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Owing to the prevalence, the considerable risk of accidents and cardiovascular consequences, optimal treatment of obstructive sleep apnea syndrome is of crucial importance. However, many patients look for alternative conservative or surgical therapies to continuous positive airway pressure to avoid discomfort and local side-effects owing to the mask. Scientific data are lacking for most of the alternative methods. However, it has been proven that intra-oral appliances can reduce mild-to-moderate respiratory disturbances; the maxillo-mandibular osteotomy is efficient in the short- and long-term but is preferred in special situations such as craniofacial dysmorphias. Weight reduction and body positioning cannot be recommended as a single treatment for obstructive sleep apnea syndrome. Resections of muscular tissue within the soft palate have to be strictly avoided. Efficacy of gentle soft palate procedures is difficult to predict and often decreases in the years following this treatment. Multilevel surgery concepts are of increasing interest, although more data from prospective, controlled studies are needed.

Background: Continuous positive airway pressure (CPAP) treatment in obstructive sleep apnea syndrome (OSAS) requires pressure titration usually performed during attended in-hospital polysomnography. This manual titration procedure is not well standardized. The aim of the study was to ascertain whether a new automatic titration device is as effective as standard manual titration in determining constant CPAP pressure., Methods: We included 38 patients with a newly diagnosed OSAS. Participants were randomly assigned to attended in-laboratory manual titration and automatic titration in two consecutive nights. Fixed CPAP pressure was set at the optimal pressure determined during the second night. The follow-up period was 6 weeks. Main outcomes were apnea/hypopnea index (AHI) and Epworth sleepiness scale (ESS)., Results: AHI (manual: baseline 40.5+/-21.5/h vs. treatment 6.4+/-3.3/h (p<0.001); automatic: 53.3+/-28.1/h vs. 7.8+/-3.3/h (p<0.001)) and ESS (manual: 11.3+/-4.7 vs. 8.8+/-5.1 (ns); automatic: 11.5+/-5.6 vs. 7.0+/-3.8 (p<0.05)) showed a similar improvement in both groups. Pressure recommendation by the device and the technician, although not statistically different (8.7+/-2.9 vs. 9.0+/-3.3 mbar), corresponded only in 50% of the patients., Conclusions: Automatic titration effectively predicts constant CPAP pressure for long-term treatment when performed during an attended polysomnography. Careful evaluation of raw data and polysomnography recording is mandatory before choosing a fixed CPAP pressure after automatic titration.

The obesity hypoventilation syndrome (OHS) is defined by extreme overweight (BMI 30 kg/m2), daytime hypoventilation (PaCO2 > 45 mm Hg, the absence of other known causes of hypoventilation) and sleep-related breathing disorders. Obesity impairs breathing due to a restrictive ventilatory disorder, reduction of the capacity of respiratory muscles and diminishment of the ventilatory response. The restriction cannot serve as the only explanation of OHS because body weight or compliance on the one hand and hypoventilation on the other hand only correlate weakly. Obesity increases the work of breathing by greater body mass with its increased oxygen demand, impaired diaphragmatic mobility, upper airway obstruction, and oxygen desaturation which result in an inadequacy of oxygen demand and supply. The adjustment of the chemoreceptors can avoid the overload on the capacity of the respiratory muscles, at least in a number of patients or in the course of the disease. This disproportion results in hypercapnia. Furthermore, the level of leptin is an important factor in the pathophysiology of OHS. The blood level of leptin correlates with the body fat mass in humans. However, there seems to be a relative leptin deficiency in the brain in overweight humans. Therefore, in contrast to animals, leptin cannot sufficiently increase ventilation in man to avoid hypercapnia.

