Inspiratory Muscle Dysfunction Mediates and Predicts a Disease Continuum of Hypercapnic Failure in Chronic Obstructive Pulmonary Disease.

INTRODUCTION: Advanced chronic obstructive pulmonary disease (COPD) is associated with chronic hypercapnic failure. The present work aimed to comprehensively investigate inspiratory muscle function as a potential key determinant of hypercapnic respiratory failure in patients with COPD. METHODS: Prospective patient recruitment encompassed 61 stable subjects with COPD across different stages of respiratory failure, ranging from normocapnia to isolated nighttime hypercapnia and daytime hypercapnia. Arterialized blood gas analyses and overnight transcutaneous capnometry were used for patient stratification. Assessment of respiratory muscle function encompassed body plethysmography, maximum inspiratory pressure (MIP), diaphragm ultrasound, and transdiaphragmatic pressure recordings following cervical magnetic stimulation of the phrenic nerves (twPdi) and a maximum sniff manoeuvre (Sniff Pdi). RESULTS: Twenty patients showed no hypercapnia, 10 had isolated nocturnal hypercapnia, and 31 had daytime hypercapnia. Body plethysmography clearly distinguished patients with and without hypercapnia but did not discriminate patients with isolated nocturnal hypercapnia from those with daytime hypercapnia. In contrast to ultrasound parameters and transdiaphragmatic pressures, only MIP reflected the extent of hypercapnia across all three stages. MIP values below -48 cmH2O predicted nocturnal hypercapnia (area under the curve = 0.733, p = 0.052). CONCLUSION: In COPD, inspiratory muscle dysfunction contributes to progressive hypercapnic failure. In contrast to invasive tests of diaphragm strength only MIP fully reflects the pathophysiological continuum of hypercapnic failure and predicts isolated nocturnal hypercapnia.

[Prognostic factors in an individualised approach to non-pharmacological therapy of COVID-19: from oxygen and mechanical ventilation to extracorporeal membrane oxygenation]. / Prognostische Faktoren bei einem schrittweisen Ansatz zur nicht-pharmakologischen Therapie von Sauerstoff und mechanischer Beatmung bis hin zur extrakorporalen Membranoxygenierung bei COVID-19.

BACKGROUND: Our centre followed a stepwise approach in the nonpharmacological treatment of respiratory failure in COVID-19 in accordance with German national guidelines, escalating non-invasive measures before invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO). The aim of this study was to analyse this individualized approach to non-pharmacologic therapy in terms of patient characteristics and clinical features that may help predict more severe disease, particularly the need for intensive care. METHOD: This retrospective single-centre study of COVID-19 inpatients between March 2020 and December 2021 analysed anthropometric data, non-pharmacological maximum therapy and survival status via a manual medical file review. RESULTS: Of 1052 COVID-19-related admissions, 835 patients were included in the analysis cohort (54% male, median 58 years); 34% (n=284) received no therapy, 40% (n=337) conventional oxygen therapy (COT), 3% (n=22) high flow nasal cannula (NHFC), 9% (n=73) continuous positive airway pressure (CPAP), 7% (n=56) non-invasive ventilation (NIV), 4% (n=34) intermittent mandatory ventilation (IMV), and 3% (n=29) extracorporeal membrane oxygenation (ECMO). Of 551 patients treated with at least COT, 12.3% required intubation. A total of 183 patients required ICU treatment, and 106 (13%) died. 25 (74%) IMV patients and 23 (79%) ECMO patients died. Arterial hypertension, diabetes and dyslipidemia was more prevalent in non-survivors. Binary logistic analysis revealed the following risk factors for increased mortality: an oxygen supplementation of ≥2 L/min at baseline (OR 6.96 [4.01-12.08]), age (OR 1.09 [1.05-1.14]), and male sex (OR 2.23 [0.79-6.31]). CONCLUSION: The physician's immediate clinical decision to provide oxygen therapy, along with other recognized risk factors, plays an important role in predicting the severity of the disease course and thus aiding in the management of COVID-19.

Analysis of an Individualised Stepwise Approach to Non-Pharmacological Therapy in COVID-19.

