Daytime polysomnography for early diagnosis and treatment of patients with suspected sleep-disordered breathing

Excessive daytime sleepiness (EDS) is a common complaint among patients with sleep-disordered breathing (SDB). Population-based studies on traffic and industrial accidents suggest a relationship between EDS and life-threatening events, and adults with EDS have cognitive and memory problems. Nocturnal polysomnography (nPSG) is essential for diagnosing SDB but it is time and energy consuming. We examined the usefulness of daytime polysomnography (dPSG) for the early diagnosis and treatment of patients with suspected SDB. We studied 108 consecutive patients aged 51.9 +/- 13.5 years (mean+/-SD). All patients underwent dPSG and nPSG. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and the number of 3% desaturation episodes per hour (desaturation index: DSI) were calculated. All patients were classified into two groups. The REM group consisted of subjects who had an AHI < or = 25/h, AHI(REM)/AHI(NREM) > 2, and AHI(NREM) < 15/h. Those who did not satisfy these criteria were placed in the NREM group. Continuous positive airway pressure (CPAP) titration was performed for patients whose AHI was > or =20/h on dPSG. Using the international classification of sleep disorders, 96 patients were diagnosed as obstructive sleep apnea [including five upper airway resistance syndrome (UARS) patients], six patients were snoring, four had idiopathic hypersomnia due to a medical condition, and two had circadian rhythm sleep disorders. The sensitivity of dPSG for AHI was 81.0%, specificity was 100%, and accuracy was 83.5%. The sensitivity and accuracy of dPSG for AHI in the REM group were considerably lower than in the NREM group. There was no significant difference for optimal CPAP between dPSG and nPSG. In the five patients with UARS, their AHI, DSI, and arousal index on dPSG were 0.92 +/- 1.2/h, 2.9 +/- 3.4/h, and 29.3 +/- 3.5/h, respectively, and their AHI and DSI on nPSG were 3.2 +/- 2.5/h and 2.8 +/- 2.4/h, respectively. However, their respiratory effort-related arousals were 37.9 +/- 7.4/h, and their arousal index was 33.2 +/- 6.3/h. The five patients with UARS were also treated with CPAP, and their daytime sleepiness was improved. Although dPSG has limitations, these results indicate that dPSG recording is clinically useful for the diagnosis of and determination of types of treatment in patients with suspected SDB.     

Sleep-disordered breathing and quality of life of railway drivers in Greece

BACKGROUND: Sleep-disordered breathing (SDB) and especially obstructive sleep apnea (OSA) are associated with daytime sleepiness and an increased risk for motor vehicle crashes. Previous studies have assessed the prevalence of OSA among professional drivers, but no study so far has focused on railway drivers. The aim of this study was to assess the prevalence of SDB among Greek railway drivers, and correlate it with daytime sleepiness, quality of life, and symptoms. METHODS: The following three different questionnaires were anonymously answered by 226 train drivers: a general questionnaire on their demographics and sleep habits; the Greek version of the Epworth sleepiness scale (ESS); and the Medical Outcomes Study 36-item short form (SF-36). Of the 226 drivers, 50 underwent a sleep study, a physical examination, and an assessment of their respiratory function. RESULTS: Participants were all men, had a mean (+/-SD) age of 46.9+/-3.9 years, were overweight (mean body mass index [BMI], 28.7+/-3.7 kg/m2), and were smokers (59.7%). Snoring was reported by 69.9% of them, and apneas by 11.5%. The mean ESS score was 5.4+/-3.2. SF-36 scores were similar to those of the Greek population. The mean apnea-hypopnea index (AHI) was 11+/-14 events per hour, and the mean pulse oximetric saturation was 93.2+/-2.5%. According to AHI severity, they were divided into the following three groups: group 1, normal breathing function in sleep (n=19; AHI, <5 events per hour); group 2, mild OSA (n=20; AHI, 5.1 to 15 events per hour); group 3, moderate/severe OSA (n=11; AHI, >15 events per hour). The three groups differed in terms of BMI, and neck, waist, and hip circumferences. No difference was detected, though, in ESS and SF-36 scores. CONCLUSION: The majority of the Greek railway drivers are overweight and smokers. The most common reported symptom in the questionnaires is snoring, without significant daytime impairment, while sleep studies show a potentially higher prevalence of OSA. Trial registration: Democritus University of Thrace Identifier: 2979/5-2003. Trial registration: Union of the Greek Railway Drivers Identifier: 536/10-2003.     

