When individuals with OSA who breathe through their mouths have their mouths taped shut during sleep, many continue “mouth puffing” — ie, exhaling through their mouths — either intermittently or completely. This was among research findings recently published in Sleep and Breathing. The findings came from researchers in Taiwan, who developed, tested, and gathered data from a mouth-puffing detector (MPD) designed for home use.
Patients with OSA who mouth breathe tend to have more severe OSA and inferior oximetric variables, as well as more severe and more prevalent lateral pharyngeal wall collapse and tongue base collapse. Mouth taping is a common approach to prevent individuals with OSA from breathing through the mouth during sleep, which is considered detrimental to health, said investigators. Having observed that patients who are mouth-taped “perform a mouth puffing phenomenon when they are asleep possibly indicating that they are trying to breathe through the mouth,” the researchers developed the MPD to gather data on mouth-puffing that could be used for analysis.
The researchers recruited 18 patients aged 23 to 57 years with OSA-related symptoms such as snoring and day-time sleepiness at a dental clinic in Taiwan. Patients with psychiatric or neurological disorders, diabetes, chronic renal disease, cancer, cardiovascular diseases, and cigarette or alcohol addiction were excluded. The patients were mouth-taped during a sleep study, during which data was collected via a combination of the MPD, wireless fingertip pulse oximetry, and overnight polysomnography.
Study participants underwent polysomnography during 1 night at a sleep laboratory. All signals from pulse oximetry and the MPD were stored immediately in a microcontroller and transmitted to a router using bluetooth technology. The router transmitted the signals to a cloud server, which processed and stored them. Sleep was recorded by video placed above the bed to confirm the data obtained from the device.
The ranges of mouth puffing were acquired from 3 axes, x (mediolateral), y (vertical), and z (anteroposterior), and within ranges from −2 to +2 g. Each axis had a sampling frequency of 125 Hz and was able to detect ranges from −3 to +3 centimeter per second squared. The MPD device, composed of 2 accelerometers, was positioned on each cheek and secured with tape.
To obtain the fingertip pulse oximeter data, the investigators calculated oxygen-related variables, including the oxygen desaturation index (ODI, defined as a reduction in blood oxygen saturation to lower than 3% below the baseline), T90 (percentage of oxygen saturation under 90% in total sleep time), mean oxygen saturation (SpO2) , and lowest SpO2. The signals of puffing when mouth-taped were calculated per minute.
The researchers found that patients did mouth puff when they slept with their mouths taped, and the MPD was able to pick up the signals of mouth puffing. They classified the mouth-puffing signals into 4 types: no mouth puffing, intermittent mouth puffing (IMP), side mouth puffing, and complete mouth puffing (CMP). When the data were divided into minutes, IMP scores were found to differ significantly from those of no mouth puffing with respect to the apnea-hypopnea index (AHI), ODI, and T90 (AHI, 0.75 vs 0.31; ODI, 0.75 vs 0.30; T90, 5.52 vs 1.25; P <.001). Participants with severe OSA displayed a higher IMP percentage than those with mild to moderate OSA and the control group (severe, 38%; mild to moderate, 65%; control, 95%; P <.001).
Researchers concluded that their MPD offered a simple means to detect mouth puffing among patients who were mouth-taped during sleep and to collect data that might be useful for clinicians in evaluating patients with OSA. “Our study supports the observation that the mouth puffing phenomenon during sleep when mouth-taped and mouth breathing during sleep are highly correlated,” the investigators said, adding that future studies are needed to explore the relationship between mouth puffing and OSA severity.
Jau JY, Kuo TBJ, Li LPH, et al. Mouth puffing phenomena of patients with obstructive sleep apnea when mouth-taped: device’s efficacy confirmed with physical video observation. Sleep Breath. Published online March 11, 2022. doi:10.1007/s11325-022-02588-0