Background: Long-term compliance is suboptimal in the treatment of the obstructive sleep apnea syndrome (OSAS)., Objectives: We compared the efficacy of and the adherence to automatic continuous positive airway pressure (APAP) and constant continuous positive airway pressure (CPAP) based on a night-by-night analysis., Methods: We performed a randomized, single-blind crossover study in 20 patients with moderate-to-severe OSAS. After diagnostic polysomnography and manual titration, patients were treated for 8 weeks with both constant CPAP and APAP in random order. Compliance and leakage were analyzed night by night using the software LOGSoft of the Magellan iPAP device., Results: The reduction in the apnea/hypopnea index (baseline 32.9 +/- 19.1/h, CPAP 4.6 +/- 2.9/h, APAP 5.6 +/- 3.6/h; p < 0.001 compared to baseline) and the Epworth Sleepiness Scale (baseline 10.3 +/- 5.7, CPAP 6.6 +/- 4.8, APAP 4.9 +/- 4.6; p < 0.001 compared to baseline) did not significantly differ between the treatment modes. Leakage time and compliance per night were not statistically different (leakage CPAP 31 +/- 57 min, APAP 25 +/- 49 min; compliance CPAP 383 +/- 116 min, APAP 382 +/- 107 min). There was no correlation between leakage and compliance. Thirteen patients (65%) preferred APAP at the end of the study., Conclusions: Treatment efficacy and adherence are similar with CPAP and APAP. There is a trend towards lower leakage with APAP therapy. Patients prefer the automatic mode to fixed pressure., (Copyright (c) 2008 S. Karger AG, Basel)

Although continuous airway pressure therapy (CPAP) represents the standard treatment for obstructive sleep apnea syndrome (OSAS) auto-adjusting CPAP (APAP) devices were developed which adapt the treatment pressure to the actual requirement of the patients. The aim of automatic CPAP therapy is to improve the patients' acceptance of positive pressure treatment. The devices react to respiratory flow, flattening of the inspiratory flow contour, snoring, generator speed or the upper airway impedance. In recent years several studies showed that auto CPAP effectively treats respiratory disturbances, improves sleep profile and the self-assessment of the patients equally as good as the gold standard constant CPAP. Moreover, APAP reduces the treatment pressure substantially. Although an improvement of the patient's compliance has not consistently been proven, most patients prefer APAP versus constant CPAP. APAP devices use different algorithms depending on the primary purpose of the application. Therefore, a clear distinction between automatic titration and treatment is of major relevance. While titration devices aim at the finding of one single pressure which is fixed to a constant CPAP device, automatic treatment means the chronic use of APAP at home for optimal adaptation of the treatment pressure to the actual requirements of the patient. A high constant CPAP level, huge pressure variability, insufficient compliance with constant CPAP may be indications for APAP treatment. The main reason for automatic titration is the standardisation of the initiation process.

Background: Although continuous positive airway pressure therapy (CPAP) is the treatment of choice for obstructive sleep apnoea syndrome (OSAS), there is a portion of patients in which CPAP is not usable. Bilevel treatment serves as an alternative for these patients. For uncomplicated OSAS, auto-adjusting CPAP based on the forced oscillation technique (APAPFOT) has proved to be equally as effective as constant CPAP, and is preferred by the patients. The aim of this study was to investigate the question whether, in the event of primary CPAP intolerance, high pressures (>or =12 cm H2O) or SAS with > or =10% central respiratory disorders, APAPFOT is as effective as bilevel therapy in reducing respiratory disturbances., Material/methods: 27 patients (23 m, 4 f, age 57.2+/-13.1 years, BMI 33.5+/-7.8 kg/m2) were treated with bilevel and APAPFOT for 6 weeks each in a prospective randomized cross-over study. The efficacy of the treatment modes was examined polysomnographically., Results: Both modalities significantly improved the respiratory disturbances (AHI: baseline 49+/-27.3/h, bilevel 9.8+/-12.5, p<0.01, APAPFOT 13.8+/-13.2, p<0.01) and sleep quality (arousals: baseline 43+/-28.3/h, bilevel 17.7+/-8.8, p<0.01, APAPFOT 20.5+/-10.7, p<0.01), with no significant differences between the modalities. Under APAPFOT, mean treatment pressure was substantially reduced (bilevel 8.3+/-2.5, APAPFOT 5.1+/-1.7, p<0.01). The majority of patients gave preference to APAPFOT for long-term treatment (21 vs. 6 patients, p<0.05)., Conclusions: In patients with difficult-to-treat OSAS, APAPFOT has proved to be just as effective as bilevel therapy, but has the advantage of meeting with greater acceptance.