Efficacy of adaptive servoventilation in treatment of complex and central sleep apnea syndromes

BACKGROUND: Complex sleep apnea syndrome (CompSAS) is recognized by the concurrence of mixed or obstructive events with central apneas, the latter predominating on exposure to continuous positive airway pressure (CPAP). Treatment of CompSAS or central sleep apnea (CSA) syndrome with adaptive servoventilation (ASV) is now an option, but no large series exist describing the application and effectiveness of ASV. METHODS: Retrospective chart review of the first 100 patients who underwent polysomnography using ASV at Mayo Clinic Sleep Center. RESULTS: ASV titration was performed for CompSAS (63%), CSA (22%), or CSA/Cheyne Stokes breathing patterns (15%). The median diagnostic sleep apnea hypopnea index (AHI) was 48 events per hour (range, 24 to 62). With CPAP, obstructive apneas decreased, but the appearance of central apneas maintained the AHI at 31 events per hour (range, 17 to 47) [p = 0.02]. With bilevel positive airway pressure (BPAP) in spontaneous mode, AHI trended toward worsening vs baseline, with a median of 75 events per hour (range, 46 to 111) [p = 0.055]. BPAP with a backup rate improved the AHI to 15 events per hour (range, 11 to 31) [p = 0.002]. Use of ASV dramatically improved the AHI to a mean of 5 events per hour (range, 1 to 11) vs baseline and vs CPAP (p < 0.0001). ASV also resulted in an increase in rapid eye movement sleep vs baseline and CPAP (18% vs 12% and 10%, respectively; p < 0.0001). Overall, 64 patients responded to the ASV treatment with a mean AHI < 10 events per hour. Of the 44 successful survey follow-up patients contacted, 32 patients reported some improvement in sleep quality. CONCLUSION: The ASV device appears to be an effective treatment of both CompSAS and CSA syndromes that are resistant to CPAP.     

The effect of correction of sleep-disordered breathing on BP in untreated hypertension

OBJECTIVES: To compare BP response to 3 weeks of nasal continuous positive airway pressure (CPAP) in hypertensive patients with and without sleep-disordered breathing (SDB). DESIGN: A controlled, interventional trial of nasal CPAP in patients with and without SDB. Participants and setting: Twenty-four men, aged 30 to 60 years, with mild to moderate untreated hypertension recruited from employee health and primary care clinics. METHODS: Based on in-laboratory polysomnography, 14 hypertensive patients had SDB, defined by five or more episodes of apnea and hypopnea per hour of sleep (apnea-hypopnea index [AHI], > or = 5), and 10 had no SDB (AHI, < 5). We performed 24-h ambulatory BP monitoring on all patients at baseline, during CPAP, and after CPAP treatment. In patients with an AHI > or = 5, nasal CPAP was titrated to reduce the AHI to < 5. Patients with an AHI < 5 received CPAP of 5 cm H(2)O to control for any potential effect of CPAP per se on BP. Both groups received CPAP for 3 weeks. RESULTS: After adjusting for age and body mass index, the mean nocturnal systolic and diastolic BP changes after CPAP treatment in the SDB group were significantly different from those in the no-SDB group: -7.8 vs +0.3 mm Hg (p = 0.02), and -5.3 vs -0.7 mm Hg (p = 0.03), respectively. There was a similar, although statistically insignificant, difference in the adjusted mean daytime systolic and diastolic BP changes after CPAP treatment between the two groups (-2.7 vs +0.4 mm Hg and -2.3 vs -1.7 mm Hg, respectively). CONCLUSIONS: Three weeks of nasal CPAP treatment of SDB in hypertensive men caused the lowering of nocturnal systolic and diastolic BP values, suggesting that increased nocturnal BP in persons with hypertension was causally related to the apnea and hypopnea events of SDB.     

