Some people need extra oxygen at night as well as CPAP. Oxygen from a concentrator or tank is added to the CPAP airflow (“bleed-in”). Here’s what the manufacturer rules say. Your clinician decides whether you need it and at what flow.
Maximum oxygen flow by machine
| Machine | Max supplemental oxygen flow | Source |
|---|---|---|
| ResMed AirSense 11 | 15 L/min | AirSense 11 user guide |
| ResMed AirSense 10 | 4 L/min | AirSense 10 user guide |
| ResMed AirCurve 10 ASV | 15 L/min (CPAP, ASV modes); 4 L/min (ASVAuto) | AirCurve 10 ASV user guide |
If your oxygen prescription is above your machine’s limit, tell your clinician or supplier. It’s one of the real differences between the AirSense 11 and AirSense 10.
The on/off order (fire safety)
ResMed’s AirSense 11 guide says:
| Step | Do this |
|---|---|
| Starting therapy | Make sure the CPAP is on and blowing air before you turn on the oxygen |
| Stopping therapy | Turn the oxygen off first, then the CPAP |
| Why | So oxygen doesn’t accumulate inside the device and create a risk of fire |
| Always | No supplemental oxygen while smoking or near an open flame |
The AirSense 10 guide gives the same instruction (AirSense 10 user guide).
A practical habit: if you get up in the night, turn the oxygen off before you stop the CPAP, and turn it back on only once the CPAP is running again. SmartStop ends therapy a few seconds after you take the mask off, so with oxygen bleed-in, follow your clinician’s advice on whether to keep SmartStop on.
Your data may be off
ResMed notes that some AirSense 11 measurements “may be inaccurate in the presence of leaks or supplemental oxygen”. The AirSense 10 guide says accuracy may be reduced by supplemental oxygen. Bear that in mind when reading your AHI or leak figures in myAir or OSCAR (myAir and OSCAR explained).
Bilevel and ASV
For Medicare, the bilevel criteria in LCD L33800 are measured while breathing your prescribed oxygen (FIO₂). For example, central sleep apnea coverage requires improvement on the home settings while on that oxygen (LCD L33800). See BiPAP and ASV: Medicare rules.
Getting the oxygen
Home oxygen comes from a stationary concentrator, cylinders, or a portable concentrator. For nighttime bleed-in, the setup and flow are your clinician’s and supplier’s call. Medicare’s oxygen benefit has its own qualifying tests and a rental structure: see Medicare home oxygen coverage. For choosing equipment, see the oxygen concentrator buyer’s guide and 5 LPM vs 10 LPM.
Checklist
| Check | Done? |
|---|---|
| Oxygen flow is prescribed and within your CPAP’s maximum | |
| You know the order: CPAP on first, oxygen off first | |
| No smoking, candles or open flames in the room | |
| Supplier has set up the connection to your CPAP | |
| Clinician knows your CPAP data may be less accurate |
Verdict
CPAP with oxygen is common and workable. Stay within your machine’s limit (15 L/min on the AirSense 11, 4 L/min on the AirSense 10). Always start the CPAP before the oxygen and stop the oxygen before the CPAP. Keep flames away, and don’t treat the machine’s AHI as exact while on oxygen.
Related: APAP vs CPAP vs BiPAP, AirSense 11 settings explained.