老年阻塞性睡眠呼吸暂停患者血管内皮功能和心脑血管事件的相关性

目的 回顾性分析老年阻塞性睡眠呼吸暂停综合征(OSAS)患者的血管内皮功能和心脑血管事件的相关性及对预后的影响. 方法 OSAS患者79例(OSAS组),老年OSAS组和非老年OSAS组分别为39例和40例;排除OSAS诊断的老年患者60例(老年非OSAS组).通过电话和门诊进行随访,随访时间中位数25个月.所有患者均接受:(1)彩色多普勒超声测定肱动脉血流介导的血管舒张功能(FMD);(2)检查和测定睡眠呼吸事件、血清生化指标;(3)随访心脑血管事件. 结果 (1)老年OSAS组FMD低于老年非OSAS组(P<0.05).(2)老年OSAS组体质指数高于老年非OSAS组(P<0.01),最低血氧饱和度、平均血氧饱和度低于老年非OSAS组(P<0.01,P<0.05).多因素Logistic回归分析结果显示,空腹血糖升高是FMD主要危险因素(OR=1.83,95%CI:1.11～3.03),其次是最低血氧饱和度(OR=0.92,95% CI:0.85～1.00).(3)老年OSAS组心脑血管事件发生率高于非老年OSAS组和老年非OSAS组(χ~2=7.339,P<0.05).多因素Logistic回归分析结果显示,FMD与患者预后密切相关(OR=1.33,95%CI:1.06～1.66),其次是超敏C反应蛋白(OR=0.51,95% CI:0.34～0.76). 结论 老年OSAS患者血管内皮功能受损更为严重,心脑血管事件发生率增加.OSAS可能通过间歇低氧和炎性反应等多种机制损伤血管内皮功能,参与影响患者预后.     

夜间持续气道正压通气有助于降低中重度阻塞性睡眠呼吸暂停综合征伴高血压患者的收缩压

背景阻塞性睡眠呼吸暂停综合征(OSAS)与高血压相关,持续气道正压通气(CPAP)可有效改善OSAS患者的睡眠情况,但在血压控制方面的效果尚存争议。目的探究CPAP在中重度OSAS合并高血压患者血压控制中的作用。方法选取阜外心血管病医院高血压诊治中心2010年9月至2014年9月诊断为中重度OSAS合并高血压患者117例进行回顾性分析(失访31例),其中对照组65例,只给予常规降压药物治疗;CPAP治疗组52例,除常规药物治疗外加用CPAP治疗。每3月随访1次,2014年10月1日截止,对照组随访(41.95±22.18)月,CPAP组随访(39.43±24.74)月(P0.05)。比较两组患者血压变化情况,分析CPAP对OSAS合并高血压患者血压的影响。结果除糖尿病比例外,两组患者基本情况的差异无统计学意义,CPAP组呼吸暂停低通气指数、氧减饱和度指数更高。经过治疗后,CPAP组收缩压下降较对照组更明显[(12.6±18.1)比(4.5±16.8)mm Hg,P=0.02],但两组舒张压下降的差异无统计学意义[(10.0±12.4)比(6.9±15.0)mm Hg,P=0.23],并且治疗组增加降压药种类的患者明显少于对照组(2.0%比20.3%,P0.01)。结论 CPAP可在药物治疗基础上进一步降低中重度OSAS合并高血压患者的收缩压。     

