KPAP: The Next Treatment Evolution for Sleep Apnea
An Interview with Dr. William Noah, Chairman and Chief Scientific Officer, SleepRes
For decades, continuous positive airway pressure (CPAP) has been the cornerstone therapy for obstructive sleep apnea (OSA), yet its promise remains hamstrung by low long-term adherence. As we explored in our previous post, the fundamental challenge isn’t efficacy — CPAP can profoundly reduce apnea–hypopnea events — but rather patient tolerance. This persistent adherence gap has spurred countless incremental tweaks, from humidification to bilevel modes, but few innovations have fundamentally reimagined how positive airway pressure is delivered.
Enter KPAP — Kairos Positive Airway Pressure — and the team at SleepRes, Inc. led by pulmonologist, innovator, and KPAP inventor Dr. William H. Noah, chairman and chief scientific officer. Building on early physiologic insights and patient-centered research, KPAP reframes PAP therapy by modulating pressure in synchrony with the respiratory cycle rather than maintaining a single continuous level. By timing therapeutic pressure “at the right moment,” the technology aims to preserve airway patency while reducing unnecessary pressure — potentially lowering discomfort, minimizing side effects, and improving real-world tolerance.
The company has received FDA 510(k) clearance of the company’s Kricket™ PAP device powered by KPAP — a milestone in bringing this concept out of theory and into clinical practice. This article talks with Dr. Noah about the science, the journey from bench to bedside, and what KPAP could mean for the future of OSA treatment.
KPAP concept and differentiation
What originally led you and your team to pursue KPAP as a new approach to positive airway pressure therapy?
In April 2021, I stopped seeing patients in my practice and dedicated all my time to finding a better way with CPAP. I really didn’t have a particular idea. I put together a laboratory on my farm outside Nashville, Tennessee and began testing PAP devices/masks from all around the world. Almost immediately it seemed to me the problem was inspiratory pressure, not expiratory. In addition, our literature clearly showed late expiration was the crucial time for therapy, not inspiratory as most assumed. It appeared that current devices were engineered backwards.
But there was no way to reduce inspiratory pressure (IPAP) below expiratory pressure (EPAP) with current devices. That was taboo. I had to first invent a way. In July 2021, I 3-D printed the first V-Com® to test my new theory about reducing inspiratory pressure, and I released it on the market in June 2022 at APSS. Early CPAP devices had reduced inspiratory pressure, which made breathing more natural, but the field (including me) had developed the wrong understanding after bilevel PAP (BPAP) was released. It is unfortunate that the initial BPAP study had only 13 patients (with mean BMI 55 and 3 on oxygen) and we somehow extrapolated this to routine OSA.
V-Com was released just to get more clinical data on reducing inspiratory pressure and to start challenging the old mindset in the field. But at that point in June 2022, I turned my whole focus on this concept I had for KairosPAP (KPAP).
How would you describe KPAP’s mechanism in physiologic terms to clinicians familiar with CPAP?
Where CPAP was “continuous” PAP, it has become more “constant” PAP, and devices are engineered to deliver constant therapy pressure to the mask through the whole respiratory cycle. KPAP focuses on the concept of a Kairos (Greek for “critical time”) in the airway. There is a critical time (Kairos) that pressure is required which is the later part of expiration. KairosPAP (KPAP) just delivers the therapy pressure during the Kairos (last 25% of respiratory cycle). Otherwise KPAP reduces the pressure to increase comfort and decrease side effects.What makes KPAP fundamentally different from conventional PAP systems?
Current PAP systems (BPAP, CPAP with expiratory pressure reduction algorithms) are engineered to reduce expiratory pressure (which compromises the airway) and increase inspiratory pressure (to ventilate unnecessarily) and increase TECSA. They are backwards. They provide therapy pressure at the wrong time. They are the anti-Kairos. KPAP provides therapy pressure at just the correct time in the airway to optimize patency and lung volume. The clues were in our literature 30 and even 40 years ago.
Which key limitations of CPAP does KPAP aim to solve most directly?
This is a very long answer. To be brief, pressure and timing of pressure are the main issues with CPAP. By reducing the overall pressure, and adjusting the timing to be more natural, we have created a better experience with less side effects.
Where does KPAP currently fall short compared with traditional CPAP?
We may find no shortcomings to standard CPAP. But we have no data yet in COPD and obesity hypoventilation syndrome (OHS). For now, you can still use the Kricket device to provide APAP/CPAP in patients with OSA and COPD or OHS but turn KPAP off. We also have no data yet in children. Again, you can still use the Kricket APAP/CPAP device (down to 66lbs) but no data with KPAP. Obviously, patients with chronic respiratory failure requiring ventilation should not be on any traditional CPAP device.
Patient selection and product–market fit
Which OSA patient phenotype do you believe is the best match for KPAP?
Great question. Do you mean endotypes or phenotypes? As far as endotype, you can use Kricket wherever you would use CPAP and turn KPAP on for uncomplicated cases. KPAP would likely be advantageous over CPAP in patients who have increased loop gain. The reduced inspiratory pressure should reduce the likelihood of TECSA (JCSM, March 2025).
Do you see KPAP primarily as a second-line therapy for CPAP-intolerant patients or eventually first-line in certain groups? Why?
