Effect of nasal continuous positive airway pressure on edema in patients with obstructive sleep apnea

BACKGROUND AND PURPOSE: Previous research has identified an association between idiopathic edema and obstructive sleep apnea (OSA) in women, but a causal relationship between OSA and edema has not been established. This study was undertaken to determine whether nasal continuous positive airway pressure (CPAP) lessens edema in patients with idiopathic edema and OSA. PATIENTS AND METHODS: This was a case-series study that enrolled eight ambulatory, obese, adults with bilateral, pitting pre-tibial edema and OSA from an inner city family practice and a suburban family practice from July 1995 until March 2003. Enrollees underwent subjective and physical examination assessment of changes in edema after initiation of nasal CPAP. RESULTS: All but one of the subjects had severe OSA. The edema was typically 1+ to 2+, and the duration of the edema ranged from 6 months to more than 20 years. Seven of the eight subjects experienced a reduction in the amount of edema following nasal CPAP (P=0.04). CONCLUSIONS: In subjects with OSA and idiopathic edema, nasal CPAP reduces the amount of edema. If valid, these results indicate that OSA can cause edema.     

气道正压通气对睡眠呼吸暂停综合征的疗效

目的:了解阻塞型睡眠呼吸暂停综合征(OSAS)患者在经鼻持续气道正压通气(nCPAP)治疗前后的睡眠特征和心身状况变化。方法:nCPAP治疗35例OSAS患者,治疗前、后分别采用多导睡眠分析仪对患者进行检查,分析治疗前、后多导睡眠图(PSG)各项指标改变。结果:治疗后患者临床症状消除,睡眠结构、最低血氧饱和度及呼吸紊乱指数等各项指标均有明显改善(P<0·01)。结论:nCPAP治疗不仅使睡眠呼吸暂停综合征(SAS)患者嗜睡、疲乏等临床症状消失,明显改善睡眠结构,而且改善心身健康状况。     

Improvement of subjective work performance among obstructive sleep apnea patients after treatment with continuous positive airway pressure

Obstructive sleep apnea syndrome (OSAS) is a significant problem for some patients presenting with snoring and excessive daytime sleepiness. The 'golden standard' therapy in OSAS is considered to be nasal continuous positive airway pressure (CPAP). The effects of CPAP on work performance in sleep apnoics has not been studied previously. One hundred and fifty-two patients with OSAS participated in an open label study. The patients were diagnosed as suffering from severe OSAS after they underwent overnight polysomnography showing that their apnea indexes were at least 20. The participants answered four questions concerning self-perceived work performance prior to and after using CPAP during 6 months. There were highly statistically significant decreases (P < 0.000001) in work performance difficulties as graded by the patient. The results of this study indicate that CPAP treatment improves subjective work performance in patients suffering from OSAS.     

Seasonal effects on the continuous positive airway pressure adherence of patients with obstructive sleep apnea

ObjectiveThis study examined seasonal differences in continuous positive airway pressure (CPAP) therapy adherence among patients with obstructive sleep apnea (OSA).MethodsPatients aged ≥20 years with OSA who had used CPAP devices on the automatic setting for >12 consecutive months (n = 141) were included in this retrospective study from December 2015–2016. The information of CPAP use (pressure, hours of actual use) was extracted from database downloaded from patients’ CPAP devices. Patients were divided into adherent and non-adherent groups using the cutoff point of 70% CPAP use for ≥4 h daily over the 1-year study period. CPAP use data were averaged for each season.ResultsPatients in the adherent group were significantly older than those in the non-adherent group (p < 0.001). In the adherent group, the rate of ≥4 h daily CPAP use was significantly lower, the daily duration of CPAP use was significantly shorter, and the residual apnea–hypopnea index (AHI; events/hour) was significantly higher in summer than in other seasons (all p < 0.001). In the non-adherent group, the duration of daily CPAP use and the AHI differed significantly between winter and summer (p = 0.008 and p < 0.001, respectively).ConclusionsSeasonal changes were associated with the CPAP adherence of patients with OSA. The study findings suggest that there is possibility of increasing the duration of CPAP use by adjusting the bedroom environment in hot and humid seasons.     

