AirSense 11 · AirSense 10 · AirCurve · Nonin 3150 BLE or wired XPod
Your ResMed can record oxygen. We read it.
Pair a compatible Bluetooth oximeter to your ResMed and the machine writes its oxygen and pulse readings straight onto the same SD card as your therapy, second for second. CPAP Clarity reads that data automatically when you import the card, and shows ODI, minimum SpO2, and time below 88 percent next to your AHI for the same night.
A feature even a lot of clinicians do not know about
ResMed machines can take readings from an external pulse oximeter and log them onto the SD card, alongside your flow, pressure, and events. The AirSense 11 does it wirelessly, pairing over Bluetooth with a wrist-worn Nonin 3150 BLE. The AirSense 10 and AirCurve 10 do it with a cable, through a ResMed oximetry adapter module and a Nonin finger sensor. There is no Bluetooth pairing on those older machines, so do not buy the wireless 3150 for an AirSense 10.
These are prescription, lab-grade devices used in overnight studies. They are not cheap, and they are not for everyone. But if you already own one, or your doctor has prescribed one to work through an oxygen problem, its readings are already on your CPAP card. There is no second file to export. Import the card and the oxygen comes in with it.
If you do not have a paired oximeter, a consumer recording ring is the more practical way to track overnight oxygen, and CPAP Clarity reads those too.
- SpO2 from a paired oximeter on your ResMed: the full walkthrough of machines, the oximeter, and the setup.
- The Wellue O2 Ring option: the affordable consumer recording ring, imported separately.
- AHI and ODI: how the two metrics relate: why a clean AHI can sit next to an abnormal oxygen night.
What CPAP Clarity reads from the recording
Because your ResMed writes the oximeter readings to the SD card with its own timestamps, the oxygen data lines up exactly with your breathing. No guessing which reading matches which event across two separate apps.
The single lowest oxygen value of the night, with motion filtered out. Catches brief severe dips the average hides. Read directly from what the machine recorded, cross-checked sample for sample against OSCAR.
Oxygen Desaturation Index at the AASM-recommended 3% threshold. Counts each time your SpO2 drops more than 3 percent below your stable overnight level and recovers, divided by recording hours.
ODI at the 4% threshold most US clinics still use, because Medicare's hypopnea definition uses 4%. CPAP Clarity reports both so you have the number your clinician asks for.
The total minutes your SpO2 sat below 88 percent, the threshold US rules use when considering supplemental oxygen, plus the percent of recording time. A standard reporting line on clinical oximetry.
Every night joins your therapy session by date. The dashboard shows AHI, leak, and usage alongside ODI3, ODI4, mean SpO2, and minimum SpO2 for the same night, so a low-AHI night with a bad oxygen dip stands out.
Paired oximeter vs a consumer ring vs a sleep study
| Feature | Paired oximeter | Consumer ring | In-lab sleep study |
|---|---|---|---|
| Aligned to your CPAP clock | Yes: Second-for-second, no export | Partial: Joined by calendar date | Yes: All channels time-synced |
| Continuous overnight SpO2 | Yes: 1 second cadence | Yes: ~4 second cadence | Yes: Medical-grade continuous |
| ODI + minimum SpO2 + time below 88% | Yes: All reported | Yes: All reported | Yes: Clinical reporting standard |
| Cost + access | No: Prescription, ~$1000 | Yes: Consumer, low cost | Partial: Covered but needs referral |
| Sleep stages + airflow | No: Not measured | No: Not measured | Yes: Essential for apnea typing |
| Diagnoses apnea | No: Screening only | No: Screening only | Yes: Standard of care |
The paired oximeter's edge is fidelity and alignment: lab-grade accuracy, one-second cadence, and readings already time-synced to your therapy. Its cost is the trade-off. For most people a consumer ring is the sensible choice.
Which should you use?
you already own or are prescribed a compatible medical oximeter. You want lab-grade accuracy and oxygen that lines up second for second with your therapy.
you want overnight ODI and minimum SpO2 without a prescription or a four-figure cost. A recording ring exports a CSV this site reads, joined to your CPAP night by date.
you suspect untreated apnea and need a diagnosis, or home oximetry is flagging a problem and your physician needs the full airflow and respiratory-effort picture.
What a concerning night might look like
Representative example. Numbers below are illustrative, not a real user's data.
In a representative concerning night, the recording might show ODI3 of about 4 events per hour with a mean SpO2 near 87 percent, a minimum of 79 percent, and several hours below 88 percent across an eight-hour night. The CPAP side of that same night might read an AHI under 2.
