[The effect of genioglossus activity to velopharyngeal surgery in patient with obstructive sleep apnea hypopnea syndrome]

Objective: To investigate the effect of genioglossus (GG) activation at sleep onset on the outcome of velopharyngeal surgery in obstructive sleep apnea hypopnea syndrome (OSAHS) patients. Methods: Thirty-five patients between April 2014 and February 2015 in Beijing Tongren Hospital with OSAHS underwent overnight polysomnography with synchronous genioglossus electromyography (GGEMG) using intraoral electrodes. The upper airway (UA) anatomy was evaluated by three-dimensional computer tomography (3D-CT) in OSAHS patients. Then, all of the patients received velopharyngeal surgery, including revised uvulopalatopharyngoplasty (UPPP) with uvula preservation or UPPP combined transpalatal advancement pharyngoplasty. All patients were followed-up using polysomnography 3-6 months after surgery. T-test or Wilcoxon test were used to compare the variables between groups, and Spearman correlation analysis was used to test the correlation between parameters. Results: Thirty-five patients received velopharyngeal surgery. Twenty-two patients (62.86%) were responders, and 13 patients (37.14%) were non-responders. Responders had a higher mean GGEMG during sleep onset (15.31±3.74 vs. 9.92±2.93, t=4.504, P=0.001). The decreased AHI was significantly positively related to the sleep onset mean GGEMG (r=0.541, P=0.004) and the change in GGEMG (r=0.422, P=0.028). The decreased AHI was significantly negatively related to the minimal cross sectional airway area (mCSA,ρ=0.629,P=0.000) and the minimal lateral airway dimension (mLAT, ρ=0.484, P=0.009) at velopharynx. Conclusions: The outcome of velopharyngeal surgery was affected by the mean GGEMG during sleep onset. We speculated that the patient with higher GGEMG at sleep onset and narrower velopharynx were more suitable candidates for velopharyngeal surgery.

[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.