The effect of longitudinal sleep monitoring on clinician agreement in obstructive sleep apnea diagnosis: The ELSA study

There is strong evidence for clinically relevant night-to-night variability of respiratory events in patients with suspected obstructive sleep apnea. Sleep experts retrospectively evaluated diagnostic data in 56 patients with suspected obstructive sleep apnea. Experts were blinded to the fact that they were diagnosing the same case twice, once based on a short report of a single in-laboratory respiratory polygraphy and once with the additional information of 14 nights of pulse oximetry at home. All experts (n = 22) were highly qualified, 13 experts (59.1%) treated > 100 patients with suspected obstructive sleep apnea per year. In 12 patients, the apnea-hypopnea index in the respiratory polygraphy was < 5 per hr, but the mean oxygen desaturation index of 14 nights of pulse oximetry was ≥ 5 per hr. The additional information of 14 nights of pulse oximetry helped to diagnose obstructive sleep apnea with a 70% consensus in two of those patients (16.7% [95% confidence interval: 4.7/44.8]). In eight patients, experts could not agree to a 70% consensus regarding continuous positive airway pressure therapy recommendation after respiratory polygraphy. The additional information of multiple-night testing led to a consensus in three of those cases (37.5% [95% confidence interval: 14/69]). Change of obstructive sleep apnea diagnosis and continuous positive airway pressure recommendation was significantly negatively associated with the number of treated obstructive sleep apnea patients > 100 per year compared with 0-29 patients per year (Coef. [95% confidence interval] -0.63 [-1.22/-0.04] and -0.61 [-1.07/-0.15], respectively). Experts found already a high level of consensus regarding obstructive sleep apnea diagnosis, severity and continuous positive airway pressure recommendation after a single respiratory polygraphy. However, longitudinal sleep monitoring could help increase consensus in selected patients with diagnostic uncertainty.

Successful hemostatic radiotherapy for massive airway bleeding from infectious pulmonary cavity: a case report

We present a patient with life-threatening airway bleeding from an infectious pulmonary cavity with limited treatment options. Bronchial artery embolization was unsuccessful. Surgery was not feasible due to compromised lung function. Lung transplant was considered but not endorsed. Palliative hemostatic radiotherapy with 20 Gy in 5 fractions was delivered to the site of bleeding as a last resort. Hemoptysis gradually disappeared within a month and did not recur during the 4‑month follow-up. There were no side effects. We highlight the potential of radiotherapy for massive hemoptysis of infectious etiology, especially in cases with exhausted standard treatment options.

[Surgical or bronchoscopic lung volume reduction for emphysema therapy]

More than 20 years ago, surgical lung volume reduction (LVRS) was already established in patients with advanced emphysema as a palliative therapy option that reduces respiratory distress and improves lung function and quality of life. In addition, bronchoscopic procedures (BLVR) aimed at volume reduction have existed for just over 10 years. The advantages and disadvantages of LVRS and BLVR are discussed in this article.

Improved glucose tolerance after initiation of Elexacaftor / Tezacaftor / Ivacaftor in adults with cystic fibrosis

BACKGROUND

The novel triple CFTR modulator therapy Elexacaftor/Tezacaftor/Ivacaftor (ELX/TEZ/IVA) improves lung function, body mass index (BMI), sinus clearance, and quality of life in patients with cystic fibrosis. Whether treatment with ELX/TEZ/IVA is associated with improved glucose tolerance is unknown.

METHODS

This cohort study included adults with CF and at least one copy of F508del.. Study assessments before treatment and at least 3 months after ELX/TEZ/IVA initiation included an oral glucose tolerance test (OGTT) with glucose and insulin measurements, BMI, lung function test, and sweat chloride levels. We used an analysis of response profiles to calculate changes in outcomes.

RESULTS

33 patients (27.8 ± 6.3 years; 73% male; 64% F508del homozygous) were included. After a median of 184 [IQR, 107 - 278] days following treatment initiation 16 (48.5%) patients improved their glucose tolerance category, while 13 (39.4%) remained unchanged and 4 (12.1%) deteriorated. Overall, 60, 90 and 120 min OGTT glycemia decreased significantly from 11.9 ± 2.7 mmol/l to 10.6 ± 2.8 mmol/l (p = 0.012), 10.4 ± 3.0 mmol/l to 8.4 ± 3.6 mmol/l (p = 0.002) and 7.3 ± 3.1 mmol/l to 5.7 ± 3.0 mmol/l (p = 0.012). HbA1c levels also improved significantly, from 5.50±0.24% to 5.39±0.25% (p = 0.039).

CONCLUSION

In adult patients with CF and at least one copy of F508del, treatment with the triple CFTR modulator was associated with possible improvement of glucose tolerance without increases of insulin secretion. Early initiation of treatment as assessed through long-term prospective trials is mandatory to demonstrate if decreased glucose control is preventable or even reversible.

Partial Pressure of Arterial Oxygen in Healthy Adults at High Altitudes: A Systematic Review and Meta-Analysis

Importance

With increasing altitude, the partial pressure of inspired oxygen decreases and, consequently, the Pao2 decreases. Even though this phenomenon is well known, the extent of the reduction as a function of altitude remains unknown.

Objective

To calculate an effect size estimate for the decrease in Pao2 with each kilometer of vertical gain among healthy unacclimatized adults and to identify factors associated with Pao2 at high altitude (HA).

Data Sources

A systematic search of PubMed and Embase was performed from database inception to April 11, 2023. Search terms included arterial blood gases and altitude.

Study Selection

A total of 53 peer-reviewed prospective studies in healthy adults providing results of arterial blood gas analysis at low altitude (<1500 m) and within the first 3 days at the target altitude (≥1500 m) were analyzed.

Data Extraction and Synthesis

Primary and secondary outcomes as well as study characteristics were extracted from the included studies, and individual participant data (IPD) were requested. Estimates were pooled using a random-effects DerSimonian-Laird model for the meta-analysis.

Main Outcomes and Measures

Mean effect size estimates and 95% CIs for reduction in Pao2 at HA and factors associated with Pao2 at HA in healthy adults.

Results

All of the 53 studies involving 777 adults (mean [SD] age, 36.2 [10.5] years; 510 men [65.6%]) reporting 115 group ascents to altitudes between 1524 m and 8730 m were included in the aggregated data analysis; 13 of those studies involving 305 individuals (mean [SD] age, 39.8 [13.6] years; 185 men [60.7%]) reporting 29 ascents were included in the IPD analysis. The estimated effect size of Pao2 was -1.60 kPa (95% CI, -1.73 to -1.47 kPa) for each 1000 m of altitude gain (τ2 = 0.14; I2 = 86%). The Pao2 estimation model based on IPD data revealed that target altitude (-1.53 kPa per 1000 m; 95% CI, -1.63 to -1.42 kPa per 1000 m), age (-0.01 kPa per year; 95% CI, -0.02 to -0.003 kPa per year), and time spent at an altitude of 1500 m or higher (0.16 kPa per day; 95% CI, 0.11-0.21 kPa per day) were significantly associated with Pao2.

Conclusions and Relevance

In this systematic review and meta-analysis, the mean decrease in Pao2 was 1.60 kPa per 1000 m of vertical ascent. This effect size estimate may improve the understanding of physiological mechanisms, assist in the clinical interpretation of acute altitude illness in healthy individuals, and serve as a reference for physicians counseling patients with cardiorespiratory disease who are traveling to HA regions.

