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Resumen El soporte respiratorio no invasivo (SRNI) comprende 2 modalidades de tratamiento, la ventilacion mecanica no invasiva (VMNI) y la terapia de alto flujo con canulas nasales (TAFCN) que se aplican en pacientes adultos, pediatricos y neonatales con insuficiencia respiratoria aguda (IRA). Sin embargo, el grado de acuerdo entre las distintas especialidades sobre el beneficio de estas tecnicas en diferentes escenarios clinicos es controvertido. El objetivo del presente consenso fue elaborar una serie de recomendaciones de buena practica clinica para la aplicacion de soporte no invasivo en pacientes con IRA, avaladas por todas las sociedades cientificas involucradas en el manejo del paciente adulto y pediatrico/neonatal con IRA. Para ello se contacto con las diferentes sociedades implicadas, quienes designaron a su vez a un grupo de 26 profesionales con suficiente experiencia en su aplicacion. Se realizaron 3 reuniones presenciales para consensuar las recomendaciones (hasta un total de 71) fundamentadas en la revision de la literatura y en la actualizacion de la evidencia disponible en relacion con 3 categorias: indicaciones, monitorizacion y seguimiento del SRNI. Finalmente, se procedio a votacion telematica de cada una de las recomendaciones, por parte de los expertos de cada sociedad cientifica implicada. Para la clasificacion del grado de acuerdo se opto por un sistema analogico de clasificacion facil e intuitivo de usar, y que expresara con claridad si el procedimiento relacionado con el SRNI debia hacerse, podia hacerse o no debia hacerse.

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied. (C) 2020 SEPAR. Published by Elsevier Espana, S.L.U. All rights reserved.

Rationale: Noninvasive ventilation (NIV) is an effective treatment in obesity hypoventilation syndrome (OHS) with severe obstructive sleep apnoea (OSA) but there is paucity of evidence in OHS patients without severe OSA phenotype. Methods: In this multicentre (16 sites in Spain), open-label parallel group clinical trial, we randomly assigned 98 stable ambulatory patients with untreated OHS and apnoea-hypopnoea index Results:49 patients were randomised in each group and 48 patients were analysed in each one of them. During a median [IQR] follow-up of 4.98 [2.98; 6.62] years, mean (SD) hospitalization days/year was 2.60 (5.31) in the control group and 2.71 (4.52) in the NIV group [adjusted rate ratio (95% CI) 1.07 (0.44; 2.59) (p = 0.882)]. Cardiovascular events occurred in 11 (23%) participants in the control group and 10 (21%) in the NIV group (hazard ratio (95% CI) 0.96 (0.40;2.30), p=0.927). Similar results were observed in the per-protocol analysis [rate ratio (95% CI) 1.21 (0.43;3.41) (p=0.717)]. Death occurred in 9 (19%) participants in both arms (adjusted hazard ratio (95% CI) 1.07 (0.41;2.82), p=0.893). Similar results were found in the per-protocol analysis [rate ratio (95% CI) 1.38 (0.50;3.79) (p=0.529)]. Conclusion: In stable ambulatory patients with OHS without severe OSA, NIV and lifestyle modification had similar long-term hospitalization days-year. Larger studies are necessary to better determine the long-term benefit of NIV in this subgroup of OHS.

Rationale: Obesity hypoventilation syndrome (OHS) has been associated with cardiac dysfunction. However, randomized trials have assessing the impact of long-term noninvasive ventilation (NIV) or CPAP on cardiac structure and function assessed by echocardiography are lacking. Methods: In a pre-specified secondary analysis of the largest multicenter randomized controlled trial of OHS〔Pickwick project, n=221 patient with OHS and coexistent severe obstructive sleep apnea (OSA)〕, we compared the effectiveness of 3 years of NIV and CPAP on structural and functional echocardiographic changes. At baseline and annually during 3 sequential years patients underwent transthoracic two-dimensional and doppler echocardiography. Echocardiographers were blinded to the treatment allocation. Statistical analysis was performed using a linear mixed-effects model with a treatment group/repeated measures interaction to determine the differential effect between CPAP and NIV. Results:196 patients were analyzed, 102 treated with CPAP and 94 treated with NIV. Systolic pulmonary artery pressure decreased from 40.5±1.47 mmHg at baseline to 35.3±1.33 mmHg at 3 years with CPAP and from 41.5±1.56 mmHg to 35.5±1.42 with NIV (p Conclusion: In patients with OHS and concomitant severe OSA, long-term treatment with NIV and CPAP led to similar degrees of improvement in pulmonary hypertension and LVDF.

