New Lower Pressure CPAP’s Efficacy Equivalent to Traditional Device

The substantially lower pressure applied by a new CPAP device for treating obstructive sleep apnea (OSA) is just as effective as the continuous pressure of traditional CPAP but considerably more comfortable, according to a clinical study.

Results of the study comparing the new technology—known as KPAP developed by SleepRes—to traditional continuous positive airway pressure (CPAP) have been published online by Sleep Medicine.

Nearly 50 million Americans live with OSA, putting them at increased risk for heart attack, stroke, high blood pressure, heart failure, and falling asleep while driving. CPAP is widely used by healthcare professionals to treat the condition, and the technology has successfully reduced OSA events, which obstruct a patient’s airway during sleep.

Nevertheless, about half of patients who begin traditional CPAP therapy stop using it because of the problems they often experience with it. The most common problem is the breathing discomfort associated with the constant airway pressure and air leak around the mask.

In this study, pressure applied during the breathing cycle by KPAP decreased by up to 5 cm of water (H₂O) below the level a patient would normally receive from traditional CPAP. In doing so, it was found that KPAP reduced the leak by half. For example, a patient normally requiring 10 cm H₂O with traditional CPAP would experience only 5 cm H₂O during most of the respiratory cycle with KPAP. While not part of the study, researchers expect to ultimately find that reduced pressure and leak will lead to more patients better tolerating the therapy.

“CPAP has been considered the gold-standard of care for OSA for nearly 40 years, yet over that time, all attempts to improve comfort with CPAP have involved reducing pressure during exhalation, which has not led to improved patient adherence to therapy. This study showed that lowering pressure during inhalation, which can make breathing feel more natural, does not affect the therapy’s effectiveness and is overwhelmingly reported to be more comfortable,” said David P. White, M.D., professor of medicine at Harvard Medical School and a study author. “We’re excited about this initial study and about the potential this technology has for helping many people who currently find CPAP intolerable or just uncomfortable.”

Different from CPAP, which provides consistent, full pressure throughout the breathing cycle, the KPAP algorithm applies multiple drops in pressure during inhalation, also known as inspiration, only to return to full pressure at the “right time,” near the end of exhalation. The new technology—Kairos PAP or KPAP—is derived from the Greek word Kairos, which means “at the right time,” referring to the period in which pressure is applied during a sleeping patient’s breathing cycle.

The study included two randomized clinical trials among participants aged 18 to 70 with a recent OSA diagnosis (within one year). The Efficacy trial compared KPAP’s and CPAP’s effects on the Apnea-Hypopnea Index (AHI), the primary diagnostic tool for measuring the severity of OSA, expressed in the number of OSA events (apneas and hypopneas) a patient experiences per hour of sleep. In the second trial, known as the Comfort trial, researchers administered a range of different pressure levels to test awake patients’ preference for KPAP versus CPAP.

The Efficacy trial monitored 48 patients with CPAP experience in a lab using a standard polysomnogram and a split-night design, meaning 3.5 hours each on KPAP and CPAP, the order being randomly assigned. KPAP reduced AHI more than CPAP by a mean difference of 0.5 events per hour (P=0.007), a statistically significant reduction that—while not clinically meaningful—confirmed that KPAP provides efficacy comparable to CPAP. Unintentional leak, which is CPAP air leakage occurring around the mask or through the mouth, also shrank by KPAP by more than 50 percent (P<0.001) compared to CPAP.

The Comfort trial assessed 150 patients with no CPAP experience in-office on their preference for KPAP versus CPAP. The trial’s two primary endpoints were comparisons of patients whose preference for KPAP or CPAP was assessed on two different baseline pressures of 9 and 13 cm H20.

During the tests, these two baseline pressure levels remained continuous for CPAP throughout the participants’ breathing cycles. But with KPAP, the pressure at the 9 cm H₂O level dropped by 4 cm during inspiration while the pressure at the 13 cm H₂O level fell by 5 cm during inspiration. Researchers found that at the 9 cm and 13 cm baseline levels, 69% and 84% of participants, respectively, preferred KPAP over CPAP (P<0.001).

In addition to these endpoints, researchers also measured a range of other KPAP pressure drops from both the 9 cm and 13 cm baselines. Overall, in combining data for all levels, 93% of patients preferred KPAP over CPAP for the 9 cm H₂O baseline while 95% preferred KPAP for the 13 cm H₂0 baseline.

“As a sleep medicine physician, I am most excited about providing KPAP to my own patients,” stated William Noah, M.D., inventor of KPAP and chief science officer for SleepRes. “Because CPAP is initially difficult for most patients to tolerate and 93% to 95% of new patients prefer KPAP, which provides the same therapy with only half the leak, we anticipate many physicians will ultimately want to ensure that the CPAP devices they prescribe for their patients will have KPAP as an option.”

Based in Murfreesboro, Tenn., SleepRes develops technologies aimed at improving outcomes for patients with pulmonary and sleep disorders. The company has developed KPAP, a first-of-its-kind algorithm aimed at reducing pressure for comfort, and still providing therapy at precisely the right time.

*KPAP is currently for investigational use only and is not for sale in the United States.