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Evidence from both animal and human studies now supports the development of ventilator-induced diaphragm dysfunction (VIDD) starting as early as 24 h after initiation of mechanical ventilation in the intensive care unit (ICU). However, although the concept of VIDD is now widely accepted, there remain several unanswered questions regarding its pathophysiology, rate of development, and (potentially) recovery after mechanical ventilation.This state-of-the-art opinion article briefly explains VIDD and provides an update on its clinical and prognostic relevance. It then focusses on state-of-the-art diagnostic approaches to determine diaphragm function, strength, and control (neural and peripheral), highlights knowledge gaps relevant to VIDD, and discusses the use of diaphragm pacing for VIDD prevention. It is suggested that future research projects in mechanically ventilated patients would ideally use both cortical and cervical phrenic nerve stimulation studies over time (including also diaphragm electromyography) as the gold standard techniques. This approach has not yet been utilized in a longitudinally designed study in the ICU. Application of these gold standard techniques would allow better understanding of the true pathophysiology and rate of development of VIDD. Notably, these techniques would be superior to diaphragm ultrasound, which yields surrogate markers of diaphragm function only without any direct measure of diaphragm strength or control. It is also suggested that such translational research would further advance understanding of diaphragm pacing as a very promising treatment option for VIDD.

In comparison to other chronically ill people, patients suffering from chronic obstructive pulmonary disease (COPD) have many additional difficulties to face and conquer. Due to the contribution of avoidable causes of their illness (“smokers’ lung”), society holds people with COPD responsible for their disease, which in return often leads to stigmatization and social isolation. In addition, COPD patients commonly belong to a less privileged social class, own a low socioeconomic status, and lower education. Their physical symptoms are easily observable and – by employing moderate adherence – treatable. Nonetheless, the influence of COPD on a patient’s psyche often plays an overly prominent role during therapy. “There is only half a patient laying on the examination table,” a revelation that sums up the current state of COPD research and the result of the expert meeting “Luftschlösser” (“castles in the clouds”), which took place in spring 2018. Within the limits of the meeting, participants identified practically applicable approaches aiming to enhance the patient management of this challenging patient group. These considerations are supposed to support healthcare professionals in their daily work and aim to improve the therapy as well as the outcome for COPD patients.

Background: Chronic obstructive pulmonary disease (COPD) and coronary heart disease (CHD) often occur together. However, COPD is underdiagnosed among CHD patients. Objectives: This study investigated the prevalence of COPD and relevant pulmonary function test (PFT) impairments in patients with acute myocardial infarction (AMI). Methods: Patients undergoing coronary angiography for AMI were prospectively included. Body plethysmography, lung diffusing capacity, blood gas analysis, and echocardiography were performed. The following patient subgroups were compared: with versus without COPD, ST elevation myocardial infarction (STEMI) versus non-STEMI (NSTEMI). The prevalence of PFT impairments was also recorded. Results: A total of 100 patients (51 with NSTEMI, 49 with STEMI) were included. Twenty patients had diagnosed COPD, of whom 15 were diagnosed for the first time; 80% of all COPD patients were not receiving COPD therapy. Patients with COPD had higher maximum creatine kinase (p = 0.008) and troponin T (p = 0.054) levels than those without COPD. Hypoxaemia was more common in COPD patients (lower oxygen saturation [p = 0.008] and partial pressure of oxygen [PaO2] [p = 0.005]). PaO2 was significantly lower in STEMI compared with NSTEMI (p = 0.017). Independent of a COPD diagnosis, 65 patients had relevant PFT impairments. Conclusions: The high prevalence of undiagnosed COPD and relevant pulmonary function impairments in this cohort of patients with AMI, and the fact that pulmonary disease was untreated in the majority of COPD patients, highlight the importance of a general pulmonary workup of patients with AMI. Furthermore, patients with CHD should undergo screening for COPD, given the fact that COPD patients had larger infarction size.

