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.

Recommendations for clinical management of excessive daytime sleepiness in obstructive sleep apnoea - A Delphi consensus study.

STUDY OBJECTIVE: Excessive daytime sleepiness is common with obstructive sleep apnoea and can persist despite efforts to optimise primary airway therapy. The literature lacks recommendations regarding differential diagnosis and management of excessive daytime sleepiness in obstructive sleep apnoea. This study sought to develop expert consensus statements to bridge the gap between existing literature/guidelines and clinical practice. METHODS: A panel of 10 international experts was convened to undertake a modified Delphi process. Statements were developed based on available evidence identified through a scoping literature review, and expert opinion. Consensus was achieved through 3 rounds of iterative, blinded survey voting and revision to statements until a predetermined level of agreement was met (≥80 % voting "strongly agree" or "agree with reservation"). RESULTS: Consensus was achieved for 32 final statements. The panel agreed excessive daytime sleepiness is a patient-reported symptom. The importance of subjective/objective evaluation of excessive daytime sleepiness in the initial evaluation and serial management of obstructive sleep apnoea was recognised. The differential diagnosis of residual excessive daytime sleepiness in obstructive sleep apnoea was discussed. Optimizing airway therapy (eg, troubleshooting issues affecting effectiveness) was addressed. The panel recognised occurrence of residual excessive daytime sleepiness in obstructive sleep apnoea despite optimal airway therapy and the need to evaluate patients for underlying causes. CONCLUSIONS: Excessive daytime sleepiness in patients with obstructive sleep apnoea is a public health issue requiring increased awareness, recognition, and attention. Implementation of these statements may improve patient care, long-term management, and clinical outcomes in patients with obstructive sleep apnoea.

[Latest news on RA-ILD]. / Aktuelles zur RA-ILD.

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is of high clinical relevance. It not only affects the quality of life but also makes a significant contribution to the mortality rate of patients with rheumatoid arthritis. RA-ILD can present with all known radiological and histopathological patterns seen in other interstitial pneumonias. Among these pneumonias, diffuse alveolar damage (DAD), followed by usual interstitial pneumonia (UIP) has the worst prognosis. In addition, acute exacerbation of RA-ILD, which can occur at any time during the disease, is highly lethal. An algorithm for the diagnosis and treatment of RA-ILD is pending and will be addressed in the following article. In addition to immunosuppressants and disease-modifying antirheumatic drugs (DMARD), antifibrotics have recently gained importance in the therapy of RA-ILD.

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.

Randomized Clinical Study of Temporary Transvenous Phrenic Nerve Stimulation in Difficult-to-Wean Patients.

Rationale: Diaphragm dysfunction is frequently observed in critically ill patients with difficult weaning from mechanical ventilation. Objectives: To evaluate the effects of temporary transvenous diaphragm neurostimulation on weaning outcome and maximal inspiratory pressure. Methods: Multicenter, open-label, randomized, controlled study. Patients aged ⩾18 years on invasive mechanical ventilation for ⩾4 days and having failed at least two weaning attempts received temporary transvenous diaphragm neurostimulation using a multielectrode stimulating central venous catheter (bilateral phrenic stimulation) and standard of care (treatment) (n = 57) or standard of care (control) (n = 55). In seven patients, the catheter could not be inserted, and in seven others, pacing therapy could not be delivered; consequently, data were available for 43 patients. The primary outcome was the proportion of patients successfully weaned. Other endpoints were mechanical ventilation duration, 30-day survival, maximal inspiratory pressure, diaphragm-thickening fraction, adverse events, and stimulation-related pain. Measurements and Main Results: The incidences of successful weaning were 82% (treatment) and 74% (control) (absolute difference [95% confidence interval (CI)], 7% [-10 to 25]), P = 0.59. Mechanical ventilation duration (mean ± SD) was 12.7 ± 9.9 days and 14.1 ± 10.8 days, respectively, P = 0.50; maximal inspiratory pressure increased by 16.6 cm H2O and 4.8 cm H2O, respectively (difference [95% CI], 11.8 [5 to 19]), P = 0.001; and right hemidiaphragm thickening fraction during unassisted spontaneous breathing was +17% and -14%, respectively, P = 0.006, without correlation with changes in maximal inspiratory pressure. Serious adverse event frequency was similar in both groups. Median stimulation-related pain in the treatment group was 0 (no pain). Conclusions: Temporary transvenous diaphragm neurostimulation did not increase the proportion of successful weaning from mechanical ventilation. It was associated with a significant increase in maximal inspiratory pressure, suggesting reversal of the course of diaphragm dysfunction. Clinical trial registered with www.clinicaltrials.gov (NCT03096639) and the European Database on Medical Devices (CIV-17-06-020004).

