Is my CPAP working? How to read your own data
Your CPAP or BiPAP machine records data every night: how long you used it, how much air leaked around your mask, how many breathing events it counted, and more. That data can show you patterns across your own nights. It cannot, on its own, tell you whether your therapy is working the way it should — that call belongs to your sleep clinician, usually alongside a follow-up sleep study.
AirwayLab reads the SD card your machine already writes to and shows the same metrics that appear on a standard machine report, usage, leak and AHI, plus the flow waveform underneath them: the shape of every breath, not just the summary count. Five of those numbers are below, in plain language, with a note on where each typical range comes from.
This page is informational, not a diagnosis. It describes what your data can show, never what to do about it. Bring what you notice to your clinician — your clinician can help interpret these findings in context.
Five things your data can show you
Usage hours per night
How many hours per night your machine ran, logged automatically every session.
Many insurers use 4 or more hours a night, on at least 70% of nights over a 30-day period, as a usage benchmark — a Medicare/CMS compliance standard, not a clinical target.
What a compliance report looks at →Leak
How much air is escaping around your mask, measured at the high end of the night (the 95th percentile) so a few short mask shifts don't skew the number.
AirwayLab's working cut-offs (colour bands, not a clinical reference range): green up to 24 L/min, amber up to 40 L/min, at the 95th percentile.
Residual events per hour (AHI)
The apnea and hypopnea events your machine's own onboard algorithm counted and reported, per hour of use.
AirwayLab's working cut-offs (colour bands, not a clinical reference range): green up to 5 events/hr, amber up to 10. It's reliable when elevated, but can read low even when RERA-like sequences or flow limitation are present elsewhere in the data.
Full AHI definition →Flow limitation (breath shape)
Scored from the shape of each breath — not just whether an event was counted, but how the airflow curve itself looked.
A breath-shape score measuring how far your breathing deviates from normal flow patterns.
Scored 0 to 9: nine breath-shape traits, each 0-1, summed. Typical nights score 0 to 3 and scores above 3 are rare. AirwayLab's own working bands sit lower, green up to 1.0 and amber up to 2.0, and are not a clinical reference range.
How every metric is computed →Oxygen (if you have an oximeter)
Only available if you also upload a separate pulse oximeter file alongside your SD card data.
Your average blood oxygen level throughout the night. Normal range is 94-98%.
What AirwayLab does not do
- AirwayLab is not a medical device and is not cleared or approved by the FDA, CE, TGA, or any regulatory body. It provides no diagnosis of sleep apnea or any other condition — only educational and informational content.
- AirwayLab does not tell you what to change on your machine. Any prescription or pressure-setting change is a decision for your clinician.
- AirwayLab is not a substitute for your clinician. Your clinician can help interpret these findings in context.
- All core analysis runs in your browser. Your data stays on your device unless you choose to share it.
Frequently Asked Questions
What does AHI mean on my machine?
AHI stands for Apnea-Hypopnea Index — the number of apnea and hypopnea events your machine counted and reported, per hour of use, as detected by the device's own algorithm. It's the single number most compliance reports lead with.
My AHI is low but I still feel tired, what can the data show?
A low AHI does not rule out other patterns in the same night of data. Flow limitation, RERA-like sequences and breathing pattern instability can all sit underneath a normal AHI, which counts only apneas and hypopneas. The sections above show where those patterns appear in your own waveform. Your clinician can help interpret these findings in context.
How do I get the data off my CPAP?
ResMed AirSense/AirCurve and BMC Luna/RESmart machines store nightly data on a removable SD card inside the machine. Take the card out, read it with a computer's built-in slot or a USB SD card reader, and select the whole SD card (BMC cards keep their files at the root), no manufacturer account or cloud service required.
Full getting-started walkthrough →Does AirwayLab change my settings?
No, never. AirwayLab only reads the data your machine already recorded — it cannot and does not write anything back to your device or change any setting.
Is my data private?
Yes. All core analysis runs in your browser by default; your data stays on your device unless you choose to share it. The analysis engine is open source (GPL-3.0) and publicly auditable.