BACKGROUND: Early intubation versus use of conventional or high-flow nasal cannula oxygen therapy (COT/HFNC), continuous positive airway pressure (CPAP), and non-invasive ventilation (NIV) has been debated throughout the COVID-19 pandemic. Our centre followed a stepwise approach, in concordance with German national guidelines, escalating non-invasive modalities prior to invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO), rather than early or late intubation. OBJECTIVES: The aims of the study were to investigate the real-life usage of these modalities and analyse patient characteristics and survival. METHOD: A retrospective monocentric observation was conducted of all consecutive COVID-19 hospital admissions between March 2020 and December 2021 at a university-affiliated pulmonary centre in Germany. Anthropometric data, therapy, and survival status were descriptively analysed. RESULTS: From 1,052 COVID-19-related admissions, 835 patients were included (54% male, median 58 years). Maximum therapy was as follows: 34% (n = 284) no therapy, 40% (n = 337) COT, 3% (n = 22) HFNC, 9% (n = 73) CPAP, 7% (n = 56) NIV, 4% (n = 34) IMV, and 3% (n = 29) ECMO. Of 551 patients treated with at least COT, 12.3% required intubation. Overall, 183 patients required intensive unit care, and 106 (13%) died. Of the 68 patients who received IMV/ECMO, 48 died (74%). The strategy for non-pharmacological therapy was individual but remained consistent throughout the studied period. CONCLUSIONS: This study provides valuable insight into COVID-19 care in Germany and shows how the majority of patients could be treated with the maximum treatment required according to disease severity following the national algorithm. Escalation of therapy modality is interlinked with disease severity and thus associated with mortality.

Decannulation/Weaning Potential and Success in Home Intensive Care.

BACKGROUND: The number of patients receiving home long-term ventilation has risen considerably in recent decades owing to medical advancements. Experts believe that the potential for ventilator weaning or tracheostoma removal is currently insufficiently exploited. OBJECTIVE: The objective of this study was to investigate the characteristics, prognosis, and decannulation/weaning potential of patients under home intensive care. METHODS: In this retrospective analysis of 607 patients on home intensive care, decannulation/weaning status and survival were documented for a 2-year period after initial assessment. At the time of hospital discharge, when clinicians had deemed the weaning process concluded, an independent expert noninvasively assessed the long-term decannulation/weaning. Comparative analyses based on specific criteria, such as ventilation and decannulation/weaning status, age, and underlying diseases, were performed. Potential predictors of survival were identified via multivariable logistic regression. RESULTS: Eighteen percent of patients were decannulated/weaned within 2 years after hospital discharge and had better mean survival than patients not decannulated/weaned (552 vs. 420 days, p < 0.001). More than half of these patients were identified to have decannulation/weaning potential based on the assessment of the independent expert. Patients with neuromuscular and neurological diseases had the best survival (546 and 501 days), patients with postsurgical conditions and cardiological diseases the worst (346 and 323 days). Underlying disease and decannulation/weaning status were significant predictors of 2-year survival. CONCLUSION: Successful decannulation/weaning of patients on long-term home intensive care is associated with better survival. Even in the absence of decannulation/weaning potential at the time of hospital discharge, patients may develop decannulation/weaning potential over time, which should therefore be assessed repeatedly.

Sleep-related breathing disorders in idiopathic pulmonary fibrosis are frequent and may be associated with pulmonary vascular involvement.

