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Sleep Apnea-Hypopnea Syndrome is a common chronic sleep respiratory disorder in adults. However, the subtype classification of SAHS and the corresponding treatment options have been a clinical challenge. In this work, we propose a novel SAHS detection and classification method, which uses C4/A1 single-channel EEG signal, oronasal flow signal and abdominal displacement signal. Firstly, we proposed a method of sleep staging based on EEG signals combined with SAHS classification, which significantly reduced the rate of false positives that appear in the waking period. Secondly, the data preprocessed by the sliding window was manipulated by Long-Short Term Memory-Convolutional Neural Network (LSTM-CNN) to identify distinct four types: normal, hypopnea events, OSAS and CSAS + MSAS. The overall classification accuracy achieves 83.94% (with 86.07% sensitivity), and the false-positive rate is 5.34% (a decrease from 28.19%), which indicates a significant improvement. Compared with PSG method, our proposed method provides promising results and improves the accuracy of SAHS detection and classification through non-invasive methods. This SAHS subtype classification method is expected to be a powerful aid to physicians in clinical diagnosis, offering the possibility of personalized treatment for patients.

Background and objective The aim of this study was to assess the utility of bispectrum-based oximetry approaches as a complementary tool to traditional techniques in the screening of pediatric sleep apnea-hypopnea syndrome (SAHS). Methods 298 blood oxygen saturation (SpO2) signals from children ranging 0–13 years of age were recorded during overnight polysomnography (PSG). These recordings were divided into three severity groups according to the PSG-derived apnea hypopnea index (AHI): AHI Results An optimum subset with features from all the proposed methodological approaches was obtained: variables from bispectrum, as well as PSD, ODI3, Age, and Sex. In the 3-class classification task, the MLP model trained with these features achieved an accuracy of 76.0% and a Cohen's kappa of 0.56 in an independent test set. Additionally, high accuracies were reached using the AHI cutoffs for diagnosis of moderate (AHI = 5 e/h) and severe (AHI = 10 e/h) SAHS: 81.3% and 85.3%, respectively. These results outperformed the diagnostic ability of a MLP model built without using bispectral features. Conclusions Our results suggest that bispectrum provides additional information to anthropometric variables, ODI3 and PSD regarding characterization of changes in the SpO2 signal caused by respiratory events. Thus, oximetry bispectrum can be a useful tool to provide complementary information for screening of moderate-to-severe pediatric SAHS.

Introduction and objectives In recent years, with the rise of sleep-disordered breathing, we have been seeing more articles related to post-operative complications after adenotonsillectomy in children with sleep apnea-hypopnea syndrome (OSAS), especially in those with severe sleep apnea. The objective of this study was to evaluate post-operative complications in children with severe OSAS compared to children who had adenotonsillectomy for a different reason, and establish whether they needed admission to an intensive care unit or not. Methods All children undergoing adenotonsillectomy in our hospital in the last 5 years were initially included in this study. Complications were analysed with a retrospective review. Results Two hundred and twenty-nine children admitted for adenotonsillectomy were finally included. In the whole group, complications occurred in 3.5% of children, 2.2% corresponding to respiratory complications. Children with sleep apnea (3.23% vs 1.47%, P=.39) or severe sleep apnea (3.77% vs 1.70%, P=.32) presented a higher incidence of respiratory complications, which was not statistically significant and was far below those published by other authors. All respiratory complications took place in the immediate post-operative period (operating theatre or anaesthesia recovery), with none in the paediatric ward. Conclusions In our population, children who undergo adenotonsillectomy, without any other comorbidities, malformation syndrome or neuromuscular disease, are more than 2 years old and have an immediate postoperative period without incidence, do not need to be systematically admitted to an intensive care unit, even if they present with severe OSAS.

