Central Apneas Showing Up on CPAP: Treatment-Emergent CSA Explained

You finally got your CPAP dialed in — leaks are low, the mask is comfortable — but now your data shows a new kind of event: central apneas, sometimes labeled "clear airway" (CA) or "CSR" on your report. It can feel like the therapy is causing a new problem. In most cases it isn't, and there's a name for what you're seeing: treatment-emergent central sleep apnea, or TECSA.

This guide explains what TECSA is, why it tends to appear after starting CPAP, why it usually fades on its own, and — importantly — when persistent central events deserve a conversation with your sleep clinician.

What treatment-emergent CSA (TECSA) is

Sleep apnea events come in two main flavors. An obstructive apnea happens when your airway physically collapses or is blocked, even though your brain is still telling you to breathe. A central apnea is different: the airway is open ("clear"), but your brain briefly stops sending the signal to breathe. That's why machines label these as clear-airway (CA) events — the device detects no airflow and no obstruction.

Treatment-emergent central sleep apnea (TECSA) — also called complex sleep apnea — describes a specific pattern:

• You were diagnosed with obstructive sleep apnea (OSA).
• Once CPAP splints your airway open, the obstructive events largely resolve.
• But now central events appear or persist, sometimes enough to keep your overall AHI elevated.

Clinically, TECSA is generally defined as a central apnea index of 5 or more events per hour that emerges once obstructive events are controlled on PAP therapy. If the distinction between event types is new to you, our primers on central vs obstructive apnea and the three types of apnea lay out the differences in plain language.

How common is it? TECSA shows up in roughly 5–15% of OSA patients during PAP titration — so while it's not the typical experience, it's far from rare, and it's a well-recognized phenomenon among sleep physicians.

Why central events can appear after starting CPAP

It can seem paradoxical that fixing one breathing problem reveals another. Here's the short version of what's happening.

CPAP is designed to splint the airway open with a steady cushion of pressurized air. It reliably treats obstructive events because those are a mechanical, plumbing problem — pressure props the airway open. But CPAP doesn't directly correct the breathing drive itself, the brainstem rhythm that decides when and how hard to breathe. Central events come from that control system, not from a blocked airway.

A few things can nudge that control system off balance when therapy begins:

• Newly stable airflow. Before CPAP, frequent obstructions kept your CO₂ levels bouncing around. Suddenly delivering clean, open-airway breathing can briefly destabilize the feedback loop that regulates breathing, leading to over- and under-breathing cycles (this instability is sometimes described as high loop gain).
• Lower CO₂ levels. Easier breathing can drop your carbon dioxide just below the threshold that triggers your next breath, producing a pause.
• Arousals and adjustment. The first weeks on CPAP often mean fragmented, lighter sleep as you adapt — and breathing control is naturally less steady in lighter sleep.

The key reframe: a rise in clear-airway events on CPAP usually reflects a temporary instability in breathing control, not a sign the machine is harming you or that your obstructive apnea is worse. To see how these events sit alongside hypopneas, RERAs, and obstructive events on your report, see CPAP event types decoded.

The reassuring part — it often resolves on continued CPAP

Here's the good news, and it's the most important takeaway: TECSA frequently goes away on its own.

Reported spontaneous resolution sits in the range of roughly 60–80%, typically within a few weeks to a few months of continued CPAP use. As your body adapts to therapy and your breathing-control system re-stabilizes on the steady pressure, the central events tend to taper down.

That's why one of the standard, clinician-guided management paths for TECSA is simply watchful waiting on CPAP — staying the course on your prescribed therapy while your provider monitors the trend. The pressure isn't the enemy here; continued, consistent use is often part of the solution.

This is exactly the kind of situation where a trend matters far more than any single night. One night with elevated centrals tells you almost nothing — natural night-to-night variation is large (more on that in why your AHI changes night to night). What you want to watch is the direction over weeks.

This is where seeing your own data clearly pays off. SomniCharts imports your ResMed, Philips Respironics (including the encrypted DreamStation 2), and Löwenstein prisma data and automatically breaks out your central-vs-obstructive event split over time in plain language. Instead of guessing, you can watch whether your clear-airway events are trending down (they usually do) — and bring that clear, dated trend line to your doctor instead of a single confusing report.