PURPOSE: Sleep-related breathing disorders (SRBD) may be associated with a worse prognosis in idiopathic pulmonary fibrosis (IPF). However, the prevalence of sleep disorders in IPF and the pathophysiological link between SRBD and IPF is unclear. PATIENTS AND METHODS: In this prospective trial, consecutive patients with stable IPF underwent polysomnography and cardiopulmonary exercise testing. Epworth sleepiness scale, Regensburg insomnia scale, and Pittsburgh sleep quality index were evaluated. Exclusion criteria were oxygen supplementation therapy, lung emphysema, and heart failure. For pairwise comparison of categorical data, the two-proportion z-test was applied. Correlation between continuous variables was assessed via the Pearson correlation coefficient. Patients without and with SRBD were compared. To find predictors for SRBD in IPF, multivariable logistic regression was applied. RESULTS: A total of 74 IPF patients were evaluated and 45 patients (11 female, median age 74 years, forced vital capacity 71.3%, DLCO 53.9%) were analyzed. Any kind of sleep disorder was found in 89% of patients. SRBD was present in 49% (81% obstructive sleep apnea, 19% central sleep apnea), insomnia in 40%, and periodic leg movements in 47% of subjects. The SRBD subgroup presented with a significantly lower performance (workload(peak)%pred 86.5 vs. 101.0 (p = 0.036); V'O2(AT) 618.5 ml/min vs. 774.0 ml/min (p = 0.043)) and exhibited a significantly higher V'E/V'CO2(peak) of 43.0 l/l vs. 38.5 l/l (p = 0.037). In search of predictors for SRBD by logistic regression, workload(peak)%pred was identified as a significant variable (p = 0.033). CONCLUSIONS: SRBD is frequent in IPF. Pulmonary vascular limitations may represent the pathophysiological link between IPF and SRBD. Workload(peak)%pred may be an independent risk factor for the occurrence of SRBD.

Initial Proportion and Dynamic of B.1.1.7 SARS-CoV-2 in a Large City in the West of Germany.

Rationale: Several mutational variants of SARS-CoV-2 have been identified in the past months with increasing prevalence worldwide. Some variants, such as B.1.1.7, are of high relevance due to increased transmissibility, facilitating virus spread and calling for stricter containment measures. Objectives: The aim of this study was to examine proportion and dynamic of B.1.1.7 in SARS-CoV-2-positive samples in a large city in the west of Germany. Methods: Consecutive SARS-CoV-2-positive samples from a local outpatient clinic, obtained over a period of 4 weeks (mid-January to mid-February 2021), were examined for the presence of the variant B.1.1.7. The size of B.1.1.7 infection clusters was compared with non-B.1.1.7 clusters. The transmissibility of SARS-CoV-2 variant B.1.1.7 was described based on corresponding cases of an infection cluster in a local child daycare centre. Results: Among 226 SARS-CoV-2-positive cases, B.1.1.7 was detected in 74 subjects (33%). The 7-day moving mean of the B.1.1.7 proportion started at 20% and reached 50% only 3 weeks later. B.1.1.7 clusters comprised 10.7 ± 12.1 persons per cluster, while non-B.1.1.7 clusters were considerably smaller (5.1 ± 5.8). One specific B.1.1.7 infection cluster in a 40-children daycare centre started with one teacher leading to 11 infected children and 8 infections among teachers. The infection spread to 6 families and one other daycare centre, with a total 43 SARS-CoV-2-positive subjects. Conclusions: We found a rapid increase in the SARS-CoV-2 variant B.1.1.7 with larger infection clusters than non-B.1.1.7. These results suggested a rapid increase in the B.1.1.7 proportion and a renewed increase in the total number of SARS-CoV-2 infections for the time following the analysed period. Considering the rapid emergence and spread of viral variants, close monitoring of mutation events is essential. Therefore, routine whole-genome sequencing appears to be useful in addition to searching for known mutations.

Severity stages of obesity-related breathing disorders - a cross-sectional cohort study.

INTRODUCTION: There is a general underappreciation of the spectrum of obesity-related breathing disorders and their consequences. We therefore compared characteristics of obese patients with eucapnic obstructive sleep apnea (OSA), OSA with obesity-related sleep hypoventilation (ORSH) or obesity hypoventilation syndrome (OHS) to identify the major determinants of hypoventilation. PATIENTS AND METHODS: In this prospective, diagnostic study (NCT04570540), obese patients with OSA, ORSH or OHS were characterized applying polysomnography with transcutaneous capnometry, blood gas analyses, bodyplethysmography and measurement of hypercapnic ventilatory response (HCVR). Pathophysiological variables known to contribute to hypoventilation and differing significantly between the groups were specified as potential independent variables in a multivariable logistic regression to identify major determinants of hypoventilation. RESULTS: Twenty, 43 and 19 patients were in the OSA, ORSH and OHS group, respectively. BMI was significantly lower in OSA as compared to OHS. The extent of SRBD was significantly higher in OHS as compared to OSA or ORSH. Patients with ORSH or OHS showed a significantly decreased forced expiratory volume in 1 s and forced vital capacity compared to OSA. HCVR was significantly lower in OHS and identified as the major determinant of hypoventilation in a multivariable logistic regression (Nagelkerke R2 = 0.346, p = 0.050, odds ratio (95%-confidence interval) 0.129 (0.017-1.004)). CONCLUSION: Although there were differences in BMI, respiratory mechanics and severity of upper airway obstruction between groups, our data support HCVR as the major determinant of obesity-associated hypoventilation.

