Alexander Blau

Positive Airway Pressure Initiation: A Randomized Controlled Trial to Assess the Impact of Therapy Mode and Titration Process on Efficacy, Adherence, and Outcomes

STUDY OBJECTIVES (1) To determine the efficacy of automatically adjusted positive airway pressure (APAP) with a comfort feature (A-Flex) at reducing apneas and hypopneas in participants with moderate to severe OSA. (2) To determine the relative difference between A-Flex, continuous positive airway pressure (CPAP), and APAP-derived optimal pressure for CPAP (CPAP(APAP)) on adherence to treatment. (3) To determine the relative difference between APAP with A-Flex, CPAP, and CPAP(APAP) on long-term change in functional outcomes. DESIGN Randomized, double-blinded, 3-arm, multicenter trial. SETTING University and Veterans Affairs medical centers. PATIENTS OR PARTICIPANTS 168 participants were randomized, and 140 completed the 180-day study. INTERVENTIONS (1) A-Flex; (2) CPAP; (3) APAP for 14 days and then switched to CPAP at a fixed pressure. MEASUREMENTS AND RESULTS Apnea-hypopnea indices, average and minimum oxygen saturation, time spent < 90% were significantly poorer for A-Flex vs. CPAP at the initiation of study treatment; with the exception of minimum oxygen saturation, these differences were absent at 180 days. A-Flex had lower average leak values at both 3 and 6 months. There were no significant differences between groups in major efficacy, adherence, and outcome (subjective sleepiness, objective vigilance, blood pressure, quality of life) measures. No differences between groups in attitudes toward use were observed at 3 or 6 months; participant ratings for CPAP were significantly higher than A-Flex on treatment satisfaction and benefit, but not different for sleep quality and mask comfort. CONCLUSIONS We found that A-Flex shows equivalency, but non-superiority (except for average leak values), in efficacy, adherence, and functional outcomes compared to CPAP after either 3 or 6 months. CLINICAL TRIAL REGISTRY Positive Pressure Treatment of Obstructive Sleep Apnea, http://www.clinicaltrials.gov, NCT00636181.

Cardiac autonomic modulation and sleepiness: Physiological consequences of sleep deprivation due to 40 h of prolonged wakefulness

The autonomic nervous system (ANS) is modulated by sleep and wakefulness. Noninvasive assessment of cardiac ANS with heart rate variability (HRV) analysis is a window for monitoring malfunctioning of cardiovascular autonomic modulation due to sleep deprivation. This study represents the first investigation of dynamic ANS effects and of electrophysiological and subjective sleepiness, in parallel, during 40 h of prolonged wakefulness under constant routine (CR) conditions. In eleven young male healthy subjects, ECG, EEG, EOG, and EMG chin recordings were performed during baseline sleep, during 40 h of sleep deprivation, and during recovery sleep. After sleep deprivation, slow-wave sleep and sleep efficiency increased, whereas HRV - global variability and HRV sympathovagal balance - was reduced (all p<0.05). Sleep-stage-dependent analysis revealed reductions in the sympathovagal balance only for NREM sleep stages (all p<0.05). Comparison of the daytime pattern of CR day one (CR baseline) with that of CR day two (CR sleep deprivation) disclosed an increase in subjective sleepiness, in the amount of unintended sleep, and in HRV sympathovagal balance, with accompaniment by increased EEG alpha attenuation (all p<0.05). Circadian rhythm analysis revealed the strongest influence on heart rate, with less influence on HRV sympathovagal balance. Hour-by-hour analysis disclosed the difference between CR sleep deprivation and CR baseline for subjective sleepiness at almost every single hour and for unintended sleep particularly in the morning and afternoon (both p<0.05). These findings indicate that 40 h of prolonged wakefulness lead in the following night to sleep-stage-dependent reduction in cardiac autonomic modulation. During daytime, an increased occurrence of behavioral and physiological signs of sleepiness was accompanied by diminished cardiac autonomic modulation. The observed changes are an indicator of autonomic stress due to sleep deprivation - which, if chronic, could potentially increase cardiovascular risk.

