Effects of an Air Purifying Device (PureNight) on Sleep Quality in Obstructive Lung Disease

Objective There are many detrimental effects of obstructive airway disease. One of the hallmark effects is poor sleep quality. Due to the association of air pollutants with worsening respiratory symptoms, a logical intervention to improve sleep quality may be air filtration. A novel air filtration system, the PureNight SystemTM, which delivers pre-filtered air around the head of a sleeping person, may offer a solution to decrease exposure to noxious triggers during time spent sleeping and improve sleep quality. One method to measure sleep quality is to use 24-hour actigraphy. The actigraph is a small, wrist-worn device that contains a pizo-electric bender element, or accelerometer, that measures wrist movement. Algorithms interpret the movement on an epoch-by-epoch basis and identify sleep/wake states and circadian rhythms from activity counts. Study Design We propose to study the effect of the Pure Night TM air filtration system on a cohort of patients with chronic obstructive airway disease with self-reported poor sleep quality due to nocturnal respiratory symptoms. We hypothesized that patients using the Pure Night TM system would have fewer nocturnal awakenings and a consolidation of sleep time measured by actigraphy and better sleep quality measured by quality of sleep questionnaires than when not using the device. In a cross-over randomized clinical trial, baseline measurements were compared to treatment with the PureNight TM device and with "sham" filtration. Sleep variables including data on circadian rhythms were compared using a within-subject design between test conditions. Methodology Each subject underwent baseline actigraphy over 7 days followed by two seven day treatment arms with a 7-day wash-out period between treatment arms. Subject slept with the PureNight during each arm of the study. The systems used in each arm of the study were identical except one arm had a sham filter replacing the HEPA filter of the PureNight TM system in random order. Participants completed the Pittsburgh Sleep Quality Index at the start of the study and at the end of each treatment phase. Objective estimates of sleep were calculated from the actigraphy recordings using the device's proprietary software.