Sleep Unit Research Articles

Syndrome d’apnée hypopnée obstructif du sommeil en Afrique Sub-saharienne : une revue de la littérature

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is common, under diagnosed and severe. It increases cardiovascular morbidity and mortality, reduces life expectancy and alters the quality of life.The objective of this work was to review the scientific literature on OSAHS in Sub-Saharan Africa from 2009 to September 2019.A search on PubMed, Science Direct, African Index Medicus, African Journals on line and Google scholar found a total of 43 references relevant to the theme.OSAHS publications are scarce in sub-Saharan Africa with no data for 36 countries. Practitioners’ level of knowledge about the disease was low. Polygraphy and / or polysomnography were not available in the majority of Sub-Saharan African countries. The prevalences obtained remained higher than those found in Europe and USA. OSAHS predominated in men, with a peak around 55 years old. The most consistent risk factor was obesity. The association OSAHS chronic pathology remained frequent. The excessive cost of continuous positive pressure, surgery and the lack of health insurance in these countries limited access to treatment.We need to improve the knowledge, in sub-Saharan Africa, of practitioners in the field of sleep medicine, to make polysomnography available in public health structures, to create sleep units in teaching hospitals to strengthen practical training and finally to make accessible treatment.

Treatment with CPAP in Elderly Patients with Obstructive Sleep Apnoea.

The population pyramid is changing as a result of the ever-increasing life expectancy, which makes it crucial to acquire an in-depth understanding of the diseases that most often affect the elderly. Obstructive sleep apnoea (OSA) affects 15%–20% of the population aged over 65 years. Despite this prevalence, there have been very few specific studies on the management of OSA in this age group, even though over 60% of the patients aged over 65-70 years who attend sleep units with suspicion of OSA receive treatment with continuous positive airway pressure (CPAP), on the basis of an extrapolation of the positive results achieved by CPAP in clinical trials involving middle-aged males. However, the latter’s form of presentation, evolution and, probably, prognosis comparing with OSA are not the same as those of elderly patients. Recent clinical trials performed on an exclusive series of elderly patients have shed light on the possible role of CPAP treatment in elderly patients with OSA, but there are still many questions that need to be answered. The physiological increase in the number of sleep-related disorders with the passing of years, and the lack of validated diagnostic and therapeutic tools for this age group are probably the greatest obstacles to define, diagnose and treat OSA in the elderly.

Measurement of upper airway resistances: A simple way to assess its collapsibility?

The collapsibility of the upper airway is a key factor in the pathogenesis of obstructive sleep apnea (OSA). The exact measurement of this parameter, typically performed by obtaining the critical pressure (Pcrit), has not been introduced into clinical practice. The techniques that are used to measure the upper airway resistance could provide information on its the collapsibility of the airway. The aim of this study was to associate resistance in the upper airway with the presence of OSA. Using a cross-sectional design with a control group, consecutive cases that were seen in the Chest Diseases Sleep Unit were recruited after undergoing nocturnal polysomnography. The upper airway collapsibility was determined based on the change in its resistance from the standing position to the supine position with a flow interruption (Rint) device by measuring the angle formed between the pressure/flow lines (PF angle) between the two positions. The PF angle was greater in the OSA group than in the controls: 7.5° (4) vs. 4° (2) (P < .001), with a positive correlation between the width of the angle and the apnea-hypopnea index (AHI) (r: 0.28, P = .03). Placing the threshold level at 10°, a sensitivity of 25% was obtained, along with a specificity of 96%, for the diagnosis of OSA. The measurement of resistance in the upper airway using flow interruption (Rint) can predict the presence of moderate and severe OSA with high specificity but low sensitivity.

