinctions

Active Pneumothorax (Absolute Contraindication)

• Withhold all positive airway pressure therapy until the pneumothorax resolves 1
• This applies regardless of pneumothorax size
• The concern is that positive pressure may worsen air leak and expand the pneumothorax
• Some clinicians may consider ICU observation if the patient critically needs ventilatory support, but this represents ceiling-of-care decision-making 1

Asymptomatic Bullae/Blebs Without Pneumothorax (Relative Contraindication)

The evidence here is more nuanced:

Historical concern vs. actual risk:

• There is a documented case report of recurrent pneumothorax in a patient with subpleural blebs on nasal intermittent positive pressure ventilation 2
• However, this represents a single case in the literature
• The theoretical risk is that positive pressure could rupture thin-walled bullae

Practical clinical experience:

• Hyperbaric oxygen therapy (which involves significant pressure changes) has been safely administered to patients with pulmonary blebs/bullae with extremely low barotrauma rates (0.00045%) 3
• Many centers accept these patients for pressure-based therapies 3

Clinical Decision Algorithm

Step 1: Rule out active pneumothorax

• Obtain chest imaging before initiating CPAP if bullae/blebs are known or suspected
• If pneumothorax present → Do not use CPAP

Step 2: Assess bulla characteristics if no pneumothorax

• Large, thin-walled bullae with severe underlying lung disease: Exercise extreme caution; consider alternative OSA treatments
• Small, incidental bullae in otherwise healthy lungs: CPAP can likely be used with close monitoring
• Multiple or enlarging bullae: Higher risk; may warrant pulmonology consultation before CPAP initiation

Step 3: If proceeding with CPAP in presence of bullae

• Start with lower pressures and titrate gradually
• Educate patient on pneumothorax symptoms (sudden chest pain, dyspnea)
• Consider more frequent follow-up initially
• Document shared decision-making discussion about theoretical risks

Important Caveats

Post-pneumothorax timing:

• After pneumothorax resolution, wait at least 6 weeks before considering CPAP 4
• If surgical pleurodesis was performed, reassess after 6 weeks with imaging 4
• Activities that increase intrathoracic pressure (including spirometry) should be avoided for 2 weeks post-resolution 1

Specific airway clearance considerations:

• Positive expiratory pressure (PEP) devices and intrapulmonary percussive ventilation should be avoided with active pneumothorax 1
• These generate similar positive pressures as CPAP

The critical error to avoid: Confusing asymptomatic incidental bullae (which may allow cautious CPAP use) with active pneumothorax (which absolutely contraindicates positive pressure) 1. Always obtain current imaging if there is any clinical suspicion of pneumothorax before initiating or continuing CPAP therapy.