Endotyping Sleep Apnea One Breath at a Time: An Automated Approach for Separating Obstructive from Central Sleep-disordered Breathing.

Rationale: Determining whether an individual has obstructive or central sleep apnea is fundamental to selecting the appropriate treatment. Objectives: Here we derive an automated breath-by-breath probability of obstruction, as a surrogate of gold-standard upper airway resistance, using hallmarks of upper airway obstruction visible on clinical sleep studies. Methods: From five nocturnal polysomnography signals (airflow, thoracic and abdominal effort, oxygen saturation, and snore), nine features were extracted and weighted to derive the breath-by-breath probability of obstruction (Pobs). A development and initial test set of 29 subjects (development = 6, test = 23) (New York, NY) and a second test set of 39 subjects (Solingen, Germany), both with esophageal manometry, were used to develop Pobs and validate it against gold-standard upper airway resistance. A separate dataset of 114 subjects with 2 consecutive nocturnal polysomnographies (New York, NY) without esophageal manometry was used to assess the night-to-night variability of Pobs. Measurements and Main Results: A total of 1,962,229 breaths were analyzed. On a breath-by-breath level, Pobs was strongly correlated with normalized upper airway resistance in both test sets (set 1: cubic adjusted [adj.] R2 = 0.87, P < 0.001, area under the receiver operating characteristic curve = 0.74; set 2: cubic adj. R2 = 0.83, P < 0.001, area under the receiver operating characteristic curve = 0.7). On a subject level, median Pobs was associated with the median normalized upper airway resistance (set 1: linear adj. R2 = 0.59, P < 0.001; set 2: linear adj. R2 = 0.45, P < 0.001). Median Pobs exhibited low night-to-night variability [intraclass correlation(2, 1) = 0.93]. Conclusions: Using nearly 2 million breaths from 182 subjects, we show that breath-by-breath probability of obstruction can reliably predict the overall burden of obstructed breaths in individual subjects and can aid in determining the type of sleep apnea.

High sensitivity of PD-L1 analysis from pleural effusion in nonsmall cell lung cancer.

Background: Programmed cell death protein 1 (PD-1)/programmed cell death protein ligand 1 (PD-L1) immune checkpoint inhibitors have been approved for monotherapy of metastatic nonsmall cell lung cancer (mNSCLC) depending on tumour cells' PD-L1 expression. Pleural effusion is common in mNSCLC. The significance of immunocytochemistry PD-L1 analysis from pleural effusion samples is unclear. Aim: The aim of the study was to analyse the sensitivity regarding immunocytochemistry PD-L1 analysis of pleural effusion in NSCLC as compared to immunohistochemistry of pleural biopsies. Patients and Methods: Fifty consecutive subjects (17 female, median age 72.5 years, seven never-smokers) were enrolled in this prospective controlled two-centre study. Inclusion criteria were pleural effusion, suspected or known lung cancer, indication for pleural puncture and thoracoscopy, and written informed consent. Immunocytochemistry and immunohistochemistry PD-L1 analyses were performed with the Dako-PDL1-IHC-22C3pharmDx assay. Analysis for sensitivity, specificity, and positive and negative predictive value was performed for PD-L1 detection from pleural effusion. Results: 50 subjects underwent pleural puncture and thoracoscopy. Pathological diagnoses were lung cancer (48), lymphoma (1) and mesothelioma (1). Sensitivity, specificity, positive predictive value and negative predictive value of PD-L1-testing with expression ≥50% defined as positive were 100% (95% CI 46-100%), 63% (36-84%), 45% (18-75%) and 100% (66-100%), and with expression ≥1% defined as positive 86% (56-97%), 43% (12-80%), 75% (47-92%) and 60% (17-93%). Conclusion: PD-L1 analysis in tumour-positive pleural effusion samples shows a very high sensitivity and negative predictive value, especially regarding PD-L1 expression levels ≥50% (European Medicines Agency approval). Negative results are reliable and help in the decision against a first-line checkpoint inhibitor monotherapy. However, a 1% cut-off level (United States Food and Drug Administration approval) leads to a markedly lower negative predictive value, making other invasive procedures necessary (NCT02855281).