Portable monitoring in sleep apnea

Portable sleep apnea monitoring or home testing for sleep-disordered breathing focuses on recent developments of these powerful diagnostic tools. Evidence-based reviews and innovative single studies with specific systems are considered. Systems become less intrusive and self applicable. Electrocardiogram-derived respiration, photoplethysmogram analysis, midsagittal jaw movements, and respiratory sound analysis are reviewed. Categories of systems with 4 to 6 channels and 1 to 3 channels are introduced and presented. The importance of a high pretest probability is elucidated. Open research questions regarding these systems are mentioned. Technological issues are not most important in this debate. The health economic aspects in using portable sleep apnea monitoring have to be considered as well. Portable monitoring of sleep apnea is probably less expensive than cardiorespiratory polysomnography and can help to overcome the limited availability of sleep lab-based diagnostic places. But by increasing the quantity of investigations it may cause additional costs too.

Diagnostik schlafbezogener Atmungsstörungen mittels portabler Verfahren

Portable monitoring of sleep disordered breathing is the first diagnostic method not only in Germany but today in other countries as well. The conditions under which portable monitoring can be done with reliable results are now well defined. The limitations for the use of portable monitoring are specified as well. The devices used for portable monitoring are classified in four categories according to the number and the kind of signals recorded. New technical developments in the field of portable monitoring (polygraphy) use an indirect assessment of sleep disordered breathing based on signals not directly recording respiration. The recording of ECG and deriving respiration, the analysis of the plethysmographically recorded pulse wave, the recording of jaw movements using magnets, and advanced analysis of respiratory sounds are recent approaches. These new methods are presented with few studies until now. More and larger clinical studies are needed in order to show which of these systems is useful in the diagnosis of sleep disordered breathing and which are the specific strengths and weaknesses.

Preliminary results from a telemedicine referral network for early diagnosis of sleep apnoea in sleep laboratories

We conducted a feasibility study to find out whether a simple preliminary examination using telemedicine for diagnosis was sufficient to identify sleep-related breathing disorders (SRBD). Night-time pulse oximetry recordings were made in normal home surroundings on patients suffering from sleep apnoea/SRBD by doctors with a range of non-specialist backgrounds. The readings were transmitted to the relevant sleep laboratory, examined and the results returned to the referring doctor. From 80 patients (aged 29 to 60 years), 58 complained about characteristic symptoms (snoring, daytime sleepiness); 33 of these patients showed additional symptoms of associated diseases. In eight patients associated diseases were found without any symptoms. The findings were compatible with SRBD in 58 cases (73%); 12 of these were asymptomatic patients. A total of 57 patients had to be referred to a sleep laboratory for differential diagnosis by full polysomnography. Of the 22 patients (28%) without pathological findings following pulse-oximetry, 12 were symptomatic. The system described here is suitable for the creation of referral networks and for the identification of patients from institutions not trained in sleep medicine, who would otherwise not have been referred for specific diagnosis to a sleep laboratory.

Portable sleep monitoring in patients with disorders in falling asleep or maintaining sleep

BACKGROUND The most common diagnoses in sleep medicine are insomnia, sleep disordered breathing (SDB) and periodic leg movements (PLM). These disorders may coincide. This study examined the role of portable sleep monitoring in the diagnostic process and which sleep medicine diagnoses are additionally found in patients with disorders of initiating and maintaining sleep. METHODS A total of 217 patients, including 103 men (47.5%) and 114 (52.5%) women aged 52.2 ± 13.6 years with disorders of initiating or maintaining sleep were included in the study. Patients with known SDB were excluded. Patients were investigated using a stepwise diagnostic procedure with clinical interviews, questionnaires, clinical examination and portable sleep recording with electromyography (EMG) of the tibialis anterior muscle to diagnose SDB and PLM. RESULTS Of the patients 125 (57.6%) were diagnosed with insomnia according to the International Classification of Sleep Disorders (ICSD) and 70 (56%) had no other sleep disorder. Out of the 217 patients SDB was found in 107 (49.3%) patients, PLM in 90 patients (41.5%) and in 78 patients (35.9%) restless legs syndrome (RLS) was diagnosed. Among the 125 patients with insomnia 44 patients had RLS/PLMD and 35 had SDB in addition whereas SDB and RLS/PLMD were found in 33 subjects. All 3 disorders insomnia, RLS/PLMD and SDB were found in 24 subjects. CONCLUSIONS Out of 217 patients with a complaint of non-restorative sleep only 125 were finally diagnosed with insomnia. As 25.3% of patients showed combinations of sleep disorders, 49.3% with SDB and 41.5% with RLS/PLMD portable monitoring with electromyography of the legs is recommended. The investigation with a portable sleep monitoring system including an EMG of the tibialis muscle is very useful in patients with insomnia in addition to a clinical interview and questionnaires.