The effects of nasal continuous positive airway pressure on platelet activation in obstructive sleep apnea syndrome

OBJECTIVE: A case-controlled study to assess the effects of nasal continuous positive airway pressure (CPAP) on platelet activation in patients with obstructive sleep apnea (OSAS) syndrome. METHODS: We recruited 65 patients with suspected OSAS for this study. Blood samples were taken with the patient in the supine position in the morning immediately after polysomnography, and 1 night and 3 months after the start of nasal CPAP therapy to measure an index of platelet activation (IPA+), which reflected both the quantity and quality of platelet activation. Significant OSAS was defined as an apnea-hypopnea index (AHI) of > or = 10 events per hour. RESULTS: There were 42 patients with significant OSAS and 23 control subjects with AHI < 10 events per hour. The mean (+/- SD) age for the OSAS patients was 48 +/- 9 years, the mean body mass index was 30.7 +/- 4.8, the mean AHI was 47 +/- 25 events per hour, the mean arousal index (AI) was 37 +/- 23 events per hour, and the mean minimum arterial oxygen saturation was 74 +/- 11%. Following multiple linear regression analyses of the clinical and polysomnography parameters, AI was the independent factor that correlated best with the baseline IPA+ (beta-coefficient, 0.386; p = 0.006). Following nasal CPAP treatment with a mean objective CPAP compliance of 3.9 +/- 1.9 h per night, there was a significant decrease in IPA+ from 15.1 +/- 12.2 U (at baseline) to 12.2 +/- 5.2 U (p < 0.001) and 9.8 +/- 4.3 U (p = 0.005), respectively, after 1 night and 3 months, whereas no significant change was noted among the control subjects. Using univariate analysis of variance to compare the changes in IPA+ between the two groups at 3 months with adjustment for the baseline value, nasal CPAP reduced IPA+ by 5.63 (SE, 1.85), whereas IPA+ increased in control subjects by 1.33 (SE, 1.27) [least-squared mean difference between groups, 3.34; 95% confidence interval, 0.42 to 6.26; p = 0.026]. CONCLUSIONS: OSAS, through repeated episodes of arousals, may lead to platelet activation, which can be reduced by nasal CPAP therapy.     

Randomized crossover trial of two treatments for sleep apnea/hypopnea syndrome: continuous positive airway pressure and mandibular repositioning splint

Mandibular repositioning splints (MRSs) and continuous positive airway pressure (CPAP) are used to treat the sleep apnea/hypopnea syndrome (SAHS). There are some data suggesting that patients with milder symptoms prefer MRS, but there are few comparative data on outcomes. Therefore, we performed a randomized crossover trial of 8 weeks of CPAP and 8 weeks of MRS treatment in consecutive new outpatients diagnosed with SAHS (apnea/hypopnea index [AHI] >or= 5/hour, and >or= 2 symptoms including sleepiness). Assessments at the end of both limbs comprised home sleep study, subjective ratings of treatment value, sleepiness, symptoms, and well-being, and objective tests of sleepiness and cognition. Forty-eight of 51 recruited patients completed the trial (12 women; age [mean +/- SD], 46 +/- 9 years; Epworth 14 +/- 4; median AHI, 22/hour; interquartile ratio [IQR], 11-43/hour). Significant (p 相似文献   

Determinants of continuous positive airway pressure compliance in a group of Chinese patients with obstructive sleep apnea.

OBJECTIVE: To assess continuous positive airway pressure (CPAP) compliance and factors associated with CPAP compliance among Chinese patients with obstructive sleep apnea (OSA). DESIGN: A prospective study of 112 consecutive patients with newly diagnosed OSA commencing CPAP treatment. SETTING: A university teaching hospital. Measurements and results: The following factors were evaluated for any correlation with objective CPAP compliance (effective mask pressure [hours per day]) at 1 month and 3 months: age, baseline apnea-hypopnea index (AHI), common OSA symptoms, minimum arterial oxygen saturation (SaO(2)), mean SaO(2), arousal index (AI), Epworth sleepiness scale (ESS), education level, CPAP levels, satisfaction with CPAP, side effects, and machine cost. There were 101 male and 11 female patients, with a mean (+/- SD) age of 45.6 +/- 1.2 years; body mass index, 29.3 +/- 5.2 kg/m(2); AI, 60 +/- 18/h; AHI, 48 +/- 24/h; minimum SaO(2) of 70 +/- 17%; and mean SaO(2) of 86 +/- 7%. ESS fell from 12.9 +/- 4.0 (baseline) to 5.2 +/- 4.7 at 3 months (p < 0.001). Objective CPAP compliance was 5.4 +/- 1.6 h/d and 5.3 +/- 1.6 h/d, while 75% and 72% of our patients were using CPAP objectively for > or = 4 h/d and at least 70% of the nights per week at 1 month and 3 months, respectively. Following univariate analysis of variance, a high baseline AHI (p = 0.006 and p = 0.004) was associated with higher objective CPAP compliance at 1 month and 3 months, respectively. CONCLUSION: CPAP usage and compliance were high in this patient population. A high baseline AHI was the only significant independent predictor of better CPAP compliance.     