Continuous positive airway pressure treatment with nasal pillows in obstructive sleep apnea: long-term effectiveness and adherence

BackgroundsMask-related side effects can negatively influence adherence to continuous positive airway pressure (CPAP). Nasal pillows (P) can be an alternative to the standard nasal masks (N), although there are no data about their long-term efficacy. This study aimed to assess long-term effectiveness and adherence to CPAP therapy delivered with nasal pillows in obstructive sleep apnea syndrome (OSAS) patients.MethodsA retrospective observational design involving a series of consecutive CPAP-naïve patients affected by OSAS. After an initial mask fitting session all patients were allowed to choose the type of nasal interface (N or P) they preferred. Outcomes were assessed 5 days after CPAP titration, and after 2 and 12 months. Patients were offered the option of switching to an alternative mask if needed.ResultsData from 144 patients were analyzed. Subjects were predominantly male (76%), middle aged (58.14 ± 12.86), moderately obese (body mass index: 33.89 ± 7.56), and affected by severe OSAS (apnea-hypopnea index: 47.60 ± 21.31). A total of 102 patients (70.8%) chose P, and 42 (29.2%) chose N. Clinical and polygraphic features, and CPAP pressure levels were similar in P and N groups, both at baseline and at 12 months. A good adherence to treatment was observed in both groups (P, 5.5 ± 1.8 h; N, 5.3 ± 1.5 h). Seventy-six patients (53%) reported at least one side effect during the whole study period, without statistically significant between-group differences. Nostril pain was the most frequent side effect in P.ConclusionsNasal pillows showed equal long-term effectiveness and objective adherence as standard nasal masks.     

Prevalence of obstructive sleep apnea in patients with posttraumatic stress disorder and its impact on adherence to continuous positive airway pressure therapy: a meta-analysis

ObjectiveAlthough some authors have recently investigated the co-occurrence of posttraumatic stress disorder (PTSD) and obstructive sleep apnea (OSA), the topic remains insufficiently studied. The aim of this meta-analysis was to detect the pooled prevalence of OSA in PTSD and its impact on adherence to continuous positive airway pressure (CPAP) therapy.MethodsWe conducted a search for articles published until August 20, 2016, in PubMed, Embase, the Cochrane Library, and PsycINFO. The literature search identified 194 articles, and 12 studies were included in the meta-analysis.ResultsThe pooled prevalence rates of OSA based on different apnea–hypopnea index (AHI) criteria in PTSD patients was 75.7% (95% confidence interval [CI] = 44.1–92.5%) (AHI ≥5) and 43.6% (95% CI = 20.6–69.7%) (AHI ≥10), respectively. Subgroup analysis showed that there was a significant difference between the prevalence of OSA in veterans with PTSD compared to nonveterans or mixed samples. Patients with PTSD and OSA demonstrated significantly lower adherence to CPAP therapy (regular use: g = −0.658, 95% CI = −0.856 to −0.460; time of average use per night: g = −0.873, 95% CI = −1.550 to −0.196) compared with those with OSA alone.ConclusionsOSA is commonly seen in patients with PTSD. Given its negative impact on the adherence to CPAP therapy, the possibility of OSA should be monitored carefully in patients with PTSD.     

Treating obstructive sleep apnea with continuous positive airway pressure reduces risk of recurrent atrial fibrillation after catheter ablation: a meta-analysis