One-Lung Ventilation during Rigid Bronchoscopy Using a Single-Lumen Endotracheal Tube: A Descriptive, Retrospective Single-Center Study

Using one-lung ventilation (OLV) through a single-lumen endotracheal tube (SLT) in the untreated lung during rigid bronchoscopy (RB) and jet ventilation, high oxygenation can be guaranteed, whilst procedures requiring thermal energy in the other lung are still able to be used. This pilot study aimed to examine the bronchoscopy-associated risks and feasibility of OLV using an SLT during RB in patients with malignant airway stenosis. All consecutive adult patients with endobronchial malignant lesions receiving OLV during RB from 1 January 2017 to 12 May 2021 were included. We assessed perioperative complications in 25 RBs requiring OLV. Bleeding grades 1, 2, and 3 complicated the procedure in two (8%), five (20%), and five (20%) patients, respectively. The median saturation of peripheral oxygen remained at 94% (p = 0.09), whilst the median oxygen supply did not increase significantly from 0 L/min to 2 L/min (p = 0.10) within three days after the bronchoscopy. The 30-day survival rate of the patients was 79.1% (95% CI 58.4-91.1%), all of whom reported an improvement in subjective well-being after the bronchoscopy. OLV using an SLT during RB could be a new treatment approach for endobronchial ablative procedures without increasing bronchoscopy-associated risks, allowing concurrent high-energy treatments.

Severe Obstructive Sleep Apnea Disrupts Vigilance-State-Dependent Metabolism

The direct pathophysiological effects of obstructive sleep apnea (OSA) have been well described. However, the systemic and metabolic consequences of OSA are less well understood. The aim of this secondary analysis was to translate recent findings in healthy subjects on vigilance-state-dependent metabolism into the context of OSA patients and answer the question of how symptomatic OSA influences metabolism and whether these changes might explain metabolic and cardiovascular consequences of OSA. Patients with suspected OSA were assigned according to their oxygen desaturation index (ODI) and Epworth Sleepiness Scale (ESS) score into symptomatic OSA and controls. Vigilance-state-dependent breath metabolites assessed by high-resolution mass spectrometry were used to test for a difference in both groups. In total, 44 patients were eligible, of whom 18 (40.9%) were assigned to the symptomatic OSA group. Symptomatic OSA patients with a median [25%, 75% quartiles] ODI of 40.5 [35.0, 58.8] events/h and an ESS of 14.0 [11.2, 15.8] showed moderate to strong evidence for differences in 18 vigilance-state-dependent breath compounds compared to controls. These identified metabolites are part of major metabolic pathways in carbohydrate, amino acid, and lipid metabolism. Thus, beyond hypoxia per se, we hypothesize that disturbed sleep in OSA patients persists as disturbed sleep-dependent metabolite levels during daytime.

Mortality Related to Chronic Obstructive Pulmonary Disease during the COVID-19 Pandemic: An Analysis of Multiple Causes of Death through Different Epidemic Waves in Veneto, Italy

Mortality related to chronic obstructive pulmonary disease (COPD) during the COVID-19 pandemic is possibly underestimated by sparse available data. The study aimed to assess the impact of the pandemic on COPD-related mortality by means of time series analyses of causes of death data. We analyzed the death certificates of residents in Veneto (Italy) aged ≥40 years from 2008 to 2020. The age-standardized rates were computed for COPD as the underlying cause of death (UCOD) and as any mention in death certificates (multiple cause of death-MCOD). The annual percent change (APC) in the rates was estimated for the pre-pandemic period. Excess COPD-related mortality in 2020 was estimated by means of Seasonal Autoregressive Integrated Moving Average models. Overall, COPD was mentioned in 7.2% (43,780) of all deaths. From 2008 to 2019, the APC for COPD-related mortality was -4.9% (95% CI -5.5%, -4.2%) in men and -3.1% in women (95% CI -3.8%, -2.5%). In 2020 compared to the 2018-2019 average, the number of deaths from COPD (UCOD) declined by 8%, while COPD-related deaths (MCOD) increased by 14% (95% CI 10-18%), with peaks corresponding to the COVID-19 epidemic waves. Time series analyses confirmed that in 2020, COPD-related mortality increased by 16%. Patients with COPD experienced significant excess mortality during the first year of the pandemic. The decline in COPD mortality as the UCOD is explained by COVID-19 acting as a competing cause, highlighting how an MCOD approach is needed.

Rapid and reversible control of human metabolism by individual sleep states

Sleep is crucial to restore body functions and metabolism across nearly all tissues and cells, and sleep restriction is linked to various metabolic dysfunctions in humans. Using exhaled breath analysis by secondary electrospray ionization high-resolution mass spectrometry, we measured the human exhaled metabolome at 10-s resolution across a night of sleep in combination with conventional polysomnography. Our subsequent analysis of almost 2,000 metabolite features demonstrates rapid, reversible control of major metabolic pathways by the individual vigilance states. Within this framework, whereas a switch to wake reduces fatty acid oxidation, a switch to slow-wave sleep increases it, and the transition to rapid eye movement sleep results in elevation of tricarboxylic acid (TCA) cycle intermediates. Thus, in addition to daily regulation of metabolism, there exists a surprising and complex underlying orchestration across sleep and wake. Both likely play an important role in optimizing metabolic circuits for human performance and health.

BAY 2253651 for the treatment of obstructive sleep apnea: a multi-center, double-blind, randomized controlled trial (SANDMAN)

For obstructive sleep apnoea (OSA), few mechanical treatment options are available and no pharmacotherapy is approved [1–3]. However, safe and efficacious pharmacotherapy would have substantial appeal for many people with OSA.

BAY 2253651 is a nasally applied genioglossus muscle activator via pharyngeal mucosal receptor stimulation (potassium channel blocker) aimed to treat obstructive sleep apnoea. Although well-tolerated and safe, there was no significant therapeutic effect.https://bit.ly/3zDbyia

[CME/Antworten: Nacht-zu-Nacht-Variabilität der obstruktiven Schlafapnoe]

According to current recommendations, the diagnosis of obstructive sleep apnea (OSA) is established by a single-night sleep study. However, recent reports suggest a remarkable night-to-night variability of OSA severity. We report on a 76-year-old man with suspected OSA who underwent six sleep studies within 13 months. Sleep studies demonstrated a remarkable variability of respiratory events based on an apnea-hypopnea index (AHI) varying between 1.1 and 43.1/h. There were no changes in body weight, alcohol intake, medication or comorbidities during the evaluation period. Due to diagnostic uncertainty and missing subjective benefit, the initially implemented CPAP therapy was stopped after one year of therapy. Considering night-to-night variability of OSA severity, single-night sleep studies might not be accurate enough in order to reliably diagnose or exclude OSA.

The Swiss Prison Study (SWIPS): Protocol for Establishing a Public Health Registry of Prisoners in Switzerland

Background

The health aspects, disease frequencies, and specific health interests of prisoners and refugees are poorly understood. Importantly, access to the health care system is limited for this vulnerable population. There has been no systematic investigation to understand the health issues of inmates in Switzerland. Furthermore, little is known on how recent migration flows in Europe may have affected the health conditions of inmates.