Background: For the treatment of nonsevere obstructive sleep apnea syndrome (OSAS), mandibular advancement devices (MADs) are employed as an alternative to nasal continuous positive airway pressure (CPAP) therapy. However, very few specific data on the effectiveness of MADs in this group of patients are available. We therefore compared an individually adjustable intraoral sleep apnea device (ISAD) that permits movements of the lower jaw in three dimensions, with CPAP in the treatment of patients with an apnea/hypopnea index (AHI) < or = 30/h., Methods: In a randomized crossover study, 16 men and 4 women (mean +/- SD age, 56.5 +/- 10.2 years; body mass index, 31.2 +/- 6.4; AHI, 17.5 +/- 7.7/h) were treated for 6 weeks with each modality., Results: In the initial phase, a significant improvement in AHI (baseline, 17.5 +/- 7.7/h; ISAD, 10.5 +/- 7.5/h [p < 0.05]; CPAP, 3.5 +/- 2.9/h [p < 0.01]) and in breathing-related arousals (baseline, 8.9 +/- 6.1/h; ISAD, 3.7 +/- 3.3/h [p < 0.01]; CPAP, 1.4 +/- 1.6/h [p < 0.01]) was achieved with both modalities. Considering all 20 subjects, after 6 weeks of treatment, normalization of the respiratory parameters was seen only with CPAP. However, 30% of the patients had a lasting reduction in AHI to < 10/h with the ISAD also. The patients considered the ISAD to be easier to use (scale of 1 to 6: ISAD, 1.8 +/- 1.1; CPAP, 3.1 +/- 1.5 [p < 0.05]), and indicated greater utilization of the device in comparison with CPAP., Conclusion: Even in patients with mild-to-moderate OSAS, CPAP is the more effective long-term treatment modality. In the individual case, the better compliance seen with the ISAD may be advantageous.

Cold passover and heated humidifiers are employed for the prevention of side-effects associated with continuous positive airway pressure (CPAP) treatment. However, to date, it has not been possible to separately measure the humidity of inspired and expired air. The aim of this study was to compare the relative humidity of the inspired air and the water loss during respiration between cold passover and heated humidifiers under CPAP. Humidity and temperature were determined separately for the respiratory phases, without humidification, with cold passover and heated humidifiers in 10 healthy subjects. Humidity was measured with a capacitive hygrometer, temperature with a "Type K" thermosensor, and impedance of the total respiratory system with impulse oscillometry. The relative humidity (rH) of the inspired air (mean+/-SD) increased significantly from 24.0+/-9.1%, rH (34.8+/-1.0 degrees C, no humidifier) to 34.5+/-10.1%, rH (34.6+/-1.0 degrees C) under cold humidification, and to 53.9+/-13.2% rH (35.0+/-1.1 degrees C) under heated humidification. With heated humidification, water loss was reduced by 38% compared to cold humidification. The impedance increased from 5.7+/-1.8 cmH2O x L x s(-1) (no humidifier) to 6.7+/-1.8 cmH2O x L x s(-1) (heated humidifier). The authors conclude that the use of a heated humidifier during continuous positive airway pressure appreciably increases the relative humidity of the inspired air and reduces the water loss during respiration.

Background: The measurement of impedance permits reliable detection of obstructive apneas, hypopneas and upper airways resistance syndrome.Objective: To establish whether impedance-controlled self-adjusting positive airway pressure therapy (APAP(FOT)) is equally as good as constant continuous positive airway pressure (CPAP) in the treatment of sleep apnea syndrome (OSAS).Methods: Twenty men and five women with OSAS (age 52.8+/-9.0 years, body mass index (BMI) 31.4+/-5.0 kg/m(2), AHI 32.2+/-18.1/h (mean+/-SD)) underwent baseline polysomnography, manual CPAP titration and two nights of treatment, one with APAP(FOT), one with constant CPAP.Results: With both modes, a significant reduction in respiratory disturbances was seen (apnea/hypopnea index (AHI) baseline 32.2+/-18.1/h, constant CPAP 6.6+/-8.7, APAP(FOT) 5.5+/-3.8/h, P<0.001 baseline vs. each treatment mode). Under APAP(FOT), the sleep profile was normalized (S3/4 baseline 16.3+/-13.9% total sleep time (TST), APAP(FOT) 21.6+/-10.9% TST, P<0.05, rapid eye movement (REM) 14.2+/-6.7% TST vs. 20.3+/-7.3% TST, P<0.01), while with constant CPAP, a tendency towards improvement was found. The mean treatment pressure with APAP(FOT) was significantly lower than the constant CPAP (5.7+/-2.1 vs. 8.3+/-1.6 mbar, P<0.001).Conclusion: We conclude that APAP(FOT) is at least as effective as constant CPAP in normalizing sleep and breathing in OSAS.

