Characteristics of Sleep Apnea in Obstructive Sleep Apnea Patients with Mixed Breathing Patterns

Abstract

Objectives: Varieties of mixed breathing patterns such as mixed or central sleep apnea in patients with obstructive sleep apnea (OSA) may observed during polysomnography. Our object is to compare the general feature and sleep apnea characteristics between OSA with and without mixed breathing pattern. Methods: Total 244 patients who were diagnosed as OSA [apnea-hypopnea index (AHI) ≥5 /h] were studied retrospectively. Mixed breathing pattern was defined as mixed apnea index plus central apnea index (MCAI) with ≥5 /h (Mix-OSA). OSA without mixed breathing pattern (Non-mix-OSA) was defined with MCAI with <5 /h. Central sleep apnea syndrome was excluded. We investigated differences of the distribution and shifting of apnea index across sleep stage, position and sleep time between Mix-OSA and Non-mix-OSA group. Results: The prevalence of Mix-OSA was 42 of 244 OSA patients (17.2%). There were no significant differences in demographics except higher AHI in Mix-OSA group. Mix-OSA showed a significant increment of MCAI and hypopnea index during non rapid eye movement sleep while Non-mix-OSA showed increased obstructive apnea index (OAI) in rapid eye movement sleep period. In both groups, supine body position was related to high OAI. There were no meaningful differences in sleep apnea according to the timing of sleep in both groups. Conclusions: OSA patients with mixed breathing pattern had more severe OSA than Non-mix-OSA. There were some significant differences in sleep apnea characteristics between OSA with and without mixed breathing pattern. However, their clinical significance still remains unclear. J Korean Sleep Res Soc 2013;10:45-50