Evaluation of a multicomponent grading system for obstructive sleep apnoea: the Baveno classification.

New findings on pathophysiology, epidemiology, and outcome have raised concerns on the relevance of the apnoea-hypopnoea index (AHI) in the classification of obstructive sleep apnoea (OSA) severity. Recently, a multicomponent grading system decision integrating symptomatology and comorbidities (Baveno classification), was proposed to characterise OSA and to guide therapeutic decisions. We evaluated whether this system reflects the OSA population, whether it translates into differences in outcomes, and whether the addition of AHI improves the scheme. A total of 14 499 OSA patients from the European Sleep Apnoea Database cohort were analysed. The groups were homogeneously distributed and were found to clearly stratify the population with respect to baseline parameters. Differences in sleepiness and blood pressure between the groups were analysed in a subgroup of patients after 24-36 months of treatment. Group A (minor symptoms and comorbidities) did not demonstrate any effect of treatment on outcome. However, groups B (severe symptoms, minor comorbidities), C (minor symptoms, severe comorbidities) and D (severe symptoms and comorbidities) were associated with improvement in either or both parameters with treatment. The AHI is an essential prerequisite of the diagnosis; however, adding the AHI did not improve the classification. Rather, it was inferior with respect to guiding the treatment decision. Thus, the Baveno classification allows a better stratification of the OSA population and may provide a better guidance for therapeutic decisions in OSA.

Combining biopsy tools improves mutation detection rate in central lung cancer.

In central exophytic lung cancer, the detection rate of oncogenic mutations and PDL1 positivity may be increased by combined sampling by forceps and EBUS-TBNA. The additional sampling of mediastinal lymph node and ctDNA may not be of additional benefit. https://bit.ly/2Ve41EF.

Cardiopulmonary Exercise Testing Allows Discrimination Between Idiopathic Non-specific Interstitial Pneumonia and Idiopathic Pulmonary Fibrosis in Mild to Moderate Stages of the Disease.

It is unclear whether there are cardiopulmonary exercise testing (CPET) parameters which may indicate poor prognosis in the early course of fibrosing interstitial lung disease. 27 untreated consecutive subjects (13 idiopathic non-specific interstitial pneumonia (iNSIP), 14 idiopathic pulmonary fibrosis (IPF); 19 male; age 69 ± 10 years) were enrolled in this observational pilot study. Subjects underwent routine pulmonary function testing and CPET. Statistically, the t test and the Mann-Whitney-U test were applied in the presence of normal and non-normal distribution (according to Shapiro-Wilk), respectively. Analyzing the whole cohort, only mild functional impairments were determined. Comparison of iNSIP and IPF groups detected significant differences for the CPET parameters V'O2Peak[%pred] (p = 0.011), V'O2/kgPeak (p = 0.033), Watt[%pred] (p = 0.048), V'E/V'CO2 (Rest: p = 0.016; AT: p = 0.011; Peak: p = 0.019; Slope: p = 0.040), V'E/V'O2 (Rest: p = 0.033 AT: p = 0.014; Peak: p = 0.035). CPET parameters may indicate IPF-specific impairments even in mild disease. It may be hypothesized that these parameters are early biomarkers of poor prognosis.

Choosing an Adequate Test to Determine Fitness for Air Travel in Obese Individuals.

