Background/Objectives: Volatile organic compounds (VOCs) are emerging as non-invasive biomarkers of metabolic and disease-related processes, yet their reliable detection from complex biological matrices such as urine remains analytically challenging. This study aimed to establish a robust, non-targeted headspace solid-phase microextraction gas chromatography–mass spectrometry (HS–SPME GC–MS) workflow optimized for very small-volume urinary samples. Methods: We systematically evaluated the effects of pH adjustment and NaCl addition on VOC extraction efficiency using a 75 µm CAR/PDMS fiber and a sample volume of only 0.75 mL. Method performance was further assessed using concentration-dependent experiments with representative VOC standards and by application to real human urine samples analyzed in technical triplicates. Results: Acidification to pH 3 markedly improved extraction performance, increasing both total signal intensity and the number of detectable VOCs, whereas alkaline conditions and additional NaCl produced only minor effects. Representative VOC standards showed compound-specific linear dynamic ranges with minimal carry-over within the relevant analytical range. Application to real urine samples confirmed high analytical reproducibility, with triplicates clustering tightly in principal component analysis and most metabolites exhibiting relative standard deviations below 25%. Conclusions: The optimized HS–SPME GC–MS method enables comprehensive, non-targeted urinary VOC profiling from limited sample volumes. This workflow provides a robust analytical foundation for exploratory volatilomics studies under sample-limited conditions and supports subsequent targeted method refinement once specific compounds or chemical classes have been prioritized.

Abstract Background Community-acquired pneumonia (CAP) is a common reason for presentation to the emergency department (ED), but accurate diagnosis is challenging due to overlapping and often nonspecific clinical features. Data on the frequency and spectrum of alternative diagnoses in patients initially diagnosed with CAP in the ED are limited. The aim of this study was to evaluate the diagnostic concordance of an initial ED diagnosis of CAP, characterize common alternative discharge diagnoses, and analyze clinical, laboratory, imaging utilization, and vital sign parameters associated with confirmed CAP. Methods We conducted a retrospective analysis of diagnostic concordance and differential diagnoses in 1,385 adult patients who presented to the ED of Hannover Medical School and were initially diagnosed with CAP. Initial ED diagnoses were compared with discharge diagnoses. Results The cohort comprised 37% female and 63% male patients with a median age of 71 years (IQR 58–79). Comparison between initial ED and discharge diagnoses demonstrated that suspected CAP was confirmed in 52% (n = 663) of cases. The most common differential diagnoses were other pulmonary conditions (n = 297, 41%), cardiac conditions (n = 150, 21%), and renal conditions (n = 95, 13%). Patients with confirmed CAP showed significantly higher C-reactive protein (CRP) levels (82 mg/L [IQR 37–159] vs. 57 mg/L [IQR 22–127]; p < 0.001) and slightly higher body temperature (37.1 °C [IQR 36.4–38.0] vs. 36.8 °C [IQR 36.2–37.7]; p < 0.001) than those with alternative diagnoses. Conclusion Only about half of patients initially diagnosed with CAP in the emergency setting had a confirmed diagnosis at discharge, indicating that CAP in this context should be regarded as a working diagnosis rather than a definitive entity. Isolated laboratory, imaging, and vital sign parameters showed limited ability to distinguish CAP from alternative diagnoses, highlighting the importance of structured reassessment after admission to confirm or revise the initial diagnosis and to reduce misclassification and unnecessary antibiotic use.

This study explores the relationship between patient activation, adherence behaviors, asthma knowledge, and response to monoclonal antibody (mAb) therapy in severe eosinophilic asthma (SEA). Despite advances in mAb therapies, some SEA patients continue to experience uncontrolled symptoms. Understanding these factors could lead to more effective, personalized treatment strategies. Participants diagnosed with SEA and undergoing mAb therapy for 6-9 months were recruited from three German university outpatient clinics. They were categorized using the Biologics Asthma Response Score (BARS) into responders, partial responders, and non-responders. Data collection focused on demographic details, lung function, medication history, patient activation (PAM13-D), and adherence (A14 questionnaire). Statistical analyses assessed the impact of adherence and knowledge on treatment outcomes. Of the 140 participants, 61% were responders, 24% partial responders, and 15% non-responders. Age, sex distribution, smoking status, pack-years, eosinophil levels, ExNO and lung function parameters were comparable across response groups. A14 scores and asthma knowledge differed significantly across response groups, whereas PAM13-D did not. In ordinal logistic regression, asthma knowledge remained associated with BARS-defined response category after adjustment. A negative attitude towards drugs was associated with response category in univariate analysis, but this association was attenuated after adjustment. Better asthma knowledge was associated with BARS-defined response to mAb therapy, while PAM13-D and overall A14 score were not independently associated with response. Medication attitude may still be clinically relevant, but their association with response should be interpreted cautiously. These findings support a patient-centered approach that considers asthma knowledge, adherence-related behaviors and medication attitudes during biologic treatment. Prospective studies are needed to determine whether targeted education and adherence support can improve clinical outcomes.