Rationale: Obesity hypoventilation syndrome (OHS) is commonly treated with noninvasive ventilation (NIV) or CPAP. NIV is more complex and costly but provides ventilatory support. To date there have been no long-term or cost trials comparing these treatment modalities. Methods: We performed a large, randomized, multicenter, open-label controlled trial in Spain to compare the long-term effectiveness of NIV and CPAP using hospitalization days/year-patient as the primary end point. We carried out a simple cost analysis including effectiveness cost during 3 year of follow-up. We included the following cost groups: visits, adjustment of NIV, tests, medication, therapies and hospital resources utilization. A sensitivity analysis was conducted according to 3 different scenarios guided by the International Gross Domestic Product. Results: In total, 215 patients with untreated OHS and severe obstructive sleep apnea (OSA) were randomized to NIV or CPAP therapy and followed at least 3 years. The effectiveness was close between arms (mean difference NIV-CPAP: -0.19, 95% CI -1.13 to 0.75). The cost per patient/year was lower in the CPAP arm (1,898.2€; SD 1939.5) than the cost in the NIV arm (2,809.3€; SD 2901.6), mean difference -911.1€ (p Conclusions: In stable patients with OHS and severe OSA, despite NIV having a slight advantage in effectiveness, CPAP could be considered the first line of treatment due to its lower cost but, a case-by-case assessment is recommended to detect patients who would benefit from a switch to NIV.

Rationale: Obesity hypoventilation syndrome (OHS) is commonly treated with CPAP or noninvasive ventilation (NIV). NIV is more complex and costly but it provides ventilatory support. To date there have been no long-term trials comparing these treatment modalities. Methods: We performed a large, multicenter, open-label controlled trial in Spain to compare the long-term effectiveness of NIV and CPAP: respiratory function, Epworth sleepness scale (ESS), other clinical symptoms, blood pressure (BP) and health related quality of life (HRQL). The analysis was performed according to the intention-to-treat principle. Results: In total, 215 patients with untreated OHS and severe obstructive sleep apnea (OSH) were randomized to NIV or CPAP therapy and followed at least 3 years. PaCO2, bicarbonate and pH improved significantly with both treatments without group differences. FEV1 and FVC improved with positive airway pressure (PAP) but without significant group differences. The 6-MWD test did not improve with either PAP modality and there were no significant group differences. ESS and other clinical symptoms like dyspnea or unrefreshing sleep improved similarly with CPAP and NIV therapy. Both systolic and diastolic BP improved significantly with PAP but without group differences. HRQL tests (SF-36 physical and mental, FOSQ and VAWS) improved with PAP without any significant group differences. Conclusions: In stable patients with OHS and severe OSA, NIV and CPAP have similar long-term effectiveness improving respiratory function, symptoms, BP and HRQL. Given that CPAP has lower complexity and cost, CPAP may be the preferred treatment modality until more studies become available.

Background: Noninvasive ventilation (NIV) and continuous positive airway pressure (CPAP) are the habitual treatments for obesity hypoventilation syndrome (OHS). Despite differences in cost and complexity between them, there are no long-term effectiveness studies comparing both treatments. Objectives: We performed a large multicenter randomized open-labell controlled study to determine the comparative long-term effectiveness of NIV and CPAP using hospitalization days as the primary outcome measure. Methods: Sequentially screened OHS patients with severe sleep apnea were randomized into the above-mentioned arms for at least 3 years of follow-up. Hospital resources utilization, mortality, cardiovascular events incidence, dropouts, compliance and side effects were evaluated. Statistical analysis was performed using intention-to-treat protocol evaluating event/year per patient and incidence by negative binomial, logistic and Cox regressions models and survival analysis. A secundary analysis by compliance subgroups was performed. Results: 215 patients were randomized and 202 were available for primary analysis. The median follow-up was 5.42 years. The hospital days/year was 2.19±5.65 for CPAP and 1.44±3.07 for NIV (adjusted p=0.12). Other hospital resources utilization, cardiovascular events incidence, mortality, dropouts, compliance and side effects were similar between arms. The better compliance subgroup had lower hospital resources utilization and mortality regardless of the treatment used. Conclusion: NIV and CPAP have similar long-term effectiveness. Because CPAP has economical advantages and simplicity, CPAP should be the preferable treatment for OHS patients with severe OSA.