Aim: To evaluate the prevalence of Sleep ApneaâHypopnea Syndrome (SAHS) in patients who were admitted with Acute Coronary Syndrome (ACS) to the Coronary Care Unit (CCU) and the clinical predictors of SAHS in patients with ACS and to compare the results of the simple sleep test (SST) with polysomnography (PSG). Methods: This was a prospective study that included patients who were admitted to the CCU with ACS, which was confirmed by coronary angiography. Demographic and anthropometric data, cardiovascular risk factors and measures on the Epworth Sleepiness Scale were collected. The SST was conducted with the ApneaLink⢠device during hospitalization or after discharge. Patients with an apneaâhypopnea index (AHI) â¥10/h were invited to participate in PSG. Results: Ninety-one patients with ACS were consecutively included over 4 months. Of the 58 patients who completed the study 43 (74.1%) were male. The mean age was 61.7 ± 12.2 years, and the mean body mass index was 27.4 ± 3.5 kg/m2. The median time for SST performance was 17.5 days. This study was compatible with SAHS in 25 cases (43.1%). Patients who had an AHI â¥10/h in the SST were submitted to PSG and SST simultaneously. The median interval between the ACS and the execution of PSG was 30 days. PSG confirmed that all the cases detected by SST were positive. Conclusion: In our study, we found a high prevalence of SAHS in patients who were admitted to the CCU with ACS (43.1%). These results support the need for SAHS screening in patients who are hospitalized with ACS. The SST may have a role in the screening of SAHS in this population. Resumo: Objetivo: Avaliar a prevalência da Síndrome de Apneia-Hipopneia do Sono (SAHS) em doentes internados na Unidade de Cuidados Intensivos Coronários (UCIC); determinar fatores clínicos preditivos de SAHS; comparar os resultados obtidos com o estudo de sono simplificado (ESS) com os da polissonografia (PSG). Métodos: Estudo prospetivo de doentes internados na UCIC com Síndrome Coronária Aguda (SCA), confirmado por coronariografia. Foram avaliados dados demográficos e antropométricos, fatores de risco cardiovascular e valores da escala de sonolência de Epworth. O ESS foi realizado com ApneaLinkTM durante o internamento ou após a alta. Os doentes com índice de apneia-hipopneia (IAH) â¥10/h foram convidados a realizar PSG. Resultados: Durante 4 meses foram selecionados consecutivamente 91 doentes com SCA. Cinquenta e oito doentes completaram o estudo, sendo 43 (74,1%) do sexo masculino, média etária de 61,7 ± 12,2 anos e índice de massa corporal médio de 27,4 ± 3,5 kg/m2. A mediana de tempo para realização do ESS foi de 17,5 dias. O estudo foi compatível com SAHS em 25 casos (43,1%). Aos doentes com IAH â¥10/h no ESS foi proposta a realização de PSG e ESS em simultâneo. A mediana do tempo entre SCA e a PSG foi de 30 dias. A PSG confirmou a positividade de todos os casos detetados pelo ESS. Conclusão: No nosso estudo detetámos uma elevada prevalência de SAHS em doentes com SCA internados na UCIC (43,1%). Os resultados suportam a necessidade de um método de rastreio da SAHS em doentes internados com SCA. O ESS pode ter um papel importante no rastreio da SAHS nesta população. Keywords: Sleep Apnea Syndrome, Acute Coronary Syndrome, Prevalence, Screening, Palavras-chave: Síndrome de apneia do sono, Síndrome coronária aguda, prevalência, rastreio

a Unidad del Sueno, Servicio de Neumologia, Hospital Vall d’Hebron, Barcelona, Spain, (Ciberes) b Unidad Multidisciplinar de Trastornos del Sueno, Hospital Txagorritxu, Vitoria, Spain, (Ciberes) c Unidad de Neumologia, Hospital de Requena, Valencia, Spain, (Ciberes) d Servicio de Neumologia, Hospital Universitario Miguel Servet, IACS, Zaragoza, Spain, (Ciberes) e Servei de Pneumologia, Hospital del Mar-IMIM, Hospital de Sabadell, UPF, UAB, Barcelona, Spain, (Ciberes) f Servicio de Neumologia, Hospital San Pedro de Alcantara, Caceres, Spain, (Ciberes) g Servei de Pneumologia, Hospital Universitari Sagrat Cor, UB, Barcelona, Spain, (Ciberes) h Unidad de Sueno, Hospital Universitario Complejo Asistencial de Burgos, Spain, (Ciberes) i Servicio de Neumologia, Hospital Universitario Complejo Asistencial de Burgos, Spain, (Ciberes)

Resumen Los trastornos respiratorios del sueno se han clasificado como obstructivos, centrales o mixtos, atendiendo a la presencia o no de estimulo respiratorio. Esta clasificacion puede resultar un tanto simplista, limitando la comprension de los complejos mecanismos que subyacen en la aparicion de uno u otro tipo de eventos, que podrian tener un origen comun en la inestabilidad del control respiratorio. Mientras los eventos obstructivos responden a la presion positiva continua sobre la via aerea (CPAP), es mas dificil el tratamiento de los eventos centrales. La aparicion o deterioro de apneas centrales y la resolucion incompleta de los eventos obstructivos con la aplicacion de CPAP en algunos sujetos, se reconoce como un nuevo tipo de trastorno respiratorio del sueno: el sindrome complejo de apneas del sueno. En la siguiente revision se repasan las diferentes formas de apneas centrales, se exponen los aspectos fundamentales de la patogenia, diagnostico y epidemiologia del sindrome complejo de apneas del sueno y se discuten las posibilidades terapeuticas.