IntroductionRecent studies have suggested that there is a strong relationship between obstructive sleep apnea (OSA) and atrial fibrillation (AF). However, they have not identified whether treating OSA with continuous positive airway pressure (CPAP) might reduce rates of recurrent AF.ObjectiveTo investigate the recurrent risk of AF after catheter ablation among patients with OSA who did receive or did nor receive CPAP therapy.MethodsA systematic review of PubMed, Embase, Medline, Cochrane library, China National Knowledge Infrastructure (CNKI) and Wan-fang databases was conducted to obtain relevant cohort studies and randomized controlled trials (RCTs). Study characteristics of AF patients were extracted, and their recurrent outcomes were recorded. A meta-analysis was then conducted using Review Manager software, version 5.3. In total, seven eligible cohort studies and three randomized controlled trials involving 1217 participants with AF after catheter ablation were included. These participants were divided into a CPAP group (n = 619, 50.86%) and non-CPAP group (n = 598, 49.14%).ResultsAfter a mean follow-up of 16.33 ± 10.34 months, 408 patients (33.52%) experienced recurrent AF, and the recurrence rate differed between the CPAP and non-CPAP groups (24.88% vs 42.47%; RR 0.60; 95% CI 0.51–0.70; p = 0.000). Overall, patients treated with CPAP had a lower risk of recurrent AF after catheter ablation than those who did not, and about 17.59% of cases with recurrent AF could be attributed to not receiving CPAP. Meanwhile, the results indicated that CPAP therapy decreased the left atrial diameter (LAD) (WMD –6.28; 95% CI –7.00 to −5.56; p = 0.000) and increased left ventricular ejection fraction (LVEF) (WMD 7.37; 95% CI 6.98–7.76; p = 0.000).ConclusionOSA had an increased risk of recurrent AF after successful catheter ablation, and CPAP treatment for AF patients with OSA might have significantly mitigated the recurrent risks.     

Nasal CPAP treatment for obstructive sleep apnea: developing a new perspective on dosing strategies and compliance

Nasal continuous positive airway pressure (CPAP) is presently considered as the “treatment of choice” for obstructive sleep apnea (OSA). Though some OSA patients adhere to treatment recommendations and ultimately respond quite well to CPAP therapy, there is a substantial subgroup for which compliance is a particularly difficult issue. Despite receiving recommendations to the contrary and for reasons that are incompletely understood, the majority of OSA patients settle for a partial compliance pattern. Whether a partial compliance schedule is beneficial or harmful is virtually unexamined: Unlike other medical treatments, there are few data concerning the “dose–response relationship” of CPAP to its desired effects. We argue that CPAP “dose” is a function not only of CPAP pressure but of time-on-CPAP as well. Critical questions that remain unanswered are what “dose” of CPAP is needed to effect an appropriate treatment outcome and which treatment outcomes should form the basis of our recommendations. Recent placebo-controlled studies comparing CPAP to suboptimal CPAP pressures may be informative in this regard. Directions for future research are suggested.     

Effects of continuous positive airway pressure therapy on systemic inflammation in obstructive sleep apnea: A meta-analysis

Objectives

Our meta-analysis was performed to estimate the effect of continuous positive airway pressure (CPAP) therapy on systemic inflammation in patients with obstructive sleep apnea (OSA).

Methods

A comprehensive literature search of PubMed and EMBASE was performed for literature published up to January 2013. Standardized mean difference (SMD) was calculated to estimate the treatment effects of pre- and post-CPAP therapy.

Results

A total of 35 studies involving 1985 OSA patients were included in the meta-analysis. Each study investigated one or more inflammatory markers: 24 studies on C-reactive protein (CRP), 16 studies on IL-6, 3 studies on IL-8, and 12 studies on tumor necrosis factor α (TNF-α). The results showed that the SMD (95% confidence interval [CI]) for CRP, IL-6, IL-8, and TNF-α were 0.452 (95% CI, 0.252–0.651), 0.299 (95% CI, 0.001–0.596), 0.645 (95% CI, 0.362–0.929), and 0.478 (95% CI, 0.219–0.736) in pre- and post-CPAP therapy, respectively. The subgroup analyses seemed to support better benefits with therapy duration of ?3 months and more adequate compliance (?4 h/night).

Conclusions

CPAP therapy could partially suppress systemic inflammation in OSA patients, and substantial differences were present among the various inflammatory markers.     

