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What Is the AirCurve 11 ASV?

The ResMed AirCurve 11 ASV is a bilevel machine that runs Adaptive Servo Ventilation therapy. It is physically similar to the other AirCurve 11 models, but the therapy it delivers is different enough that it belongs in its own category. ASV is not a comfort upgrade over a regular AutoCPAP. It is a specific treatment for a specific problem: central sleep apnea and complex sleep apnea, where the brain intermittently stops sending the drive signal to breathe rather than the airway collapsing.

If you are on an AirCurve 11 ASV, your sleep physician chose it because a standard AutoCPAP or bilevel was not the right fit. That is worth understanding, because it shapes what your therapy data will and will not show. This review covers what the device records, what it cannot record, and how to read the data you do have. We also walk through what each setting means so you can have a more productive conversation with your provider.

ResMed sits at the top of the CPAP market for a reason, and the AirCurve 11 platform has solid hardware, a quiet motor, and integrated climate control through the ClimateLine tube system. The ASV variant adds the specialized breath-by-breath pressure support algorithm. The tradeoff is price: ASV machines are considerably more expensive than AutoCPAP or standard bilevel devices because the therapy is prescription-limited and the algorithm is substantially more complex.

Until recently, reading the detailed ASV data on your own computer meant either OSCAR (powerful but complex) or nothing. CPAP Clarity now reads the AirCurve 11 ASV SD card format directly in your browser, no installation, no account, no subscription.

Who Is ASV For?

This part matters because ASV is often confused with regular bilevel therapy.

ASV is prescribed when: your sleep study shows central sleep apnea, complex (mixed) sleep apnea, treatment-emergent central apneas on a standard CPAP, or periodic breathing patterns including Cheyne-Stokes respiration. The machine solves a problem that pressure alone cannot. It watches your breathing, learns your personal target minute ventilation, and adds bursts of pressure support when you stop breathing on your own.

ASV is NOT for: uncomplicated obstructive sleep apnea. If your events are primarily caused by airway collapse, an AutoCPAP like the ResMed AirSense 11 or a standard bilevel is usually the right device.

ASV also has a labeled contraindication for some patients with chronic symptomatic heart failure with reduced left ventricular ejection fraction. This is tied to the 2015 SERVE-HF trial result, which is why ASV prescribing carries an FDA-labeled warning rather than a soft recommendation, and why the decision sits with your sleep physician and is often coordinated with your cardiologist. If you were prescribed an AirCurve 11 ASV, your physician has already weighed this. We are not your doctor and this article is not medical advice.

If you are reading this because you were recently switched from a CPAP or bilevel to an ASV, the short version is: your provider saw something in your previous data that pointed at central apnea rather than obstructive. The AirCurve 11 ASV is designed to treat that specific pattern.

What the AirCurve 11 ASV Records

Every night, the AirCurve 11 ASV writes waveform data, event records, and daily summaries to its SD card. Here is what CPAP Clarity decodes from that data.

Therapy pressure waveform: The continuous mask pressure sampled at 25 Hz, stored in the PLD file. You can see how the machine adjusted pressure across the night, including the characteristic breath-by-breath pressure support swings that are the signature of ASV therapy.

Target EPAP: The expiratory positive airway pressure the machine is delivering at the end of each breath. On ASV Auto, this floats between your prescribed minimum and maximum EPAP.

Pressure support range: The difference between IPAP and EPAP on each breath. Unlike a fixed bilevel, ASV varies pressure support breath-by-breath within your prescribed range to match your ventilation target.

Target minute ventilation: The personalized ventilation target the machine is trying to maintain. This is an ASV-specific signal that standard bilevels do not expose. CPAP Clarity captures it from the PLD file.

Leak rate: Mask seal measurement in liters per minute, converted from the raw L/s storage format.

Respiratory rate, tidal volume, minute ventilation: Per-breath measurements from the PLD file, useful for spotting nights where the machine was working harder than usual.

Flow limitation and snore indices: Airway narrowing indicators.

Hypopnea events: Partial breathing reductions, with timestamps and durations.

Apnea events: Complete breathing pauses, with timestamps and durations.

Machine settings snapshot: Mode, EPAP range, pressure support range, mask type, tube type, humidity, and climate control mode. Pulled from both Identification.json and the STR.edf fallback.

What it does not record

The AirCurve 11 ASV firmware (SW04600.16.8.5.0) has two notable gaps in its SD card output. These are device-level boundaries, not limitations of CPAP Clarity.

