Analysis of the related factors of daytime hypercapnia in obstructive sleep apnea hypopnea syndrome patients

Objective To analyze the related factors of daytime hypercapnia in patients with obstructive sleep apnea hypopnea syndrome(OSAHS). Methods A total of 22 patients with OSAHS who were admitted into the Affiliated Hospital of Xuzhou Medical University from October 2018 to May 2019 were selected. They were divided into two groups: a hypercapnia OSAHS group (n=22) and a non-hypercapnia OSAHS group (n=46). The two groups were compared for general information, arterial blood gas analysis and polysomnography related indicators. Furthermore, the correlation between partial pressure of carbon dioxide in artery (PaCO₂) and related indicators was analyzed. Results OSAHS patients with hypercapnia showed remarkable decreases in body mass index (BMI), neck circumference, chest circumference, waist circumference, hip circumference, Epworth sleepness scale (ESS) scores, and PaCO₂ compared with the non-hypercapnia OSAHS group (P<0.05 or P<0.01). However, the hypercapnia OSAHS group had significantly lower partial pressure of oxygen in artery (PaO₂), mean arterial oxygen saturation (MSaO₂),and HCO^-₃ than the non-hypercapnia OSAHS group (P<0.05 or P<0.01). PaCO₂ was positively correlated with BMI, neck circumference, chest circumference, waist circumference, hip circumference, ESS scores, HCO^-₃ and MSaO₂ (P<0.05), and PaCO₂ was significantly negatively correlated with PaO₂(P<0.05). Conclusions Daytime hypercapnia in patients with OSAHS is associated with BMI, central obesity, and MSaO₂. Therefore, more attention should be paid for OSAHS patients with elevated BMI and ESS scores, and decreased MSaO₂. The patients should be tested for arterial blood gas analysis to determine the presence of daytime hypercapnia.