[Association between mixed sleep apnea and treatment-emergent central sleep apnea]

Objective: To examine the association between mixed sleep apnea (MA) and treatment-emergent central sleep apnea (TE-CSA). Methods: A total of 256 patients meeting the diagnostic criteria of moderate to severe obstructive sleep apnea (OSA) based on overnight polysomnography (PSG) and receiving continuous positive airway pressure (CPAP) therapy in West China Hospital, Sichuan University during the period from August 2013 to November 2018 were enrolled in the study. Based on the mixed apnea index (MAI) and apnea-hypopnea index (AHI) in the baseline PSG study during non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep, the subjects were categorized into three groups of A (MAI=0/h, n=110), B (NREM-MAI≥5/h and REM-MAI<5/h, n=72) and C (REM-MAI≥5/h and NREM-MAI< 5/h, n=74). Sleep and breathing related parameters before and after CPAP therapy among three groups and the difference of TE-CSA incidence were analyzed. Results: The AHI [(44.2(26.8,64.5)/h,66.6(56.0,81.7)/h, 79.8(63.6, 88.3)/h], REM-AHI [50.0(34.7, 64.7)/h, 60.1(49.1, 70.0)/h, 66.3(56.1, 74.6)/h] and NREM-AHI[43.5(25.9, 65.1)/h,67.6(53.7, 82.4)/h,81.3(64.2, 91.5)/h]) were higher in group B and C compared to group A (all P<0.05),while the mean and lowest oxygen saturation [(92.6%±3.5%),(90.8%±3.6%),(87.3%±5.1%) and (70.6%±14.1%), (61.0%±16.0%), (47.9%±17.0%)] were lower in group B and group C compared to group A (all P<0.05). The incidence of TE-CSA after initial CPAP was 7.8% in all patients, and the incidence was significantly higher in group B of 14.1% compared to group C of 4.1% and group A of 2.7% (all P<0.05). Conclusions: TE-CSA is correlated with baseline MA, and baseline MA in NREM sleep can predict the incidence of TE-CSA after initial CPAP.