无创正压气道通气对老年脑梗死并阻塞性睡眠呼吸暂停患者预后的影响

目的探讨无创正压气道通气(CPAP)对老年脑梗死合并阻塞性睡眠呼吸暂停(OSA)患者24h动态血压和心脑血管事件的影响,并分析影响不良心脑血管事件的危险因素。方法选择鞍钢集团总医院2012年5月~2015年5月收治的老年脑梗死合并OSA患者145例,按照随机数字表分为治疗组(CPAP治疗)73例和对照组72例。评估2组患者24h动态血压,随访1年时,用Kaplan-Meier生存曲线评价2组的生存情况,采用ROC曲线分析预测心脑血管事件发生的危险因素。结果出院前2组24h收缩压、24h舒张压、昼间收缩压、昼间舒张压、夜间舒张压均有显著差异(P0.05)。随访1年时,Kaplan-Meier生存曲线显示,治疗组与对照组中位生存时间无显著差异(365dvs 362d,P0.05),治疗组心脑血管事件发生率显著低于对照组(21.9%vs 33.3%,P0.05)。ROC曲线显示,睡眠呼吸暂停指数的曲线下面积为0.70(95%CI:0.61~0.77,P=0.002)和24h收缩压的曲线下面积为0.72(95%CI:0.63~0.81,P=0.003),两者为预测心脑血管事件发生的危险因素。结论 CPAP能有效降低老年脑梗死合并OSA患者24h动态血压,降低心脑血管事件发生率。     

经鼻持续气道正压通气对脑血管病并中重度阻塞性睡眠呼吸暂停综合征患者基质金属蛋白酶9和肿瘤坏死因子α的影响研究

目的探讨经鼻持续气道正压通气(n CPAP)对脑血管病并中重度阻塞性呼吸睡眠暂停综合征(OSAS)患者基质金属蛋白酶9(MMP-9)、肿瘤坏死因子α(TNF-α)的影响。方法选取2011年7月—2012年7月雅安市人民医院收治的脑血管病患者68例,根据呼吸暂停低通气指数(AHI)分为轻度OSAS组和中重度OSAS组,每组34例;另选取同期在本院体检中心体检的健康成年人31例作为对照组。脑血管病患者均持续接受n CPAP治疗3个月,比较3组受试者血清MMP-9和TNF-α水平,轻度OSAS组和中重度OSAS组患者治疗后3个月及1、2、3年脑血管病复发率。结果轻度OSAS组、中重度OSAS组患者血清MMP-9水平高于对照组(P0.05),而轻度OSAS组与中重度OSAS组患者血清MMP-9水平比较,差异无统计学意义(P0.05)。3组受试者血清TNF-α水平比较,差异无统计学意义(P0.05)。治疗后中重度OSAS组患者血清MMP-9水平、AHI低于治疗前(P0.05),而血清TNF-α水平与治疗前比较,差异无统计学意义(P0.05)。中重度OSAS组患者治疗后3个月及1、2、3年脑血管病复发率均低于轻度OSAS组(P0.05)。结论 nCAPAP可有效降低脑血管病并中重度OSAS患者血清MMP-9水平,降低脑血管病复发率。     

高血压合并阻塞性睡眠呼吸暂停综合征患者治疗前后的血压昼夜节律变化

目的 探讨高血压合并阻塞性睡眠呼吸障碍患者持续气道内正压通气(CPAP)或手术治疗前后的血压昼夜节律变化.方法 入选高血压患者105例,根据多导睡眠仪监测结果 分为单纯高血压组47例、高血压合并轻度阻塞性睡眠呼吸暂停综合征(OSAS) 36例和高血压合并中、重度OSAS组22例.CPAP或手术治疗前后行24 h动态血压监测,比较治疗前后睡眠呼吸参数与血压昼夜节律的关系.结果 治疗前单纯高血压组昼夜血压呈非杓型占23.4%,高血压合并轻度和中、重度阻塞性睡眠呼吸暂停综合征组昼夜血压呈非杓型的分别占47.2%和59.1%.与单纯高血压组比较,差异有统计学意义(P<0.05).治疗后各组昼夜血压呈非杓型的比例均有所下降,分别为19.1%.38.9%和45.5%,与治疗前各组间比较,差异有统计学意义(P<0.05).中、重度阻塞性睡眠呼吸暂停综合征组非杓型血压下降最为明显.结论 高血压患者昼夜血压呈非杓型时应考虑合并睡眠呼吸暂停综合征,且昼夜血压变化与OSAS严重性相关,CPAP或手术治疗后非杓型明显减少.     

