Oxygen Administration in Pneumothorax

Mechanism of Action

The British Thoracic Society recommends that oxygen administration at high flow (10 L/min) reduces the partial pressure of nitrogen in the pleural capillaries, increasing the pressure gradient between the capillaries and the pleural cavity, which accelerates the absorption of trapped air 1, 2
This therapy can increase the rate of pneumothorax reabsorption up to four times faster than breathing ambient air, from 1.25-1.8% of the hemithorax volume per day to approximately 4.2% per day 1

The British Thoracic Society guidelines recommend administering oxygen at high flow (10 L/min) to hospitalized patients with pneumothorax under observation 1, 2
For undrained pneumothorax under hospital observation, the use of high-concentration oxygen (15 L/min via reservoir mask) is recommended unless the patient is at risk of hypercapnic respiratory failure 3
Caution should be exercised in patients with COPD who may be sensitive to higher concentrations of oxygen 1, 2

There is no evidence in clinical guidelines to suggest that oxygen administration in pneumothorax causes atelectasis 1, 2, 4

In patients with severe bullous lung disease, a CT scan should be performed to differentiate between bullae and pneumothorax before any intervention 5

Evaluate the size of the pneumothorax (small <2 cm or large >2 cm between the lung margin and the thoracic wall) 2
Administer oxygen at high flow (10 L/min) to hospitalized patients under observation 1, 2
Monitor oxygen saturation and respiratory status 4

High-concentration reservoir masks deliver oxygen at concentrations between 60% and 90% when used at a flow rate of 15 L/min, as recommended by the Thorax journal 6
Simple face masks at flows <5 L/min can cause increased resistance to breathing and potential CO2 rebreathing, and should be avoided, according to the Thorax journal 6

The British Thoracic Society recommends administering high-concentration oxygen at 15 L/min via a reservoir mask to patients with 25% pneumothorax under hospital observation without drainage, unless the patient has a risk of hypercapnic respiratory failure 7, 8, 9

For patients without risk of hypercapnia, the goal is to achieve an oxygen saturation of 94-98% by administering oxygen at 15 L/min via a reservoir mask 7, 8, 9
This recommendation applies specifically to patients with 25% pneumothorax under hospital observation without drainage 7, 8, 9

Patients with moderate or severe COPD, especially those with a history of previous respiratory failure or on home oxygen therapy, are at risk of hypercapnic respiratory failure and should receive oxygen at a lower concentration, with a target saturation of 88-92% 7, 8, 9, 10
Other high-risk factors include severe chest wall or spinal disease, neuromuscular disease, severe obesity, cystic fibrosis, and bronchiectasis, which may require lower oxygen concentrations and careful monitoring 10

For patients at risk of hypercapnic respiratory failure, oxygen should be initiated at 28% or 24%, or 1-2 L/min via nasal cannula, and arterial blood gas measurements should be obtained to guide adjustments 10
Monitoring should include careful measurement of respiratory and heart rates, as well as pulse oximetry, with consideration of arterial blood gas measurements in patients with confusion or unexplained agitation 10

Oxygen therapy should never be discontinued to obtain a measurement of oximetry in room air in patients who clearly require oxygen 10