What is the management of secondary pneumothorax?

Management of Secondary Pneumothorax

All patients with secondary pneumothorax require active intervention and hospitalization, with chest tube drainage as the primary treatment for most cases, given the high failure rate of simple aspiration and the significant risk of respiratory compromise in patients with underlying lung disease. 1

Initial Assessment and Stabilization

Clinical stability must be assessed immediately using specific criteria: respiratory rate <24 breaths/min, heart rate 60-120 beats/min, normal blood pressure, room air oxygen saturation >90%, and ability to speak in complete sentences. 1

• Administer high-flow oxygen (10 L/min) immediately to all hospitalized patients, as this increases pneumothorax reabsorption rate four-fold, though use caution in COPD patients who may be CO2 retainers. 1
• Any breathless patient requires immediate intervention regardless of pneumothorax size on chest radiograph. 1

Size Classification

Pneumothorax size determines treatment approach:

• Small: <2 cm rim between lung margin and chest wall (or <3 cm apex-to-cupola distance per ACCP criteria) 1
• Large: ≥2 cm rim (or ≥3 cm apex-to-cupola distance) 1

Treatment Algorithm by Clinical Presentation

Small Secondary Pneumothorax (<2 cm) with Minimal Symptoms

Observation alone is only appropriate for very limited cases:

• Pneumothorax <1 cm depth OR isolated apical pneumothorax in completely asymptomatic patients 1
• Hospitalization is mandatory even for observed cases 1
• All other small secondary pneumothoraces require active intervention 1

Simple aspiration may be attempted only in highly selected patients:

• Age <50 years, minimally breathless, and pneumothorax <2 cm 1
• Success rate is only 33-67% in secondary pneumothorax (compared to 59-83% in primary) 1
• Success rate drops to 19-31% in patients >50 years old 1
• If aspiration is successful, admit for minimum 24-hour observation before discharge 1

Large Secondary Pneumothorax (≥2 cm) - Clinically Stable

Chest tube drainage is the definitive treatment:

• Insert small-bore catheter (≤14F) or moderate-sized chest tube (16F-22F) 1
• Hospitalization is required in virtually all cases 1
• Attach to either Heimlich valve or water seal device 1
• If lung fails to reexpand quickly with water seal alone, apply suction 1
• Alternative approach: apply suction immediately after chest tube placement 1

For reliable patients refusing hospitalization (rare exception):

• May discharge with small-bore catheter attached to Heimlich valve only if lung has fully reexpanded after air removal 1
• Mandatory follow-up within 2 days 1

Large Secondary Pneumothorax - Clinically Unstable

Immediate hospitalization with chest tube insertion:

• Most patients: 16F-22F chest tube or small-bore catheter depending on degree of instability 1
• Use 24F-28F chest tube if anticipated bronchopleural fistula with large air leak or patient requires positive-pressure ventilation 1
• Initial water seal without suction is acceptable, but apply suction if lung fails to reexpand 1

Common Pitfalls and Caveats

Critical differences from primary pneumothorax management:

• Simple aspiration has much lower success rates in secondary pneumothorax (33-67% vs 59-83% in primary), making chest tube drainage the preferred initial approach for most patients 1
• Age >50 years dramatically reduces aspiration success to only 19-31%, making chest tube insertion the clear choice in older patients 1
• Underlying lung disease creates poor respiratory reserve, making observation inappropriate except in the most minimal cases 1

Technical considerations:

• Duration of symptoms >24 hours does not alter treatment recommendations 1
• Chest tubes should remain in place until lung fully expands against chest wall and air leaks resolve 1
• Natural reabsorption rate is only 1.25-1.8% of hemithorax volume per 24 hours, meaning a 15% pneumothorax takes 8-12 days to resolve without intervention 1