CPAP对中重度OSAS合并右心衰竭的疗效观察

目的 探讨持续气道内正压通气（CPAP）对中重度阻塞性睡眠呼吸暂停综合征（OSAS）合并右心衰竭患者的治疗作用.方法 收集60例中重度的OSAS合并右心衰竭患者,随机分为对照组和CPAP治疗组.对照组给予常规治疗,治疗组在常规治疗基础上加用CPAP,6个月后观察两组的临床症状、动脉血气分析、肺动脉压、六分钟步行实验变化.结果 CPAP可改善OSAS合并右心衰竭患者的临床症状、动脉血气分析、肺动脉压、以及六分钟步行实验（P〈0.05）.结论 CPAP对中重度OSAS合并右心衰竭患者有较好的治疗效果.     

老年睡眠呼吸暂停综合征患者低密度脂蛋白胆固醇水平与心脑血管疾病的相关性

目的 探讨老年睡眠呼吸暂停综合征(OSAS)患者低密度脂蛋白胆固醇(LDL-C)水平与心脑血管疾病(CVD)的相关性.方法 选取进行睡眠研究的192例老年OSAS患者为OSAS组,另选取60例老年住院患者为对照组,回顾性分析受试者一般临床资料,并依据呼吸暂停低通气指数(AHI)将OSAS组分成3个亚组,AHI 5～15...     

阻塞性睡眠呼吸暂停低通气综合征与心律失常相关性及持续正压通气疗效探讨

目的:探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)与心律失常的关系及经鼻持续正压通气(nCPAP)治疗OSAS所致心律失常的疗效。方法:对82例睡眠打鼾者同步进行夜间7h以上多导睡眠图(PSG)及24h动态心电图监测,根据PSG结果分为OSAS组64例和对照组(单纯鼾症组)18例,比较组间最长呼吸暂停时间(LAT)、平均呼吸暂停时间(MAT)、呼吸暂停低通气指数(AHI)、最低动脉血氧饱和度(mSaO2)、心律失常发生率及发生类型;对18例中重度OSAS伴心律失常患者行nCPAP治疗,比较治疗前后监测资料。结果:OSAS组LAT、MAT长于对照组,AHI高于对照组,mSaO2低于对照组(均P<0.01),OSAS组心律失常发生率显著高于对照组(P<0.01);并且随着病情加重而升高(P<0.05)。nCPAP治疗后,AHI下降,mSaO2上升,平均每小时心律失常发生次数较治疗前显著减少(均P<0.01)。结论:OSAS与心律失常之间存在显著相关性,OS-AS患者夜间心律失常与低氧血症密切相关,nCPAP可有效减少心律失常的发生。     

药物联合气道正压通气治疗OSAS并高血压52例临床观察

选取阻塞性睡眠呼吸暂停综合征(OSAS)并高血压患者52例(OSAS组)及非OSAS高血压患者48例,入院后同步进行24 h动态血压监测.两组均予低盐饮食及培哚普利和(或)苯磺酸氨氯地平口服治疗2周,其后OSAS组降压效果差者接受气道正压通气(CPAP)治疗2周,观察两组治疗前后全天平均血压变化.结果 两组日间平均收缩压(DSBP)、舒张压(DDBP)及夜间平均舒张压(NDBP)均无明显差异,OSAS组的夜间平均收缩压(NSBP)明显高于对照组(P<0.05);药物治疗2周后,OSAS组全天平均血压无明显变化,对照组明显低于治疗前(P<0.05);OSAS组30例药物降压效果欠佳者行CPAP治疗2周后血压显著下降(P<0.05).认为对OSAS并高血压患者单纯药物降压疗效欠佳,辅助CPAP治疗可提高疗效.     

