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Effective compliance (time spent at the effective pressure) with nasal CPAP in obstructive sleep apnea has been reported to be poor. The aim of our study was to evaluate effective compliance in a large European multicenter study. One hundred twenty-one consecutive newly treated patients (initial apnea-hypopnea index [AHI] = 62.0 +/- 29. 5/h, AHI under CPAP = 6.4 +/- 8.1/h, CPAP pressure = 8.7 +/- 2.6 cm H(2)O, BMI = 33.1 +/- 6.8 kg/m(2)) were randomly allocated to a group with (MC(+)) (n = 58) or without (MC(-)) (n = 63) a control unit measuring effective compliance at 1, 2, and 3 mo, which was compared with the built-in time counter data. MC(+) data were 94 +/- 10, 98 +/- 5, and 96 +/- 9% of counter data at 1, 2, and 3 mo, respectively. Using criteria of regular use already reported in the literature (at least 4 h of nCPAP per day of use and nCPAP administered more than 70% of the days) we found 77, 82, and 79% compliant patients at 1, 2, and 3 mo, respectively, 79% of the patients meeting these criteria each month. Although there were no pulmonary functions or polysomnographic differences between the two subgroups, the compliant patients did report a greater improvement in minor symptoms. We found a close correlation between effective use of CPAP and the machine run time. The main result of our study was a higher effective compliance than previously reported, approximately 80% of the patients being regular users versus 46% in a previously published study. This may result from different technical and medical follow-up.

Non-invasive ventilation (NIV) is recognised as an effective treatment for chronic hypercapnic respiratory failure. Monitoring NIV during sleep may be preferable to daytime assessment. This paper reports the findings of an international consensus group which systematically analysed nocturnal polygraphic or polysomnographic tracings recorded with either volume-cycled or pressure-cycled ventilators. A systematic description of nocturnal respiratory events which occur during NIV is proposed: leaks, obstruction at different levels of the upper airway (glottis and/or pharynx), with or without decrease of respiratory drive and asynchrony

To characterise the relation between pharyngeal anatomy and sleep related disordered breathing, 17 men with complaints of snoring were studied by all night polysomnography. Ten of them had obstructive sleep apnoea (mean (SD) apnoea-hypopnoea index 56 3 (41-7), age 52 (10) years, body mass index 31-4 (5 3) kg/m2); whereas seven were simple snorers (apnoea-hypopnoea index 6-7 (4 6), age 40 (17) years, body mass index 25-9 (4-3) kg/m2). The pharynx was studied by magnetic resonance imaging in all patients and in a group of eight healthy subjects (age 27 (6) years, body mass index 21P8 (2 2) kg/m2, both significantly lower than in the patients; p < 0 05). On the midsagittal section and six transverse sections equally spaced between the nasopharynx and the hypopharynx several anatomical measurements were performed. Results showed that there was no difference between groups in most magnetic resonance imaging measurements, but that on transverse sections the pharyngeal cross section had an elliptic shape with the long axis oriented in the coronal plane in normal subjects, whereas in apnoeic and snoring patients the pharynx was circular or had an elliptic shape but with the long axis oriented in the sagittal plane. It is suggested that the change in pharyngeal cross sectional shape, secondary to a reduction in pharyngeal transverse diameter, may be related to the risk of developing sleep related disordered breathing.

Continuous positive airway pressure (CPAP) is an effective but cumbersome treatment for obstructive sleep apnoea (OSA). Noncompliant patients need alternative therapies.We studied a tongue neurostimulation approach: targeted hypoglossal neurostimulation (THN) therapy with the aura6000 TM System. A multi-contact electrode positioned around the main trunk of the twelfth nerve connected to an implanted pulse generator stimulates segments of the nerve, activating dilator muscles. The primary objective was to improve the polysomnographically determined apnoea/hypopnoea index (AHI) at 3 months, and maintain the improvement after 12 months of treatment. 13 out of 14 operated patients were successfully implanted. At 12 months, the AHI decreased from 45¡18 to 21¡17, a 53% reduction (p,0.001). The 4% oxygen desaturation index fell from 29¡20 to 15¡16 and the arousal index from 37¡13 to 25¡14, both p,0.001. The Epworth sleepiness scale decreased from 11¡7 to 8¡4 (p50.09). THN was neither painful nor awakened patients, who all complied with therapy. There were two transient tongue paresis.The present study represents the longest study of any hypoglossal neurostimulation reported to date. We conclude that THN is safe and effective to treat OSA in patients not compliant with CPAP.

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A Ac co ou us st ti ic c a an na al ly ys si is s o of f s sn no or ri in ng g s so ou un nd d i in n p pa at ti ie en nt ts s w wi it th h s si im mp pl le e s sn no or r-Spectral analysis of snoring sound showed the existence of two different patterns. The first pattern was characterized by the presence of a fundamental frequency and several harmonics. The second pattern was characterized by a low frequency peak with the sound energy scattered on a narrower band of frequencies, but without clearly identified harmonics. The seven simple snorers and two of the 10 patients with OSA (AIH 13 and 14 events·h -1 , respectively) showed the first pattern. The rest of the OSA patients showed the second pattern. The peak frequency of snoring was significantly lower in OSA patients, with all but one OSA patient and only one simple snorer showing a peak frequency below 150 Hz A significant negative correlation was found between AHI and peak and mean frequencies of the snoring power spectrum (p<0.0016 and p<0.0089, respectively).In conclusion, this study demonstrates significant differences in the sound power spectrum of snoring sound between subjects with simple snoring and obstructive sleep apnoea patients.