Perampanel in chronic insomnia

ObjectivesInsomnia is the most prevalent sleep disorder in the general population, and one of the most frequent reasons for consultation in the Sleep Units. Perampanel is an antiepileptic also effective on the structure of sleep, and in restless legs syndrome. We describe the first study that evaluates perampanel in patients with chronic insomnia. Patients and methodsObservational retrospective cohorts study of 66 patients with chronic resistant insomnia, 33 exposed to perampanel, other 33 as non-exposed group. All patients attended in Neurology or Psychiatry Consultation, from November 2017 to November 2018. Patients included had been treated with more than 4 different drugs in the previous 4 years. We reviewed age, sex, insomnia etiology, years of evolution, number of previously used drugs, and the results of perampanel for insomnia after 3 months of treatment in the exposed cohort, measured by the improvement of 3 or more points in the ISI and Pittsburgh scales, as well as the average of hours of sleep gained. Non-exposed patients were matched with this variables, but never treated with perampanel. ResultsWe have included 66 patients. In the exposed cohort: we describe 33 patients with chronic resistant insomnia, 20 women (60 %), 13 men (40 %). Average age 53.48 years, average time of evolution: 11.25 years. Main etiology: depression 13 cases (40 %). After the combination of perampanel 2–4 mg (100 %) with antidepressants (17 cases, 51.5 %) or anxiolytics (12 cases, 36.36 %) along 3 months: the total number of hours of sleep improves in 2.5 h, the scale ISI improves by 6 points (± 2.1 SD, p = 0.02), and Pittsburgh scale improves in 4 points (± 1.7, p = 0.04). In non-exposed cohort, the improvement of the ISI scale was 2.2 points (±0.8, p = 0.06), on the Pittsburgh scale was 1.6 points (± 0.5, p = 0.01). The main adverse effect was irritability in 3 patients, without withdrawal perampanel. The treatment was abandoned by 4 patients (12.12%): 1 due to persistent irritability (3%), 2 due to lack of efficacy (6 %), 1 due to pregnancy wish (3 %). ConclusionThe combination of Perampanel with an antidepressant, or an anxiolytic, improves the quality of sleep measured by ISI and Pittsburgh scales (statistically significant), probably due to its antagonistic action on glutamate. A clinical trial compared with placebo would be necessary to corroborate these results.

Modeling Obstructive Sleep Apnea Voices Using Deep Neural Network Embeddings and Domain-Adversarial Training

Obstructive Sleep Apnea (OSA) is a sleep breathing disorder affecting at least 3-7% of male adults and 2-5% of female adults between 30 and 70 years. It causes recurrent partial or total obstruction episodes at the level of the pharynx which causes cessation of breath during sleep. The number of obstruction episodes per sleep hour, known as Apnea-Hypopnea Index (AHI), along with the degree of the daytime sleepiness, determine the severity of OSA. Usually, OSA is diagnosed at a Sleep Unit in a hospital by the time-consuming polysomnography (PSG) test. Based on the expected impact of anatomical and physiological effects of the altered structure of the upper airway in OSA patients' voices, the assessment of OSA from speech has been proposed as a simple way to help in the diagnostic process. In this paper, we review previous research to assess OSA from speech and underline the difficulty of a weak connection between OSA and speech. We present results to model OSA using, to the best of our knowledge, for the first time Deep Learning on the largest existing database of OSA voice recordings and speakers' clinical variables. Using state-of-the-art speaker recognition techniques: acoustic subspace modeling (i-vectors), and deep neural network embeddings (x-vectors), we confirm the weak connection between speech and OSA. We hypothesize that this weak effect is mediated by undesired sources of variability as speakers' age, body mass index (BMI), or height, and we propose Domain-Adversarial Training (DAT) to remove them. Our results show that, taking BMI as adversarial domain, when classifying voices from OSA extreme cases (AHI ≤ 10 vs. AHI ≥ 30) accuracy increases from 69.39% to 76.60%. We hope these results can encourage the use of adversarial-domain neural networks to remove the undesired effects of clinical variables or other speaker factors when assessing health disorders from speech.

In-Home Diagnosis of Obstructive Sleep Apnea Using Automatic Video Analysis

Study objectivesTo evaluate the diagnostic accuracy of a non-invasive technology based on image processing for the identification of obstructive sleep apnea (OSA) and its severity at patients’ home. MethodsObservational, prospective, diagnostic accuracy study to evaluate the degree of measure agreement between Sleepwise (SW), in-laboratory attended polysomnography (PSG) and a home sleep apnea test (HSAT). 38 consecutive subjects with suspected OSA referred as outpatients to the sleep unit were recruited from September 2016 to September 2017. All patients underwent in-laboratory attended PSG and image processing with SW simultaneously overnight. Subsequently, a HSAT and image processing with SW were performed simultaneously overnight at patients’ home, and the 2 nights after, patients underwent only image processing with SW consecutively. ResultsIn-laboratory polysomnography and SW had a Lin's concordance correlation coefficient of 0.933 and a κ of 0.930. Between HSAT and SW the Lin's concordance correlation coefficient was 0.842 and a κ of 0.571. Agreement between two consecutive nights with SW recording showed a Lin's concordance correlation coefficient of 0.923 and a κ of 0. 837. ConclusionsSW was highly accurate for non-invasive and automatic diagnosis of OSA in outpatients compared to standard methods for OSA diagnosis either in-laboratory attended PSG or HSAT. SW proved to be a technique with repeatable and concordant results on different nights for the same patient. We conclude SW is a non-invasive, easy-to-use, portable, effective and highly accurate system for the in-home diagnosis of OSA.