Objective

The Swiss Prison Study (SWIPS) is a large-scale observational study with the aim of establishing a public health registry in northern-central Switzerland. The primary objective is to establish a central database to assess disease prevalence (ie, International Classification of Diseases-10 codes [German modification]) among prisoners. The secondary objectives include the following: (1) to compare the 2015 versus 2020 disease prevalence among inmates against a representative sample from the local resident population, (2) to assess longitudinal changes in disease prevalence from 2015 to 2020 by using cross-sectional medical records from all inmates at the Police Prison Zurich, Switzerland, and (3) to identify unrecognized health problems to prepare successful public health strategies.

Methods

Demographic and health-related data such as age, sex, country of origin, duration of imprisonment, medication (including the drug name, brand, dosage, and release), and medical history (including the International Classification of Diseases-10 codes [German modification] for all diagnoses and external results that are part of the medical history in the prison) have been deposited in a central register over a span of 5 years (January 2015 to August 2020). The final cohort is expected to comprise approximately 50,000 to 60,000 prisoners from the Police Prison Zurich, Switzerland.

Results

This study was approved on August 5, 2019 by the ethical committee of the Canton of Zurich with the registration code KEK-ZH No. 2019-01055 and funded in August 2020 by the “Walter and Gertrud Siegenthaler” foundation and the “Theodor and Ida Herzog-Egli” foundation. This study is registered with the International Standard Randomized Controlled Trial Number registry. Data collection started in August 2019 and results are expected to be published in 2021. Findings will be disseminated through scientific papers as well as presentations and public events.

Conclusions

This study will construct a valuable database of information regarding the health of inmates and refugees in Swiss prisons and will act as groundwork for future interventions in this vulnerable population.

Trial Registration

ISRCTN registry ISRCTN11714665; http://www.isrctn.com/ISRCTN11714665

International Registered Report Identifier (IRRID)

DERR1-10.2196/23973

Obstructive sleep apnoea and the progression of thoracic aortic aneurysm: a prospective cohort study

BACKGROUND

Obstructive sleep apnoea (OSA) is associated with an increased prevalence of aortic aneurysms and it has also been suggested that severe OSA furthers aneurysm expansion in the abdomen. We evaluated whether OSA is a risk factor for the progression of ascending thoracic aortic aneurysm (TAA).

METHODS

Patients with TAA underwent yearly standardised echocardiographic measurements of the ascending aorta over 3 years and two level III sleep studies. The primary outcome was the expansion rate of TAA in relation to the apnoea-hypopnoea index (AHI). Secondary outcomes included surveillance for aortic events (composite end-points of rupture/dissection, elective surgery or death).

RESULTS

Between July 2014 and March 2020, 230 patients (median age 70 years, 83.5% male) participated in the cohort. At baseline, 34.8% of patients had AHI ≥15 events·h^-1. There was no association between TAA diameter and AHI at baseline. After 3 years, mean±sd expansion rates were 0.55±1.25 mm at the aortic sinus and 0.60±1.12 mm at the ascending aorta. In the regression analysis, after controlling for baseline diameter and cardiovascular risk factors, there was strong evidence for a positive association of TAA expansion with AHI (aortic sinus estimate 0.025 mm, 95% CI 0.009-0.040 mm; p<0.001 and ascending aorta estimate 0.026 mm, 95% CI 0.011-0.041 mm; p=0.001). 20 participants (8%) experienced an aortic event; however, there was no association with OSA severity.

CONCLUSION

OSA may be a modest but independent risk factor for faster TAA expansion and thus potentially contributes to life-threatening complications in aortic disease.

Increased augmentation index in patients with Ehlers-Danlos syndrome

Background

Ehlers-Danlos Syndrome (EDS) comprises a heterogeneous group of diseases characterized by joint hypermobility, connective tissue friability, and vascular fragility. Reliable prognostic factors predicting vascular disease progression (e.g. arterial aneurysms, dissections, and ruptures) in EDS patients are still missing. Recently, applanation tonometry derived augmentation index (AIx), an indirect marker of arterial stiffness, has shown to be positively associated with progression of aortic disease in Marfan syndrome. In this study, we assessed aortic AIx in patients with EDS and matched healthy controls.

Methods

We performed noninvasive applanation tonometry in 61 adults with EDS (43 women and 18 men aged 39.3 ± 14.6 years) and 61 age-, gender-, height-, and weight-matched healthy controls. Radial artery pulse waveforms were recorded and analyzed using the SphygmoCor System (AtCor Medical, Sydney, NSW, Australia). Calculated AIx was adjusted to a heart rate of 75/min. Groups were compared and association between AIx and EDS was determined by univariate and multivariate regression analysis.

Results

EDS patients were categorized in classical type EDS (34%), hypermobile type EDS (43%), vascular type EDS (5%), or remained unassignable (18%) due to overlapping features. EDS patients showed a significantly increased aortic AIx compared to healthy controls (22.8% ± 10.1 vs 14.8% ± 14.0, p < 0.001). EDS showed a positive association with AIx; independent of age, sex, height, blood pressure, medication, and pack years of smoking.

Conclusions

Patients with EDS showed elevated AIx, indicating increased arterial stiffness when compared to healthy controls. Further investigations are needed in order to assess the prognostic value of increased AIx for cardiovascular outcomes in patients with EDS.

Patterns of nightly CPAP usage in OSA patients with suboptimal treatment adherence

BACKGROUND AND OBJECTIVES

Low adherence impairs the effectiveness of continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnoea (OSA), but knowledge on CPAP usage micro-patterns is mostly lacking. Thus, the aim of this study was to analyse usage micro-patterns among patients with suboptimal CPAP adherence.

METHODS

We analysed CPAP usage datasets comprising the initial 31 nights of therapy. By employing a threshold of 4 h usage in at least 70% of nights, we subdivided the patients into suboptimal and optimal users. We investigated single CPAP start- and stop-points, and introduced the parameter "interruption-rate", by dividing the amount of therapy interruptions per night by the usage duration per night. This parameter represents the amount of interruptions per 1 h of CPAP usage. Group comparison analysis was performed via t-test, Wilcoxon rank sum-test, and via Chi²-test.

RESULTS

We included datasets of 48 suboptimal and 48 optimal users (55.9 ± 11.3 years, 83.3% men) in the analysis. Interruption-rate was significantly higher among suboptimal users, when compared with optimal users (median (quartiles) 0.24 (0.14/0.45) versus 0.15 (0.05/0.28), p < 0.001∗). Suboptimal users were more likely to report that CPAP reduced their sleep quality, waked them up at night, and that CPAP side effects or problems with the device impaired their adherence.

CONCLUSIONS

CPAP usage micro-patterns are more fragmented among OSA patients with lower overall adherence. These patterns might result from impaired sleep quality, due to CPAP side effects, and device-associated problems.

Night-to-night variability of respiratory events in obstructive sleep apnoea: a systematic review and meta-analysis

Background

It is current practice to use a single diagnostic sleep study in the diagnostic workup of obstructive sleep apnoea (OSA). However, a relevant night-to-night variability (NtNV) of respiratory events has been reported.