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.

[Hypersensitivity Pneumonitis - an important differential diagnosis of infiltrative lung diseases]. / Exogen allergische Alveolitis ­ Eine wichtige Differenzialdiagnose der infiltrativen Lungenerkrankungen.

Hypersensitivity pneumonitis (HP) is an inflammatory and/or fibrotic disease of the lung parenchyma and terminal bronchioles caused by an allergic reaction to inhaled antigens. The immune response following antigen exposure results in lymphocytic inflammation as well as granuloma formation.The typical histologic pattern of HP consists of cellular interstitial pneumonia, cellular bronchiolitis, and epithelioid cell granulomas. The additional presence of fibrosis has a significant impact on the course as well as the prognosis of the disease and represents a therapeutic approach. Therefore, a classification into a non-fibrotic and a fibrotic phenotype is proposed.The diagnosis of HP is made by high-resolution computed tomography (HRCT) of the lung, evaluation of possible antigen exposure, and bronchoscopy with bronchoalveolar lavage and, if necessary, forceps biopsy. If the diagnosis is inconclusive, transbronchial cryobiopsy or surgical lung biopsy may need to follow. A multidisciplinary board is critical in making the diagnosis.

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.

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.

Research Priorities for Patients with Heart Failure and Central Sleep Apnea. An Official American Thoracic Society Research Statement.

Background: Central sleep apnea (CSA) is common among patients with heart failure and has been strongly linked to adverse outcomes. However, progress toward improving outcomes for such patients has been limited. The purpose of this official statement from the American Thoracic Society is to identify key areas to prioritize for future research regarding CSA in heart failure.Methods: An international multidisciplinary group with expertise in sleep medicine, pulmonary medicine, heart failure, clinical research, and health outcomes was convened. The group met at the American Thoracic Society 2019 International Conference to determine research priority areas. A statement summarizing the findings of the group was subsequently authored using input from all members.Results: The workgroup identified 11 specific research priorities in several key areas: 1) control of breathing and pathophysiology leading to CSA, 2) variability across individuals and over time, 3) techniques to examine CSA pathogenesis and outcomes, 4) impact of device and pharmacological treatment, and 5) implementing CSA treatment for all individualsConclusions: Advancing care for patients with CSA in the context of heart failure will require progress in the arenas of translational (basic through clinical), epidemiological, and patient-centered outcome research. Given the increasing prevalence of heart failure and its associated substantial burden to individuals, society, and the healthcare system, targeted research to improve knowledge of CSA pathogenesis and treatment is a priority.

Effects of continuous positive airway pressure therapy on daytime and nighttime arterial blood pressure in patients with severe obstructive sleep apnea and endothelial dysfunction.

PURPOSE: A nocturnal non-dipping or rise in blood pressure (BP) is associated with poor cardiovascular outcome. This study aimed to test whether continuous positive airway pressure (CPAP) therapy can reduce nocturnal BP and normalize the 24-h BP profile in patients with severe obstructive sleep apnea (OSA) and erectile dysfunction as a surrogate for endothelial dysfunction (ED). PATIENTS AND METHODS: Eighteen consecutive patients with OSA and ED on stable antihypertensive medication (age 55.8 ± 9.5 years, body mass index 35.5 ± 3.8 kg/m2, apnea-hypopnoea index 66.1 ± 27.4/h) were treated with CPAP for 6 months (average daily use 5.8 ± 2.3 h). Twenty-four hour BP recordings were performed using a portable monitoring device. Rising was defined as an increase, whereas non-dipping was defined as a fall in nocturnal BP of less than 10% compared to daytime values. Serum noradrenaline levels as markers of sympathetic activity were measured at baseline and at 6 month follow up. RESULTS: Compared to baseline, nocturnal systolic and diastolic BP were significantly reduced after CPAP therapy (128.5 ± 14 to 122.9 ± 11 mmHg, p = 0.036; 76.2 ± 9 to 70.5 ± 5 mmHg, p = 0.007). The frequency of non-dipping and rising nocturnal systolic BP, as well as mean nocturnal heart rate, was reduced after CPAP treatment (73 to 27%, p = 0.039; 20 to 7%, p = 0.625; from 81.5 ± 10 to 74.8 ± 8 beats per minute p = 0.043). Serum levels of noradrenaline were significantly lower after CPAP therapy (398 ± 195 ng/l vs. 303 ± 135 ng/l, p = 0.032). CONCLUSION: In patients with severe OSA and clinically apparent ED, CPAP therapy was associated with a decrease in nocturnal BP and serum noradrenaline levels, as well as a normalization of the 24-h BP profile.

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.