Telemonitor care helps CPAP compliance in patients with obstructive sleep apnea: a systemic review and meta-analysis of randomized controlled trials.

Background:This was a meta-analysis of continuous positive airway pressure (CPAP) compliance. We compared telemonitor (TM) care with usual care and supervised PAP titration (SPT) in the sleep unit with home auto-adjusting pressure titration (HAPT) in patients with obstructive sleep apnea (OSA).Methods:We searched PubMed, Web of Science, Scopus, and Medline for appropriate randomized controlled trials (RCTs) that compared TM care with usual care for patients with OSA. Review Manager 5.3 was used for all comparisons and analyses.Results:Our meta-analysis included 19 studies involving a total of 2464 patients with OSA; CPAP compliance was significantly higher in the TM care group [mean difference (MD) 0.68 h, 95% confidence interval (CI) 0.48–0.89 h, I2 = 49%] compared with the usual care group. When we compared SPT and HAPT, two groups did not exhibit significantly different levels of CPAP compliance (MD −0.34 h, 95% CI −0.72–0.05 h, I2 = 91%). Subgroup analysis comparing the SPT with HAPT in CPAP compliance was grouped by follow-up time (⩾3 months or <3 months). Once again, there were no between-group differences in either long-term (MD = 0.56 h, 95% CI = 1.39–0.26 h, I2 = 91%), or short-term (MD = 0.34 h, 95% CI = 0.26–0.27 h, I2 = 14%) follow up.Conclusions:TM care was associated with significantly greater CPAP compliance compared with usual care. Also, HAPT was not inferior to SPT for CPAP compliance.

Mobile health application to support CPAP therapy in obstructive sleep apnoea: design, feasibility and perspectives

BackgroundCurrent continuous positive airway pressure (CPAP) devices can be monitored remotely; however, in-person visits are kept for clinical follow-up in order to promote CPAP use and resolve potential side-effects. Mobile health is a promising way to provide remote and easy clinical control for CPAP follow-up and support. We aimed to evaluate the feasibility and acceptance by obstructive sleep apnoea (OSA) patients and healthcare professionals of a newly designed mobile app (Appnea-Q) to promote clinical control through a self-monitoring tool for patients with CPAP supervised by sleep professionals.MethodsAppnea-Q incorporates a simple follow-up questionnaire with automated responses, together with frequent problems and lifestyle recommendations sections. Feasibility, acceptance and usefulness were assessed. First, an internal validation was performed during outpatient CPAP follow-up visits with sleep professionals from various sleep units. Second, an external validation was performed in a subgroup of 15 patients at home.ResultsMost patients (n=75) considered the app useful and were willing to use it and recommend it (72–88%). Up to 64.87% agreed on its capacity to reduce hospital visits. Appnea-Q was rated as acceptable (79.37±19.29) by the system usability score. Sleep professionals (n=30) concurred on its usefulness for OSA patient follow-up, particularly during the first month of CPAP therapy. The external validation showed its feasibility among 11 out of 15 patients and their data were received accordingly on the professionals' web platform.ConclusionsAccording to our validation process, and the viewpoints of the patients and professionals, our new mobile app is a feasible and well-received tool for personal OSA management. Future clinical trials should substantiate its performance and cost-effectiveness in the clinical arena.

Coordinated program between primary care and sleep unit for the management of obstructive sleep apnea

The purpose of this study is to develop and validate a work model in the primary health-care setting for identifying patients with obstructive sleep apnea–hypopnea syndrome (OSAHS) based on clinical variables and an ambulatory sleep monitoring study. After screening, patients with mild–moderate OSAHS could be managed by primary care physicians, whereas those identified with severe OSAHS would be referred to specialists from sleep units for starting specific treatment. The proposed model does not move the entire health-care process to a generally overburdened primary care level and favors the coordinated work and the necessary flexibility to adapt the model to challenges and perspectives of OSAHS.