阻塞性睡眠呼吸暂停综合征患者心律失常发生情况及持续气道正压通气的治疗效果

目的探讨阻塞性睡眠呼吸暂停综合征(OSAS)患者心律失常发生情况及持续气道正压通气(CPAP)的治疗效果。方法选取2012年3月—2014年6月在宜春市人民医院就诊并接受治疗的OSAS患者145例,按照OSAS严重程度分为轻度组52例、中度组45例和重度组48例,另选取同期35例体检健康者作为对照组。比较各组受试者最长呼吸暂停时间(LAT)、平均呼吸暂停时间(MAT)、夜间平均血氧饱和度(MSa O2)、睡眠呼吸紊乱指数(AHI)及心律失常发生率。OSAS并发心律失常患者采用CPAP治疗,比较CPAP治疗前后MAT、AHI、MSa O2、最高心率、最低心率及心律失常发生频率。结果 145例OSAS患者发生心律失常82例,心律失常发生率为56.6%。各组受试者LAT、MAT、AHI、MSa O2及心律失常发生率比较,差异有统计学意义(P0.05)。Spearman相关性分析结果显示,OSAS严重程度与心律失常发生率呈正相关(r=0.304,P0.05)。OSAS并发心律失常患者治疗后AHI、LAT、最高心率、心律失常发生频率低于治疗前,MSa O2、最低心率高于治疗前(P0.05)。结论 OSAS患者易并发心律失常,且随着OSAS病情加重心律失常发生率随之升高;CPAP治疗可有效减少OSAS并发心律失常患者低氧血症、酸中毒等的发生,降低心律失常发生频率。     

Continuous positive airway pressure improves daytime baroreflex sensitivity and nitric oxide production in patients with moderate to severe obstructive sleep apnea syndrome.

Individuals with obstructive sleep apnea syndrome (OSAS) are at high risk for cardiovascular morbidity and mortality. The effects of OSAS severity and nocturnal continuous positive airway pressure (CPAP) on daytime baroreflex sensitivity (BRS) and nitric oxide (NO) production were investigated in OSAS patients. Fifty-one consecutive males with OSAS and 29 age-matched healthy men underwent the Valsalva test and standard polysomnography. Patients with an apnea-hypopnea index (AHI) of >or=20 episodes per hour were randomized to receive CPAP treatment for 3 months (n=14) or no such treatment (n=19). The BRS index measured from the overshoot phase (phase IV) of the Valsalva maneuver and plasma NO concentration were significantly lower, whereas the AHI, oxygen desaturation time, arousal index, percentage of sleep stage 1, and systolic blood pressure were significantly greater, in patients with an AHI of >or=20/h than in those with an AHI of <20/h or in controls. The 24-h urinary excretion of norepinephrine was significantly reduced and the plasma NO concentration was significantly increased after one night of CPAP. The BRS index for phase IV and the Valsalva ratio were significantly increased in the CPAP group after the 3-month treatment period but remained unchanged in the non-CPAP group of OSAS patients. The daytime BRS index and NO production were thus inversely related to the severity of OSAS, and successful CPAP treatment improved these parameters in patients with moderate to severe OSAS. CPAP may therefore reduce the risk of cardiovascular complications due to endothelial dysfunction or increased sympathetic activity.     

老年睡眠呼吸暂停患者血液流变学和C-反应蛋白的变化

目的 探讨老年阻塞性睡眠呼吸暂停综合征（OSAS）患者血浆高敏C-反应蛋白（hsCRP）和血液流变学的改变.方法 选取经多导睡眠图确诊且未经治疗的老年OSAS患者59例为OSAS组,30例多导睡眠图（PSG）检查正常者为对照组,分别测定两组患者hsCRP水平及纤维蛋白原和血浆黏度的水平.结果 OSAS组与对照组相比血浆hsCRP水平（P＜0.01）、纤维蛋白原（P＜0.01）和血浆黏度（P＜0.01）的水平增高.纤维蛋白原（r=0.776,P=0.01）、血浆黏度（r=0.702,P=0.01）、hsCRP（r=0.256,P=0.01）与呼吸紊乱指数（AHI）之间有相关性.结论 OSAS患者hsCRP、纤维蛋白原和血浆黏度的水平升高,且与OSAS严重程度有关.这些改变是心脑血管的危险因子之一.     

Continuous positive airway pressure intolerance associated with elevated nasal resistance is possible mechanism of complex sleep apnea syndrome

Purpose

Complex sleep apnea syndrome (CompSAS) is diagnosed after an elimination of obstructive events with continuous positive airway pressure (CPAP), when a central apnea index ??5/h or Cheyne?CStokes respiration pattern emerges in patients with obstructive sleep apnea syndrome (OSAS). However, the pathophysiology of CompSAS remains controversial.