Degradation of high power laser diodes is related to defect formation in the active parts of the laser. Extended defects can develop both at the facets, and inside the cavity. Their characterization is necessary for understanding the mechanisms driving the degradation. Cathodoluminescence is very useful for studying defects in degraded lasers. The main degradation mechanisms are discussed, supported by a thermomechanical model.

Introduction Home respiratory polygraphy (HRP) is a cost-effectiveness choice to polysomnography (PSG) for diagnosis and treatment in patients with high obstructive sleep apnea (OSA) suspicion what includes 40% of patients needing sleep study. There is not randomized control trial (RCT) focus in the same objective including the entire population needing sleep study (intermediate-high OSA suspicion). Objectives Demonstrate if HRP is a non-inferior effective and a cost-effective alternative to PSG for diagnosis and treatment in most OSA suspicion patients. Method A multicentric, non-inferiority RCT included patients with intermediate-to-high OSA suspicion from 8 centers in Spain. Patients were randomized to be managed (diagnosis and treatment decision-marking) according to PSG or HRP results for 6 months of follow-up. Sleep and quality of life questionnaires, ambulatory 24 hours blood pressure monitoring, CPAP compliance, PSG at 6 months and side effects were collected. An Epworth scale inter-group difference less than -2 in the lower bound of 1-side 95% CI was the non-inferiority premise. QALYS changes were used in a Bayesian cost-effectiveness analysis. Results 430 patients were randomized. At 6 months, changes in the Epworth scale, EuroQol, SF36, FOSQ, analogical scale, PSG and blood pressure were similar between groups. Epworth scale non-inferiority premise was -0.24 adjusted by baseline values and sites. In the cost-effectiveness plane, HRP had similar effectiveness (QALYS different -0.0043) and 421€ lower cost than PSG. Conclusion In this large RCT, HRP was a clear cost-effectiveness alternative to PSG for management of most patients with OSA suspicion. Present results can decrease costs and waiting list across countries.

The effects of coupling between clockwise and counterclockwise modes in ring resonators due to back reflections from QPM gratings in nonlinear crystals are investigated. We demonstrate, using simulations, that the non-phase-matched back reflection due to typical imperfections of the QPM grating has a relevant magnitude and can give rise to the coupling. We developed an analytical model and evaluated parameters of a singly resonant OPO in the presence of this coupling, which indicates that the threshold pump power is doubled in the limit of strong coupling. We also evaluated the effect of the coupling with respect to resonant power enhancement for cavity-enhanced nonlinear frequency mixing applications, finding that the enhancement is reduced by up to a factor four. Experimental observations based on PPLN and orientation-patterned GaAs crystals and model predictions are in good agreement. We propose and demonstrate a method for active stabilization of ring resonators with mode coupling that relies on the dissimilarity of the coupled forward and backward modes.

Sleep apnea-hypopnea syndrome (SAHS) is characterized by recurrent episodes of upper airway collapse, which may be complete (apnea) or partial (hypopnea). The direct consequences of upper airway collapse are falls in oxygen saturation levels and arousals, which are, in turn, responsible for excessive daytime sleepiness and neurological and psychiatric disorders.1,2 The prevalence of SAHS has been estimated to be about 4% to 6% in men and 2% to 4% in women.3,4 Underdiagnosis of SAHS is a universal problem5; in Spain, it is estimated that fewer than 10% of cases are diagnosed, and, consequently, treated.6 SAHS is usually diagnosed by polysomnography, although portable respiratory polygraphs may be used for selected patients.5,7-9 Several studies have demonstrated an association between sleep apnea and high blood pressure,4,10-14 cardiovascular and cerebrovascular disease,15-18 and traffic accidents.19-22 Continuous positive airway pressure (CPAP) is considered the treatment of choice for SAHS cases with the most pronounced symptoms,23,24 as it has been shown to improve clinical symptoms (especially daytime sleepiness), quality of life, and the apnea-hypopnea index (AHI),25-29 and also to reduce traffic accidents,30 the frequency of cardiovascular events, and even mortality.18 For all the reasons mentioned, SAHS is considered to be a public health problem of the first order.8,31

