Objective To explore the contribution of obstructive sleep apnea hypopnea syndrome(OSAHS) in the variations of blood pressure in the evening to morning and possible mechanisms.Methods In Sleep and Breathing Disorders Centre，from September 2003 to September 2007，adult patients whose Epworth sleeping scoregt;9 were undergone polysomnography(PSG) and divided into 4 groups according to apnea hyponea index(AHI).The levels of blood pressure were monitored and compared between evening and morning.Correlations between PSG indexes and variations of the systolic blood pressure(SBP) and diastolic blood pressure(DBP) were analyzed in OSAHS patients.Results 1 528 patients were enrolled in this study.There was no significant difference between the evening and morning blood pressure in the non-OSAHS group(AHIlt;5，n=172)，whereas DBP rised about 1.73 mm Hg in the mild OSAHS group(AHI≤20，n=435)，SBP and DBP rised about 3.52 and 3.71 mm Hg respectively in the moderate OSAHS group(AHI≤40，n=307)，and SBP and DBP rised about 3.72 and 4.22 mm Hg respectively in the severe OSAHS group(AHIgt;40，n=614).The variation of SBP during the night correlated positively with the arousal index in the mild OSAHS group（r=0.25，Plt;0.05），but with the body mass index (BMI) in the moderate OSAHS group（r=0.25，Plt;0.05）.In the severe OSAHS group，the variation of SBP during the night correlated positively with BMI and the longest apnea time (LA)（r=0.26，0.25，both Plt;0.05），the variation of DBP during the night correlated positively with AHI and mean apnea duration(MA)（r=0.22，0.17，both Plt;0.05），and the variation of mean arterial pressure during the night correlated positively with AHI and MA（r=0.25，0.20，both Plt;0.05）.Conclusion OSAHS may induce mild rises of the blood pressure at night.The relevant factors that influence the blood pressure are different in different severity of the OSAHS.
【Abstract】 Objective To study the effects of obstructive sleep apnea hypopnea syndrome ( OSAHS) on blood pressure variations, and explore the possible mechanism. Methods 84 adult patients ( mean age 50. 1 ±14. 8 years, male /female 67 /17) were recruited for polysomnography ( PSG) and ambulatory blood pressure monitoring. Four groups were identified based on apnea hyponea index ( AHI) ,ie. non-OSAHS group ( n=9) ,mild group ( n=19) , moderate group ( n=23) , and severe group ( n =33) .The blood pressure levels were compared among the four groups. Correlations between PSG indexes,variations of systolic blood pressure ( SBP) and diastolic blood pressure ( DBP) were analyzed. Results Inter-group blood pressure comparison showed significant differences in SBP and DBP( P lt;0. 05) , except forthe mild and the moderate OSAHS patients. As compared with the non-OSAHS patients, SBP for those with severe OSAHS was about 15 mm Hg higher, and DBP 10 mm Hg higher. Observation on SBP non-dipping rate indicated that, except for the mild and the moderate OSAHS patients where no significant differences were found, SBP non-dipping rate increased with the severity of OSAHS( the rates were 78. 3%, 57. 1% ,54. 5%, and 32. 6% , respectively for the four groups) , whereas DBP non-dipping rate significantly increased in the severe OSAHS patients( 54. 3% ) ( P lt;0. 05) . For the mild OSAHS patients, blood pressure was found to be correlated positively with the body mass index ( correlation coefficient for day time SBP was 0. 26, and for DBP was 0. 22) , the arousal index ( correlation coefficient for day time SBP was 0. 25, and for DBP was 0. 17) , and heart rate variation ( correlation coefficient for night time SBP was 0. 18, and for DBP was 0. 17) . For the moderate OSAHS patients, a positive correlation was also found between blood pressure and AHI ( correlation coefficient for day time SBP was 0. 31, and for DBP was 0. 22, correlation coefficient fornight time SBP was 0. 26) , and between blood pressure and the longest hypopnea time during sleep ( LH) ( correlation coefficient for night time DBP was 0. 2) . For the severe OSAHS patients, blood pressure was correlated positively with apnea index ( AI) ( correlation coefficient for day time SBP was 0. 61, and for DBP was 0. 5, correlation coefficient for night time SBP was 0. 57 and for night time DBP was 0. 48) . Conclusions OSAHS has ber impact on SBP than on DBP. DBP hypertension and SBP non-dipping are usually found in early OSAHS-affected patients. Factors affecting blood pressure differ with the severity of the OSAHS.
ObjectiveTo investigate the diagnostic value of oximetry in sleep apnea hypopnea syndrome (SAHS). MethodsAdult patients suspected for SAHS were enrolled between May 2010 and May 2013. The patients underwent both polysomnography (PSG) and oximetry for further diagnosis. Apnea hyponea index (AHI) and oxygen desaturation index four (ODI4) were calculated on a single night. The relationship between AHI and ODI4 were analyzed. ResultsA total of 628 adult patients were recruited.ODI4 was linearly correlated with AHI with a regression coefficient of almost 1. The cut-off values of ODI4 for indentifing SAHS and moderate to severe SAHS were 10 events per hour and 20 events per hour, with specificities of 99.9% and 99.3%, and AUCs of 0.931 and 0.934, respectively. Female, lower weight and less severe SAHS patients were easily misdiagnosed. ConclusionsThere is a high agreement between AHI and ODI4. Oximetry is less likely misdiagnose SAHS.