Insights from expiratory positive airway pressure experts at BRYGGS Medical, AirAvant Medical, CPAPnea Medical Supply, and Open Airway Dental Solutions.

By Lindsey Nolen

Sleep Review facilitated a roundtable to examine expiratory positive airway pressure (EPAP) therapies that are cleared by the US Food and Drug Administration (FDA) for obstructive sleep apnea (OSA) and snoring. EPAP makers discussed expiratory resistance levels, design optimization, efficacy, technological advancements, and more.

The panelists were:

  • Geoffrey Sleeper, BS, RRT, president, BRYGGS Medical, marketer of ULTepap for mild to moderate OSA
Geoffrey Sleeper, BS, RRT
  • Javier Collazo, co-founder/general manager/vice president, AirAvant Medical, marketer of BongoRx for mild to moderate OSA
Javier Collazo
  • T. Sal Hakim, PhD, owner, CPAPnea Medical Supply, marketer of Optipillows EPAP Mask for snoring
T. Sal Hakim, PhD
  • Sat Sharma, MD, FRCPC, FCCP, FACP, FAASM, chief medical officer, Open Airway Dental Solutions, marketer of O2Vent Optima for mild to moderate OSA and ExVent (investigational use only—FDA submission completed); medical director, Centre for Sleep and Chronobiology

Here are their insights.

Expiratory Resistance Levels

Sleeper: A study I co-investigated found that FDA-cleared nasal EPAP devices produce different expiratory pressure profiles. Three of the four devices tested (Provent, BongoRx, and ULTepap) were FDA-cleared to treat OSA, and these data were originally submitted to the FDA for the ULTepap 510(k) submission. The fourth, Theravent, was FDA-cleared to treat snoring and was included to compare the typically higher pressures generated by EPAP to treat OSA versus lower pressures to treat snoring.1 

Currently, there are two FDA-cleared EPAP devices to treat mild to moderate OSA, which are BongoRx and ULTepap. ULTepap generates higher back pressures that are substantially equivalent to those of Provent, the most widely studied EPAP device. BongoRx generates lower back pressures, similar to those of Theravent. There is a third EPAP device available today, which is the Optipillows. It has adjustable back pressures and is FDA-cleared to treat snoring. 

The trade-off between the back pressures produced by BongoRx and ULTepap is that the BongoRx may be easier to acclimate to with the lower pressures. But the ULTepap may be more effective with patients with more elevated apnea-hypopnea index (AHI). Both Provent and Theravent are off the market.

Collazo: Too much resistance may be uncomfortable for the patient to breathe against. Too little may not allow a device to achieve its therapeutic benefit.

Each EPAP device has different characteristics besides resistance that may affect effectiveness, so bench testing of resistance alone is not enough. An EPAP device cleared by the FDA for treating OSA should have been clinically tested to show a reduction in the AHI.

Hakim: With CPAP, the pressure in the upper airway remains elevated throughout the breathing cycle, causing the space in the back of the mouth to remain expanded, eliminating the risk of upper airway obstruction. With EPAP, the expiratory resistance restricts the flow of air, causing the pressure to rise during expiration and return rapidly to zero at the end of expiration. So with EPAP, the upper airway becomes expanded during expiration and tends to return to a less expanded state at the end of expiration.

Regardless of how much the pressure rises during expiration, it returns quickly to zero at the end of expiration. Because of its viscoelastic nature, the upper airway returns to a smaller size but not fully to the size that would be expected when the pressure is zero. The upper airway remains expanded at end-expiration, such that when the next inspiration begins, the risk of upper airway obstruction during inhalation is diminished. 

There is evidence that, with EPAP, the upper airway tends to remain more expanded at end-expiration compared to without EPAP.2 Another study reported the effect of using different levels of expiratory resistance in the same group of patients.3 These results showed that different levels of expiratory resistance did not change device efficacy. 

But the expiratory resistance should be high enough to cause expansion of the upper airway. It may also be important for comfort and adaptation.

Sharma: ExVent, an oral EPAP therapy, can only be used as an add-on therapy to our oral appliance/mandibular advancement device (MAD), Optima. 

ExVent comes in three strengths. The lowest generates approximately 3 cmH2O/L/s resistance, medium approximately 5 cmH2O/L/s resistance, and high 8 H2O/L/s resistance.

The more positive pressure in the airway, the less the airway collapses. With higher levels of resistance, one can treat more severe OSA. Moreover, using combination therapy with MAD and EPAP (O2Vent Optima and ExVent), less protrusion will suffice because of the additional therapeutic mechanism.

While treating OSA patients, our team initiates therapy with lesser protrusion (50%) and lower ExVent strength. For titration, one may administer a modest degree of further protrusion as tolerated by the patient and/or also increase the ExVent strength.

optima exvent
ExVent, an oral EPAP therapy, can only be used as an add-on therapy to the Optima appliance for sleep apnea.

Patient Comfort in EPAP Therapy

Sleeper: Two features help optimize patient comfort when using ULTepap. The first is the nasal pillow interface, which is similar to traditional nasal pillow CPAP. It has only incidental nasal mucosal contact and is mainly supported by the epidermis surrounding the nares. The second is the headgear, which is designed similarly to nasal pillow headgear and promotes a stable fit.

ULTepap is mainly supported by the epidermis surrounding the nares.

Collazo: Our Bongo Rx device comes standard with four sizes. The nasal seals are soft and flexible so that they can conform to the shape of the nostrils. Our type of nasal seal does not require headgear.

Hakim: The Optipillows EPAP mask allows the expiratory resistance to be adjusted. It can be adjusted to make it equal to other EPAP masks and minimized to facilitate getting used to the mask.