Methods

Of the 281 patients with suspected OSAS, all of whom underwent polysomnography conducted at Nagoya University Hospital, we enrolled 52 patients with apnea?Chypopnea index ??15/h (age 51.4?±?13.3?years). The polysomnographic findings, left ventricular ejection fraction (LVEF), and nasal resistance were compared between the CompSAS patients and OSAS patients.

Results

Forty-three patients were diagnosed with OSAS and nine patients with central sleep apnea syndrome by natural sleep PSG. Furthermore, 43 OSAS patients were classified into the OSAS patients (OSAS group, n?=?38) and the CompSAS patients (CompSAS group, n?=?5) by the night on CPAP PSG. The nasal resistance was significantly higher in CompSAS group than in OSAS group (0.30?±?0.10 vs. 0.19?±?0.07?Pa/cm³/s, P?=?0.004). The arousal index, percentage of stage 1 sleep, and oxygen desaturation index were significantly decreased, and the percentage of stage REM sleep was significantly increased in the OSAS group with the initial CPAP treatment, but not in the CompSAS group. In addition, the patients with CompSAS showed normal LVEF.

Conclusion

CPAP intolerance secondary to an elevated nasal resistance might relate to frequent arousals, which could presumably contribute to an increase in central sleep apnea. Further evaluation in a large study is needed to clarify the mechanism of CompSAS.     

The effects of continuous positive airway pressure on prehypertension and masked hypertension in men with severe obstructive sleep apnea

Obstructive sleep apnea and hypertension are common conditions that frequently coexist. Continuous positive airway pressure (CPAP) reduces blood pressure in patients with obstructive sleep apnea and sustained hypertension. However, the impact of CPAP on patients with obstructive sleep apnea and prehypertension and masked hypertension, conditions associated with increased cardiovascular risk, is unknown. Thirty-six male patients (age, 43 ± 7 years; body mass index, 28.8 ± 3.0 kg/m(2)) with untreated severe obstructive sleep apnea (apnea-hypopnea index, 56 ± 22 events/hr on polysomnography) with diagnostic criteria for prehypertension and/or masked hypertension, based on office and 24-hour ambulatory blood pressure monitoring, respectively, were studied. The patients randomized to no treatment (control; n=18) or CPAP (n=18) for 3 months had similar frequency of prehypertension and masked hypertension at study entry. There were no significant changes in blood pressure in patients randomized to the control group. In contrast, patients randomized to CPAP presented significant reduction in office systolic (from 126 ± 5 to 121 ± 7 mm Hg; P=0.001) and a trend for diastolic blood pressure (from 75 ±7 to 73 ± 8 mm Hg; P=0.08) as well as a significant decrease in daytime and nighttime systolic and diastolic blood pressure (P<0.05 for each comparison). There was a significant reduction in the frequency of prehypertension (from 94% to 55%; P=0.02) and masked hypertension (from 39% to 5%; P=0.04) only in the CPAP group. In conclusion, effective CPAP therapy promotes significant reduction in the frequency of prehypertension and masked hypertension by promoting significant blood pressure reductions in patients with severe obstructive sleep apnea.     

Effect of continuous positive airway pressure therapy on 24-hour blood pressure in patients with obstructive sleep apnea syndrome

BACKGROUND: Patients with obstructive sleep apnea syndrome (OSAS) are subject to an increased cardiovascular morbidity including systemic hypertension. Little is known about the effects of treatment with nasal continuous positive airway pressure (CPAP) on systemic hypertension. METHODS: Automated ambulatory 24-h blood pressure (BP) monitoring was performed in 88 consecutive patients who were referred for evaluation of snoring or suspected OSAS. In addition, the long-term effects of CPAP therapy on 24-h BP were assessed. RESULTS: A total of 62 patients had OSAS and 26 habitual snoring. Patients with OSAS had significantly higher mean arterial BP values than snorers (102.7 +/- 10.7 v 94.0 +/- 10.2 mm Hg; P < .01). Multiple stepwise linear regression analysis disclosed that the degree of systemic hypertension was independently associated with the severity of OSAS as determined by the apnea/hypopnea index (R = 0.43; P < .001), but not with age, body mass index, or smoking habits. Of the 62 patients with OSAS, 52 were treated with CPAP and reevaluated after 9 months. The CPAP resulted in a significant decrease in mean arterial BP (from 103.7 +/- 10.4 to 99.1 +/- 10.8 mm Hg; P < .05). For those patients with systemic hypertension whose BP improved with CPAP therapy, 24-h mean pulse pressure at baseline (r = -0.36; P < .05) as well as average heart rate during the day (r = -0.35; P < .05) turned out as predictors. CONCLUSIONS: Obstructive sleep apnea syndrome contributes, at least in part, to the development of systemic hypertension, and CPAP may improve BP values in treated OSAS patients. Predictors of a beneficial CPAP effect on BP are a high heart rate and a high pulse pressure before treatment.     