Objetivo La demanda de consultas y estudios diagnosticos del sindrome de apneas-hipopneas durante el sueno (SAHS) se ha incrementado, lo que ha llevado a importantes demoras. Por tanto, es precisa una evaluacion actualizada de la situacion del diagnostico que sirva como herramienta de gestion a especialistas y las administraciones sanitarias que tienen la responsabilidad de solventar el problema. El objetivo del presente estudio ha sido realizar un analisis descriptivo de la situacion del diagnostico del SAHS en los hospitales espanoles. Metodos Se ha realizado un estudio descriptivo, observacional y transversal. Se establecio contacto con los centros publicos y privados incluidos en el catalogo de instituciones sanitarias del Ministerio de Sanidad de 2005. Se incluyeron aquellos que evaluaban habitualmente a pacientes con SAHS. El responsable de cada centro relleno un cuestionario sobre disponibilidad de recursos y demoras para el diagnostico. Resultados De los 741 centros con los que se establecio contacto, 217 evaluaban habitualmente a pacientes con SAHS. El 88% disponia de poligrafia respiratoria (PR) (n = 168) o polisomnografia (PSG) (n = 97). La demora media en consulta fue de 61 dias, y la demora media para realizar PR, de 224 dias. La media de equipos de PR fue de 0,99/100.000 habitantes, cuando lo recomendable es 3/100.000. La demora media para PSG fue de 166 dias. La media de camas de PSG fue de 0,49/100.000 habitantes y lo recomendable es 1/100.000. Conclusiones Se observa una notable deficiencia de recursos que lleva a inaceptables listas de espera. Aunque la situacion del diagnostico de SAHS ha cambiado favorablemente con respecto a estudios previos, sigue siendo mejorable y es imprescindible que las autoridades sanitarias dediquen mas recursos a este problema de salud publica.

En este numero de Archivos de Bronconeumologia1 se realiza una revision sobre el papel de las terapias respiratorias cronicas en el sindrome de apnea-hipopnea del sueno (SAHS) y este editorial pretende enfatizar, matizar o ampliar la informacion de algunos aspectos contenidos en la revision. Hoy esta claro que la presion positiva continua en la via aerea (CPAP) obtiene una significativa mejoria clinica en pacientes adultos sintomaticos, pero existen tambien varias incertidumbres: ?Que ocurre en los pacientes poco sintomaticos con alto indice de apneas e hipopneas (IAH)? ?Hay que aumentar las indicaciones y el numero de pacientes a tratar? ?Disminuye la CPAP la mortalidad cardiovascular? ?Es realmente un tratamiento coste-efectivo? En el estudio mas importante sobre la eficacia de la CPAP en pacientes poco sintomaticos2 no se observo disminucion de eventos cardiovasculares, salvo el subgrupo con buen cumplimiento, ocurriendo algo similar en relacion al descenso de la presion arterial3. Por tanto, aunque se necesita mayor evidencia, estos resultados abogan por ampliar las indicaciones de tratamiento con CPAP incluyendo los pacientes con elevado IAH poco sintomaticos, si bien nos obliga a asegurar el cumplimiento. Aunque la CPAP reduce moderadamente la tension arterial en pacientes con SAHS, este no puede considerarse un tratamiento antihipertensivo. Un estudio ha demostrado que el Valsartan disminuye alrededor de 8 veces mas la tension que la CPAP4. A pesar de ello hay evidencia suficiente para afirmar que la CPAP tiene un papel en el control de la hipertension de los pacientes con SAHS y especialmente en pacientes con hipertension refractaria5. El nexo de union mas importante entre el SAHS y la mortalidad cardiovascular debe ser la hipertension, por tanto si la CPAP reduce la tension arterial deberia reducir la mortalidad cardiovascular. Diferentes estudios han mostrado una buena relacion de coste/efectividad considerando el proceso de diagnostico y tratamiento con CPAP o solo este ultimo, estando el ICER (incremental