Constant continuous positive airway pressure (CPAP) is the treatment of choice for the obstructive sleep apnea syndrome (OSAS). To enable the pressure to be matched more accurately to actual requirements, and thus increase patient acceptance, an autoadjusting device based on the measurement of upper airway impedance was developed (APAP(FOT)). We investigated the efficacy and compliance in continuous use at home. Fifty-two patients were treated (randomized crossover) with CPAP and APAP(FOT) for 6 wk each. Respiratory disturbances, sleep profile, and arousals improved significantly with both modes (AHI: baseline, 35.1 +/- 26/h; APAP(FOT), 5.0 +/- 5.2; CPAP, 4.3 +/- 6.3; p < 0.001 baseline versus each mode). The mean pressure with APAP(FOT) was significantly reduced as compared with CPAP (CPAP, 7.8 +/- 1.5 cm H2O; APAP(FOT), 5.7 +/- 1.8 cm H2O; p < 0.001). Under APAP(FOT) the pressure was lower than that under CPAP for 81.5 +/- 21% of the time. Although overall use did not differ, 75% of the patients preferred APAP(FOT) for home treatment. We conclude that APAP(FOT) is as efficacious as constant CPAP in the treatment of OSAS. The treatment pressure can be reduced significantly, and sleep microstructure improved with APAP(FOT). These might be the reasons for patient preference of automatic therapy.

Background and Objective: The compliance of the nasal continuous positive airway pressure treatment (nCPAP) of the obstructive sleep apnea syndrome (OSAS) depends on the patients' awareness and improvement of the symptoms. Therefore, we studied the relevance of OSAS in different aspects of the quality of life and important aspects of daily life (driving performance, working place)., Methods: 352 patients with OSAS filled in a questionnaire of sociodemographic data and impairment of quality of life. The relevance of OSAS was evaluated with polysomnography and parameters of daytime sleepiness., Results: The number of women was lower than expected from community related data. The apnea/hypopnea index was 29.9 +/- 23.4/h at baseline measurement and was reduced to 8.8 +/- 9.6/h with nCPAP (p < 0.001). The arousal index (baseline 26.6 +/- 15.3/h) fell with treatment significantly (17.7 +/- 9.2 Arousals/h, p < 0.001). The error rate in the driving simulator test was 7.8 +/- 8.9% (normal value 5.75 +/- 1.4). It was normalised with nCPAP (5.8 +/- 9.5, p < 0.001). 42.3% of patients reported about sleep apnea related symptoms for more than five years before diagnosis. The patients rated their physical fitness on a scale (0 to 6) at 2.9 +/- 1.3. It increased significantly with treatment to 3.4 +/- 1.3 an (p < 0.001). The mental activity improved significantly, too. The daytime sleepiness improved from 3.4 +/- 1.5 to 3.1 +/- 1.5 (p < 0.001). 32.3% of the patients reported that they fell asleep while steering at least once in the last month, 13.0% reported about more than five episodes/month. 5.3% of the patients thought their job in danger because of OSAS. 65.1% felt their performance in job to be impaired., Conclusion: OSAS impairs patients in different aspects of daily life, especially in the working place. The latency between the onset of symptoms and diagnosis is longer than expected. NCPAP treatment improves the symptoms of OSAS significantly both in criteria of polysomnography and self-assessment of the patients.