The population pyramid is changing due to the increasing longevity of the population, making it a priority to have better knowledge of those diseases that have an increasingly major impact in advanced age. Sleep apnea-hypopnea syndrome (SAHS) affects 15-20% of individuals over 65 years. However, despite this high prevalence and that one in four sleep studies are conducted on the elderly in this country and that more 60% of these were treated with CPAP, there are few specific studies in this age group on the diagnosis and management of this syndrome. The physiological increase of the number of sleep respiratory disorders with the passing of time may be the biggest obstacle when defining, diagnosing and treating SAHS in the elderly. In any case and while more solid scientific evidence is obtained, the National SAHS Consensus, as well as the Guidelines on the diagnosis and treatment of SAHS, recommend that, within logical limits, age itself should not be an obstacle to offering the elderly diagnostic help and treatment similar to that offered to the rest of the population.

The sleep apnea/hypopnea syndrome is a very common sleep disorder, characterised by disrupted breathing during sleep. Depending on the extent of the disruptions to sleep, these are classified as apneas or hypopneas. In order to locate these apneic events an analysis of respiratory signals recorded for an entire night's sleep is necessary. However, identifying and classifying apneic events is a complex task, given the error associated with the process for digitising signals, variability in expert criteria and the complexity of the signals themselves. This article describes a fuzzy-logic-based automated system for detecting apneic events and classifying them as apneas or hypopneas. The aim is to equip this system with mechanisms for dealing with imprecision and reasoning affected by uncertainty. The ultimate goal was to assist the physician in diagnosing the sleep apnea/hypopnea syndrome. Results in terms of locating events in the polysomnogram showed sensitivity and specificity of 0.87 and 0.89, respectively. A receiver operating curve index of 0.88 was obtained for the classification of events as apneas or hypopneas.

Nowadays, sleepiness in patients with sleep apnea-hypopnea syndrome (SAHS) is understandable. It is somewhat more difficult to explain why most patients with SAHS enrolled in epidemiologic studies, even those with a high apnea-hypopnea index, do not experience excessive daytime sleepiness. The reasons for this discrepancy lie beyond mere polysomnographic events. This review examines data from the literature that may help us understand why these patients do not experience daytime sleepiness. It also analyzes studies that support and refute sleepiness as a marker of cardiovascular risk in patients with SAHS, and discusses the mechanisms that might increase this risk.

Introduction Sleep apnea–hypopnea syndrome (SAHS) is an emerging disease with high prevalence. There is controversy as to whether cardiac abnormalities are due to the disease itself or to the arterial hypertension frequently associated with this disease. Objectives To analyze echocardiographic abnormalities in a population of SAHS patients depending on the presence or absence of hypertension at the time of diagnosis and after six months of treatment with continuous positive airway pressure (CPAP). Methods We studied 85 consecutive patients diagnosed with SAHS who required treatment with CPAP (Hypertensive: 43, nonhypertensive: 42). We performed a baseline echocardiogram after six months of treatment. We analyzed morphological (wall thickness, diameters, ejection fraction) and functional (peak E- and A-wave velocities, deceleration time, Tei index) parameters of the left and right ventricles. Results Hypertensive patients were older and had higher blood pressure values, but there were no differences between groups in other clinical parameters. The hypertensive group had greater septal thickness (hypertensive: 12.1 ± 2.3; nonhypertensive: 10.8 ± 2.1 mm; p = 0.01). There were also differences in impairment of left (hypertensiveHT: 92.9%, nonhypertensive: 65%, p = 0.002) and right (hypertensive: 74.4%, nonhypertensive: 42.1%, p = 0.006) ventricular filling. After six months of treatment, an improvement of the myocardial performance index was noted in nonhypertensive patients (baseline Tei: 0.55 ± 0.1 vs. 6-month Tei: 0.49 ± 0.1; p = 0.01), whereas no significant change was observed in hypertensive patients. Conclusions Cardiac abnormalities in SAHS patients are increased in the presence of associated hypertension. Treatment with CPAP for six months improves cardiac abnormalities in nonhypertensive patients but not in hypertensive patients.