Erweiterte ambulante Polygraphie bei Patienten mit Ein- und/oder Durchschlafstörungen

BACKGROUND The most common diagnoses in sleep medicine are insomnia, sleep disordered breathing (SDB) and periodic leg movements (PLM). These disorders may coincide. This study examined the role of portable sleep monitoring in the diagnostic process and which sleep medicine diagnoses are additionally found in patients with disorders of initiating and maintaining sleep. METHODS A total of 217 patients, including 103 men (47.5%) and 114 (52.5%) women aged 52.2 ± 13.6 years with disorders of initiating or maintaining sleep were included in the study. Patients with known SDB were excluded. Patients were investigated using a stepwise diagnostic procedure with clinical interviews, questionnaires, clinical examination and portable sleep recording with electromyography (EMG) of the tibialis anterior muscle to diagnose SDB and PLM. RESULTS Of the patients 125 (57.6%) were diagnosed with insomnia according to the International Classification of Sleep Disorders (ICSD) and 70 (56%) had no other sleep disorder. Out of the 217 patients SDB was found in 107 (49.3%) patients, PLM in 90 patients (41.5%) and in 78 patients (35.9%) restless legs syndrome (RLS) was diagnosed. Among the 125 patients with insomnia 44 patients had RLS/PLMD and 35 had SDB in addition whereas SDB and RLS/PLMD were found in 33 subjects. All 3 disorders insomnia, RLS/PLMD and SDB were found in 24 subjects. CONCLUSIONS Out of 217 patients with a complaint of non-restorative sleep only 125 were finally diagnosed with insomnia. As 25.3% of patients showed combinations of sleep disorders, 49.3% with SDB and 41.5% with RLS/PLMD portable monitoring with electromyography of the legs is recommended. The investigation with a portable sleep monitoring system including an EMG of the tibialis muscle is very useful in patients with insomnia in addition to a clinical interview and questionnaires.

Stellenwert der Nicht-nCPAP-Verfahren in der Therapie des obstruktiven Schlafapnoe-Syndroms@@@Relevance of non-CPAP treatment options in the therapy of the obstructive sleep apnoea syndrome

ZusammenfassungEin Großteil der Patienten mit einem obstruktiven Schlafapnoe-Syndrom (OSAS) sucht nach konservativen oder operativen Behandlungsverfahren mit deren Hilfe sie die kontinuierliche Positivdruckatmung (CPAP) vermeiden können. Angesichts der hohen Prävalenz der Erkrankung und der Beeinträchtigung der Patienten wird eine Vielzahl von Methoden angeboten, mit denen eine definitive Heilung oder entscheidende Besserung der Erkrankung versprochen wird. Demgegenüber können nur selten fundierte Daten angegeben werden, die eine evidenzbasierte Bewertung der Verfahren ermöglicht. Ziel dieser Arbeit war es daher, den wissenschaftlichen Kenntnisstand zu den Nicht-CPAP-Verfahren zu erfassen und dem Schlafmediziner Empfehlungen zur Beratung und Behandlung der Patienten zu geben. Die Datenlage stellete sich für die meisten Nicht-nCPAP-Verfahren als sehr unbefriedigend dar. Ausreichende Untersuchungen liegen lediglich für die Unterkieferprotrusionsschienen, die beim leichten bis allenfalls mittelgradigen OSAS eine signifikante Besserung der Atmung bewirken können, und die maxillo-mandibuläre Osteotomie, die auch im Langzeitverlauf ausreichend effizient ist, jedoch nur Einzelfällen angewandt wird, vor. Gewichtsreduktion oder Lagetherapie können nicht als alleinige, allenfalls als ergänzende Therapie des OSAS empfohlen werden. Muskelresezierende Verfahren am Weichgaumen sind abzulehnen. Aber auch die Effekte muskelschonender Operationsverfahren am Weichgaumen sind individuell kaum vorhersehbar und lassen über die Jahre oft nach. Die Ergebnisse nach Operationen an and eren anatomischen Regionen scheinen dagegen stabil zu bleiben. Kombinierte Eingriffe im Sinne einer Multi-Level-Chirurgie gewinnen sekundär nach erfolgloser oder abgebrochener Beatmungsbehandlung an Bedeutung, auch wenn hier noch weitere Daten nötig sind. Alle übrigen Verfahren entbehren der ausreichenden Validierung oder sind beim Schlafapnoe-Syndrom als nicht indiziert anzusehen.SummaryMany patients with the obstructive sleep apnoea syndrome (OSAS) look for alternative conservative or surgical therapies to avoid treatment with continuous positive airway pressure. In view of the high prevalence and the relevant impairment of the patients, lots of methods are offered that promise a definitive cure or relevant improvement of OSAS. The “Apnoea” working group of the German Society of Sleep Medicine and Research established a task force to evaluate the scientific literature on non-CPAP therapies in the treatment of OSAS according to the standards of evidence-based medicine (EBM). This paper presents the results of the task force. The authors performed a literature search until 21 December 2005 (Medline and hand search of relevant papers). The studies were evaluated according the recommendations of the “Oxford Centre for Evidence-based Medicine Levels of Evidence”. The data were unsatisfactory for most of the methods. Sufficient data were available for intraoral appliances (IOA) and maxillomandibular osteotomy (MMO). IOAs can reduce mild to moderate respiratory disturbances; MMOs are efficient in the short- and long-term but are performed only in special situations such as craniofacial dysmorphias. Weight reduction and body positioning cannot be recommended as a single treatment of OSAS. Most surgical procedures still lack sufficient data according to EBM criteria. Resections of muscular tissue within the soft palate have to be strictly avoided. But even success following gentle soft palate procedures is difficult to predict and often decreases over the years. Results in other anatomical regions seem to be more stable over time. Today combined surgeries in the sense of multilevel surgery concepts are of increasing interest in the secondary treatment after failure of nasal ventilation therapy, although more data from prospective controlled studies are needed. There is no evidence for any other treatment options studied in this paper.