Background and Objectives: To investigate the parameter daytime sleepiness in patients with the sleep apnea syndrome (SAS), a test for measurement of sustained attention was developed. The present studies were performed on volunteers undergoing preemployment medical examinations and SAS patients to determine the extent to which test results are in agreement with the symptoms of SAS and traffic accident reports, and also with daytime sleepiness, and whether learning or therapeutic effects can be seen with repeated tests prior to and following treatment with nasal continuous positive airway pressure (nCPAP)., Participants: 125 healthy volunteers, and two groups of 28 SAS patients each., Design: Study A: The volunteers underwent a single attention test and completed a questionnaire concerned with traffic accidents and symptoms of sleep-related breathing disorders. Study B: SAS patients underwent two attention tests before treatment. Study C: SAS patients underwent one attention test before and one after nCPAP therapy., Results: Study A: The error rate in volunteers without symptoms of sleep-related breathing disorders (51 persons) was 4.7 +/- 4.3% (number of errors 14.1 +/- 12.9), 95% CI: 1.2 (number of errors 3.6). No dependence of the error rate on age, BMI or sex was found. In persons with a history of apneic events (n = 10), the error rate was 10.6 +/- 10.0% (number of errors 31.8 +/- 30), in those with more than two accidents during the last 5 years (n = 4), it was increased to 15.3 +/- 9.7% (number of errors 45.9 +/- 29.1). Study B: Among SAS patients, no significant learning effect was seen, and prolongation of the test duration beyond 30 min had no effect on the test results. Study C: The error rate improved significantly with nCPAP [10.6 +/- 13.5 vs. 6.4 +/- 8.9% (number of errors 31.8 +/- 40. 5 vs. 19.2 +/- 26.7), p < 0.001]., Conclusions: The attention test can be helpful for the measurement of daytime sleepiness, and CPAP therapy can improve test performance., (Copyright 2000 S. Karger AG, Basel)

Study Objective: Automatic titration using the forced oscillation technique (FOT) has recently been developed for the treatment of obstructive sleep apnea syndrome (OSAS). So far, it is not known if therapy with automatic nasal continuous positive airway pressure (nCPAP) using a preset upper pressure limitation or a free range (which might lead to higher mean pressure) is preferable with regard to obstructive events, sleep stages, and pressure characteristics., Design: After diagnostic polysomnography, patients were randomly assigned to two settings with the self-adjusting nCPAP (APAP) device based on the FOT. In mode 1, the pressure variation ranged from 4 to 15.5 cm H(2)O, and in mode 2, the pressure variation ranged from 4 cm H(2)O to an individual upper pressure limit., Patients: Eleven men, aged 53.0 +/- 6.8 years with a body mass index of 32.4 +/- 5.1 kg/m(2) and an apnea-hypopnea index (AHI) of 31.6 +/- 26.6/h., Measurements and Results: Manually titrated pressure was at 9.3 +/- 2.1 cm H(2)O, the mean pressure in mode 1 was 5.4 +/- 1.0 cm H(2)O (p < 0.01), and the mean pressure in mode 2 was 5.1 +/- 0.7 cm H(2)O (p < 0.01). A reduction of respiratory events (baseline AHI, 31.6 +/- 26.6/h; AHI in mode 1, 3.4 +/- 4.5; AHI in mode 2, 5.0 +/- 7.2; each with p < 0.001) and an increase in the "rapid eye movement" stage of sleep (baseline, 13.0 +/- 5.5%; mode 1, 22.0 +/- 7.7 [p < 0. 05]; mode 2, 23.0 +/- 7.9 [p < 0.01]) were achieved. In mode 1, the mean pressure was below the manual pressure 91.7 +/- 9.3% of the time, and in mode 2, the mean pressure was below the manual pressure 90.4 +/- 6.3% of the time. The manual pressure was exceeded by 5.5 +/- 7.4% (mode 1) and by 5.2 +/- 3.1% (mode 2)., Conclusion: We conclude that nCPAP therapy based on the FOT permits the adequate treatment of OSAS with significantly lower pressure than manually titrated nCPAP therapy does. A presetting of an upper pressure limit has no advantage compared to free range.