Sleep apnea-hypopnea syndrome (SAHS) is a highly prevalent disease in the general population and, due to its social and health repercussions, has become a major public health problem. The definition of this syndrome, as well as that of respiratory event, have been refined. The role of inflammatory mechanisms in the development of cardiovascular disease is currently under investigation and biological markers will probably be added, both in the definition of SAHS and in the choice of treatment. Although the gold standard in diagnosis is polysomnography, respiratory polygraphy has become a valid and complementary alternative, since this technique is a simplified method that can be performed in the home to confirm or exclude this disease. Expert systems such as single-channel devices may help to simplify diagnosis. Currently, the mainstay of treatment is still continuous positive airway pressure (CPAP); this modality is mainly indicated in patients with moderate or severe SAHS and has been shown to reduce mortality in this group.

The objective of the present study was to determine the relation between resting cardiac output in patients with sleep apnea-hypopnea syndrome but without arterial hypertension or heart failure as measured indirectly by the carbon dioxide rebreathing method and left ventricular function evaluated by transthoracic echocardiography. We also compared the variability and reproducibility of the measurements obtained by the equilibrium and exponential methods. In patients with sleep apnea-hypopnea syndrome there was a modest but significant association between resting cardiac output and left ventricular shortening fraction (r=0.690; P=.001) and left ventricular ejection fraction (r=0.690; P=.001). In addition, mean (SD) cardiac output obtained by the equilibrium method showed a lower coefficient of variability (0.21 [0.08]) than that of the exponential method (0.16 [0.09]) (P

syndrome is associated with an overall deterioration in the patient’s health and affects between 1 and 2 million people in Spain. The objective of the present study was to evaluate the diagnostic and therapeutic resources available in Spain for dealing with this problem in terms of both infrastructure and human resources. METHODS: We selected 461 general hospitals, 457 (99.1%) of which answered a questionnaire in the course of a telephone interview. RESULTS: At the time of response, 219 hospitals (47.5%) reported performing sleep studies. Conventional polysomnography was available in 53% of those hospitals, respiratory polygraphy was used in 42%, and oximetry in 5%. In 47% of the hospitals, continuous positive airway pressure was titrated empirically in most cases; the number of patients being treated with CPAP was 109 752, that is, 269 per 100 000 population in Spain. CONCLUSIONS: The level of resources available for diagnosing and treating sleep apnea-hypopnea syndrome, although improving, is clearly still inadequate. Currently, only 0.49 polysomnograph and 0.72 polygraph machines are available per 100 000 population, whereas 1 and 3 machines, respectively, are deemed necessary. Only 5% to 10% of the affected population has been diagnosed, and in 47% of the hospitals interviewed continuous positive airway pressure is not properly titrated. These results should be a clarion call to the health authorities to take the appropriate steps to address this health problem.