The impact of cardiac resynchronization therapy on obstructive sleep apnea in heart failure patients: a pilot study

BACKGROUND: Cardiac resynchronization therapy (CRT) has been shown to improve cardiac function and reduce Cheyne-Stokes respiration but has not been evaluated in patients with obstructive sleep apnea (OSA). In this pilot study, we investigated the impact of both CRT and CRT plus increased rate pacing in heart failure (ie, congestive heart failure [CHF]) patients with OSA. We hypothesized that through increased cardiac output CRT/pacing would reduce obstructive events and daytime symptoms of sleepiness. METHODS: Full polysomnograms were performed on CHF patients who were scheduled for CRT, and those patients with an apnea-hypopnea index (AHI) of > 5 events per hour were approached about study enrollment. Patients had a pre-CRT implant baseline echocardiogram and an echocardiogram a mean (+/- SEM) duration of 6.6 +/- 1.4 months post-CRT implant; polysomnography; and responded to the Minnesota Living with Heart Failure questionnaire, the Epworth sleepiness scale, and the Functional Outcomes of Sleep Questionnaire. An additional third polysomnography was performed combining CRT with a pacing rate of 15 beats/min above the baseline sleeping heart rate within 1 week of the second polysomnography. Assessments for the change in cardiac output during the polysomnography were performed using circulation time to pulse oximeter as a surrogate. RESULTS: Twenty-four patients were screened, and 13 patients (mean age, 68.6 years; body mass index, 28.7 kg/m(2)) had evidence of OSA. The mean AHI decreased from 40.9 +/- 6.4 to 29.5 +/- 5.9 events per hour with CRT (p = 0.04). The mean baseline ejection fraction was 22 +/- 1.7% and increased post-CRT to 33.6 +/- 2.0% (p < 0.05). The reduction in AHI with CRT closely correlated with a decrease in circulation time (r = 0.89; p < 0.001) with CRT. Increased rate pacing made no additional impact on the AHI or circulation time. CRT had a limited impact on sleep architecture or daytime symptom scores. CONCLUSIONS: CRT improved cardiac function and reduced the AHI. Reduced circulatory delay likely stabilized ventilatory control systems and may represent a new therapeutic target in OSA.     

睡眠呼吸暂停综合征患者持续气道正压通气治疗前后微觉醒的变化及意义

目的探讨微觉醒的发生机制、临床意义及其在睡眠呼吸障碍性疾患诊断治疗中的应用价值。方法270例打鼾者均按国际标准方法进行多导睡眠呼吸监测（PSG）,据此计算睡眠呼吸暂停低通气指数(AHI)、睡眠潜伏期(SL)、每小时氧减饱和度4%以上的次数(ODI4)及每小时微觉醒的次数(MAI)。其中28例患者应用持续气道正压通气(CPAP)同时复查PSG,在治疗前后均填写Epworth睡眠问卷(ESS)以评价患者嗜睡的改善程度。结果270例鼾症患者中,247例符合睡眠呼吸暂停低通气综合征(SAHS)的诊断,其AHI、ODI4、MAI及SL平均值分别为(43±27)次/h,(44±23)次/h,(29±16)次/h,(12±17)分。AHI与MAI,ODI4与MAI均呈正相关(r均为0.38,P均<0.001)。MAI与SL显著负相关(r=-0.15,P=0.02),AHI与SL、ODI4与SL均无相关性(r分别为-0.09,-0.02,P均>0.1)。经CPAP治疗,28例患者的呼吸暂停基本消失,ODI4由(48±25)次/h降至(4±9)次/h,MAI由(27±18)次/h减至(15±9)次/h,主观(ESS)及客观(SL)评价均显示白天嗜睡改善。结论应用专门的计算机软件辅助分析SAHS患者睡眠状态下的脑电变化,可以判读最短持续时间达3秒的微觉醒。MAI可以作为白天嗜睡的重要指标,在SAHS诊断和CPAP疗效判断方面与AHI具有互补性。     

Creatine phosphokinase elevation in obstructive sleep apnea syndrome: an unknown association?