The spectrum of obstructive sleep apnea in infants and children with Down Syndrome

ObjectiveDescribe the spectrum of OSA across time in infants and children with Down syndrome. MethodsRetrospective records review of children who underwent formal polysomnography (PSG) in one of two Australian tertiary sleep centres over selected 3.5-year periods. 152 children were identified, then all sleep study and treatment records were retrieved for the lifetime of the child through 2018. Results3.8 ± 3.2 studies (range 1–17) were retrieved per child and 38.2% had mild disease at worst. Children having only 1 study were more likely to have a normal or mild result than those having ≥2 (chi-square 11.25, p-value 0.0008) Studies were more often severe in children age <2 compared to those ≥2 years, (chi-square 12.87, p = 0.005). After age 2 years, OSA severity increased with age. Amongst 91 (56.4%) children with ≥2 studies, 71 (78.0%) had moderate or severe disease at some time. Studies evaluating the effects of surgery (most often adenotonsillectomy) showed resolution of disease to mild or normal in 53.3%. Where ≥2 studies were evaluated, the last study polarised towards normal or mild disease 40 (44.0%), or treatment titrations 34 (37.4%) with moderate or severe disease in 17 (18.7%). ConclusionsIn a tertiary sleep unit, a full spectrum of sleep disordered breathing in Down syndrome was seen from infancy onwards. Children having only one study were more likely to have normal results. Children with multiple studies reflected disease surveillance, including follow-up after treatment interventions.

Comprehensive management of obstructive sleep apnea by telemedicine: Clinical improvement and cost-effectiveness of a Virtual Sleep Unit. A randomized controlled trial.

IntroductionObstructive sleep apnea (OSA) is a prevalent disease associated with significant morbidity and high healthcare costs. Information and communication technology could offer cost-effective management options.ObjectivesTo evaluate an out-of-hospital Virtual Sleep Unit (VSU) based on telemedicine to manage all patients with suspected OSA, including those with and without continuous positive airway pressure (CPAP) therapy.MethodsThis was an open randomized controlled trial. Patients with suspected OSA were randomized to hospital routine (HR) or VSU groups to compare the clinical improvement and cost-effectiveness in a non-inferiority analysis. Improvement was assessed by changes in the Quebec Sleep Questionnaire (QSQ), EuroQol (EQ-5D and EQ-VAS), and Epworth Sleepiness Scale (ESS). The follow-up was 3 months. Cost-effectiveness was assessed by a Bayesian analysis based on quality-adjusted life-years (QALYs).ResultsThe HR group (n: 92; 78% OSA, 57% CPAP) compared with the VSU group (n: 94; 83% OSA, 43% CPAP) showed: CPAP compliance was similar in both groups, the QSQ social interactions domain improved significantly more in the HR group whereas the EQ-VAS improved more in the VSU group. Total and OSA-related costs were lower in the VSU group than the HR. The Bayesian cost-effectiveness analysis showed that VSU was cost-effective for a wide range of willingness to pay for QALYs.ConclusionsThe VSU offered a cost-effective means of improving QALYs than HR. However, the assessment of its clinical improvement was influenced by the choice of the questionnaire; hence, additional measurements of clinical improvement are needed. Our findings indicate that VSU could help with the management of many patients, irrespective of CPAP use.

Circulating microRNA profile as a potential biomarker for obstructive sleep apnea diagnosis

Evaluation of microRNAs (miRNAs) could allow characterization of the obstructive sleep apnea (OSA) and help diagnose it more accurately. We aimed to examine circulating miRNA profiles to establish the differences between non-OSA and OSA patients. Additionally, we aimed to analyse the effect of continuous positive airway pressure (CPAP) treatment on the miRNA profile. This observational, longitudinal study included 230 subjects referred to the Sleep Unit due to suspected OSA. Expression profiling of 188 miRNAs in plasma was performed in 27 subjects by TaqMan-Low-Density-Array. OSA-related miRNAs were selected for validation by RT-qPCR in 203 patients. Prediction models were built to discriminate between non-OSA and OSA: 1) NoSAS-score, 2) differentially expressed miRNAs, and 3) combination of NoSAS-score plus miRNAs. The differentially expressed miRNAs were measured after 6 months of follow-up. From the 14 miRNAs selected for validation, 6 were confirmed to be differentially expressed. The areas under the curve were 0.73 for the NoSAS-score, 0.81 for the miRNAs and 0.86 for the combination. After 6 months of CPAP treatment, miRNA levels in the OSA group seem to approximate to non-OSA levels. A cluster of miRNAs was identified to differentiate between non-OSA and OSA patients. CPAP treatment was associated with changes in the circulating miRNA profile.

