Does oxygen (O2) promote reabsorption of a pneumothorax?

From the Guidelines

Oxygen therapy is recommended to promote the reabsorption of a pneumothorax, as it creates a gradient that accelerates the resolution of the trapped air. When a patient with a pneumothorax receives supplemental oxygen, it replaces the nitrogen in the blood, creating a concentration gradient that draws nitrogen from the pleural space into the bloodstream 1. The standard approach involves administering high-flow oxygen at 10-15 L/min via a non-rebreather mask for several hours to days, depending on the size of the pneumothorax and the patient's clinical condition.

Key Considerations

• The physiological basis for this treatment is that air in a pneumothorax is primarily composed of nitrogen, which is poorly soluble in blood 1.
• By breathing high concentrations of oxygen, the nitrogen in the blood decreases, enhancing the absorption of nitrogen from the pleural space.
• This approach may reduce the need for more invasive interventions like chest tube placement in appropriate cases.
• The addition of high flow oxygen therapy has been shown to result in a four-fold increase in the rate of pneumothorax reabsorption during periods of oxygen supplementation 1.

Clinical Guidelines

• According to the BTS guidelines, supplemental high flow (10 l/min) oxygen should be given to patients with symptomatic pneumothoraces where feasible 1.
• The BTS guideline for oxygen use in adults in healthcare and emergency settings recommends using a reservoir mask at 15 L/min if admitted for observation, aiming at 100% saturation, as oxygen accelerates clearance of pneumothorax if drainage is not required 1.

Patient Selection

• This therapy is most effective for small, spontaneous pneumothoraces (less than 15-20% of the hemithorax) in stable patients.
• Patients with larger pneumothoraces or those who are unstable may require more invasive interventions.

From the Research

Oxygen Therapy and Pneumothorax Resolution

• The administration of supplemental oxygen has been shown to improve the resolution of pneumothorax in various studies 2, 3, 4.
• A study published in the Journal of Pediatric Surgery found that supplemental oxygen accelerated the spontaneous resolution of injury-induced pneumothorax in a visceral pleural injury model 2.
• Another study published in the Journal of Thoracic Disease found that oxygen therapy increased the resolution rate of primary spontaneous pneumothorax 3.
• A study published in Respiration; International Review of Thoracic Diseases found that the inhalation of supplemental oxygen hastened the absorption of pneumothorax, particularly in patients with smaller pneumothoraces (<30%) 4.

Mechanism of Oxygen Therapy

• The "nitrogen wash-out" theory suggests that oxygen supplementation can enhance the resorption rate of air from the pleural cavity by washing out nitrogen from the pneumothorax 5.
• This theory is supported by animal models, but clinical data in patient populations are mainly retrospective and have limitations in terms of sample size and study design 5.

Clinical Implications

• The use of oxygen therapy in patients with pneumothorax, regardless of the presence or absence of hypoxemia, is a common practice, but its effectiveness and indications need to be further studied 5, 6.
• Prospective clinical studies with adequate methodology are recommended to address the question of whether or not oxygen therapy should be used to treat pneumothorax 5.
• Interventional pulmonology techniques, such as bronchoscopic sealing of air leaks, may be useful in treating persistent air leak and bronchopleural fistula in patients with pneumothorax 6.