STUDY OBJECTIVES: To evaluate the impact of obstructive sleep apnea syndrome (OSAS) on serum creatine phosphokinase (CK) levels. DESIGN: Single-center prospective cross-sectional study. SETTING: Academic sleep disorder center. PATIENTS: Two hundred one consecutive patients (mean [+/- SD] age, 54.9 +/- 11.0 years; 155 men and 46 women; mean body mass index, 31.3 +/- 6.9 kg/m(2)) with suspected sleep-disordered breathing. MEASUREMENTS AND RESULTS: OSAS was confirmed in182 patients (apnea-hypopnea index [AHI], > 5 events per hour) and was ruled out in 19 patients (control subjects) by standard polysomnography. Sixty-six OSAS patients and 1 control patient showed an unexplained CK elevation. The mean baseline CK level was significantly higher in patients with severe OSAS (AHI, > 30 event per hour; n = 89) compared to those with mild-to-moderate OSAS (AHI, 5 to 30 events per hour; n = 93) and control subjects (191.4 +/- 12.9 vs 134.3 +/- 7.5 vs 107.1 +/- 7.9 U/L, respectively; p < 0.01). Receiver operating curve analysis identified an optimal cutoff value of > 148 U/L (r = 0.660) for CK, which yielded a positive predictive value of 99%, a sensitivity of 43%, and a specificity of 95% for the diagnosis of OSAS. The mean nocturnal oxyhemoglobin saturation was the main predictor of CK level (r = 0.47; p < 0.001). Continuous positive airway pressure (CPAP) treatment resulted in a significant decline of CK levels both in patients with mild-to-moderate OSAS (n = 38; 129.7 +/- 13.4 vs 96.7 +/- 7.6 U/L, respectively; p < 0.001) and in patients with severe OSAS (n = 39; 187.7 +/- 18.9 vs 132.2 +/- 12.9 U/L, respectively; p < 0.001). CONCLUSIONS: One third of our study population showed a mild-to-moderate elevation in CK level, which was highly predictive of OSAS. The application of CPAP therapy in OSAS patients resulted in a significant decrease in CK level. We speculate that OSAS may account for a substantial number of cases of unexplained CK elevation (ie, hyperCKemia). Further studies should address the prevalence of OSAS in patients with mild-to-moderate hyperCKemia.     

Influence of nasal resistance on initial acceptance of continuous positive airway pressure in treatment for obstructive sleep apnea syndrome

BACKGROUND: Continuous positive airway pressure (CPAP) is considered as the standard therapy for obstructive sleep apnea syndrome (OSAS), but some patients with OSAS are unable to accept CPAP due to nasal obstruction and poor nasal airflow. OBJECTIVES: We assessed the influence of nasal resistance before beginning CPAP treatment on the initial acceptance of CPAP in OSAS patients. METHODS: The study subjects comprised 77 patients (74 males, 3 females) with primary OSAS, all of whom received CPAP treatment with nasal masks. Before trials, all subjects underwent overnight polysomnography, and nasal resistance was measured with active anterior rhinomanometry in the seated position on the first day of CPAP trial. RESULTS: The CPAP treatment was accepted by 56 patients after the initial trials with overnight polysomnography. Body mass index, the number of apnea/hypopnea episodes per hour (apnea/hypopnea index; AHI), and the number of episodes per hour with an oxygen desaturation of >3% (oxygen desaturation index) were significantly higher (p<0.01) and nasal resistance was lower (p=0.003) in patients who accepted CPAP than in those who did not. Logistic regression analysis, with patient age, body mass index, Epworth sleepiness scale score, AHI, oxygen desaturation index, and nasal resistance before CPAP treatment as explanatory variables, showed that nasal resistance (OR+0.1 Pa/cm3/s: 1.48; p=0.002) and AHI (OR+1 event/h: 0.93; p=0.003) were significant factors for CPAP non-acceptance. CONCLUSIONS: Nasal resistance before the beginning of CPAP treatment has a significant effect on the acceptance of CPAP in OSAS patients, and hence, could be a predictive parameter for the initial acceptance of CPAP.     