Introduccion Dadas la elevada prevalencia del sindro-me de apnea-hipopnea del sueno (SAHS), la gran demanda de polisomnografia convencional (PSG) y las largas listas de espera, son necesarios metodos alternativos para el diagnos-tico del SAHS y el ajuste de la ventilacion mecanica con pre-sion positiva continua en la via aerea (CPAP). En este ulti-mo aspecto las CPAP automaticas podrian ser importantes no solo como tratamiento, sino tambien para recomendar una presion de CPAP optima fija Objetivos Definir un protocolo para evaluar el funciona-miento de una CPAP automatica en un modelo mecanico; determinar el comportamiento de la CPAP automatica du-rante la PSG; definir la utilidad de la CPAP automatica para identificar una presion de CPAP optima en pacientes con SAHS, y valorar la eficacia de la presion fija determinada por la CPAP automatica mediante una PSG convencional Metodos Se realizaron cuatro protocolos utilizando el Autoset-T (AT) como modelo: a) se reprodujeron en el labo-ratorio, mediante un modelo mecanico, apneas, hipopneas, limitaciones del flujo, ronquidos y flujos normales y se com-probo la actuacion del AT; b) se examino el comportamiento de la CPAP automatica en tiempo real durante una PSG rea-lizada en 12 pacientes con un SAHS severo; c) se ajusto la CPAP con AT y PSG en un grupo para comprobar su con-cordancia en 39 pacientes con SAHS, y d) se estudio la efica-cia de la presion de CPAP recomendada por el AT mediante PSG en un grupo de 14 pacientes con SAHS Resultados Se observo un rapido incremento en la pre-sion de CPAP con el AT en respuesta a las apneas o ronqui-dos en el modelo mecanico durante la PSG convencional (desde un valor basal de 4 cmH2O hasta una presion semiop-tima [11 ± 1 cmH2O] tardo solo una media de 2,8 ± 3,1 min). Una vez alcanzado el flujo normal, la CPAP disminuye len-tamente y responde con mucha sensibilidad ante minimas anormalidades, especialmente al ronquido, pero no se modi-fica ante algunos tipos de limitacion de flujo. En el grupo de 39 pacientes, la presion visual obtenida del AT era similar a la recomendada por la PSG en la mayoria de los casos (71%). La PSG realizada tras un mes de utilizar la presionde CPAP recomendada por AT detecto un numero normal de apneas, hipopneas (indice de apneas-hipopneas [IAH], 6 ± 2) y despertares (10 ± 2) en los pacientes con SAHS Conclusiones El AT incrementa rapidamente la presion ante eventos respiratorios, mantiene un patron respiratorio normal en la mayoria de los pacientes y el analisis visual de la presion de AT permite una correcta identificacion de la presion optima de CPAP fija para el tratamiento del SAHS

Objetivo: Evaluar la relacion de la resistencia nasal (RN) con la tolerancia y el cumplimiento del tratamiento con presion positiva continua en la via aerea (CPAP) en pacientes con sindrome de apnea-hipopnea obstructiva del sueno (SAHS). Material y metodo: Se estudio a 125 pacientes con indice de apneas-hipopneas (IAH) media (desviacion tipica) de 53 ± 21, en tratamiento con CPAP. La RN fue medida antes de iniciar el tratamiento mediante rinomanometria anterior activa, considerando los valores de flujo (ml/s) a 150 Pa de presion en cada fosa nasal. Se valoro la tolerancia y el cumplimiento de la CPAP a las 2 semanas, a los 6 meses y al ano del tratamiento. Resultados: La media de la presion de CPAP prescrita fue de 9 ± 2 cmH2O. En 70 pacientes (56%) se considero que la rinomanometria era patologica. No observamos correlacion entre los flujos nasales y la presion de CPAP establecida (r = 0,018). El cumplimiento objetivo del tratamiento en el primer ano fue de 5 ± 1,5 h/dia. En este periodo, los efectos secundarios nasales mas frecuentes fueron sintomas funcionales, tales como hidrorrinorrea, picor o estornudos (24%), sequedad oronasal (21%) y obstruccion nasal subjetiva (6%). No hubo diferencias significativas en la tolerancia y el cumplimiento de la CPAP entre los pacientes con rinomanometrias normal y patologica. Conclusiones: En el paciente con SAHS, la RN valorada con rinomanometria anterior no se correlaciona con el nivel de presion optima de CPAP y no influye en su tolerancia ni en su cumplimiento.

Objetivo Construccion de un algoritmo para el diagnos-tico del sindrome de apneas-hipopneas durante el sueno (SAHS) mediante el uso optimizado y secuencial de la pul-sioximetria nocturna (PN) y la poligrafia respiratoria AutoSet® (AS) en pacientes con alta sospecha clinica de SAHS Metodos Realizacion simultanea de una PN y AS en 145 pacientes con alta sospecha clinica de SAHS (al menos dos de: roncopatia cronica, apneas presenciadas y repetidas, y somnolencia diurna patologica). El diagnostico de SAHS se realizo con un indice de apneas-hipopneas (IAH) (obtenido mediante AS) = 10. Para la construccion del algoritmo diag-nostico se siguieron los siguientes pasos: calculo de la preva-lencia de SAHS; calculo del mejor punto de corte diagnosti-co en el indice de desaturaciones mayores o iguales al 4% (ID 4%) respecto al IAH; analisis del valor predictivo positi-vo (VPP) y negativo (VPN) para dicho valor y correlacion y concordancia entre ID 4% e IAH segun la existencia y gra-vedad de SAHS Resultados La prevalencia global de SAHS fue del 83,4%. El mejor punto de corte se obtuvo para un ID 4% = 10 (sensibilidad [S]: 82%; especificidad [E]: 83%). Los VPP y VPN para la prevalencia calculada fueron de 0,95 y 0,29, respectivamente. La correlacion y concordancia global entre el ID 4% e IAH fue de 0,84 y 0,93, respectivamente. En pa-cientes sin SAHS fueron de 0,49 y 0,35, y ambas aumenta-ron progresivamente en SAHS leves, moderados y graves (0,90 y 0,95, respectivamente, en SAHS graves). Con todos estos datos se construyo el algoritmo diagnostico segun el cual la obtencion de un ID 4% = 30 en la PN (S: 72%; E: 100%) evitaria la realizacion de una AS posterior, mientras que un ID 4% Conclusiones La utilizacion secuencial de la PN y la AS permite ahorrar un numero importante de estudios polisom-nograficos en poblaciones con alta sospecha clinica de SAHS