Relationship between reflux diseases and obstructive sleep apnea together with continuous positive airway pressure treatment efficiency analysis

BackgroundObstructive sleep apnea (OSA) is known to be highly associated with reflux diseases. There is evidence that continuous positive airway pressure (CPAP) can decrease the clinical symptoms of gastroesophageal reflux (GER) in OSA patients, but whether CPAP can decrease nocturnal laryngopharyngeal reflux (LPR) episodes is still lack of strong evidence.ObjectiveTo investigate the efficiency of CPAP on LPR and the relationship between LPR, GER and OSA.Study designretrospective study.MethodsForty adult patients who had confirmed OSA by polysomnography and suspected LPR were enrolled. Their results of synchronous polysomnography and 24 h esophageal and oropharyngeal Dx-pH monitoring were analyzed. Twenty-seven OSA patients were treated with CPAP on the second night. The nocturnal reflux parameters with and without CPAP treatment were compared.Results15.0% and 42.5% of OSA patients were associated with LPR and GER through Dx-pH monitoring respectively. Nevertheless, more than one reflux attack falling below pH6.0 of oropharynx during sleep time was detected in 80.0% patients. There was a significant inverse correlation between the lowest/mean pH values of oropharynx and obstructive apnea index (OAI), so was the lowest pH values of esophagus. Significant positive correlation was calculated between the total number of reflux episodes below pH6.0 of oropharynx and apnea–hypopnea index (AHI)/OAI/hypopnea index (HI). A similar positive correlation was also significant between AHI/OAI and GER parameters. The assessment of the efficacy of CPAP treatment showed significant difference both in GER and LPR related parameter.ConclusionsOSA patients have a higher incidence of nocturnal LPR and GER. CPAP treatment can effectively reduce both GER and LPR attacks while disordered sleep events reduced in OSA patients.     

Auditory event-related potentials before and after treatment with nasal continuous positive airway pressure in sleep apnea syndrome

Auditory event-related potentials (ERP), multiple sleep latency tests, mini-mental state exam, and depression tests were studied in 15 patients with obstructive sleep apnea syndrome (OSA). The P3 wave latency of ERP was significantly increased compared with 15 age-matched control subjects. After 4 weeks and after 1 year of treatment of OSA by nasal continuous positive airway pressure (CPAP), there was no significant improvement in the abnormalities of ERP. These observed changes in ERP were not correlated with excessive daytime sleepiness, depression, nocturnal hypoxemia, and sleep fragmentation. The cause of increased P3 latency has not been elucidated, but a chronic cerebral insult was suspected.     

Enhanced cardiorespiratory coupling in patients with obstructive sleep apnea following continuous positive airway pressure treatment

Background

Weak cardiorespiratory coupling (CRC) has been suggested in patients with obstructive sleep apnea (OSA), but the effects of continuous positive airway pressure (CPAP) on CRC remain unclear. We investigated the effects of CPAP treatment on CRC in patients with severe OSA to examine possible reversibility of altered CRC.

Methods

High-resolution electrocardiograms (ECGs) and respiratory signals were simultaneously recorded for 13 never-treated OSA patients at baseline and after CPAP treatment. The analyses were performed on a 15-min daytime recording of ECG and respiration. Heart rate variability (HRV) indices were extracted from ECGs. After computing the sample entropy (SampEn) to quantify the regularity of both heart rate (SampEn_RR) and respiration rhythm (SampEn_resp), cross-sample entropy (cross-SampEn) was calculated to measure the interaction between the two signals. Cross-SampEn denotes asynchrony between heart rate and respiration, and thus negatively correlates with CRC.

Results

Lower SampEn_RR and higher cross-SampEn as well as a shift toward sympathetic dominance were found in OSA patients compared with age- and gender-matched controls. CPAP treatment was associated with improved sympathovagal balance, increased SampEn_RR, and enhanced CRC, corresponding to a decrease in the cross-SampEn value from 0.71 ± 0.08 to 0.49 ± 0.06 (P < .001). The effect sizes for the CPAP-induced changes in sympathovagal balance, SampEn_RR, and cross-SampEn were medium to large (0.54–0.90).