Obstructive vs. central apnea split. The firmware records every apnea event as a generic "Apnea" text without labeling it as obstructive or central. This is unusual compared to the AirSense 10, AirSense 11, and AirCurve 10, all of which do differentiate. On your AirCurve 11 ASV, CPAP Clarity shows apneas as "unclassified" rather than split into OSA and CSA. Your total AHI is still accurate. The machine itself is still distinguishing events internally to drive the ASV algorithm. It just does not persist the OSA/CSA label to the SD card.

Cheyne-Stokes respiration logging. The same firmware does not write Cheyne-Stokes episode annotations to the SD card. No _CSL.edf files are created, and no CSR markers appear in the event file. This is the ironic part: ASV users are on ASV precisely because they have central or complex apnea patterns that often include Cheyne-Stokes breathing, and the machine is responding to those patterns in real time through pressure support. It just does not log the episode windows where we could read them later.

Both limitations are documented in the firmware and consistent across 181 nights of contributor data we tested against. If a future firmware revision exposes either field, CPAP Clarity will pick it up automatically.

How to Read Your AirCurve 11 ASV Data

Reading your data requires only the SD card in the machine and a computer.

Power off your AirCurve 11 ASV. The SD card slot is on the side of the machine behind a small door. Remove the card.
Insert the card into your computer. If your computer does not have a built-in SD card reader, a USB-C SD card reader (opens in new tab) costs a few dollars.
Open cpapclarity.com in your browser. No installation, no account, no subscription required.
Drop the whole SD card folder onto the import area. Select the entire SD card contents. Do not navigate into DATALOG or SETTINGS. CPAP Clarity detects the ResMed AirCurve 11 ASV format automatically.
View your data. Your AHI, pressure graph, EPAP and pressure support ranges, leak trends, target ventilation, and therapy score appear within seconds. Your health data never leaves your device.

For a detailed walkthrough with screenshots, see how to use CPAP Clarity.

The AirCurve 11 ASV stores several months of summary data in STR.edf plus full per-night detail in DATALOG for every night since the last card format. If you have been on the same card since you got the machine, you likely have everything.

Understanding Your AirCurve 11 ASV Numbers

Once your data is imported, here is what to look at first.

AHI and the apnea breakdown

Your AHI is the total breathing disruptions per hour. On the AirCurve 11 ASV, this includes unclassified apneas plus hypopneas. For a general introduction to what AHI means, see what is AHI.

On ASV, a low AHI is the expected outcome, because that is literally what the therapy is designed to produce. If your AHI is consistently above 5 despite the machine working correctly, talk to your provider. An ASV that cannot bring your AHI down is telling you something.

Because your firmware records every apnea as unclassified rather than obstructive or central, the donut chart on your dashboard will show apneas as a single "Apnea" slice. The dashboard surfaces an explicit note explaining this is a device firmware limit rather than a CPAP Clarity issue, so when you bring your data to your sleep physician you can point at the note and the distinction is clear.

Pressure support in action

The signature of ASV therapy is watching pressure support change breath-by-breath. When you are breathing normally, the machine holds pressure support near your minimum. When your breathing drive falters, the machine boosts pressure support toward your maximum to keep ventilation on target. This is what separates ASV from a standard bilevel where pressure support is a fixed number.

On the pressure graph, you can see this as a varying gap between the IPAP and EPAP curves across the night. Flat gap, stable breathing. Widening gap, the algorithm stepping in. This visual is one of the reasons pulling your data is useful. Your machine screen cannot show you this.

Target ventilation tracking

CPAP Clarity captures the target minute ventilation channel that is specific to ASV mode. This is the personalized ventilation goal the machine is trying to maintain. Comparing your actual minute ventilation against the target tells you whether the algorithm is succeeding. Large or prolonged gaps are worth raising with your provider.

Leak and comfort

Leak handling on the AirCurve 11 ASV is identical to other ResMed machines. Low leak is normal and healthy. Persistent high leak suggests mask fit, headgear tension, or sleeping position problems before suggesting a different mask. See how to fix CPAP mask leaks for practical troubleshooting.

AirCurve 11 ASV Settings Explained

CPAP Clarity reads your complete settings directly from the SD card. Here is what each one means.