La polisomnografia de siesta (PSG-S) es un metodo abreviado de diagnostico en el sindrome de apnea-hipopnea del sueno (SAHS). Aunque el diagnostico de SAHS se establece con un indice de apnea-hipopnea (IAH) mayor de 10, el tratamiento con ventilacion a presion positiva continua nasal (CPAP) se inicia con un IAH superior a 30 Objetivo Conocer la rentabilidad diagnostica de la PSG-S para iniciar el tratamiento con CPAP y evaluar los diferentes tipos de registros polisomnograficos hallados Metodos A 296 pacientes con sospecha clinica de SAHS se les realizo una PSG-S de 3 h de duracion. Las PSG-S se consideraron: a) positivas cuando el IAH era mayor de 30; b) normales cuando el IAH era inferior a 10 con sueno NREM y REM (mayor del 10%); c) nulas si el paciente durmio menos de 60 min, y d) no concluyentes, donde se definieron 3 subgrupos: IAH entre 10 y 30 con REM; IAH menor de 30 sin REM y sospecha de sindrome de resistencia aumentada de la via aerea superior (SRAVAS) La suma de las polisomnografias positivas y las normales se considero diagnostica; la suma de las nulas y las no concluyentes se considero no diagnostica. Segun el episodio respiratorio mas frecuente, las polisomnografias de siesta positivas fueron consideradas obstructiva predominante, hipopnea predominante, central-mixta, central-obstructiva y miscelanea Resultados En un 70% las PSG fueron diagnosticas (55% positivas mas 15% normales), y el 30% no diagnosticas (12% nulas mas 18% no concluyentes). Las PSG-S positivas se desglosaron en obstructivas predominantes (55%), hipopneas predominantes (29%), central-mixta (8%), central-obstructiva (4%) y miscelanea (4%) Conclusiones La rentabilidad diagnostica de la PSG-S para iniciar tratamiento con CPAP es elevada y existe una notable frecuencia del subgrupo definido como “hipopneas predominantes”

a Unidad del Sueno, Servicio de Neumologia, Hospital Vall d’Hebron, Barcelona, Spain, (Ciberes) b Unidad Multidisciplinar de Trastornos del Sueno, Hospital Txagorritxu, Vitoria, Spain, (Ciberes) c Unidad de Neumologia, Hospital de Requena, Valencia, Spain, (Ciberes) d Servicio de Neumologia, Hospital Universitario Miguel Servet, IACS, Zaragoza, Spain, (Ciberes) e Servei de Pneumologia, Hospital del Mar-IMIM, Hospital de Sabadell, UPF, UAB, Barcelona, Spain, (Ciberes) f Servicio de Neumologia, Hospital San Pedro de Alcantara, Caceres, Spain, (Ciberes) g Servei de Pneumologia, Hospital Universitari Sagrat Cor, UB, Barcelona, Spain, (Ciberes) h Unidad de Sueno, Hospital Universitario Complejo Asistencial de Burgos, Spain, (Ciberes) i Servicio de Neumologia, Hospital Universitario Complejo Asistencial de Burgos, Spain, (Ciberes)

origin HR accelerated after more than 85% of events. Conclusions: In the absence of a flow signal, the origin of the apneic events can be estimated based on associated features. We found that during bothOAandCA, respiratory effort decreases; however CA is characterized by half of OA respiratory amplitude, and starts usually after a deep breath. HR behaves differently during events of different origin, may be due to an increase in autonomicsympathetic stress caused by upper airway obstruction in OA. These findings are important for sleep apnea screeningdevices thatmaymonitoronly someof the respiratory signals (generally effort), and pulse rate or ECG.