The Kricket APAP/CPAP device with KPAP will immediately become first line therapy. It has already obsoleted other CPAP devices. It provides CPAP/APAP like other devices but also has KPAP which most patients prefer. Even for the small group of patients who prefer the feel of CPAP over KPAP initially, you would still prescribe a Kricket device with KPAP turned off. That patient may have problems with leak or TECSA, or possibly aerophagia or noise complaints from their spouse, where you would later turn the KPAP algorithm on. I cannot think of a clinical reason you would prescribe another CPAP device over Kricket.
What proportion of today’s CPAP population do you estimate could be good KPAP candidates?
100% of CPAP candidates would be Kricket candidates. Those with COPD or OHS and children should have KPAP turned off. In White et al (Sleep Medicine 2024) 94% of newly diagnosed patients (n=150) chose KPAP at various pressure drops over CPAP.
Are there specific clinical characteristics—pressure needs, anatomy, breathing pattern—that predict response?
That has not been examined in a systematic way. Obviously, patients requiring higher pressure are more likely to prefer KPAP. I would make it available to everyone initially.
Evidence and clinical validation
What key clinical studies of KPAP or the SleepRes system have been completed to date?
What findings have been most encouraging so far (efficacy, adherence, patient preference)?
Two well-designed, sufficiently powered randomized trials using PSG: one with CPAP vs KPAP (n=50), one with Philips APAP vs SleepRes APAP vs SleepRes APAP + KPAP (n=35)
In both trials (whether CPAP or APAP) the efficacy of KPAP was equal. In addition, KPAP had nearly 50% less unintentional leak.
In addition, there was the patient preference trial mentioned above.
The most encouraging thing to me is the efficacy data. It proves my whole theory of a Kairos (critical time) in the airway in late expiration. Dr Mark Sander, the inventor of flow-triggered bilevel PAP which revolutionized ventilation therapy around the world, has been so much help and counsel to me over the past 3 years. We have spent hours and hours discussing airway physiology and timing of pressure. With these efficacy trials, he says the theory phase is over, and it’s now data; we have proven the Kairos in late expiration. Finding the Kairos was the key. KairosPAP is the logical development.
What key questions about KPAP still need to be answered?
Are randomized or comparative trials versus CPAP underway or planned?
Yes, the biggest question is increased adherence. We have a large multicenter adherence trial planned once we enter the market. We have a lot of anecdotal experience suggesting increased tolerance from other trials. We also have nearly 1000 sleep clinicians who have compared breathing on KPAP to CPAP and 99% preferred KPAP, but adherence is behavioral, not just comfort based.
Several leaders in the field have told me even if long term adherence does not increase much, they would still use Kricket exclusively because of the increased comfort and decreased side effects (leak, TECSA, etc).
The other big question is does the reduced mean pressure with KPAP improve cardiovascular (CV) outcomes. We have a trial planned with Drs. Jelic, Gottlieb, and Redline to look at levels of CV inflammatory markers in CPAP vs KPAP.
Multiple other studies are planned, and we are developing future versions of KPAP that we believe will be even more comfortable.
Adoption, timeline, and strategy
What feedback have you heard most often from patients who have used KPAP, particularly those transitioning from CPAP?
In a trial involving long term CPAP patients switched to KPAP (n=200) for usability evaluation of the Kricket device, patients wanting their Kricket device back after the 3 month trial concluded was the most common feedback.
What barriers to adoption do you anticipate from clinicians, payers, or patients?
Payers: None. Kricket is already covered by all payers. It is the same code (E0601) and exact cost of any other CPAP device (You can think of KPAP as an add on without cost).
Patients: None. Knowledgeable patients will only want a Kricket device and may have trouble getting one the first few months as manufacturing volumes increase.
Clinicians: Having to switch cloud programs and download reports will be the main barrier. That’s why we made our cloud and download reports so intuitive and similar to what everyone is used to viewing. The developer of our cloud was over Care Orchestrator and Encore at Philips, but ResMed reports are simpler, so we aimed more at that. I hate changing reports, so we made switching effortless.
Where is SleepRes currently in regulatory clearance and commercialization?
Kricket with KPAP received FDA clearance in December 2025 and is currently in commercialization with launch planned before the Sleep Meeting in Baltimore (June 2026).
When do you anticipate broader clinical availability of KPAP? Is there anything else you’d like to tell us about your strategy to market?
We plan to increase volume as fast as we can while focusing on quality first. 250,000 PAP devices are sold in the US alone each month. That is our first goal as we head into other markets around the globe. And wait till you see our interfaces (masks). We are releasing science into the mask for the first time in decades. We also have new algorithms for BPAP ST, AVAPS, and ASV that have patent pending new technology. Our strategy is to lead with physiology and have engineering follow, not the other way around.
What excites you most about KPAP’s potential impact on sleep apnea care over the next decade?
CPAP is the superior treatment in the field. Only CPAP increases lung volume for pharyngeal wall stiffness. Only CPAP treats concentric collapse reliably.
Oral appliances, the “pill” (AD109), hypoglossal nerve stimulators, upper airway surgery, etc. will never replace PAP in the more severe or obese patients. CPAP has a myriad (>10,000) studies supporting it.
The two main mechanisms of CPAP occur in late expiration which is the Kairos (critical time). Instead of creating a new therapy, we just took the gold standard therapy in the field and made it so much better. Breathing is believing. If you haven’t you should breathe on KPAP compared to CPAP.
Thanks so much to Dr. Noah for taking the time to speak on KPAP and the future of OSA care. We are certainly excited to monitor its place in physician and patient workflows.
As always, we will continue to bring you leading information on the science, tech, and practice of sleep apnea care.
- Chris & Robson.