Methods

We evaluated the NtNV of respiratory events in adults with suspected or already diagnosed OSA who underwent more than one diagnostic sleep study. Data sources were PubMed, Cochrane and Embase up to 23 January 2019. Random-effects models were used for evidence synthesis. For moderator analysis, mixed-effects regression analysis was performed. The study was registered with PROSPERO (CRD42019135277).

Results

Of 2143 identified papers, 24 studies, comprising 3250 participants, were included. The mean Apnoea-Hypopnoea Index (AHI) difference between the first and second night was −1.70/hour (95% CI −3.61 to 0.02). REM time differences (first to second night) were significantly positive associated with differences in mean AHI (β coefficient 0.262 (95% CI 0.096 to 0.428). On average, 41% (95% CI 27% to 57%) of all participants showed changes of respiratory events >10/hour from night to night. Furthermore, 49% (95% CI 32% to 65%) of participants changed OSA severity class (severity thresholds at 5/hour, 15/hour and 30/hour) at least once in sequential sleep studies. Depending on the diagnostic threshold (5/hour, 10/hour or 15/hour), on average 12% (95% CI 9% to 15%), 12% (95% CI 8% to 19%) and 10% (95% CI 8% to 13%) of patients would have been missed during the first night due to single night testing.

Conclusion

While there was no significant difference between mean AHI in two sequential study nights on a group level, there was a remarkable intraindividual NtNV of respiratory events, leading to misdiagnosis and misclassification of patients with suspected OSA.

Low repeatability of Epworth Sleepiness Scale after short intervals in a sleep clinic population

STUDY OBJECTIVES

The purpose of this study was to evaluate the short-term repeatability of the Epworth Sleepiness Scale (ESS) in patients with suspected obstructive sleep apnea and to determine whether transitory sleepiness of the patient influenced ESS results.

METHODS

Adult participants with suspected obstructive sleep apnea taking part in a study on the diagnostic accuracy of repeated sleep studies were eligible. For assessment of repeatability, the agreement between 2 sequential ESS scores obtained within 1 day (same-day group) or on different days within 1 week (same-week group) was evaluated. By analyzing the within-day repeatability, a possible influence of situational sleepiness on ESS results was assessed. By comparing correlations of sequential scores between both groups, a potential influence of test day-specific sleepiness on ESS results was evaluated. Data were analyzed using Bland-Altman plots, intraclass correlation coefficients, standard error of measurement analysis, and relative amounts of ESS discrepancies beyond 2, 3, 5, and 7 points.

RESULTS

Forty participants (mean age, 47.7 ± 15.4 years; 67.5% men) were included in this study, with 20 in each group. Bland-Altman analysis demonstrated considerable variability of repeated scores (mean ± 1.96 × SD = 1.93 [-3.81 to 7.66]). Discrepancies of at least 3 points between sequential ESS scores were found in 48% of all participants. Comparison of ESS repeatability between both groups showed no evidence for a difference.

CONCLUSIONS

A clinically relevant variability in ESS scores was found, even when repeated on the same day, possibly because of situational sleepiness influencing ESS results. Changes in ESS in response to interventions should be interpreted with caution because of its low test-retest reliability.

[CME: Nacht-zu-Nacht-Variabilität der obstruktiven Schlafapnoe]

Die aktuellen Leitlinien empfehlen, unkomplizierte Patientinnen und Patienten mit Verdacht auf obstruktive Schlafapnoe (OSA) mittels einer einzigen Schlafuntersuchung zu diagnostizieren. Eine kürzlich veröffentlichte Meta-Analyse konnte hingegen eine ausgeprägte intra-individuelle Variabilität respiratorischer Parameter von Nacht zu Nacht zeigen. Wir präsentieren den Fall eines 76-jährigen Patienten mit Verdacht auf OSA, der innerhalb von 13 Wochen sechs Schlafuntersuchungen unterzogen wurde. Hierbei präsentierte sich eine relevante Variabilität des AHI zwischen 1,1 und 43,1/h. Es konnten keine relevanten Unterschiede betreffend Gewicht, Alkoholkonsum, Medikation und Begleiterkrankungen zwischen den Schlafuntersuchungen festgestellt werden. Aufgrund fehlender subjektiver Wirksamkeit wurde die CPAP-Therapie nach einem Jahr gestoppt. Die ausgeprägte Nacht-zu-Nacht-Variabilität respiratorischer Parameter stellt eine akkurate OSA-Diagnostik mittels einer einzelnen Schlafuntersuchung in Frage.

[An Uncommon Cause of Arterial Hypertension]

An Uncommon Cause of Arterial Hypertension Abstract. A 54-year-old patient was suffering from arterial hypertension, which was not treated sufficiently despite an antihypertensive therapy with three different types of drugs. In addition, the patient complained an increase in weight of ten kilos during the last year and a new onset of diabetes mellitus type 2. Investigations as to secondary forms of hypertension by MRI revealed an adrenal tumor with a diameter of approx. 6 cm suspect for an adrenal carcinoma. An ACTH-independent cushing syndrome was diagnosed by 24-hour urines collection, 1-mg dexamethasone supression test, and midnight-cortisol measurement. After a laparoscopic tumor excision, histopathological analyses confirmed an adrenal carcinoma.

[CME: Obstructive Sleep Apnea: A Common Disease]

CME: Obstructive Sleep Apnea: A Common Disease Abstract. Obstructive sleep apnea is a common sleep related breathing disorder with a collapse of the upper respiratory tract, leading to repetitive oxygen desaturations and 'micro arousals'. If the physiological sleep architecture is impaired, patients are at risk for an increased daytime sleepiness and an increased blood pressure. Main risk factors are central obesity, age, male sex, (and snoring). By means of weight loss, alcohol restriction, and continuous nocturnal positive pressure ventilation (CPAP), the obstructive sleep apnea syndrome can be treated, with mandibular advancement devices representing a second-choice therapy.

Effects of suboptimal adherence of CPAP therapy on symptoms of obstructive sleep apnoea: a randomised, double-blind, controlled trial

Introduction

Continuous positive airway pressure (CPAP) is currently the treatment of choice for sleepiness in patients with obstructive sleep apnoea (OSA); however, adherence is often thought to be suboptimal. We investigated the effects of suboptimal CPAP usage on objective and subjective sleepiness parameters in patients with OSA.

Material and methods

In this 2-week, parallel, double-blind, randomised controlled trial we enrolled moderate-to-severe OSA patients with excessive pre-treatment daytime sleepiness (Epworth sleepiness scale (ESS) score >10 points) who had suboptimal CPAP adherence over ≥12 months (mean nightly usage time 3–4 h). Patients were allocated through minimisation to either subtherapeutic CPAP (“sham CPAP”) or continuation of CPAP (“therapeutic CPAP”). A Bayesian analysis with historical priors calculated the posterior probability of superiority.

Results

Between May, 2016 and November, 2018, 57 patients (aged 60±8 years, 79% male, 93% Caucasian) were allocated in total, and 52 who completed the study (50% in each arm) were included in the final analysis. The unadjusted ESS score increase was 2.4 points (95% CI 0.6–4.2, p=0.01) in the sham-CPAP group when compared to continuing therapeutic CPAP. The probability of superiority of therapeutic CPAP over sham CPAP was 90.4% for ESS, 90.1% for systolic blood pressure and 80.3% for diastolic blood pressure.