Sharma: Utilizing EPAP, in addition to the mandibular advancement, means patients will experience less teeth, jaw, temporomandibular (TMJ), and occlusive/bite change issues. 3D-printed MADs cause fewer teeth issues; however, TMJ pain/discomfort and occlusive changes remain a significant concern.

Our device will often obviate and prevent such TMJ and occlusive issues and lead to greater patient comfort, success of therapy, and improved outcomes.4

Mouth breathing remains a major issue for the lack of success of nasal EPAPs.

Evolution of EPAP Therapy

Collazo: Originally, EPAP devices were disposable and required adhesive to create a seal. EPAP devices now are reusable and have soft silicone nasal seals. They also come in multiple sizes.

Hakim: EPAP devices have been in use for more than 15 years. Most clinical research has been completed using Provent and Theravent, which use a two-way valve mounted on a sticky disc taped tightly around the nostril to create a seal. Often, they did not stick well and leaked.

Once the early EPAP devices adhered to the skin, they could not be removed (a new one would have to be used). They had a fixed resistance and were also relatively costly.

New EPAP masks use a nasal pillow-type mask and were introduced in the past four years to be more patient-friendly and reusable. Once a patient gets used to the EPAP mask, EPAP masks provide the same outcome and efficacy as the old EPAP devices but at less cost.

Optipillows EPAP
Optipillows uses a nasal pillow-style interface.

Sharma: A 2015 meta-analysis and recent reviews conclude that the devices are highly portable and easy to use, and there are no reported major side effects or complications.5

For that reason, nasal EPAP might be an alternative for certain OSA patients who are either intolerant to PAP or in unusual circumstances without electricity, and for those with mild or position-dependent OSA without concurrent chronic medical problems. Further studies are needed to evaluate long-term efficacy and delineate clinical and polysomnographic profiles of patients who would be best suited for this therapy.

Successful Patient Introduction to EPAP

Sleeper: The single most important factor for successful therapy is the initial acclimation to the device. The patient must be instructed that, as they fall asleep, they should breathe through the device and exhale through their mouth. Their mouth should close, and the therapeutic pressure should be activated.

Hakim: The challenges are similar to those with CPAP nasal pillow masks. Some patients complain about having the head strap, the size or shape of the nasal pillows not matching well with their nostrils, or the mask not staying in place. All require patience and adjustments.

Most often, when there is a problem, we try to help them by making sure they are using the mask correctly, by using the right size nasal pillows, and by readjusting the tension on the head strap. On rare occasions, some patients complain because of nose irritation, which can be resolved with skin lotion. 

Sharma: Nasal EPAP devices have less discomfort than the CPAPs. CPAP does have an EPAP component as well, and the therapy is continuous. But the comfort level and acceptance are better with EPAP-only therapies; however, more studies are required. Our combination therapy has extensive clinical experience and multiple published studies demonstrating efficacy, compliance, and patient adherence.6

Cost Compared to CPAP

Sleeper: The financial burden is entirely borne by the patient, but the out-of-pocket expense is typically $170 to $300. This is usually less than typical out-of-pocket and deductible expenses for CPAP.

Hakim: EPAP masks can be a welcome supplement to the options available for treating sleep-disordered breathing. In cases where patients refuse to use a CPAP machine because of inconvenience, for those who become non-compliant, and in view of the shortage of CPAP machines because of the recent recall, the EPAP masks can be a viable alternative.

Sharma: There are no long-term studies on nasal EPAP devices reducing the health care burden in OSA. The EPAP devices for COPD are preliminary and do not have much clinical experience and other data. Our combination therapy with MAD and oral EPAP has several published studies. There was a cost analysis performed in Canada that demonstrated significant cost savings over five years.7

Since MADs in general and a combination of MAD and EPAP specifically have much better adherence to therapy, the comorbid conditions such as hypertension, cardiovascular diseases, neurological diseases, drowsy driving, and improved functionality and productivity at work will lead to reducing the overall burden on health care systems and so many economic and other benefits.


1. Sleeper G, Rashidi M, Strohl KP, et al. Comparison of expiratory pressures generated by four different EPAP devices in a laboratory bench setting. Sleep Med. 2022 Aug;96:87-92.

2. Braga CW, Chen Q, Burschtin OE, et al. Changes in lung volume and upper airway using MRI during application of nasal expiratory positive airway pressure in patients with sleep-disordered breathing. J Appl Physiol (1985). 2011 Nov;111(5):1400-9.

3. Rosenthal L, Massie CA, Dolan DC, et al. A multicenter, prospective study of a novel nasal EPAP device in the treatment of obstructive sleep apnea: efficacy and 30-day adherence. J Clin Sleep Med. 2009 Dec 15;5(6):532-7.

4. Sharma S, Conflitti A, Reiter H, et al. Long term complications and adverse effects associated with O2 Vent Optima Oral Appliance and ExVent accessory in obstructive sleep apnea patients. Dent Res Oral Health. 2024;7:50-7.

5. Riaz M, Certal V, Nigam G, et al. Nasal expiratory positive airway pressure devices (Provent) for OSA: a systematic review and meta-analysis. Sleep Disord. 2015;2015:734798.

6. Sharma S, Conflitti A, Reiter H, et al. Effect on sleep quality and daytime functioning with O2 Vent Optima oral appliance and expiratory positive pressure accessory (ExVent) in obstructive sleep apnea patients. Dent Res Oral Health. 2024;7:43-9.

7. Metwali AM, Rana S, Sharma V, Bloomfield L. Substantial cost savings with novel oral appliance O2Vent Optima compared to CPAP therapy in Canada. SLEEP 2024 accepted abstract.

Top photo: AirAvant’s Bongo Rx is an EPAP therapy cleared by the FDA for mild to moderate OSA.