Complicaciones más frecuentes al inicio del uso de la CPAP en nuestro medio

INTRODUCCIÓN: al comienzo del tratamiento con presión positiva continua en la vía aérea (CPAP) por el síndrome de apnea/hipopnea del sueño (SAHS) pueden surgir distintos tipos de problemas que impidan su correcto uso o incluso su abandono. Por esto es preciso conocer cuáles son las principales complicaciones tanto para informar al paciente como para dar soluciones de forma temprana.MATERIAL Y MÉTODO: se estudiaron a 120 pacientes diagnosticados con SAHS que comenzaron el tratamiento con CPAP nasal. Se realizaron cuestionarios para valorar su sueño previo al tratamiento e identificar los factores que influyeran en la adaptación a la CPAP. Pasados al menos 2 meses, se realizaron cuestionarios en los que preguntaba sobre las complicaciones surgidas y la tolerancia al tratamiento.RESULTADOS: las molestias ocasionadas por la mascarilla o correas de fijación fueron las complicaciones más frecuentes, así como las lesiones ocasionadas por las mismas (ca- llosidades, excoriaciones), que desaparecieron en 2-3 semanas. Es frecuente la sequedad de mucosas matutina y tiende a persistir. El ruido de los equipos causó molestias inicialmente, en especial a los acompañantes. Los episodios de congestión nasal y enrojecimiento ocular matutino se relacionaron con la mala fijación de la mascarilla. Un 38 % no cumplió correcta- mente, con pocas horas de uso. 4 pacientes rechazaron el tratamiento.DISCUSIÓN: la CPAP nasal conlleva complicaciones iniciales a detectar precozmente ya que, aunque la mayoría son problemas esporádicos o breves, persisten en algunos pacien- tes y pueden causar mal cumplimiento del tratamiento. Pasados 2 meses con complicaciones, se aconseja valorar el cambio de mascarillas o emplear humidificadores. Desde las unidades de sueño, es preciso advertir al paciente de estas complicaciones y su desaparición normal.

Validation of NoSAS (Neck, Obesity, Snoring, Age, Sex) score as a screening tool for obstructive sleep apnea: Analysis in a sleep clinic

IntroductionScreening methods have become increasingly important due to the growing number of patients suspected of having obstructive sleep apnea (OSA) being referred to sleep clinics. The Lausanne NoSAS (Neck circumference, Obesity, Snoring, Age, Sex) score test is a simple, efficient, and easily employed tool enabling identification of individuals at risk for the disease. The score ranges from 0 to 17 and the patient has a high probability of OSA if they have a NoSAS score of 8 or higher. ObjectivesTo evaluate the performance of the NoSAS score as a screening tool for the diagnosis of OSA in a sleep clinic. MethodsProspectively, for 12 months, we included all the patients referred by primary care physicians to our sleep unit for clinical evaluation who had undergone in-lab polysomnography (PSG) and completed the NoSAS score. This test assigns 4 points for a neck circumference of more than 40cm, 3 points for a body-mass index of 25kg/m2 to less than 30kg/m2 or 5 points for having a body-mass index of 30kg/m2 or more, 2 points for snoring, 4 points for being older than 55 years of age and 2 points for being male. ResultsOf the 294 patients, 70.7% were male, aged 53.5±12.1 years, with a neck circumference of 41.0±3.6cm and a BMI of 30.8±5.1kg/m2. OSA was present in 84.0% of the patients, 34.8% with moderate OSA and 36.4% severe OSA. Using the NoSAS model for the prediction of all OSA, moderate/severe OSA and severe OSA, the area under the ROC (Receiver Operating Characteristic) was 0.770 (IC95%: (0.703; 0.837), p<0.001), 0.746 (IC95%: (0.691; 0.802), p<0.001) and 0.686 (IC95%: (0.622; 0.749), p<0.001), respectively, thus confirming the diagnostic ability of the NoSAS model.With a NoSAS score ≥7, the sensitivity and positive predictive value (PPV) were 94.3% and 87.6% for all OSA, 94.9% and 62.8% for moderate/severe OSA and 100% and 33.8% for severe OSA, respectively. With the same cut-off, the negative predictive value (NPV) for moderate/severe and severe OSA were 67.9% and 100%, respectively. Each increase in the NoSAS score was associated with an increase in the probability of OSA, reaching a 97% OSA probability for a score of 17. ConclusionsThe NoSAS score showed high sensitivity and PPV for OSA with specificity and diagnostic accuracy steadily increasing with higher scores. Furthermore, a low score showed high predictive value for the exclusion of moderate/severe OSA. Overall, our results suggest that, in primary care, this score can be a powerful tool for stratifying and prioritizing patients in the diagnosis of OSA. Nevertheless, more studies are needed to evaluate the efficacy of this score in hospital health care, in younger populations, with a predominance of female and non-obese individuals or in cardiovascular disease.

