Investigate the occurrence of obstructive sleep apnea syndrome (OSAS) and its mechanism in overwheit or obese Gastroesophageal reflux disease (GERD) patients.

To 125 overweight or obese patients Since september 2018 to june 2020 in the people's Hospital of Xinjiang Uyghur Autonomous Region underwent 24 hours esophageal acid test,routine pulmonary function, impulse oscillation,sleep monitoring and esophageal manometry.According to 24 hours esophageal acid test results divided into two groups as GERD (case group) and non-GERD (control group),to compare the incidence of OSAS in two groups and the effect of the respiratory mechanical properties,esophageal function and analyze the correlation between esophageal reflux related indexes, esophageal functional indexes and sleep disordered index (AHI).

Under the factors of sex, age, nationality, weight and body mass indax(BMI)are same in the two groups,incidence of OSAS in case group was significantly higher than that in control group(P＜0.001). In sitting position, total elastic resistance of airway,central,Peripheral airway resistance and resistance of impulse oscillation in 5~35 Hzin case group were significantly higher than those in the control group (P＜0.05), There was no significant difference in the airway reactance between two groups under impulse oscillation in 5~35 Hz (P＞0.05) . In supine position, total elastic resistance of airway,central,Peripheral airway resistance , elastic resistance and reactance under impulse oscillation in 5~35 Hz of case group were significantly higher than those in the control group (P＜0.05). The difference of gastroesophageal pressure and the size of esophageal hiatus in the case group was significantly higher than that in the control group (P＜0.05). The pressure of lower esophageal sphincter and the score of distal contraction in the case group were significantly lower than those in the control group (P＜0.05),the pressure of upper esophageal sphincter and the length of the lower esophageal sphincter in the case group were lower than those in the control group, and the distal contraction delay time was longer than that in the control group, but the difference was not statistically significant (P＞0.05). Demeester score, proximal esophageal reflux percentage, esophageal hiatus size and gastroesophageal pressure difference were positively correlated with AHI (r＞0), and the correlation was statistically significant (P＜0.05). Distal systolic delay and expiratory pressure difference were negatively correlated with AHI (r＜0), and the correlation was statistically significant (P＜0.05).

GERD in obese or overweight patients is one of the important risk factor of OSAS and esophageal acid reflux and esophageal dysfunction are closely related to the severity of OSAS in GERD patients. A series pathophysiological changes caused by long-term stimulation of throat and airway mucosa by esophageal acid reflux may be one of the potential mechanisms of it.