Today, invasive and non-invasive home mechanical ventilation have become a well-established treatment option. Consequently, in 2010, the German Respiratory Society (Deutsche Gesellschaft fur Pneumologie und Beatmungsmedizin, DGP) has leadingly published the Guidelines on "Non-Invasive and Invasive Mechanical Ventilation for Treatment of Chronic Respiratory Failure." However, continuing technical evolutions, new scientific insights, and health care developments require an extensive revision of the Guidelines. For this reason, the updated Guidelines are now published. Thereby, the existing chapters, namely technical issues, organizational structures in Germany, qualification criteria, disease-specific recommendations including special features in pediatrics as well as ethical aspects and palliative care, have been updated according to the current literature and the health care developments in Germany. New chapters added to the Guidelines include the topics of home mechanical ventilation in paraplegic patients and in those with failure of prolonged weaning. In the current Guidelines, different societies as well as professional and expert associations have been involved when compared to the 2010 Guidelines. Importantly, disease-specific aspects are now covered by the German Interdisciplinary Society of Home Mechanical Ventilation (DIGAB). In addition, societies and associations directly involved in the care of patients receiving home mechanical ventilation have been included in the current process. Importantly, associations responsible for decisions on costs in the health care system and patient organizations have now been involved.

Today, invasive and non-invasive home mechanical ventilation have become a well-established treatment option. Consequently, in 2010, the German Respiratory Society (DGP) has leadingly published the guidelines on "Non-Invasive and Invasive Mechanical Ventilation for Treatment of Chronic Respiratory Failure." However, continuing technical evolutions, new scientific insights, and health care developments require an extensive revision of the guidelines. For this reason, the updated guidelines are now published. Thereby, the existing chapters, namely technical issues, organizational structures in Germany, qualification criteria, disease-specific recommendations including special features in pediatrics as well as ethical aspects and palliative care, have been updated according to the current literature and the health care developments in Germany. New chapters added to the guidelines include the topics of home mechanical ventilation in paraplegic patients and in those with failure of prolonged weaning. In the current guidelines, different societies as well as professional and expert associations have been involved when compared to the 2010 guidelines. Importantly, disease-specific aspects are now covered by the German Interdisciplinary Society of Home Mechanical Ventilation (DIGAB). In addition, societies and associations directly involved in the care of patients receiving home mechanical ventilation have been included in the current process. Importantly, associations responsible for decisions on costs in the health care system and patient organizations have now been involved.

Background: Pulmonary rehabilitation (PR) has a positive impact on functional status and quality of life in patients with interstitial lung disease (ILD). Objectives: This study investigated the effects of PR in hypercapnic ILD patients receiving nighttime noninvasive positive pressure ventilation (NPPV). Methods: Consecutive ILD patients referred to a specialized inpatient PR center were included. All participated in a PR program. Those with hypercapnia received NPPV (NPPV group; n = 29); the remaining patients served as comparison group (n = 319). Results: PR improved the 6-min walk distance by 64.4 ± 67.1 m versus baseline (p < 0.0001) in NPPV patients and by 43.2 ± 55.1 m (p < 0.0001) in the comparison group (difference 21.1 m, 95% confidence interval 0.5-41.8; p = 0.045). There was no change in total lung capacity during PR in NPPV recipients or the comparison group. Forced vital capacity significantly increased from baseline in the comparison, but not the NPPV group. NPPV recipients were significantly more likely than the comparison group to have improved dyspnea during PR (p = 0.049). There was no improvement in the 36-item Short Form (SF-36) physical component score in the NPPV group after PR, but there was in the comparison group. PR improved the SF-36 mental component score versus baseline in both groups. Conclusion: An individually tailored PR plus nighttime NPPV appears feasible in hypercapnic ILD patients and significantly improves exercise capacity and quality of life.

Background: Correct measurement of PO2 and PCO2 is essential to establish appropriate therapy such as long-term oxygen therapy (LTOT) in patients suffering from respiratory failure. Objectives: We aimed to compare common invasive and noninvasive methods for assessing blood gas components for spot check analysis. Methods: Arterial (PaO2, PaCO2) and capillary blood gas (PCBGO2, PCBGCO2) measurements were taken consecutively in a randomized order and were compared with noninvasive measurements obtained from the transcutaneous monitoring of PO2 and PCO2 (PtcO2, PtcCO2, sensor-temperature 44°C). Capillary samples were taken from both arterialized earlobes, where samples of right earlobes were defined as a reference value. Pain assessment of all measurements was evaluated by each subject using the 100-mm visual analogue scale. Results: 83 patients and 17 healthy subjects were included. The mean difference between PaO2 and PtcO2 was 11.9 ± 15.0 mm Hg, with lower limits of agreement (LLA) of -17.4 mm Hg (95% confidence interval (CI) -22.5 to -12.3 mm Hg), and upper limits of agreement (ULA) of 41.1 mm Hg (95% CI 36.0-46.2 mm Hg). The comparison of PaO2 with PCBGO2 showed a mean difference of 5.6 ± 7.2 mm Hg (LLA -11.0; ULA 19.6 mm Hg). The mean difference between PaCO2 and PtcCO2 was 1.1 ± 4.9 mm Hg (LLA -8.6; ULA 10.8 mm Hg) and that between PaCO2 and PCBGCO2 was 0.7 ± 2.0 mm Hg (LLA -3.3; ULA 4.8 mm Hg). The analysis of capillary blood gases (36.2 ± 22.3 mm) was rated as more painful than the analysis of arterial blood gases (26.1 ± 20.6 mm), while transcutaneous measurement was rated as the least painful method (1.9 ± 7.4 mm; all p < 0.0001). Conclusions: The comparison of different methods for blood gas measurements showed substantial differences between capillary and arterial PO2 and between transcutaneous and arterial PO2. Therefore, arterial PO2 analysis is the essential method evaluating indication for LTOT. Nevertheless, comparative analysis further indicated capillary PCO2 as an adequate surrogate for arterial PCO2.