Conclusions

Patients with moderate-to-severe OSA and daytime sleepiness are still getting a substantial benefit from suboptimal CPAP adherence, albeit not as much as they might get if they adhered more. Whether a similar statement can be made for even lower adherence levels remains to be established in future trials.

Prevalence of Obstructive Sleep Apnea in Patients with Thoracic Aortic Aneurysm: A Prospective, Parallel Cohort Study

BACKGROUND

The pathogenesis and etiology of thoracic aortic aneurysms (TAA) are largely unknown. Preliminary data from patients with aortic dissection and abdominal aneurysms suggest a causal link of obstructive sleep apnea (OSA) on aortic disease.

OBJECTIVES

The aim of the study was to assess the prevalence of OSA in patients with TAA compared to a matched control group.

METHOD

In this prospective parallel-cohort study, we 2-to-1 matched 208 patients with verified TAA (at the aortic sinus and/or ascending aorta) to 104 controls without TAA according to sex, age, height, weight, and left ventricular ejection fraction. All participants underwent an ultrasound of the thoracic aorta and a level III respiratory polygraphy. OSA was defined as apnea-hypopnea index ≥5/h. The prevalence of OSA was compared with conditional logistic regression and controlling for the matching variables.

RESULTS

A total of 312 patients (mean age 65 ± 11 years, 82% male, mean body mass index 27 ± 4 kg/m2) were successfully 2-to-1 matched in the final model. Prevalence of OSA was significantly higher in the TAA-group when compared to the matched control group (63 vs. 47%; odds ratio 1.87 [95% CI 1.05-3.34]; p = 0.03). When applying a higher apnea-hypopnea index threshold (≥15/h), the odds ratio increased to 3.25 (95% CI 1.65-6.42; p < 0.001). The median apnea-hypopnea index was higher in patients with TAA (9.2/h [3.3-20.0] vs. 4.5/h [2.2-11.1], p < 0.001).

CONCLUSIONS

Patients with TAA have a higher prevalence of OSA when compared to the general population. Since OSA is effectively treatable and might contribute to the pathogenesis of TAA, further longitudinal trials are needed to assess the association between OSA and TAA.

Impact of hypertension on cerebral microvascular structure in CPAP-treated obstructive sleep apnoea patients: a diffusion magnetic resonance imaging study

PURPOSE

Obstructive sleep apnoea (OSA) is a highly prevalent sleep-related breathing disorder associated with hypertension, impaired peripheral vascular function and an increased risk of stroke. Evidence suggests that abnormalities of the cerebral microcirculation, such as capillary rarefication, may be present in these patients. We evaluated whether the presence of hypertension may affect the cerebral capillary architecture and function assessed by Intravoxel Incoherent Motion (IVIM) magnetic resonance imaging (MRI) in patients with continuous positive airway pressure (CPAP)-treated OSA.

METHODS

Forty-one patients (88% male, mean age 57 ± 10 years) with moderate-to-severe OSA were selected and divided into two groups (normotensive vs. hypertensive). All hypertensive OSA patients were adherent with their antihypertensive medication. Cerebral microvascular structure was assessed in grey (GM) and white matter (WM) using an echo-planar diffusion imaging sequence with 14 different b values. A step-wise IVIM analysis algorithm was applied to compute true diffusion (D), perfusion fraction (f) and pseudo-diffusion (D*) values. Group comparisons were performed with the Wilcoxon-Mann-Whitney-Test. Regression analysis was adjusted for age.

RESULTS

Diffusion- and perfusion-related indexes in middle-aged OSA normotensive patients were quantified in both tissue types (D [10^-3 mm²/s]: GM = 0.83 ± 0.03; WM = 0.72 ± 0.03; f (%) GM = 0.09 ± 0.01; WM = 0.06 ± 0.01; D* [10^-3 mm²/s]: GM = 7.72 ± 0.89; WM = 7.38 ± 0.98). In the examined tissue types, hypertension did not result in changes on the estimated MRI IVIM index values.

CONCLUSION

Based on IVIM analysis, cerebral microvascular structure and function showed no difference between hypertensive and normotensive patients with moderate-to-severe OSA treated with CPAP. Treatment adherence with antihypertensive drug regime and, in turn, controlled hypertension seems not to affect microvascular structure and perfusion of the brain.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02493673.

Endocrine responses during CPAP withdrawal in obstructive sleep apnoea: data from two randomised controlled trials

The aim of this investigation was to elucidate the effect of CPAP withdrawal on neurometabolic and cardiometabolic markers in patients with obstructive sleep apnoea. We evaluated 70 patients (mean age 61±10 years, 82% men) treated with CPAP in two 2-week, parallel, randomised controlled trials. CPAP withdrawal resulted in elevated 3,4-dihydroxyphenylglycol, norepinephrine and cortisol after 2 weeks of CPAP withdrawal; however, no statistically significant changes of the renin-angiotensin-aldosterone system (RAAS) determinants were documented. In summary, CPAP withdrawal may be more prominently linked to short-term increases in sympathetic activation than hypothalamic-pituitary-adrenal axis or RAAS activation. ClinicalTrials.gov Identifier: NCT02493673 and NCT02050425.

On-Line Analysis of Exhaled Breath Focus Review

On-line analysis of exhaled breath offers insight into a person's metabolism without the need for sample preparation or sample collection. Due to its noninvasive nature and the possibility to sample continuously, the analysis of breath has great clinical potential. The unique features of this technology make it an attractive candidate for applications in medicine, beyond the task of diagnosis. We review the current methodologies for on-line breath analysis, discuss current and future applications, and critically evaluate challenges and pitfalls such as the need for standardization. Special emphasis is given to the use of the technology in diagnosing respiratory diseases, potential niche applications, and the promise of breath analysis for personalized medicine. The analytical methodologies used range from very small and low-cost chemical sensors, which are ideal for continuous monitoring of disease status, to optical spectroscopy and state-of-the-art, high-resolution mass spectrometry. The latter can be utilized for untargeted analysis of exhaled breath, with the capability to identify hitherto unknown molecules. The interpretation of the resulting big data sets is complex and often constrained due to a limited number of participants. Even larger data sets will be needed for assessing reproducibility and for validation of biomarker candidates. In addition, molecular structures and quantification of compounds are generally not easily available from on-line measurements and require complementary measurements, for example, a separation method coupled to mass spectrometry. Furthermore, a lack of standardization still hampers the application of the technique to screen larger cohorts of patients. This review summarizes the present status and continuous improvements of the principal on-line breath analysis methods and evaluates obstacles for their wider application.

Quantification of intrathoracic fat adds prognostic value in women undergoing myocardial perfusion imaging

AIM

Amongst patients with coronary artery disease (CAD), women experience relatively worse outcomes as compared to men. Evidence to date has failed to explore unique female imaging targets as major determinants of cardiovascular risk. We sought to assess the prognostic value of epicardial (EFV) and intrathoracic fat volume (IFV) quantification in women and men with suspected and known CAD.