Genioglossus activity during sleep in normal control subjects and children with obstructive sleep apnea

Children with obstructive sleep apnea syndrome (OSAS) have more collapsible airways compared with normal subjects, yet sustain stable breathing during wakefulness and part of sleep. This indicates successful neuromuscular compensation. Using a custom intraoral surface electrode to record pharyngeal dilator muscle activity (the genioglossus [EMGgg] normalized to the wakeful baseline), we performed overnight polysomnograms in three groups of children: (1) patients with OSAS without continuous positive airway pressure (CPAP) (n = 13); (2) patients with OSAS with CPAP (n = 5); and (3) control subjects without CPAP (n = 13). Our objective was to evaluate the EMGgg as a function of sleep state and during disordered breathing, compared with stable sleep and wakefulness. In control subjects, the EMGgg decreased from wakefulness to Stage 2 (mean +/- SD, 65 +/- 6%), and further during REM (51 +/- 9%) (p < 0.05). In patients with OSAS, the EMGgg for apneic breaths during REM (37 +/- 9%) was lower than during stable breathing (83 +/- 17%) (p < 0.05) and wakefulness (p < 0.05). CPAP lowered the EMGgg in patients with OSAS during all sleep states. These data indicate that (1) EMGgg compensatory mechanisms remain active during sleep in patients with severe OSAS; (2) EMGgg reductions are temporally associated with sleep apnea events; and (3) REM sleep is associated with the lowest and most variable EMGgg.     

In vivo platelet activation is increased during sleep in patients with obstructive sleep apnea syndrome

BACKGROUND: Patients with obstructive sleep apnea syndrome (OSAS) have an increased risk of cardiovascular events including myocardial infarction and stroke. OBJECTIVE: To determine whether in vivo platelet activation and the generation of procoagulant platelet-derived microparticles (PMP) are increased during sleep in patients with OSAS. METHODS: In vivo platelet activation and PMP formation was determined using flow cytometry in 12 patients with untreated OSAS during and after sleep (4 and 7 a.m.). To study the effect of treatment with continuous positive airway pressure (CPAP), the measurements were repeated at the same time points after initiation of CPAP therapy. Healthy volunteers served as controls (n = 6). RESULTS: Patients with OSAS had an increased percentage of platelets positive for the activation-dependent epitopes CD63 and CD62P during sleep (4 a.m.) compared to controls (4.8 +/- 0.8 vs. 1.9 +/- 0.4% for CD63, p < 0.01, and 2.0 +/- 0.5 vs. 1.1 +/- 0.3% for CD62P, p < 0.05). In OSAS patients, the amount of CD63- and CD62P-positive platelets was significantly elevated at 4 compared to 7 a.m. (4.8 +/- 0.8 vs. 2.6 +/- 0.4% for CD63 and 2.0 +/- 0.5 vs. 1.1 +/- 0.2% for CD62P, p < 0.05), but not in the control group. The levels of PMP were similar in patients with OSAS and controls at 4 and 7 a.m. After 1 night of CPAP therapy, there was a trend to reduced levels of CD63- and CD62P-positive platelets at 4 a.m. CONCLUSIONS: Patients with OSAS have increased in vivo platelet activation during sleep, which may contribute to the increased incidence of cardiovascular events in patients with OSAS.     

