摘要
To the Editor:Obstructive sleep apnea(OSA)is a common sleep-disordered breathing.Previous studies reported that the incidence of daytime hypercapnia in patients with OSA was 26.2%in China[1]and 14%in Japan.[2]However,Weitzenblum et al[3]demonstrated that daytime hypercapnia in patients with OSA might not be secondary to sleep apneas/hypopneas,but might due to the comorbidities,such as chronic obstructive pulmonary disease or severe obesity.Obesity hypoventilation syndrome(OHS)is defined as a conjunction of obesity(body mass index[BMI]≥30 kg/m^(2)),daytime hypercapnia(partial pressure of carbon dioxide in arterial blood[PaCO_(2)]≥45 mmHg)and sleep disordered breathing,after excluding other causes for alveolar hypoventilation.[4]Since patients with OHS were not completely excluded in previous studies,[1,2]we assumed that the incidence of daytime hypercapnia in Chinese patients with OSA might be low.
基金
supported by grant from the National Key Technology Research and Development Project(No.2013BAI09B10)from the Ministry of Science and Technology of China.