Objective Overnight polysomnography (PSG) is thegold standard diagnostic tool for sleep apnea-hypopneasyndrome (SAHS) in children. The aim of the present studywas to evaluate the usefulness of diagnostic respiratorypolygraphy in children with clinically suspected SAHSreferred to our sleep-disordered breathing clinic. Patients and Methods We studied 53 children referredwith clinical suspicion of SAHS; 29 (54.7%) were boys andthe mean (SD) age was 6.4 (2.9) years. After a medicalhistory was taken and a physical examination performed, patients underwent respiratory polygraphy (Edentec)simultaneously with overnight PSG in the sleep laboratory. The 2 diagnostic tools were compared using statisticalanalysis. Results SAHS was defined by an obstructive apnea-hypopnea index (OAHI) of 3 or more in overnight PSG anda respiratory disturbance index (RDI) of 3 or more inrespiratory polygraphy. The rate of diagnostic agreementwas 84.9%. The difference between the mean OAHI andRDI values was not significant (0.7 [5.4]; P =.34). Theintraclass correlation coefficient between the OAHI andRDI was 89.4 (95% confidence interval, 82.4-93.7; P When receiver operating characteristic curves werecalculated for the OAHI cutoff points used for the diagnosisof SAHS (1, 3, and 5), the best RDI cutoff for all 3 OAHI valuesconsidered was found to be 4.6. When age strata wereconsidered, in children 6 years or older the best RDI cutofffor the 3 OAHI values was 2.1. In children younger than 6 years the best RDI cutoff was 3.35 for OAHI 1 and 5.85 forOAHI 3 and 5. Conclusions Respiratory polygraphy in the sleeplaboratory is a valid method for the diagnosis of SAHS inchildren.

Objective The demand for consultations and diagnostic studies for sleep apnea-hypopnea syndrome (SAHS) has increased, and this has led to considerable delays. We therefore need an updated evaluation of the diagnostic situation to serve as a management tool for specialists and health care administrations responsible for solving the problem. The objective of the present study was to carry out a descriptive analysis of the situation regarding the diagnosis of SAHS in Spanish hospitals. Methods We undertook a descriptive cross-sectional observational study. Public and private hospitals listed in the Ministry of Health's 2005 catalog of health care institutions were contacted, and those that routinely evaluate patients for SAHS were included in the study. The person in charge of each hospital filled in a questionnaire concerning the availability of resources and waiting periods for diagnosis. Results Of the 741 hospitals we contacted, 217 routinely evaluated patients for SAHS. In 88% of these, respiratory polygraphy (RP) (n=168) or polysomnography (PSG) (n=97) was available. The mean waiting period was 61 days for consultation and 224 days for RP. The mean number of RP devices was 0.99 per 100 000 inhabitants, while the recommended number is 3 per 100 000 inhabitants. The mean waiting period for PSG was 166 days. The mean number of PSG beds was 0.49 per 100 000 inhabitants, while the recommended number is 1 per 100 000. Conclusions We observed a marked inadequacy of resources that has led to unacceptable waiting periods. While there has been a favorable change in the situation regarding SAHS diagnosis compared to previous studies, there is still room for improvement and it is urgent that health care authorities allocate more resources to this public health problem.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

The influence of the quantum well (QW) interfaces with the barrier layers on the rapid degradation of AlGaAs based high power laser bars (808 nm) is investigated. Thermal stresses induced in the device by the local heating produced by nonradiative recombination areas at the facet mirror are calculated by means of a thermomechanical model. Results show that the laser power density threshold necessary to achieve the plastic deformation, leading to the generation of dislocations and to the failure of these devices, is reduced as the quality of the QW interfaces worsens in terms of thermal boundary resistance.

Raman spectroscopy provides nondestructive information about nanoscaled semiconductors by modeling the phonon confinement effect. However, the Raman spectrum is also sensitive to the temperature, which can mix with the size effects borrowing the interpretation of the Raman spectrum. We present an analysis of the Raman spectra of Si nanowires (NWs). The influence of the excitation conditions and the temperature increase in the NWs are discussed. The interpretation of the data is supported by the calculation of the temperature inside the NWs with different diameters.

A thermomechanical model for the mechanism of rapid degradation of AlGaAs based high power laser bars (808 nm) is presented. Thermal stresses induced in the device by local heating around a facet defect by nonradiative recombination and self-absorption of photons are calculated, as well as the conditions for the beginning of plastic deformation, when these thermal stresses overcome the yield strength. The values of the power density and of the local temperature at which the yield limit is surmounted are in agreement with the threshold values for the degradation of Al based lasers given in the literature. The present model can also elucidate the role played by the packaging stress, being able to explain how this stress reduces the optical power density threshold for failure of these lasers.