Erweiterte ambulante Polygraphie bei Patienten mit Ein- und/oder Durchschlafstörungen@@@Portable sleep monitoring in patients with disorders in falling asleep or maintaining sleep

BACKGROUND The most common diagnoses in sleep medicine are insomnia, sleep disordered breathing (SDB) and periodic leg movements (PLM). These disorders may coincide. This study examined the role of portable sleep monitoring in the diagnostic process and which sleep medicine diagnoses are additionally found in patients with disorders of initiating and maintaining sleep. METHODS A total of 217 patients, including 103 men (47.5%) and 114 (52.5%) women aged 52.2 ± 13.6 years with disorders of initiating or maintaining sleep were included in the study. Patients with known SDB were excluded. Patients were investigated using a stepwise diagnostic procedure with clinical interviews, questionnaires, clinical examination and portable sleep recording with electromyography (EMG) of the tibialis anterior muscle to diagnose SDB and PLM. RESULTS Of the patients 125 (57.6%) were diagnosed with insomnia according to the International Classification of Sleep Disorders (ICSD) and 70 (56%) had no other sleep disorder. Out of the 217 patients SDB was found in 107 (49.3%) patients, PLM in 90 patients (41.5%) and in 78 patients (35.9%) restless legs syndrome (RLS) was diagnosed. Among the 125 patients with insomnia 44 patients had RLS/PLMD and 35 had SDB in addition whereas SDB and RLS/PLMD were found in 33 subjects. All 3 disorders insomnia, RLS/PLMD and SDB were found in 24 subjects. CONCLUSIONS Out of 217 patients with a complaint of non-restorative sleep only 125 were finally diagnosed with insomnia. As 25.3% of patients showed combinations of sleep disorders, 49.3% with SDB and 41.5% with RLS/PLMD portable monitoring with electromyography of the legs is recommended. The investigation with a portable sleep monitoring system including an EMG of the tibialis muscle is very useful in patients with insomnia in addition to a clinical interview and questionnaires.

Circadian Behavior of Cardiovascular Variability

The autonomous nervous system is modulated by the sleep-wake cycle and the circadian system at the same time. In order to investigate the separate circadian influence on noninvasive parameters of the cardiovascular variability which could reflect the state of the autonomic tone, we applied a 40-hours constant routine protocol on twelve healthy young volunteers. During that period continuous multi-channel recordings of EKG, EEG, EOG, EMG and respiration were performed. Out of the EKG, sampled with 512 Hz, time domain as well as frequency domain heart rate variability parameters were calculated time-variant in 15-min bins. Descriptive analysis of results revealed a clear circadian modulation of the parameters of the cardiovascular variability. Additionally effects induced by the experimental setting were observed. The findings could make contribution in the design of a noninvasive autonomic state index measure which could be used in patients as well as for daily work life conditions.