Mode: "ASV Auto" means the machine runs Adaptive Servo Ventilation with an automatically adjusting EPAP. "ASV" without "Auto" means fixed EPAP with automatic pressure support. Most users on the AirCurve 11 ASV are on ASV Auto.
Min EPAP and Max EPAP: The range within which the machine can adjust the expiratory (end of breath) pressure. Your provider sets this based on your titration study. Typical values are 4 to 15 cmH2O.
Min pressure support and Max pressure support: The range of additional pressure the machine can add on inhalation. Max PS 6 cmH2O is common; some prescriptions go higher.
Start pressure: Where the machine begins before ramping up to treatment pressure.
Mask type: Tells the machine whether you are using a nasal pillow, nasal, or full face mask. This affects how leak is interpreted.
Tube type: The AirCurve 11 ASV supports standard 15mm tubes, heated 15mm tubes, slim 19mm tubes, and the ResMed ClimateLineAir. The tube type is recorded in your settings and affects humidity and climate behavior.
Humidifier level and climate control: Manual humidifier is 0 to 8, or Auto mode lets the machine choose. Heated tube temperature is separately configurable.
Ramp: Whether the machine starts at a lower pressure and increases to your treatment level over time. Some users prefer ramp off on ASV because the therapy feels more comfortable at full treatment from the start.

All of these settings are clinical decisions made by your sleep physician. Do not change pressure settings based on your data alone. Bring your CPAP Clarity export to your next appointment instead.

Accessories and Essentials

The AirCurve 11 ASV uses standard CPAP fittings and is compatible with most universal accessories.

Masks

Mask choice is the single biggest comfort factor. The AirCurve 11 ASV works with any standard ResMed-compatible mask. For guidance on picking a mask type, see full face vs. nasal masks or try our mask finder quiz.

Popular ResMed mask options that work well with the AirCurve 11 ASV:

ResMed AirFit P30i nasal pillow mask (opens in new tab) for minimal contact
ResMed AirFit N30i nasal mask (opens in new tab) for balanced comfort and seal
ResMed AirFit F30i full face mask (opens in new tab) for mouth breathers

SD cards and readers

The AirCurve 11 ASV uses a standard SD card. Any name-brand card up to 32 GB works. See best SD card for your CPAP for specific recommendations, and grab a USB-C SD card reader (opens in new tab) if your computer lacks one.

Cleaning and maintenance

Standard ResMed cleaning practices apply. Daily mask cleaning with mild soap, weekly humidifier chamber cleaning, filter replacement on the schedule in your manual.

Helpful supplies:

CPAP cleaning wipes (opens in new tab) for quick daily mask maintenance
ResMed AirSense 11 / AirCurve 11 filters (opens in new tab)
ResMed ClimateLineAir heated tube (opens in new tab) if you need a replacement

For a complete maintenance routine, see how to clean your CPAP.

AirCurve 11 ASV vs AirCurve 10 vs AirSense 11

Feature	AirCurve 11 ASV	AirCurve 10 VAuto	AirSense 11 AutoSet
Therapy type	ASV (Adaptive Servo Ventilation)	VAuto bilevel	AutoCPAP
For	Central or complex apnea	Obstructive apnea with pressure needs	Standard obstructive apnea
Pressure support	Dynamic, breath-by-breath	Fixed or auto within range	EPR (exhale relief)
Target ventilation	Yes, personalized	No	No
OSA / CSA split in data	No (firmware limitation)	Yes	Yes
CSR logged to SD card	No (firmware limitation)	Yes	Yes
Hypopneas in data	Yes	Yes	Yes
CPAP Clarity support	Yes	Yes	Yes
Cost tier	Highest	Mid to high	Mid

The AirCurve 11 ASV sits at the top of the lineup for price and therapy complexity. The core reason is the algorithm, not the hardware.

When to Talk to Your Doctor

Your therapy data is most valuable when you share it with your sleep physician. Patterns worth bringing to your next appointment:

AHI consistently above 5 events per hour despite being on ASV. The algorithm should be driving this number down. If it is not, something needs adjustment.
Elevated or rising leak trends despite mask fit adjustments. Persistent leak limits how effective the therapy can be.
Persistent daytime sleepiness despite consistent nightly use and good AHI. There may be other factors affecting your sleep quality that your data cannot see.
A large gap between actual and target minute ventilation across multiple nights. This is an ASV-specific signal worth flagging.

CPAP Clarity generates PDF reports formatted for clinical review. Download one before your appointment. For tips on presenting your data effectively, see preparing CPAP data for your doctor.

Get Started

If you have an AirCurve 11 ASV and have not seen your detailed therapy data, now you can. Pull the SD card, open cpapclarity.com, and drop in the folder. It takes under a minute, it is completely free, and your health data stays on your device.

Analyze your AirCurve 11 ASV data now, free and private →

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AirCurve 11 ASV Review: Central Apnea Data Guide