Bronchiectasis is a chronic, often progressive respiratory disease characterized by irreversible dilation of the bronchi. It is etiologically heterogeneous and frequently associated with a significant symptom burden, multiple complications, and reduced quality of life. In recent years, the global prevalence of bronchiectasis has increased markedly, placing a substantial economic burden on healthcare systems. These consensus-based guidelines are the first German-language guidelines focused on the management of bronchiectasis in adults. They underscore the critical role of thoracic imaging - particularly computed tomography - in diagnosing and distinguishing bronchiectasis and highlight the importance of identifying the underlying etiology in guiding treatment decisions. The guidelines provide comprehensive recommendations for both pharmacological and non-pharmacological treatment strategies. Non-drug interventions include smoking cessation, physiotherapy, physical training, pulmonary rehabilitation, noninvasive ventilation, thoracic surgery, and lung transplantation. Pharmacological therapies emphasize the long-term use of mucolytics, bronchodilators, anti-inflammatory agents, and antibiotics. In addition, the guidelines address the management of upper airway involvement, common comorbidities, and acute exacerbations. They also cover sociomedical issues, disability rights, and the role of patient education and self-management in optimizing care. Special life stages - such as transition from pediatric to adult care, family planning, pregnancy, parenthood, and palliative care - are also considered. The overarching goal was to promote comprehensive, consensus-driven, and patient-centered care that accounts for individual risks and needs.

SARS-CoV-2 infection can lead to persistent symptoms (i.e., long/post-COVID), especially in unvaccinated individuals. Little is known about the sustained impact of acute severe COVID-19 on immune signatures and long/post-COVID symptoms, often associated with cardiovascular events and pulmonary impairment. The longitudinal cohort (LC) was obtained from N = 46 patients with previous severe COVID-19 and prior to SARS-CoV-2 vaccination, collected over 5 visits up to 12 months after discharge (n = 139). Long/post-COVID status was assessed by lung function and fatigue scores. Blood was analysed regarding immune cell profiles, SARS-CoV-2 antibodies, and autoantigens. LC patients were compared with 39 acute severe COVID-19 ICU patients and 28 unexposed pre-pandemic donors (UE) and correlated with clinical parameters. LC patients exhibited long-term decreased CD4+/CD8+ T cell ratio, differentiation from naïve to TEMRA, CD57+CCR7- memory, and HLA-DR+CD38+ activated CD4+ and CD8+ T cells. LC plasma profiles displayed elevated levels of markers for chronic inflammation and endothelial injury. Chronic inflammatory chemokines and cardiovascular markers remained high. These markers and autoantibodies against centromere structures negatively correlated with lung function. At 1-year post-discharge, LC patients with a COVID-19 ICU history displayed sustained significant changes in their immune profile at cellular and inflammatory levels, revealing signatures of persistent inflammation and endothelial injury.

BACKGROUND:To determine long-term immunogenicity and reactogenicity of different SARS-CoV-2 messenger RNA (mRNA) vaccines in a population ≥75 years of age in a randomized trial. METHODS:Participants were randomized to receive either BNT162b2 30 µg or a double booster dose of mRNA-1273, i.e., 100 µg, as the third and fourth vaccinations (first and second booster). The primary endpoint was the rate of a two-fold geometric mean titer (GMT) antibody increase 14 days after vaccination targeting the receptor binding domain (RBD) region of wild-type SARS-CoV-2. Secondary endpoints included neutralizing capacity against wild-type and 25 variants at 14 days (D14) and 12 months (M12). Safety was assessed by monitoring adverse events (AEs) for 7 days after vaccination. FINDINGS:Between November 2021 and September 2022, 322 participants received a SARS-CoV-2 vaccine as a first (Part A) or second booster (Part B). Primary endpoint results have been published previously. In Part A, it was reached by 100% of participants in both vaccine arms, with a higher GMT increase in the mRNA-1273 arm (ratio, 1.64). At M12, the GMT of anti-RBD immunoglobulin G (IgG) was slightly higher than at D14 (9319.7 vs 8568.4 IU/mL) in the BNT162b2 arm, while in the mRNA-1273 arm, the GMT was equal (14,163.8 vs 14,266.7 IU/mL at D14). In Part B, the primary endpoint was reached by 78.5% of participants in the BNT162b2 and 87.2% in the mRNA-1273 arm (P = 0.056), respectively, with a higher GMT increase of anti-RBD IgG for mRNA-1273 (ratio, 1.38). At M12, GMT of anti-RBD IgG was markedly lower than at D14 (9962 vs 15,248.2 IU/mL) in the BNT162b2 arm as well as in the mRNA-1273 arm (12,024.3 vs 21,325.6 IU/mL). Higher neutralizing capacity in individuals who received a booster with mRNA-1273 was detected against wild-type and 15 of 25 tested variants. Fewer participants in the mRNA-1273 arm had vaccine-related AEs (29.6% vs 38.5%), but severity was more frequently grade 2 (n = 38, 28.1% vs n = 22, 16.3%). INTERPRETATION:Long-term serological immunogenicity and virus neutralization capacity in participants ≥75 years of age were numerically better with an mRNA-1273 100 µg booster, with a comparable safety profile.