Conclusions

The findings of our study indicate reduced CRC in untreated OSA patients and suggest that CPAP treatment may reverse this abnormality.     

Daytime sleepiness after long-term continuous positive airway pressure (CPAP) treatment in obstructive sleep apnea syndrome

A modified maintenance of wakefulness test was performed in 58 patients with obstructive sleep apnea (OSA) syndrome before treatment and after long-term (554 ± 28 days) home therapy with nasal continuous positive airway pressure (CPAP). Before treatment the patients had a shorter mean sleep latency than controls (16 ± 1 vs. 27 ± 1 in, mean ± SEM, P < 0.001) After treatment, the mean sleep latency increased to 20 ± 1 min P < 0.002 as compared to baseline), but was still shorter than in controls (P < 0.001). The incomplete normalization of the mean latency contrasted with the patient's claim that they no longer felt sleepy. The improvement in daytime alertness was significantly correlated with the reduction in sleep fragmentation after CPAP treatment and with the baseline mean sleep latency. These results support the hypothesis that sleep disruption related to respiratory events plays a role in the pathogenesis of daytime sleepiness.     

持续气道正压通气治疗癫(痫)与阻塞性睡眠呼吸暂停综合征共病疗效的系统评价

目的 评价持续气道正压通气治疗癫(痫)与阻塞性睡眠呼吸暂停综合征共病的有效性.方法 以sleep apnoea、obstructive sleep apnoea、OSA、obstructive sleep apnoea syndrome、OSAS、sleepapnoea syndromes、sleep-related breathing disorder、epilepsy、continuous positive airway pressure、CPAP等英文词汇计算机检索1980年1月1日-2017年2月28日美国国立医学图书馆生物医学信息检索系统(PubMed)、荷兰医学文摘(EMBASE/SCOPUS)、Cochrane图书馆等数据库收录的关于持续气道正压通气治疗癫痼与阻塞性睡眠呼吸暂停综合征共病的随机对照临床试验、临床指南、系统评价(包括Meta分析)、病例对照研究、回顾性队列研究等.采用Jadad量表、Cochrane系统评价手册和RevMan 5.3统计软件进行文献质量评价和Meta分析.结果 共获得1197篇英文文献,经剔除重复和不符合纳入标准者,最终纳入17篇文献,包括临床指南1篇、系统评价和Meta分析各1篇、随机对照临床试验l篇、病例对照研究10篇、回顾性队列研究3篇.结果显示:(1)持续气道正压通气可以减少癫(痫)与阻塞性睡眠呼吸暂停综合征共病患者癫(痫)发作频率甚至无发作.(2)持续气道正压通气可以减少难治性癫(痫)与阻塞性睡眠呼吸暂停综合征共病患者癫(痫)发作频率.(3)持续气道正压通气可以减少老年癫(痫)与阻塞性睡眠呼吸暂停综合征共病患者癫(痫)发作频率.(4)对3项Jadad评分≥4分的临床研究共153例癫(痫)与阻塞性睡眠呼吸暂停综合征共病患者进行Meta分析,与未接受持续气道正压通气组相比,接受持续气道正压通气组癫(痫)发作频率减少＞50％的病例数增加(RR=3.170,95％ CI:1.650 ～ 6.090;P=0.001).结论 持续气道正压通气可以减少癫(痫)与阻塞性睡眠呼吸暂停综合征共病患者癫(痫)发作频率,其治疗效果取决于患者依从性,突然停止或压力不足可能导致癫痫发作频率增加,这一结论尚待更多随机对照临床试验证实.     