Prevalence and Clinical Correlates of Sleep-Disordered Breathing in Patients Hospitalized With Acute Decompensated Heart Failure

Background

Limited data are available regarding the presence of sleep-disordered breathing (SDB) assessed using polysomnography in patients hospitalized with left ventricular (LV) systolic dysfunction after acute decompensated heart failure (ADHF). We investigated the prevalence and clinical correlates of SDB in patients hospitalized with ADHF and LV systolic dysfunction.

Prevalence and severity of sleep disordered breathing in a group of morbidly obese patients.

BACKGROUND: Obesity may be complicated by sleep disordered breathing (SDB). The presence of SDB is associated with increased morbidity and mortality. Patient characteristics, pulmonary function tests and daytime arterial blood gas analyses may help to identify patients with SDB. These variables and the prevalence and severity of sleep disordered breathing were studied in a group morbidly obese patients. METHODS: Forty-eight patients, 19 men and 29 women who were referred to our clinic of internal medicine because of their obesity were included. Characteristics, pulmonary function tests and daytime arterial blood gas analyses of groups with different grades of SDB were compared. RESULTS: Male subjects had significantly more apnoeas/hypopnoeas per hour (AHI) (18.4 +/- 20.9 versus 4.8 +/- 9.4) with more desaturation, a lower mean saturation (92.6 +/- 4.1 versus 96.1 +/- 1.6) and a lower saturation nadir (73.8 +/- 12.0 versus 83.1 +/- 6.7). Five (26%) of the male subjects and none of the female subjects had severe SDB (AHI > or = 25). Subjects were divided into three groups according to the severity of their SDB: twenty-nine subjects (23 women and 6 men) with AHI < 5, 14 subjects (6 women and 8 men) with AHI > or = 5 and < 25 and 5 subjects, all men, with AHI > or = 25. Except for gender no significant differences were found between the three groups. CONCLUSION: Our study confirms the findings that morbidity obese men have SDB more frequently and more severely than obese women. Patient characteristics other than gender, pulmonary function tests and daytime blood gas analyses have no predictive value.     

Obstructive sleep apnea syndrome, sleepiness, and quality of life

OBJECTIVE: To evaluate the addition of short arousals of > 3 s on indexes of sleep-disordered breathing (SDB) and subjective sleepiness in patients with obstructive sleep apnea (OSA), and to evaluate the quality of life and reported difficulty driving with arousal index and indexes of SDB. METHOD: Data was collected from a general clinical evaluation, and evaluations using the Epworth sleepiness scale (ESS), the sleep disorders questionnaire, the Beck depression inventory (BDI), the Medical Outcomes Study 36-item short form health survey (SF-36), a questionnaire on driving difficulties and accidents, and polysomnography. RESULTS: A total of 135 male subjects (mean [+/- SD] age, 52 +/- 12.1 years; mean body mass index [BMI], 27.8 +/- 5.6 kg/m(2); mean apnea-hypopnea index [AHI], 48.7 +/- 26.8 events per hour) were studied. Of these subjects, 70.4% acknowledged having driven while sleepy. ESS scores correlated significantly with the arousal index and AHI, and negatively with the lowest arterial oxygen saturation. The "physical functioning," "general health," and "role physical" subscales of the SF-36 correlated with the arousal index. No significant correlation was seen in multiple regression analyses after adjusting for age and BMI, using "reports of sleepiness while driving" as the dependent variable. CONCLUSION: Several subjective complaints and subscales of the SF-36 correlated significantly with a frequency of SDB-related arousal of > 3 s. Patients perceived that an organic health problem had been impairing their quality of life more than an emotional problem, despite elevated scores on the BDI. However, if sleepiness while driving was common in OSA patients, it was not significant. Many clinical and polysomnographic variables may be considered as possible independent variables in the regression analysis. Other unrelated factors have a greater impact. To relate sleepiness while driving only to the usually studied variables in OSA patients is an oversimplification.     

Long-term treatment with continuous positive airway pressure improves quality of life in obstructive sleep apnoea syndrome.