METHODS AND RESULTS

Intrathoracic fat volume and EFV were calculated from non-contrast CT and analyzed in a propensity-matched cohort of 190 patients (95 women, mean age 62.5 ± 11.3 years) undergoing myocardial perfusion imaging (MPI) and coronary computed tomography angiography (CCTA) for evaluation of CAD. IFV and EFV were significantly lower in women as compared to men (198.2 ± 78.4 vs 293.2 ± 114.7 cm³ and 105.6 ± 48.9 vs 135.8 ± 60.9 cm³, p < 0.001) and showed a strong association with coronary artery calcium score (CACS) and obstructive CAD in women (p < 0.05), but not in men. Fat volumes were not related to abnormal MPI in either population (p = NS). During a median follow-up of 2.8 years, high IFV was associated with reduced event free survival (log rank = 0.019 vs low IFV) in women, but not in men. Accordingly, a multivariate Cox regression model adjusted for cardiovascular risk factors, CACS, CCTA, and MPI findings selected IFV as a significant predictor of major adverse cardiovascular events (MACE) in women (HR 1.32, 95%CI 1.18-1.55, p = 0.001).

CONCLUSION

Quantification of IFV provides incremental prognostic value for MACE in women, beyond that provided by traditional risk factors and imaging findings.

Obstructive sleep apnea and quality of life in Fabry disease: a prospective parallel cohort study

STUDY OBJECTIVES

Patients with Fabry disease (FD) report impaired quality of life and excessive daytime sleepiness. Obstructive sleep apnea (OSA) is frequently reported among patients with FD; however, its prevalence and its influence on quality of life and daytime sleepiness in this population are unclear.

METHODS

Patients with FD in a cohort from the University Hospital Zurich (n = 52) were one-to-two matched to healthy adult controls (n = 104) according to age, sex, and body mass index. Participants underwent structured interviews (including Short Form-36) and level-3 respiratory polygraphy. An apnea-hypopnea index of ≥ 5/h was defined as OSA and the severity of FD was quantified with the Mainz Severity Score Index (MSSI). Conditional logistic regression was used to compare the outcomes.

RESULTS

In patients with FD the mean MSSI was 13.3 ± 10.5 points and OSA prevalence was 19.2% vs. 9.0% in the matched control group (p = 0.09). The apnea-hypopnea index was significantly higher in patients with FD than in the control group (0.5/h [0.2-3.0] vs. 0.2/h [0.1-1.8], p = 0.026). OSA severity was associated with impaired quality of life in four dimensions for the whole study population. Furthermore, patients with FD did report significantly higher daytime sleepiness (Epworth Sleepiness Scale 7.6 points vs. 6.3 points; p = 0.01) than healthy controls.

CONCLUSION

Patients with mild FD do not have a higher OSA prevalence than matched control subjects. Differences in OSA severity did not reach clinical significance. Further studies are warranted to determine the impact of OSA in patients with moderate-to-severe FD.

Prevalence of Obstructive Sleep Apnea in Joint Hypermobility Syndrome: A Systematic Review and Meta-Analysis

STUDY OBJECTIVES

Because of associated abnormalities affecting connective tissue in various organs including airways, hypermobility syndrome has been associated with high risk for the development sleep apnea. Ehlers-Danlos syndrome (EDS) and Marfan syndrome (MFS) represent the most common hypermobility syndromes; therefore, the purpose of this review was to examine the prevalence of obstructive sleep apnea (OSA) in these populations.

METHODS

All publications and poster presentations written in English found through August 2018 that describe the prevalence of sleep apnea among people with EDS or MFS were included.

RESULTS

A total of 13 studies were identified, 7 for EDS and 6 for MFS. A combined random prevalence rate of OSA across both populations was 48.9% (95% confidence interval 38.3-59.6), with a slightly higher rate of 59.7% (39.7-77.0) for MFS versus 39.4% (28.8-51.1) for EDS. However, a high degree of heterogeneity across studies was found in both groups (EDS group: Q = 28.6 and I2 = 79.0; MFS group: Q = 37.1 and I2 = 86.5). When directly compared to the general population, patients with EDS/MFS were on average six times more likely (odds ratio 6.28 [95% confidence interval 3.31-11.93], P < 0.001, Z = 5.61) to have a diagnosis of OSA.

CONCLUSIONS

OSA is a previously underestimated EDS/MFS-related complication. The high prevalence of OSA might be the result of bony and soft-tissue abnormalities associated with these hypermobility syndromes. Untreated OSA is thought to worsen cardiovascular complications especially among those with MFS. Further research is needed to better delineate whether the prevalence of OSA is moderated by factors such as sex, body mass index, bony structure, and disorder subtype.

Real-Time Breath Analysis Reveals Specific Metabolic Signatures of COPD Exacerbations

BACKGROUND

Exacerbations of COPD are defined by acute worsening of respiratory symptoms leading to a change in therapy. Identifying altered metabolic processes in patients at risk for future exacerbations is desirable for treatment optimization, the development of new therapeutic strategies, and perhaps diagnostic value. We aimed to identify affected pathways using the profiles of volatile organic compounds in exhaled breath from patients with COPD with and without frequent exacerbations (≥ 2 exacerbations within the past 12 months).

METHODS

In this matched cohort study, exhaled breath profiles from patients with COPD and frequent exacerbations ("frequent exacerbators") and without frequent exacerbations ("nonfrequent exacerbators") were analyzed during an exacerbation-free interval using real-time secondary electrospray ionization high-resolution mass spectrometry. We analyzed exhaled breath from 26 frequent exacerbators and 26 nonfrequent exacerbators that were matched in terms of age, sex, and smoking history. To obtain new pathophysiological insights, we investigated significantly altered metabolites, which can be assigned to specific pathways. Metabolites were identified by using a Wilcoxon rank-sum test.

RESULTS

Metabolite levels from the ω-oxidation pathway, namely ω-hydroxy, ω-oxo, and dicarboxylic acids, were consistently decreased in frequent exacerbators. Additionally, several new nitro-aromatic metabolites, which were significantly increased in frequent exacerbators, were identified.

CONCLUSIONS

Real-time breath analysis by secondary electrospray high-resolution mass spectrometry allows molecular profiling of exhaled breath, providing insights about ongoing biochemical processes in patients with COPD at risk for exacerbations.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02186639; URL: www.clinicaltrials.gov.

Obstructive Sleep Apnoea in Children and Adolescents with Ehlers-Danlos Syndrome

BACKGROUND

In Ehlers-Danlos syndrome (EDS), a group of monogenic disorders affecting connective tissues, obstructive sleep apnoea (OSA) is highly prevalent in adults. The prevalence of OSA in children with EDS is unknown.

OBJECTIVES

This prospective cross-sectional study aimed at determining the prevalence of OSA in paediatric EDS patients.

METHODS

Children with EDS (n = 24) were recruited from the Children's Hospital Zurich and matched to healthy controls. Participants completed home respiratory polygraphy and questionnaires (Sleep-Related Breathing Disorder Scale [SRBD], Epworth Sleepiness Scale [ESS], and Child Health Questionnaire [CHQ]). The American Academy of Sleep Medicine criteria were applied for OSA diagnosis (obstructive apnoea-hypopnoea index [oAHI] ≥1/h). Conditional logistic regression was used to compare the prevalence of OSA and to adjust for possible confounding.

RESULTS

OSA was found in 42% of paediatric EDS patients and in 13% of matched controls (OR = 4.5, 95% CI = 0.97-20.83, p = 0.054). The median oAHI was higher in EDS patients than in controls (0.77/h, IQR = 0.19-1.76, vs. 0.24/h, IQR = 0.0-0.60, p < 0.001 adjusted for age, sex, and BMI z-score). EDS patients had lower scores in most CHQ scales and higher SRBD and ESS scores than controls (0.26, IQR = 0.1-0.35, vs. 0.07, IQR = 0-0.19, p = 0.004); 7 ± 4 vs. 5 ± 4, p = 0.033, respectively).