The Potential Role of Obstructive Sleep Apnoea in Refractory Hypertension.

This review seeks to present an overview of the recently found association between refractory hypertension (RfH) and obstructive sleep apnoea (OSA). RfH was recently defined as an extreme phenotype of resistant hypertension characterized by the lack of blood pressure control despite using ≥ 5 antihypertensive drugs at optimal doses. Current data support that the pathophysiological pathway of both types of hypertension is different. The main mechanism involved in resistant hypertension is fluid retention whereas in the case of RfH is the sympathetic over-activity. OSA is now recognized as a cause of hypertension (especially in the case of difficult-to-treat hypertension). It seems that the biological mechanism linking OSA and arterial hypertension is the sympathetic over-activity related to the respiratory events (apnoeas and hypopnoeas) during the night. So, it is not surprising that, although the literature is scarce, some studies have found a very high prevalence of OSA and an excess of sympathetic activity in patients with RfH. Finally, a very recent study demonstrated that continuous positive airway pressure (CPAP) treatment, which controls sympathetic activation in OSA patients, achieves very significant reductions in blood pressure levels in RfH patients, even greater than in those with resistant (non-refractory) hypertension. The prevalence of OSA in patients with RfH is very high. CPAP treatment achieves a clinically significant reduction in blood pressure levels in those patients with RfH (especially in night readings). Patients with RfH must be sent to a sleep unit for a study.

Continuous Positive Airway Pressure Treatment Does not Reduce Uric Acid Levels in OSA Women

ObjectivesAlthough an association between uric acid (UA) levels and obstructive sleep apnea (OSA) has been reported, the effect of continuous positive airway pressure (CPAP) on this measure is yet unclear. We aimed to investigate the effect of CPAP therapy on serum UA levels in patients with OSA. MethodsWe conducted a multicenter, open-label, randomized controlled trial in 307 women diagnosed with moderate-to-severe OSA (apnea-hypopnea index [AHI]≥15) in 19 Spanish Sleep Units. Women were randomized to CPAP (n=151) or conservative treatment (n=156) for 12 weeks. Changes in serum UA measures were assessed on an intention-to-treat basis. Additional analyses were conducted in the subgroup of women with CPAP adherence ≥4h/night and those with UA levels ≥6mg/dl. ResultsWomen had a mean (SD) age of 57.1 (10.1) years, median (first–third quartile) body mass index of 33.7 (29.0–38.5) mg/kg2 and AHI of 32.0 (22.6–48.5). The average serum UA measure was 5.11 (1.26) mg/dl, and 80 (26.1%) participants had UA≥6mg/dl. Compared with the control group, the CPAP group did not achieve any reduction in UA levels (non-adjusted intergroup difference −0.03mg/dl, 95%CI −0.20 to 0.13; p=0.702) after 12 weeks of follow-up. These results did not change when the analysis was restricted to women with CPAP adherence ≥4h/night, or the subgroup of women with hyperuricemia. ConclusionsTwelve weeks of CPAP therapy does not reduce UA levels compared to conservative treatment in women with moderate-to-severe OSA.

The use of cardiopulmonary exercise testing in identifying the presence of obstructive sleep apnea syndrome in patients with compatible symptomatology

