Lateral decubitus posture during sleep: Sub-groups of obstructive sleep apnea patients - Therapeutic value of vertical position in OSA

The incidence of obstructive sleep apnea (OSA) is steadily increasing, but to date there is no efficacious universal treatment. Therefore, measures that ameliorate this condition need special attention. Avoidance of sleep in the supine (horizontal) position has a positive influence on frequency and severity of OSA. OSA patients are "Responders" when they respond to positional therapeutic measure, while those in whom sleeping vertically does not result in lowering of apnea hypopnea index (AHI) are "Non-Responders". The aim of this study was to evaluate the number of apnea and hypopnea in responders and non-responders. One hundred and seven adult OSA patients with varying AHI, i.e. from 5 to 117, were included. We recorded the number of apnea and hypopnea in the supine position as well as in the lateral position of sleep. We categorized them in to different groups. We report, for the first time, four different groups of OSA patients in a seemingly so-called homogeneous population. One group of OSA patients, 57.0 %, responded to the lateral position in sleep and showed a decrease in their apnea and hypopnea; a second group, 23.3 %, exhibited a decrease in their apnea but not in hypopnea; a third group, 10.3 %, in whom the apnea increased but not hypopnea, while a fourth group, 9.4%, showed an increase in both apnea and hypopnea. The great majority of OSA suffers benefit from non-supine sleep position; it is recommended, therefore, that different measures be utilized to enhance sleep in the lateral position in these patients. However, the group of patients (group 4) who increase their apnea and hypopnea in the non-supine position should be discouraged to adopt this sleeping posture; however, they should be encouraged to use different therapeutic methodology such as a mandibular splint and/or the tongue restraining device.