CONCLUSION

OSA is a previously underestimated EDS-related complication increasing disease burden.

Effect of continuous positive airway pressure therapy on circadian patterns of cardiac repolarization in patients with obstructive sleep apnoea: data from a randomized trial

Background

Obstructive sleep apnoea (OSA) has been proposed as an independent risk factor for sudden cardiac death (SCD). This study takes advantage of a previous randomized trial and seeks to evaluate circadian patterns of the QTc-interval, a marker of cardiac repolarization and biomarker for SCD, in patients with OSA. We hypothesized that patients with OSA would exhibit longest QTc during the night-time and that continuous positive airway pressure (CPAP) therapy would reverse this.

Methods

One hundred eighteen patients diagnosed with moderate-to-severe OSA were randomized to receive therapeutic or subtherapeutic CPAP for 4 weeks. Of these, 84 had full 24 h-Holter monitoring data at baseline and follow-up. Weighted means of all QTc-intervals were analysed over 24 h, during four time-periods (12 pm-6 am, 6 am-12 am, 12 am-6 pm, 6 pm-12 pm) as well as during each individual hour. A two-sided P value <0.05 was considered to be of statistical significance.

Results

QTc-intervals at baseline [mean (SD) over 24 h: 407.8 ms (36.6)] were highest from 6 pm-12 pm [411.7 ms (42.0)] and shortest from 6 am-12 am [405.4 ms (39.5)]. Overall 24 h CPAP treatment effect on QTc was -11.3 ms [95% confidence interval (CI), -22.1 to -0.6; P=0.039] and was estimated to be greater from 6 pm-12 pm than from 12 pm-6 am (P=0.068). The CPAP treatment effect on QTc was driven by those patients in the highest QTc decile at baseline (all >430 ms). In these patients, CPAP led to reductions in QTc, allowing reclassification into lower risk-associated values of QTc (<430 ms).

Conclusions

In this exploratory study, CPAP treatment led to an overall reduction in the QTc-interval compared with subtherapeutic CPAP. This reduction seems more pronounced during evening hours and in patients with a QTc above 430 ms.

Obstructive sleep apnoea and quality of life in Ehlers-Danlos syndrome: a parallel cohort study

BACKGROUND

Patients with the connective tissue disorder Ehlers-Danlos syndrome (EDS) often suffer from fatigue, excessive daytime sleepiness and impaired quality of life. Obstructive sleep apnoea (OSA) may be an underlying cause for these symptoms but its prevalence in this population is unclear.

METHODS

In this prospective parallel-cohort study, we included 100 adult patients with EDS (46% hypermobile-type, 35% classical-type and 19% other), which were one-to-one matched to 100 healthy adult controls according to sex, age, weight and height. Participants underwent structured interviews (including short-form 36) and level-3 respiratory polygraphy. OSA was defined as apnoea-hypopnea index ≥5/hour. Photographic craniofacial phenotyping was conducted in a subgroup. Conditional logistic regression was used to compare the prevalence of OSA.

RESULTS

In patients with EDS, OSA prevalence was 32% versus 6% in the matched control group (OR 5.3 (95% CI 2.5 to 11.2); p<0.001). The EDS group reported impaired quality of life in all dimensions (p<0.05) and significantly higher excessive daytime sleepiness measured by the Epworth Sleepiness Scale (median (quartiles) 11 (7-14) vs 7 (5-10); p<0.001). OSA severity was positively associated with daytime sleepiness and lower quality of life in the EDS group. There was no evidence of a difference between the two study groups in terms of craniofacial phenotypes.

CONCLUSIONS

The prevalence of OSA is higher in patients with EDS than in a matched control group. This is of clinical relevance as it is associated with fatigue, excessive daytime sleepiness and impaired quality of life. Further studies are needed to assess the clinical benefit of OSA treatment in patients with EDS.

TRIAL REGISTRATION NUMBER

NCT02435745.

Real-Time Quantification of Amino Acids in the Exhalome by Secondary Electrospray Ionization–Mass Spectrometry: A Proof-of-Principle Study

BACKGROUND

Amino acids are frequently determined in clinical chemistry. However, current analysis methods are time-consuming, invasive, and suffer from artifacts during sampling, sample handling, and sample preparation. We hypothesized in this proof-of-principle study that plasma concentrations of amino acids can be estimated by measuring their concentrations in exhaled breath. A novel breath analysis technique described here allows such measurements to be carried out in real-time and noninvasively, which should facilitate efficient diagnostics and give insights into human physiology.

METHODS

The amino acid profiles in 37 individuals were determined by ion-exchange HPLC in blood plasma and simultaneously in breath by secondary electrospray ionization coupled to high-resolution mass spectrometry. Participants were split into training and test sets to validate the analytical accuracy. Longitudinal profiles in 3 individuals were additionally obtained over a 12-h period.

RESULTS

Concentrations of 8 slightly volatile amino acids (A, V, I, G, P, K, F, Orn) could be determined in exhaled breath with a CV of &lt;10%. Exhalome validation studies yielded high accuracies for each of these amino acids, on average only 3% less compared to plasma concentrations (95% CI ±13%). Higher variations were found only for amino acids with a low plasma concentration.

CONCLUSIONS

This study demonstrates for the first time that amino acids can be quantified in the human breath and that their concentrations correlate with plasma concentrations. Although this noninvasive technique needs further investigation, exhalome analysis may provide significant benefits over traditional, offline analytical methods.

Sedation during bronchoscopy: data from a nationwide sedation and monitoring survey

Background

There is limited knowledge on practice patterns in procedural sedation and analgesia (PSA), the use of propofol, and monitoring during flexible bronchoscopy (FB). The purpose of this study was to assess the current practice patterns of FBs and to focus on the use of propofol, the education of the proceduralist, and the involvement of anaesthesiologists during FB.

Methods

An anonymous questionnaire was sent to 299 pulmonologists. Only respondents who were active physicians in adult respiratory medicine performing FB were subsequently analysed.

Results

The response rate was 78 % and 27,149 FB in the previous 12 months were analysed. The overall sedation-related morbidity rate was 0.02 % and mortality was 7/100’000 FB. Sedation was used in 95 % of bronchoscopies. The main drugs used for PSA were propofol (77 %) and midazolam (46 %). In 84 % of PSAs propofol was used without the attendance of an anaesthesiologist. The use of propofol was associated with high volume bronchoscopists (p < 0.010) and career-young pulmonologists (p < 0.001). While monitoring vital parameters has become standard practice, pulmonologists reported a very low rate of systematic basic education and training in the field of PSA (50 %).

Conclusions

In Switzerland, PSA during FB is mostly performed with propofol without the attendance of an anaesthesiologist and the use of this drug is expected to increase in the future. While monitoring standards are very high there is need for policies to improve education, systematic training, and support for pulmonologists for PSA during FB.

