Abstract:Objective To investigate the correlation between blood pressure structure and nighttime sleepstructure in patients with sleep apnea syndrome (SAS) by using Shichen-based cardiopulmonary coupling (CPC)sleep monitoring technique. Methods A total of 92 patients who attended the hospital due to sleep problems were enrolled, and a Shichen-based CPC monitor and a 24-hour ambulatory blood pressure monitor were used for synchronous monitoring and data collection.According to the respiratory disturbance index (RDI) calculated based on CPC, the patients were divided into non-SAS group with 23 patients and SAS group with 69 patients, and the two groups were compared in terms of blood pressure and nighttime sleep structure. Blood pressure and nighttime sleep structure were also compared between patients with different severities of SAS, and the correlation of RDI with nighttime sleep structure during the periods of the day from 11 p.m. to 1 a.m., from 1 a.m. to 3 a.m., and from 3 a.m. to 5 a.m. was analyzed in the patients with SAS. Results The SAS group had significant increases in the prevalence rate of hypertension and the incidence rate of abnormal blood pressure rhythm, with a longer initial sleep time, a shorter deep sleep time, and a longer light sleep time.There was asignificant difference in nighttime sleep structure between the mild, moderate, and severe SAS groups (P<0.05).There were certain differences in nighttime sleep structure during the periods of the day from 11 p.m. to 1 a.m., from 1 a.m. to 3 a.m., and from 3 a.m. to 5 a.m. between the patients with different severities of SAS, and further linear regression analysis showed that RDI was positively correlated with light sleep time during the periods of the day from 11 p.m. to 1 a.m and from 3 a.m. to 5 a.m. in the patents with SAS. Conclusion Patients with SAS tend to have a high prevalence rate of hypertension and a high incidence rate of abnormal blood pressure rhythm, with disturbance of nighttimesleep structure. There is no significant difference in blood pressure structure between patients with different severities of SAS. The main differences in sleep structure are the increase in unstable sleep and the reduction in stable sleep, and the severity of SAS is positively correlated with light sleep time during the periods of the day from 11 p.m. to 1 a. m and from 3 a.m. to 5 a.m.