BACKGROUND: Air travel is physically demanding and, because obesity is rising, physicians increasingly need to assess whether such patients can fly safely. Our aim was to compare the diagnostic accuracy of two routinely used exercise tests, 50-m walk test and 6-min walk test, and hypoxic challenge testing (HCT) in obese individuals. We further explored the diagnostic potential of perceived dyspnea as measured with the Borg scale because this is often recorded subsequent to walking tests. METHODS: In this prospective study, we examined 21 obese participants (10 women, age 51 ± 15 [mean  ±  SD], BMI 36 ± 5  kg/m2). The most prevalent comorbidity was COPD (n = 11). The reference standard for in-flight hypoxia, defined as oxygen saturation below 90%, was established in an altitude chamber. Diagnostic accuracy of each index test was estimated by area under the receiver operating characteristic curve (AUC). RESULTS: Of the 21 participants, 13 (9 with COPD) were identified with in-flight hypoxia. HCT was the only test separating the reference groups significantly with AUC 0.87 (95% CI,  0.62-0.96). Neither of the walking tests predicted noticeably above chance level: 50 m walk test had an AUC of 0.63 (0.36-0.84) and 6MWT had an AUC of 0.64 (0.35-0.86). We further observed good prognostic ability of subjective dyspnea assessment when recorded after 6MWT with an AUC of 0.80 (0.55-0.93). CONCLUSIONS: In-flight hypoxia in obese individuals can be predicted by HCT but not by simple walking tests.

Transbronchial cryobiopsy in fibrosing interstitial lung disease: modifications of the procedure lead to risk reduction.

Sixty-one subjects with fibrosing interstitial lung disease were prospectively analysed to determine the efficacy of transbronchial cryobiopsy (CryoTBB) and the effect of procedural modifications which were introduced after an interim analysis of the first 19 subjects. The modifications significantly reduced complication rates from 84% to 14% (p<0.001). 30-day-mortality was 2%. The algorithm with initial CryoTBB and surgical lung biopsy (SLB) as optional step-up procedure was feasible. CryoTBB led to a confident diagnosis in 46/61 subjects (75%). Only 21% out of all subjects were forwarded for SLB. As the modified CryoTBB reduced but not eliminated the risk of severe complications, tissue sampling should be limited to patients where confident diagnosis enables life prolonging therapy. Trial registration number: NCT01714518.

Bronchoscopic Brushing from Central Lung Cancer-Next Generation Sequencing Results are Reliable.

The role of bronchoscopic brushing for tumor detection and molecular testing in central lung cancer is unclear. In this study, 50 consecutive subjects with suspected central lung cancer underwent bronchoscopic brushing (31 males, median age 70, 5 never smokers). Histological results were: NSCLC/SCLC/low-grade-NET/granulation tissue in 36/8/2/4 cases. Next generation sequencing (NGS) was feasible in 62% of tumor-positive brush smear samples. In 78% of these cases, NGS displayed identical results compared to histology samples, in 22% NGS from brush smears detected specific mutations, whereas DNA quality from forceps biopsy was insufficient for NGS analysis. Sensitivity, specificity, positive predictive value, negative predictive value of brush smear analysis were 66% (95% confidence interval 50-79), 100% (40-100), 100% (85-100), and 21% (7-46). For the combined analysis of brush smear, brush tip washing and sheath tube content sensitivity was slightly elevated at 69% (53-81). In central lung cancer, bronchoscopic brushing detects tumor cells in about two-third of cases and allows a decision for or against targeted therapy in the majority of tumor-positive cases on the basis of NGS analysis.

CPAP therapy improves erectile function in patients with severe obstructive sleep apnea.

OBJECTIVES: Erectile dysfunction (ED) is highly prevalent in obstructive sleep apnea (OSA), however, the effect of continuous positive airway pressure (CPAP) therapy on erectile function has not yet been thoroughly investigated in these patients. METHODS: Ninety-four men with severe OSA (ie, with an apnea-hypopnea-index ≥ 30/h of sleep) were prospectively evaluated for the presence and severity of ED before and after 6-12 months of CPAP therapy. The abbreviated version of the International Index of Erectile Function, (the IIEF-5) was used to rate erectile function. Furthermore, all study participants responded to standard questionnaires of daytime sleepiness (Epworth Sleepiness Scale), quality of life (WHO Wellbeing 5 questionnaire) and depression (Major Depression Inventory). RESULTS: ED as defined by an IIEF-5 score of ≤21 was present in 64 patients (68.1%). CPAP treatment significantly improved erectile function in those patients suffering from moderate and severe ED. Additionally, a trend for a correlation between the improvement of erectile function under CPAP and the hours of its use was observed. Finally, this effect was associated with larger improvements of quality of life in affected patients. CONCLUSIONS: ED is very frequent in men with severe OSA and can at least partly be reversed by long-term CPAP therapy in most seriously affected patients. The beneficial effect on erectile function may depend on CPAP compliance and is accompanied by improvements of quality of life. Randomized controlled trials are needed to confirm these findings.