Continuous positive airway pressure treatment improves baroreflex control of heart rate during sleep in severe obstructive sleep apnea syndrome

The role of the arterial baroreflex in the cardiovascular changes associated with the obstructive sleep apnea syndrome (OSAS), and the effect of nasal continuous positive airway pressure (CPAP) treatment on baroreflex function during sleep are unknown. Baroreflex control of heart rate was studied in 29 normotensive patients with OSAS under no treatment, in 11 age-matched control subjects, and in 10 patients at CPAP withdrawal after 5.5 +/- 3.7 (range 3-14) months of treatment. Baroreflex control of heart rate was assessed by "sequence method" analysis of continuous blood pressure recordings (Finapres) obtained during nocturnal polysomnography. In untreated OSAS, baroreflex sensitivity (BRS) was low during wakefulness and non-rapid eye movement (REM) stage 2 sleep compared with control subjects, and correlated inversely with mean lowest Sa(O(2)) and the blood pressure increase after apneas. After CPAP treatment, the apnea-hypopnea index was lower, and mean lowest Sa(O(2)) higher than before treatment. After CPAP, patients were more bradycardic, blood pressure and its standard deviation decreased as Sa(O(2)) improved in non-REM stage 2 sleep, and BRS increased (nocturnal wakefulness: +59%; non-REM stage 2 sleep: +68% over pretreatment values). Our data suggest that baroreflex dysfunction in OSAS may be at least partly accounted for by nocturnal intermittent hypoxemia, and can be reversed by long-term CPAP treatment.     

Long-term effects of nasal continuous positive airway pressure therapy on cardiovascular outcomes in sleep apnea syndrome

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) has been associated with increased morbidity and mortality, principally from cardiovascular disease, but the impact of nasal continuous positive airway pressure (CPAP) therapy is unclear. METHODS: We performed a long-term follow-up study of 168 patients with OSAS who had begun receiving CPAP therapy at least 5 years previously, most of whom had been prospectively followed up, having been the subject of an earlier report on cardiovascular risk factors in OSAS patients. The average follow-up period was 7.5 years. We compared the cardiovascular outcomes of those patients who were intolerant of CPAP (untreated group, 61 patients) with those continuing CPAP therapy (107 patients). RESULTS: CPAP-treated patients had a higher median apnea-hypopnea index score than the untreated group (48.3 [interquartile range (IQR), 33.6 to 66.4] vs 36.7 [IQR, 27.4 to 55], respectively; p = 0.02), but age, body mass index, and time since diagnosis were similar. Deaths from cardiovascular disease were more common in the untreated group than in the CPAP-treated group during follow-up (14.8% vs 1.9%, respectively; p = 0.009 [log rank test]), but no significant differences were found in the development of new cases of hypertension, cardiac disorder, or stroke. Total cardiovascular events (ie, death and new cardiovascular disease combined) were more common in the untreated group than in the CPAP-treated group (31% vs 18%, respectively; p < 0.05). CONCLUSIONS: The data support a protective effect of CPAP therapy against death from cardiovascular disease in patients with OSAS.     

Effect of continuous positive airway pressure on the risk of road accidents in sleep apnea patients

BACKGROUND: Continuous positive airway pressure (CPAP) reduces daytime somnolence in the obstructive sleep apnea syndrome (OSAS) and may contribute to a reduction in the risk of motor vehicle accidents. OBJECTIVE: To evaluate the effects of CPAP on automobile collisions in patients with OSAS. METHODS: We compared the number of motor vehicle accidents in 80 patients with OSAS and 80 healthy subjects during the 2 years before and the 2 years after study entry, at which CPAP treatment was initiated. RESULTS: Patients with OSAS had a 2.6 times higher risk of suffering an automobile collision compared to controls (rate ratio, RR=2.57; 95% confidence interval, CI=1.30-5.05). After 2 years of CPAP treatment, the rate of collisions was reduced more than half in patients with OSAS (RR=0.41; 95% CI=0.21-0.79), but this occurred also in controls (RR=0.49; 95% CI=0.17-1.40). The magnitude of this fall between groups was not different (p for interaction=0.68), even after adjusting for body mass index, alcohol intake and Epworth scale. CONCLUSIONS: Patients with OSAS have an increased risk of suffering a traffic collision. This risk was significantly reduced after their inclusion in the study. Yet, as this reduction also occurred in the control group, this effect may not be due to CPAP therapy.