Simulated Obstructive Sleep Apnea Increases P-Wave Duration and P-Wave Dispersion

Background

A high P-wave duration and dispersion (Pd) have been reported to be a prognostic factor for the occurrence of paroxysmal atrial fibrillation (PAF), a condition linked to obstructive sleep apnea (OSA). We tested the hypothesis of whether a short-term increase of P-wave duration and Pd can be induced by respiratory manoeuvres simulating OSA in healthy subjects and in patients with PAF.

Methods

12-lead-electrocardiography (ECG) was recorded continuously in 24 healthy subjects and 33 patients with PAF, while simulating obstructive apnea (Mueller manoeuvre, MM), obstructive hypopnea (inspiration through a threshold load, ITH), central apnea (AP), and during normal breathing (BL) in randomized order. The P-wave duration and Pd was calculated by using dedicated software for ECG-analysis.

Results

P-wave duration and Pd significantly increased during MM and ITH compared to BL in all subjects (+13.1ms and +13.8ms during MM; +11.7ms and +12.9ms during ITH; p<0.001 for all comparisons). In MM, the increase was larger in healthy subjects when compared to patients with PAF (p<0.05).

Conclusion

Intrathoracic pressure swings through simulated obstructive sleep apnea increase P-wave duration and Pd in healthy subjects and in patients with PAF. Our findings imply that intrathoracic pressure swings prolong the intra-atrial and inter-atrial conduction time and therefore may represent an independent trigger factor for the development for PAF.

Secondary electrospray ionization coupled to high-resolution mass spectrometry reveals tryptophan pathway metabolites in exhaled human breath

A real-time non-invasive breath analysis technique (secondary ESI-HRMS) reveals the hitherto unknown occurrence of tryptophan pathway metabolites in breath.

Prevalence and Risk Factors of Sleep Disordered Breathing in Fabry disease: A Prospective Cohort Study

Excessive daytime sleepiness (EDS) is a frequently reported and not well-understood symptom in patients with Fabry disease (FD). Sleep-disordered breathing (SDB) is a possible factor. As deposition of glycosphingolipids in the upper airway muscles is likely, we hypothesized that obstructive sleep apnoea (OSA) is highly prevalent in FD and positively associated with its severity.All patients with FD who are followed in the Fabry cohort of the University Hospital Zurich (n = 62) were asked to participate in this prospective cohort study. Eligible patients were prospectively investigated by assessing their daytime sleepiness using the Epworth Sleepiness Scale (ESS), the severity of FD using the Mainz Severity Score Index (MSSI), and by an ambulatory overnight respiratory polygraphy between November 1, 2013, and January 31, 2015. SDB was defined as an apnea/hypopnea index (AHI) of > 5/h.Fifty-two patients (mean ± SD age 42.8 ± 14.7 years, 33% men, mean ± SD BMI 23.4 ± 3.6 kg/m) with a median (IQR) MSSI of 12 (5-19) were included. Median (IQR) ESS was 6 (2-10) and 7 patients (14%) had an ESS > 10. Thirteen patients (25%) had SDB (78% obstructive sleep apnea, 22% central sleep apnea). In the multivariable analysis, the age was the only statistically significant predictor of SDB (OR 1.11, 95% CI 1.04-1.18, P = 0.001). ESS was associated with depression (P < 0.001) but not AHI nor age.This study shows that SDB, especially obstructive sleep apnea is highly prevalent in patients with Fabry disease. However, EDS in FD seems to be related with depression rather than SDB.ClinicalTrials.gov (identifier: NCT01947634).

CPAP vs Mandibular Advancement Devices and Blood Pressure in Patients With Obstructive Sleep Apnea: A Systematic Review and Meta-analysis

IMPORTANCE

Obstructive sleep apnea is associated with higher levels of blood pressure (BP), which can lead to increased cardiovascular risk.

OBJECTIVE

To compare the association of continuous positive airway pressure (CPAP), mandibular advancement devices (MADs), and inactive control groups (placebo or no treatment) with changes in systolic BP (SBP) and diastolic BP (DBP) in patients with obstructive sleep apnea.

DATA SOURCES

The databases of MEDLINE, EMBASE, and the Cochrane Library were searched up to the end of August 2015 and study bibliographies were reviewed.

STUDY SELECTION

Randomized clinical trials comparing the effect of CPAP or MADs (vs each other or an inactive control) on BP in patients with obstructive sleep apnea were selected by consensus. Of 872 studies initially identified, 51 were selected for analysis.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by one reviewer and checked by another reviewer. A network meta-analysis using multivariate random-effects meta-regression was used to estimate pooled differences between each intervention. Meta-regression was used to assess the association between trial characteristics and the reported effects of CPAP vs inactive control.

MAIN OUTCOMES AND MEASURES

Absolute change in SBP and DBP from baseline to follow-up.

RESULTS

Of the 51 studies included in the analysis (4888 patients), 44 compared CPAP with an inactive control, 3 compared MADs with an inactive control, 1 compared CPAP with an MAD, and 3 compared CPAP, MADs, and an inactive control. Compared with an inactive control, CPAP was associated with a reduction in SBP of 2.5 mm Hg (95% CI, 1.5 to 3.5 mm Hg; P < .001) and in DBP of 2.0 mm Hg (95% CI, 1.3 to 2.7 mm Hg; P < .001). A 1-hour-per-night increase in mean CPAP use was associated with an additional reduction in SBP of 1.5 mm Hg (95% CI, 0.8 to 2.3 mm Hg; P < .001) and an additional reduction in DBP of 0.9 mm Hg (95% CI, 0.3 to 1.4 mm Hg; P = .001). Compared with an inactive control, MADs were associated with a reduction in SBP of 2.1 mm Hg (95% CI, 0.8 to 3.4 mm Hg; P = .002) and in DBP of 1.9 mm Hg (95% CI, 0.5 to 3.2 mm Hg; P = .008). There was no significant difference between CPAP and MADs in their association with change in SBP (-0.5 mm Hg [95% CI, -2.0 to 1.0 mm Hg]; P = .55) or in DBP (-0.2 mm Hg [95% CI, -1.6 to 1.3 mm Hg]; P = .82).

CONCLUSIONS AND RELEVANCE

Among patients with obstructive sleep apnea, both CPAP and MADs were associated with reductions in BP. Network meta-analysis did not identify a statistically significant difference between the BP outcomes associated with these therapies.

Detection and Quantification of Benzothiazoles in Exhaled Breath and Exhaled Breath Condensate by Real-Time Secondary Electrospray Ionization-High-Resolution Mass Spectrometry and Ultra-High Performance Liquid Chromatography

2-Subtituted benzothiazoles are widely used industrial chemicals whose occurrence in environmental samples has been shown to be ubiquitous. However, knowledge about human exposure to these compounds and their excretion route is still scarce. Here, we demonstrate for the first time the detection of benzothiazole derivatives in exhaled breath. Real-time analysis of breath was carried out by means of secondary electrospray ionization coupled to high-resolution mass spectrometry. This coupling allowed not only the detection of these compounds in breath with a sensitivity in the pptv range but also their robust identification by comparing tandem high-resolution mass spectra from breath and standards. For further confirmation, benzothiazoles were also determined in exhaled breath condensate samples by means of ultra high-performance liquid chromatography. This approach strengthened the identification as a result of excellent matches in retention times and also allowed quantification. An estimated total daily exhalation of ca. 20 μg day(-1) was calculated for the six benzothiazole derivatives found in breath.