The aim of this study was to investigate the relationship between cardiopulmonary exercise testing (CPET) and the presence of obstructive sleep apnea syndrome (OSAS) in order to provide an innovative tool to identify patients with OSAS. A prospective nested case control design was adopted. A consecutive population of male volunteers referred to a Sleep Unit was subjected to nocturnal polysomnography, full lung function testing and maximal CPET. A stepwise linear discriminant function analysis (DFA) was applied to construct a model which could identify individuals with moderate-to-severe OSAS from healthy controls. The total of 30 volunteers formed the OSAS and 24 the non-OSAS groups. Demographic and somatometric parameters were similar between groups. Patients presented with lower Expiratory Reserve Volume (ERV: 106.7 ± 28.3 vs. 123.9 ± 22.1, p < 0.001), Leg FatigueBorg scale (3.9 ± 1.1 vs. 6.1 ± 1.4, p < 0.001), VO2peak(25.0 ± 5.9 vs. 32.9 ± 7.2 ml/kg−1/min−1, p < 0.001), peak breathing frequency (31.0 ± 5.8 vs. 35.5 ± 7.3 1/min−1, p < 0.001) and peak heart rate (151.1 ± 17.7 vs. 171.2 ± 12.6 beats/min−1, p < 0.001) compared to controls, but higher peak end-tidal CO2 (PETCO2peak:38.6 ± 4.2 vs. 35.0 ± 4.9 mmHg, p = 0.043) and peak systolic (SBP:188.3 ± 21.9 vs. 173.1 ± 17.9 mmHg, p = 0.009) and diastolic (DBP: 91.3 ± 8.2 vs. 85.4 ± 8.2 mmHg, p = 0.011) blood pressure. Stepwise DFA indicated that ERV% of predicted (0.372), PETCO2peak (−0.376), SpO2resting (0.0667), Leg Fatigue Borg scale (0.564), HRpeak (0.530) and DBPpeak (−0.543) could separate the two groups, with an overall predictive accuracy of 96.3%. Selected CPET parameters (ERV% of predicted, PETCO2peak, SpO2resting, HRpeak, DBPpeak and Leg FatigueBorg Scale) are independently associated with OSAS presence and could discriminate patients with and without this disorder.

Symptoms During CPAP Therapy Are the Major Reason for Contacting the Sleep Unit Between Two Routine Contacts.

The demand for continuous positive airway pressure (CPAP) therapy outpaces available resources in most health care settings. We sought to evaluate predictors of nonroutine CPAP follow-up visits to improve resource utilization. We randomly analyzed 1,141 of the 2,446 patients who had received at least 1 year of CPAP therapy. Reasons for contacts, type (routine = R, nonroutine = NR), and mode (face-to-face or not, physician, nurse) were collected. A total of 771 patients were classified R, and 370 NR. Age, profession, and sex did not affect the NR frequency. Symptoms increased the odds ratio for NR 12.1-fold, somnolence 34.8-fold, and suffocation at night 10.4-fold. Patients with nonroutine reasons abandoned CPAP therapy significantly (7.6-fold) more frequently than patients with routine reasons. Symptoms during CPAP therapy predicted the nonroutine contacts well. In line with this, patients with symptoms have become a priority follow-up group, and could constitute the only follow-up policy when dealing with insufficient medical resources.

Two Functional Units of the &lt;i&gt;Drosophila&lt;/i&gt; Sleep Homeostat Control Sleep Pressure and Sleep-Wake Transitions

The amount an animal sleeps is controlled by a feedback system called the sleep homeostat, in coordination with circadian and environmental inputs. The architecture of this homeostatic control remains elusive. We combine statistical and molecular studies to construct a functional description of the Drosophila sleep homeostat with two units – one that controls sleep pressure and another that regulates sleep duration. Examination of the temporal organization of sleep reveals that the sleep pressure unit generates correlations in the size of individual bouts. The magnitude of this correlation predicts the fraction of sleep recovered after deprivation, suggesting that sleep pressure in Drosophila is measured through temporal ordering of sleep bouts. Examination of bout size distributions suggests that the sleep duration unit is composed of four mutually inhibitory modules that mediate sleep-wake transitions by integrating sleep pressure, circadian and light signals. These results lay the groundwork for a unified model of sleep homeostasis.

Adaption of Power Gating in Positive Feedback Adiabatic Logic Circuits

Positive Feedback Adiabatic Logic (PFAL), a quasi static and differential logic adiabatic family, is one of the most robust, with significant reduction in power consumption has been chosen in this work. Power Gating has been adapted in order to further reduce power dissipation. It is accomplished by sleep state control units that switch circuits between awake and idle. Two power gating methodologies, footer and header, have been evaluated and compared. The functional verification and power evaluations have been performed using TSPICE simulations with 180nm TSMC CMOS parameters. Power consumption has also been examined by varying supply voltage, frequency of the power clock signal and load capacitance. The observed overhead in awake state power dissipations is compensated for with the significant decrease in idle state power dissipation.