How to Increase Oxygen Delivery with a Non-Rebreather Mask
To increase oxygen delivery with a non-rebreather mask, ensure the flow rate is set at 15 L/min—this is the only safe and effective flow rate for this device. 1, 2
Critical Flow Rate Requirements
Non-rebreather masks absolutely require 15 L/min oxygen flow to function properly. 1, 2, 3 Running the mask at lower flow rates (such as 4-10 L/min) is dangerous and can cause CO2 rebreathing, potentially leading to CO2 narcosis requiring intubation. 4
The reservoir bag must remain inflated throughout the respiratory cycle. 2 If the bag collapses during inspiration, this indicates insufficient flow rate and the patient is rebreathing exhaled CO2. 4
At the correct 15 L/min flow rate, a standard non-rebreather mask delivers 60-80% oxygen concentration (or up to 90% with optimal fit). 2, 3
Optimization Strategies Beyond Flow Rate
Improve Mask Seal
Ensure a tight mask-to-face seal to maximize oxygen delivery and minimize room air entrainment. 5 A loose-fitting mask significantly reduces delivered oxygen concentration.
Research demonstrates that tightening the mask fit can increase expired oxygen fraction from baseline to 0.85 (equivalent to inspired oxygen of 97%). 5
Consider Modified Non-Rebreather Designs
A "3-valve" non-rebreather mask (where the safety vent is replaced with a one-way valve) delivers higher oxygen concentrations than standard designs with safety vents. 5 Standard masks with safety vents typically deliver 60-80% oxygen, while 3-valve designs can approach 97% inspired oxygen when properly fitted. 2, 5
Double-trunk mask systems (modified partial rebreather with two pieces of tubing/"tusks") deliver higher PaO2 than standard non-rebreather masks at the same 15 L/min flow rate. 6, 7 In patients with interstitial lung disease, this design increased PaO2 by an additional 85 torr compared to standard non-rebreather masks. 6
When Non-Rebreather Mask is Insufficient
Escalation Algorithm
If the patient remains hypoxemic (SpO2 <94%) despite proper non-rebreather use at 15 L/min, seek senior or specialist advice immediately. 1 This indicates severe respiratory failure requiring advanced intervention.
Consider high-flow nasal oxygen (30-70 L/min) as an alternative to non-rebreather mask treatment in patients with acute respiratory failure without hypercapnia. 1, 8
Prepare for non-invasive positive pressure ventilation (CPAP/BiPAP) or intubation if oxygenation remains inadequate. 8
Critical Safety Considerations
Monitor for CO2 Retention
Obtain arterial blood gas within 1 hour of initiating non-rebreather therapy, especially in patients with COPD or other risk factors for hypercapnic respiratory failure. 1, 4
For patients with known COPD and oxygen sensitivity, target SpO2 of 88-92% rather than 94-98%, even when using high-flow oxygen. 1
Equipment Compatibility Warning
Never connect a non-rebreather mask to an oxygen concentrator with maximum output of 10 L/min. 2, 3 These devices cannot provide the required 15 L/min flow rate. Use simple face masks (5-10 L/min) or nasal cannula (1-6 L/min) with concentrators instead. 2, 3
Non-rebreather masks require wall oxygen or oxygen cylinders capable of delivering sustained 15 L/min flow. 2, 3
Clinical Monitoring
Allow at least 5 minutes at each oxygen dose before making further adjustments (except with major sudden desaturation). 1
Reassess the patient urgently if oxygen requirements are increasing or if there is a rising early warning score. 1
Verify the one-way valve between mask and reservoir bag is functioning properly and not jammed. 2