Effect of speech therapy as adjunct treatment to continuous positive airway pressure on the quality of life of patients with obstructive sleep apnea

BackgroundPatients with obstructive sleep apnea (OSA) exhibit reduced quality of life (QoL) due to their daytime symptoms that restricted their social activities. The available data for QoL after treatment with continuous positive airway pressure (CPAP) are inconclusive, and few studies have assessed QoL after treatment with speech therapy or other methods that increase the tonus of the upper airway muscles or with a combination of these therapies. The aim of our study was to assess the effect of speech therapy alone or combined with CPAP on QoL in patients with OSA using three different questionnaires.MethodsMen with OSA were randomly allocated to four treatment groups: placebo, 24 patients had sham speech therapy; speech therapy, 27 patients had speech therapy; CPAP, 27 patients had treatment with CPAP; and combination, 22 patients had treatment with CPAP and speech therapy. All patients were treated for 3 months. Participants were assessed before and after treatment and after 3 weeks of a washout period using QoL questionnaires (Functional Outcomes of Sleep Questionnaire [FOSQ], World Health Organization Quality of Life [WHOQoL-Bref], and Medical Outcomes Study 36-Item Short-Form Health Survey [SF-36]). Additional testing measures included an excessive sleepiness scale (Epworth sleepiness scale [ESS]), polysomnography (PSG), and speech therapy assessment.ResultsA total of 100 men aged 48.1 ± 11.2 (mean ± standard deviation) years had a body mass index (BMI) of 27.4 ± 4.9 kg/m², an ESS score of 12.7 ± 3.0, and apnea–hypopnea index (AHI) of 30.9 ± 20.6. After treatment, speech therapy and combination groups showed improvement in the physical domain score of the WHOQoL-Bref and in the functional capacity domain score of the SF-36.ConclusionsOur results suggest that speech therapy alone as well as in association with CPAP might be an alternative treatment for the improvement of QoL in patients with OSA.     

Hypercoagulability in patients with obstructive sleep apnea

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to cardiovascular complications such as stroke and myocardial infarction. Previous studies demonstrate that OSA patients show elevated fibrinogen levels and increased platelet aggregation that are reversed with 1 night of nasal continuous positive airway pressure treatment (NCPAP). Questioning overall coagulability in OSA, we examined whole blood coagulability in 11 chronically NCPAP treated OSA subjects, 22 previously untreated OSA subjects, and in 16 of these after 1 night of NCPAP treatment. PATIENTS AND METHODS: During full polysomnography, subjects from each group had blood drawn prior to bedtime (21:00 h) and upon waking in the morning (07:00 h). RESULTS: Untreated OSA patients had faster P.M. clotting times than chronically treated OSA patients (3.33+/-0.31 versus 6.12+/- 0.66 min, P<0.05 by ANOVA). A.M. values showed similar results (4.31+/- 0.34 min versus 7.08+/-0.52 min, P<0.05 by ANOVA) for the respective groups. One overnight treatment with nasal CPAP did not produce a significant change in A.M. whole blood coagulability (4.35 +/-0.43 to 5.31+/-0.53 min; n=16; P=0.1) in 16 treated subjects. CONCLUSIONS: These data indicate a relationship between obstructive sleep apnea and blood hypercoagulability status that appears to be reversed by chronic NCPAP treatment. These data suggest that NCPAP might protect against the development of cardiovascular complications in OSA patients.     

Findings of the Maintenance of Wakefulness Test and its relationship with response to modafinil therapy for residual excessive daytime sleepiness in obstructive sleep apnea patients adequately treated with nasal continuous positive airway pressure

ObjectiveWe aimed to examine the relationship between subjective and objective sleepiness in obstructive sleep apnea syndrome (OSAS) patients with residual sleepiness, and to determine whether baseline objective sleepiness severity predicts the response to modafinil therapy.MethodsData were obtained from a randomized, placebo-controlled modafinil (200 mg/day) study in Japanese OSAS patients with residual sleepiness receiving nasal continuous positive pressure (n-CPAP) treatment. We analyzed 50 participants whose subjective (Epworth Sleepiness Scale [ESS] total score) and objective (Maintenance of Wakefulness Test [MWT] sleep latency) sleepiness were evaluated before and after treatment. Subjects were dichotomized into two subgroups according to the mean baseline MWT sleep latency. ESS total score and MWT sleep latency changes after treatment were compared between the placebo and modafinil groups in both subgroups.ResultsThe mean baseline ESS total score and MWT sleep latency were 14.1 ± 2.8 and 14.2 ± 4.9 min, respectively; there was no significant correlation between these two variables. Patient characteristics were similar between the two subgroups (MWT sleep latency: <14 min, n = 23; ≥14 min, n = 27). In the <14-min subgroup, changes in ESS total score and MWT sleep latency after treatment were significantly greater in the modafinil group than in the placebo group (p = 0.005). In the ≥14-min subgroup, changes in these parameters did not differ between the treatment groups.ConclusionIn OSAS patients with residual sleepiness, the objective sleepiness level was not as high as expected, despite increased subjective sleepiness. Improvements in subjective and objective sleepiness seemed difficult to achieve with modafinil treatment among subjects with less objective sleepiness.     