A residual AHI below 5 events per hour is the widely used benchmark for effective CPAP therapy; the AASM defines an "optimal" titration as reducing the AHI to under 5. Some clinicians aim lower when it's comfortably achievable, but targets are individualized with your provider — there's no universal "below 2" rule. For the full picture, see what is a good AHI on CPAP.

When persistent central events need action

Most TECSA fades. But a minority of cases persist, and some warrant a closer look sooner rather than later. Loop in your sleep clinician if you notice any of the following:

• Central events that stay elevated or rise over two to three months instead of trending down.
• Returning symptoms — daytime sleepiness, morning headaches, or unrefreshing sleep coming back after an initial improvement.
• Deep oxygen drops, if you track oximetry.
• New medications, especially opioids, which are a known trigger for central apnea.
• New or known heart or kidney conditions — heart failure in particular is linked to a distinct breathing pattern called Cheyne-Stokes respiration, a waxing-and-waning cycle that's different from adjustment-phase TECSA. If your report shows periodic breathing or a CSR label, read Cheyne-Stokes respiration and the heart connection and periodic breathing on your CPAP chart, and raise it with your provider promptly.

Persistent central sleep apnea is also one of the conditions that an in-lab sleep study is specifically suited to evaluate — home sleep tests aren't designed to diagnose central apnea or hypoventilation (see in-lab PSG vs home test).

When TECSA doesn't resolve on its own, your clinician has options, and they're decided by a professional — not by trial-and-error at home. Depending on the cause, these may include:

• Switching to BiPAP or, more often for central events, adaptive servo-ventilation (ASV) — a bilevel mode built specifically to stabilize irregular breathing. (See how these machines report data in reading ResMed AirCurve bilevel and ASV data.)
• Adding supplemental oxygen.
• Other measures or medication adjustments tailored to your situation.

Note that ASV is not appropriate for everyone — it's contraindicated in certain heart-failure patients — which is exactly why this decision belongs to a clinician who knows your full medical picture.

Why you should never raise pressure to chase centrals

This is the single most important "don't" in this whole topic, so it gets its own section.

When you see your AHI tick up because of central events, the instinct is understandable: the number's high, so I need more pressure. That instinct is wrong for central apneas.

Higher CPAP pressure does not fix central events — and it can sometimes provoke them. Remember the mechanism: central apneas come from an unstable breathing drive, not a blocked airway. Cranking up the pressure does nothing to correct the brain's breathing signal, and in some people it further destabilizes the breathing-control loop (and can drive CO₂ down even more), making centrals worse. You could end up chasing a number in the wrong direction.

The defensible, safe move is always the same: use your data to have an informed conversation with your provider. Don't self-adjust your prescribed pressure to fight central events. This is true even though your machine technically shows a higher AHI — see can I adjust my own CPAP pressure and is your pressure too high or too low for why the data is for conversation, not for solo dial-turning.

A practical way to come prepared: bring a clear picture of your central-versus-obstructive trend to your appointment. Showing your clinician that your clear-airway events are (or aren't) declining over weeks turns a vague worry into a concrete, decision-ready conversation — which is exactly the kind of plain-language, multi-vendor trend view SomniCharts is built to produce automatically.

For the bigger optimization picture, head back to the Troubleshooting & Optimizing CPAP pillar.

Frequently asked questions

Is treatment-emergent CSA dangerous?

For most people, TECSA is a temporary adjustment phenomenon that resolves on continued CPAP within weeks to a few months. It becomes a concern when it persists, when symptoms return, or when it's tied to medications (like opioids) or heart conditions — situations your clinician should evaluate.

Will my central apneas go away on their own?

Often, yes. Reported spontaneous resolution is roughly 60–80% on continued CPAP. The best thing you can do is keep using your therapy consistently and watch the trend over weeks rather than reacting to a single night.

Should I lower or raise my pressure if I see central events?

Neither — not on your own. Raising pressure doesn't treat central events and can sometimes make them worse, and any prescribed-pressure change should be made by your clinician based on your data, not self-adjusted.

What's the difference between clear-airway and obstructive events on my report?

A clear-airway (central) event means the airway is open but your breathing drive paused; an obstructive event means the airway was blocked. CPAP reliably treats the obstructive type. For a deeper dive, see central vs obstructive apnea.