Continuous positive airway pressure (CPAP) is an established treatment of obstructive sleep apnoea syndrome (OSAS). While it is known that CPAP reverses the pathological breathing pattern and improves daytime sleepiness, there are no sufficient data on the long-term influence of CPAP on quality of life in patients with OSAS. Thirty-nine patients with polysomnographically verified OSAS (apnoea/hypopnoea index (AHI): (mean+/-SD) 46.8+/-21.8 events x h(-1)) were prospectively studied. All patients answered three quality of life measures (Complaint List, Nottingham Health Profile Part 1 (NHP), and Verbal Analogue-Scale "quality of life") prior to the initiation of CPAP therapy. After a mean of 9 months they were re-evaluated by polysomnography, and completed the questionnaires once again. As expected, CPAP was effective in treating the sleep-related breathing disorder. AHI decreased significantly from (mean+/-SD) 46.8+/-21.8 events x h(-1) to 3.3+/-6.3 events x h(-1), and minimum oxygen saturation increased from 77.1+/-9.3% to 89.9+/-3.4%, while body mass index did not change significantly (31.3+/-5.4 versus 30.8+/-4.8 kg x m(-2)). During long-term treatment with CPAP the Complaint List revealed a significant improvement of the extent of subjective impairment due to physical and general complaints (26.4+/-9.9 versus 20.4+/-11.1), and NHP a significant improvement of emotional reactions (19.8+/-21.7 versus 11.1+/-14.0) and energy (50.8+/-36.6 versus 32.1+/-36.7), but not of pain, physical mobility, sleep, social isolation, and quality of life as assessed by the It is concluded that long-term continuous positive airway pressure therapy is effective in improving not only pathological breathing patterns but also parameters that estimate quality of life in patients with obstructive sleep apnoea syndrome.     

Mandibular advancement titration for obstructive sleep apnea: optimization of the procedure by combining clinical and oximetric parameters

BACKGROUND: Oral appliances (OAs) have been used for the treatment of obstructive sleep apnea syndrome (OSAS), with different degrees of effectiveness having been shown in previous studies. But, in the absence of a consensual recommendation, the method of the determination of effective mandibular advancement varies from one study to another. STUDY OBJECTIVE: We prospectively evaluated an OA titration protocol based on a combined analysis of symptomatic benefit and oximetric recording to guide the progressive mandibular advancement. SETTING: University hospital sleep disorders center. PATIENTS: Forty patients with OSAS (mean [+/-SD] apnea-hypopnea index [AHI], 46 +/- 21 events per hour) found on baseline polysomnography, who were intolerant of nasal continuous positive airway pressure, completed all aspects of the study. METHODS: Two acrylic appliances connected by Herbst attachments were constructed. The mandible was advanced 1 mm every week until there was a resolution of the symptoms and a reduction in the oxygen desaturation index (ie, the number of desaturations yielding a > 3% fall in pulse oximetric saturation per hour of recording) [ODI] of <10 events per hour of recording or a maximum comfortable limit of advancement was obtained. The final response to OA was evaluated by full polysomnography recording. RESULTS: A complete response (ie, mean AHI, 5 +/- 3 events per hour; mean snoring reduction [SR], 91 +/- 13%; mean Epworth sleepiness scale [ESS] score, 5 +/- 3) was obtained in 63.6% of patients, and a limited response (ie, mean AHI, 21 +/- 11 events per hour; mean SR, 88 +/- 15%; mean ESS, 6 +/- 3) was obtained in 18.2% of patients. Twenty-five percent of mandibular advancements were motivated by an abnormal ODI (ie, 21 +/- 10 events per hour) despite resolution of the symptoms, while 20% were motivated by persistent symptoms with a normal ODI (ie, 6 +/- 2 events per hour). After a mean duration of 17 +/- 4 months, 34 patients declared that they had used the OA 5 +/- 2 days a week for 89 +/- 19% of their sleep time. CONCLUSIONS: A combination of the patient's subjective evaluation and oximetric score improves the effectiveness of the OA titration procedure.     

Effects of continuous positive airway pressure on lung function in patients with chronic obstructive pulmonary disease and sleep disordered breathing

OBJECTIVE: Sleep disordered breathing (SDB), namely hypoventilation and obstructive sleep apnoea, occur in about 50% of patients with severe chronic obstructive pulmonary disease (COPD). Previous studies that have investigated the reversal of SDB in such patients with nasally applied intermittent positive airway pressure have reported a fall in PaCO2 but little change in airflow obstruction. We reasoned that the lack of improvement in airflow obstruction may be due to insufficient expiratory pressure. Accordingly, we sought to determine the effects of chronic nasal continuous positive airway pressure (CPAP), at highest tolerable levels, upon blood gases and airflow obstruction in patients with severe COPD and SDB. METHODOLOGY: Fourteen patients were studied, ten of whom were able to tolerate CPAP (10.2 +/- 0.9 cmH2O) for at least 3 months. RESULTS: Within the CPAP compliant group, there was a fall in PaCO2 (58.0 +/- 3.5 to 48.0 +/- 0.9 mmHg, P = 0.015) associated with a rise in PaO2 (54.8 +/- 3.8 to 63.2 +/- 1.8 mmHg, P = 0.015) and forced expiratory volume in 1 s (0.95 +/- 0.13 to 1.10 +/- 0.13 L, P < 0.005). Concurrent with these improvements was a substantial fall in hospitalization rates (from 3.85 to 0.73 admissions per annum). CONCLUSION: Improvements in gas exchange, airflow obstruction and hospitalization rates were observed in patients with COPD and SDB treated with nasal CPAP during sleep.     