That kind of quiet-AHI, low-oxygen split is exactly what the paired recording is good at surfacing. The machine scored the night as calm by its own metric, but the oxygen channel did not agree. A pattern like that across weeks, brought to a sleep physician, is what these numbers are for. A single night with a sensor that slipped is not.
How to set it up
Connect the oximeter to your machine
On the AirSense 11, put the machine into Bluetooth pairing mode from the setup menu and pair the Nonin 3150 the way you would pair headphones. On the AirSense 10 or AirCurve 10, there is no pairing: plug the ResMed oximetry adapter module into the port below the SD card slot and connect the finger sensor to it. The exact wording varies by firmware.
Wear it overnight with the machine running
Wear the oximeter as you sleep. It records, and the machine pulls the readings in and writes them to the SD card through the night. You do not need to touch the oximeter's own software.
Import your SD card as usual
Take the card out in the morning, drop the whole card folder onto the import area on the Oxygen page, and let it parse in your browser. The oxygen data rides in with your therapy data.
Frequently Asked Questions
Which ResMed machines can record from a connected oximeter, and how?
The AirSense 11 pairs one over Bluetooth. The AirSense 10 and AirCurve 10 use a wired oximetry adapter module instead, with no Bluetooth pairing. Either way the readings land on the SD card. Travel and summary-only machines that do not write detailed nightly session data, such as the AirMini and the AirStart, do not carry this stream. CPAP Clarity's reading is checked sample for sample against OSCAR on the AirSense 11 path; an AirSense 10 records the same kind of ResMed oximetry file through its wired adapter, so it should read the same way, though we have not yet validated an AirSense 10 recording.
Which oximeter do I need for my machine?
It depends. The AirSense 11 pairs with the wrist-worn Nonin WristOx2 3150 BLE over Bluetooth. The AirSense 10 and AirCurve 10 use the ResMed oximetry adapter module with a Nonin finger sensor (the XPod), connected by cable. Do not buy the wireless 3150 for an AirSense 10; it will not pair. Both are prescription, lab-grade devices sold through medical suppliers, and expensive. If you do not have either, a consumer recording ring is the more affordable route to overnight oxygen, imported separately.
Do I need the oximeter's own software?
No. For CPAP Clarity, you only import your CPAP SD card. Your ResMed already wrote the oxygen readings to the card, so the oximeter's own program is optional. If you want to compare CPAP Clarity's drop counts against the device's own, that is where the oximeter software or app is handy.
Will the numbers match my oximeter's app?
The oxygen levels themselves (minimum, mean, time below a threshold) are direct reads of what the machine recorded, checked sample for sample against OSCAR, so they match the raw data. The oxygen-drop counts (ODI) are computed the standard way and may read a little differently from your Nonin software, because different tools apply the counting rules differently and the Nonin's own program may work from a finer internal signal. If they look off, a screenshot from the app helps settle it.
Is my oximetry data shared with anyone when I import it?
No. Your CPAP card is parsed entirely in your browser. The oxygen readings, like your therapy data, are stored only in your browser's local storage, on the device you imported from. Nothing about your recording is uploaded. The data hub at /data removes them when you want.
Can a paired oximeter diagnose sleep apnea?
No. A recording oximeter is a screening and tracking tool, not a sleep study and not a diagnosis. A sleep study measures airflow, respiratory effort, brain activity, and oxygen together, scored by a clinician. A pulse oximeter measures only oxygen and pulse. Overnight oximetry is a validated screening signal, and a lab-grade device gives you that signal with hospital-level accuracy, but a clean night does not rule apnea out and a bad one does not diagnose it.
Primary Sources
- Nonin Medical. WristOx2 Model 3150 with Bluetooth Low Energy. A wrist-worn recording pulse oximeter with Bluetooth Low Energy for overnight SpO2 and pulse capture.nonin.com
- American Academy of Sleep Medicine. AASM clarifies hypopnea scoring criteria. Recommends the 3% desaturation threshold; accepts 4% as an alternative.aasm.org
- U.S. Food & Drug Administration. Pulse Oximeter Basics. Explains medical vs over-the-counter vs wellness oximeters and what affects accuracy.fda.gov
Related Reading
- SpO2 From a Paired Oximeter on Your ResMed: the full walkthrough.
- Pulse Oximeters for CPAP: overnight oximetry alongside CPAP data, including the consumer-ring option.
- AHI and ODI: How the Two Metrics Relate: why a normal AHI can hide an abnormal ODI.