Background: Noninvasive positive-pressure ventilation (NPPV) using intelligent volume-assured pressure support (iVAPS) combines volume- and pressure-preset NPPV and therefore uses a variation of inspiratory positive airway pressures. Objectives: The effect of iVAPS on sleep quality in stable hypercapnic patients with chronic obstructive pulmonary disease (COPD) has not been determined. Methods: In this randomized, open-label, two-treatment, two-period, crossover study, patients were randomized to receive high-intensity (HI)-NPPV and then iVAPS or iVAPS and then HI-NPPV. Patients were studied in hospital for 2 consecutive nights, employing full polysomnography (PSG), transcutaneous partial pressure of CO2 (PtcCO2) monitoring, blood gas analysis and a visual analog scale (VAS)-based sleep questionnaire. After discharge, patients used HI-NPPV and iVAPS at home, each for 6 weeks. They had to answer a VAS question concerning sleep every morning, and were telephoned weekly and asked additional questions. At the end of each treatment period, they were visited at home for the determination of blood gases and treatment adherence, and to change the NPPV mode. Results: Fourteen patients were enrolled. In-hospital PSG measurements showed no difference in sleep quality between iVAPS and HI-NPPV. At home, patients reported more restful sleep during iVAPS than HI-NPPV (p = 0.04). Blood gases during spontaneous breathing at home did not differ with iVAPS and HI-NPPV, and there was a greater decrease in PtcCO2 during iVAPS than during HI-NPPV (p = 0.003). Conclusion: Although sleep quality in hospital was not different between iVAPS and HI-NPPV, COPD patients with chronic hypercapnic respiratory failure reported a trend towards more restful sleep at home with iVAPS. In addition, nocturnal hypercapnia was effectively treated with iVAPS.

Background: Physical activity is known to cause significant deoxygenation in patients with severe chronic obstructive pulmonary disease (COPD). Although noninvasive positive pressure ventilation (NPPV) has been shown to improve oxygenation and physical activity in these patients, no practical approach for the application of NPPV during walking has yet been established. Objective: To elucidate the most effective approach to preserving oxygenation during walking in patients with severe COPD receiving long-term NPPV. Methods: Three 12-min walking tests were performed in a randomized cross-over design on 3 consecutive days, comparing the usual and double dosages of oxygen versus NPPV plus the usual dosage of oxygen. The ventilator and oxygen tank were placed in a backpack. Results: Eleven patients (FEV1 26 ± 9% predicted) completed the study, while 8 patients refused to walk with NPPV, due to the weight of the ventilatory device (7.3 kg with NPPV vs. 3.1 kg without). PaO2 changes during walking differed [p = 0.01, repeated-measures (RM)-ANOVA], whereas dyspnea was unchanged. The difference in PaO2 change was 14.0 ± 16.6 mm Hg (unadjusted p = 0.0036, critical level = 0.017, RM-ANOVA) in favor of NPPV compared to the usual dosage of oxygen. Changes in FEV1, tidal volume and inspiratory impedance were in favor of NPPV-aided exercise (all p < 0.05, RM-ANOVA). Walking distance was reduced under NPPV (555 ± 227 m) compared to the usual (619 ± 210 m) and double (622 ± 215 m) dosages of oxygen (p = 0.024, RM-ANOVA). Conclusions: NPPV plus supplemental oxygen, but not oxygen alone, preserves oxygenation during walking in patients with severe COPD. However, dyspnea and walking distance were not improved due to the burden of carrying the heavy ventilatory equipment in a backpack.