Increased incidence of nonfatal cardiovascular events in stroke patients with sleep apnoea: effect of CPAP treatment

Obstructive sleep apnoea (OSA) is a risk factor for stroke, but little is known about the effect of OSA and continuous positive airway pressure (CPAP) on the incidence of long-term, nonfatal cardiovascular events (CVE) in stroke patients. A prospective observational study was made in 223 patients consecutively admitted for stroke. A sleep study was performed on 166 of them. 31 had an apnoea/hypopnoea index (AHI) <10 events · h(-1); 39 had an AHI between 10 and 19 events · h(-1) and 96 had an AHI ≥ 20 events · h(-1). CPAP treatment was offered when AHI was ≥ 20 events · h(-1). Patients were followed up for 7 yrs and incident CVE data were recorded. The mean ± SD age of the subjects was 73.3 ± 11 yrs; mean AHI was 26 ± 16.7 events · h(-1). Patients with moderate-to-severe OSA who could not tolerate CPAP (AHI ≥ 20 events · h(-1); n = 68) showed an increased adjusted incidence of nonfatal CVE, especially new ischaemic strokes (hazard ratio 2.87, 95% CI 1.11-7.71; p = 0.03), compared with patients with moderate-to-severe OSA who tolerated CPAP (n = 28), patients with mild disease (AHI 10-19 events · h(-1); n = 36) and patients without OSA (AHI <10 events · h(-1); n = 31). Our results suggest that the presence of moderate-to-severe OSA is associated with an increased long-term incidence of nonfatal CVE in stroke patients and that CPAP reduces the excess of incidence seen in these patients.     

Choice of oximeter affects apnea-hypopnea index

STUDY OBJECTIVES: Current Medicare guidelines include an apnea-hypopnea index (AHI) > or = 15 events per hour, in which all hypopneas must be associated with 4% desaturation, to qualify for reimbursement for therapy with continuous positive airway pressure (CPAP). The present data demonstrate the effect of pulse oximeter differences on AHI. DESIGN: Prospective study, blinded analysis. SETTING: Academic sleep disorder center. PATIENTS: One hundred thirteen consecutive patients (84 men and 29 women) undergoing diagnostic sleep studies and being evaluated for CPAP based on the Medicare indications for reimbursement. INTERVENTIONS: Patients had two of four commonly used oximeters with signal averaging times of 4 to 6 s placed on different digits of the same hand during nocturnal polysomnography. MEASUREMENTS AND RESULTS: Apneas and candidate hypopneas (amplitude reduction, > 30%) were scored from the nasal cannula airflow signal without reference to oximetry. Candidate hypopneas then were reclassified as hypopneas by each oximeter if they were associated with a 4% desaturation. Although the use of three oximeters resulted in a similar AHI (bias, < 1 event per hour), the fourth oximeter showed an overall increase in AHI of 3.7 events per hour. This caused 7 of 113 patients to have an AHI of > or = 15 events per hour (meeting the Medicare criteria for treatment) by one oximeter but not when a different oximeter was used. More importantly, when our analysis was limited to those patients whose number of candidate hypopneas made them susceptible to the threshold value of 15 events per hour, 7 of 35 patients who did not meet the Medicare AHI standard for treatment by one oximeter were reclassified when a different oximeter was used. CONCLUSION: In the present study, oximeter choice affected whether the AHI reached the critical cutoff of 15 events per hour, particularly in those with disease severity that was neither very mild nor very severe. As oximetry is not a technique that produces a generic result, there are significant limitations to basing the definition of hypopnea on a fixed percentage of desaturation in determining the eligibility for CPAP therapy.