Effect of continuous positive airway pressure treatment on seizure control in patients with obstructive sleep apnea and epilepsy

In patients with epilepsy, improvement in seizure control with treatment of coexisting obstructive sleep apnea (OSA) has been reported, but there is lack of data on the effect of continuous positive airway pressure (CPAP) compliance on seizure control in these patients. We examined the variability in seizure frequency in patients who were CPAP compliant and those who were not CPAP compliant. We undertook a retrospective review of clinical and polysomnographic data of adult patients with OSA and epilepsy seen at the Boston University Medical Center Epilepsy and Sleep Clinics between 2000 and 2010. Data were reviewed for CPAP compliance and seizure frequency after at least 6 months of CPAP use. Only patients with no changes in antiepileptic drug regimens during CPAP trial were included. Of the 660 patients identified, 41 fulfilled inclusion criteria, of whom 28 were CPAP compliant and 13 were not CPAP compliant. In the compliant group, CPAP use led to decreased seizure frequency from 1.8 per month to 1 per month (p = 0.01). In the noncompliant group, no significant difference in seizure frequency was noted between baseline (2.1 per month) and at follow-up (1.8 per month, p = 0.36). Sixteen of 28 CPAP-compliant subjects were seizure free, whereas only 3 of 13 non-CPAP compliant subjects were seizure free [relative risk (RR) 1.54, p = 0.05]. Patients with epilepsy and OSA not compliant with CPAP treatment are at higher risk of seizures than are CPAP-compliant patients. To validate this observation, further prospective studies are warranted.     

Effect of continuous positive airway pressure on regional cerebral blood flow in patients with severe obstructive sleep apnea syndrome

ObjectivesObstructive sleep apnea (OSA) is commonly associated with neural and cognitive deficits induced by recurrent hypoxemia and sleep fragment. The aims of this study were to use statistical parametric mapping (SPM) to analyze changes in regional cerebral blood flow (rCBF) in untreated patients with severe OSA before and after nasal continuous positive airway pressure (CPAP) treatment, examine the impact of OSA-related variables on rCBF, and assess the therapeutic effect of nasal CPAP treatment.MethodsThirty male patients with severe OSA underwent brain single photon emission computed tomography (SPECT) scans twice before and after nasal CPAP treatment for ≥6 months, whereas 26 healthy controls underwent a single SPECT scan. The rCBF differences were compared between two OSA sub-groups (untreated and treated) and the control group, and correlations between rCBF differences and clinical parameters were analyzed.ResultsCompared with the controls, the untreated OSA patients showed a significantly lower rCBF in multiple brain areas. After the treatment, partial reversal of the rCBF decreases was observed in the limbic and prefrontal areas. Moreover, complete reversal of the rCBF decreases was observed in the medial orbitofrontal, angular and cerebellar areas. Significant improvements in some clinical and polysomnographic variables (Epworth Sleepiness Scale, apnea–hypopnea index, CPAP duration, and arousal index) paralleled the rCBF changes after the treatment.ConclusionsDecreased rCBF in severe OSA was significantly reversible by CPAP treatment and correlated with the improvements in the apnea–hypopnea index, arousal index, CPAP duration and Epworth Sleepiness Scale. These results suggest that long-term CPAP treatment improves rCBF in areas responsible for executive, affective, and memory function.