Sleep-disordered breathing in patients with cardiovascular diseases cannot be detected by ESS, STOP-BANG, and Berlin questionnaires.

Sleep-disordered breathing (SDB) is highly prevalent in patients with cardiovascular diseases (CVD) and associated with poor outcome. At least 50% of heart failure (HF) patients present with SDB, equally divided in obstructive sleep apnea (OSA) and central sleep apnea (CSA). CVD patients with SDB do not always present with typical SDB symptoms. Therefore, we asked whether established questionnaires allow for the reliable detection of SDB. In this prospective cohort study, 89 CVD patients (54 male, 59 ± 15 years, BMI 30 ± 6 kg/m2) in stable clinical state underwent an ambulatory polygraphy. SDB was defined as an apnea-hypopnea index (AHI) ≥ 15/h. We evaluated the Epworth Sleepiness Scale (ESS), STOP-BANG and Berlin questionnaires as well as anthropometric data and comorbidities regarding their ability to predict SDB. The ESS showed no correlation with SDB. The sensitivity of the Berlin Questionnaire to detect SDB was 73%, specificity was 42%. The STOP-BANG questionnaire showed a sensitivity of 97% while specificity was 13%. Coronary heart disease and/or history of myocardial infarction, hyperuricemia and age significantly contributed to a logistic regression model predicting presence of SDB. However, our regression model explains only 36% of the variance regarding the presence or absence of SDB. The approach to find variables, which would allow an early and reliable differentiation between patients with CVD and coexistence or absence of SDB, failed. Thus, as CVD patients show a high SDB prevalence and poor outcome, only a systematic screening based on measures of respiration-related parameters (i.e., respiratory flow, blood oxygen saturation, etc.) allows for a reliable SDB assessment.

Effects of respiratory muscle training (RMT) in patients with mild to moderate obstructive sleep apnea (OSA).

PURPOSE: Different forms of training focusing on the muscles of the upper airways showed limited effects on obstructive sleep apnea (OSA) and/or snoring. We investigated the effect of generalized respiratory muscle training (RMT) in lean patients with mild to moderate OSA. METHODS: Nine male subjects (52.0 ± 10.8 years, BMI 29.1 ± 2.1 kg/m2) with obstructive sleep apnea (apnea-hypopnea index (AHI) 9-29) participated in an open, single-arm pilot study. After a 1-week build-up phase, patients underwent 4 weeks of normocapnic hyperpnea RMT five times a week for 30 min each. The initial and final measurements comprised polysomnography, pulmonary function tests, Epworth sleepiness scale (ESS), and SF-36 questionnaire (quality of life (QoL) self-assessment). The investigational site was a university-affiliated hospital for pulmonary diseases and sleep medicine, Solingen/Germany. RESULTS: Patients trained effectively, seen by a significant (p < 0.01) increase of breathing frequency (23.3 ± 1.5 /min vs. 30.6 ± 2.9 /min) and minute volume (81.2 ± 13.7 L vs. 109.1 ± 21.9 L). AHI, snoring and ESS remained unchanged after training. QoL as measured by SF-36 significantly (p < 0.05) improved after the training in the subscales "bodily pain" (79 ± 21 vs. 90 ± 12) and "change of health" (3.1 ± 0.3 vs. 2.4 ± 0.5). CONCLUSIONS: There is no evidence that AHI, pulmonary function or daytime sleepiness are affected by 5 weeks of RMT. Nevertheless, there is an improvement of parameters of quality of life. TRIAL REGISTRATION: ClinicalTrials.gov , register no. NCT 00936286.