Effects of chronic obstructive pulmonary disease patients complicated with OSAHS on hypercapnia and related factors / 中华健康管理学杂志

ABSTRACT

Objective:To analyze the effects of chronic obstructive pulmonary disease (COPD) combined with obstructive sleep apnea hypopnea syndrome (OSAHS) on hypercapnia and its related factors.Methods:In this cross-sectional study, patients with stable COPD were continuously recruited from July 2016 to December 2018 in the Respiratory Department of Peking University Third Hospital. General clinical data of patients were collected, and lung function test, arterial blood gas analysis and portable sleep monitoring were also conducted. Patients with COPD complicated with apnea hypopnea index (AHI)≥10 times/h and apnea events being mainly blockage-type events, accompanied by snoring, sleep apnea, daytime sleepiness and other symptoms were defined as overlapping group, patients with COPD complicated with AHI<10 times/h were defined as simple COPD group. Correlation analysis and logistic regression model were used to explore the determinants of daytime hypercapnia in patients with COPD.Results:Compared with simple COPD group, the median arterial partial pressure of carbon dioxide (PaCO 2) was significantly higher in the overlapping group (42.00 vs 38.95 mmHg (1 mmHg=0.133 kPa), P<0.001), and the rate of daytime hypercapnia was significantly higher (23.3% vs 3.3%, P=0.002). PaCO 2 was correlated with forced vital capacity (FVC), percent predicted forced expiratory volume in one second (FEV 1%pred), the ratio of residual volume (RV) to total lung capacity (TLC), AHI, nocturnal average transcutaneous oxygen saturation (SpO 2), nocturnal minimum SpO 2 and the total sleep time spent with SpO 2≤90% (T90) (all P<0.05). In logistic regression analysis, after adjusting for age, sex, and body mass index (BMI), only severe OSAHS, GOLD Ⅲ-Ⅳ grade (FEV 1%pred<50%), and T90>1% were independent risk factors for hypercapnia. Conclusions:OSAHS can increase the risk of hypercapnia in patients with COPD. AHI, lung function injury and T90 are closely related to hypercapnia.