Hospital-acquired pneumonia caused by Staphylococcus aureus is associated with patient morbidity and mortality, despite adequate antibiotic therapy. This illustrates the need for treatments beyond antibiotics. The pore-forming heptameric toxin α-hemolysin (Hla) is a major pathogenicity factor of S. aureus and a clinically validated target. We identify quinoxalinediones (QDS) as highly potent Hla inhibitors, conferring protection against the hallmarks of Hla-induced pathogenicity such as Ca2+ influx, cytotoxicity, hemolysis, and monolayer destruction. The effects were exerted across major Hla subtypes in all relevant cell types. QDS prevented the formation of functional pores by interacting with Hla near the phospholipid-binding site. The QDS analog, H052, was active in mouse models of S. aureus lung infections, when administered prophylactically or therapeutically, either as monotherapy or when given in combination with the antibiotic linezolid. The study provides evidence that complex bacterial toxins can be targeted in vivo by drug-like small molecules.

Die im Januar 2024 aktualisierte S3-Leitlinie zur „Epidemiologie, Diagnostik und Therapie erwachsener Patienten mit nosokomialer Pneumonie“ bietet evidenzbasierte Empfehlungen zur Verbesserung der Versorgung dieser häufigen Krankenhausinfektion. Sie ersetzt die Version von 2017 und wurde unter Beteiligung von 14 Fachgesellschaften überarbeitet. Die Leitlinie umfasst 26 Empfehlungen, etwa zur differenzierten Diagnostik (inkl. Multiplex-PCR, BAL, Biomarkern) und zur kalkulierten antimikrobiellen Therapie. Sie betont kürzere Therapiedauern, gezielte Einsatzindikationen für Kombinationstherapien und moderne Konzepte wie Antibiotic Stewardship. Neu sind Empfehlungen zu viralen und fungalen Erregern sowie ein Flussdiagramm zur initialen Therapieentscheidung. Die Gültigkeit der Leitlinie reicht bis Februar 2029.

BACKGROUND:Nosocomial pneumonia, encompassing hospital-acquired (HAP) and ventilator-associated pneumonia (VAP), remains a major cause of morbidity and mortality in hospitalized adults. In response to evolving pathogen profiles and emerging resistance patterns, this updated S3 guideline (AWMF Register No. 020-013) provides an evidence-based framework to enhance the diagnosis, risk stratification, and treatment of nosocomial pneumonia. METHODS:The guideline update was developed by a multidisciplinary panel representing key German professional societies. A systematic literature review was conducted with subsequent critical appraisal using the GRADE methodology. Structured consensus conferences and external reviews ensured that the recommendations were clinically relevant, methodologically sound, and aligned with current antimicrobial stewardship principles. RESULTS:For the management of nosocomial pneumonia patients should be divided in those with and without risk factors for multidrug-resistant pathogens and/or Pseudomonas aeruginosa. Bacterial multiplex-polymerase chain reaction (PCR) should not be used routinely. Bronchoscopic diagnosis is not considered superior to non-bronchoscopic sampling in terms of main outcomes. Combination antibiotic therapy is now reserved for patients in septic shock and high risk for multidrug-resistant pathogens, while select patients may be managed with monotherapy (e. g., meropenem). In clinically stabilized patients, antibiotic therapy should be de-escalated and focused, as well as duration shortened to 7-8 days. In critically ill patients, prolonged application of suitable beta-lactam antibiotics should be preferred. Patients on the intensive care unit (ICU) are at risk for invasive pulmonary aspergillosis (IPA). Diagnostics for Aspergillus should be performed with an antigen test from bronchial lavage fluid. CONCLUSION:This updated S3 guideline offers a comprehensive, multidisciplinary approach to the management of nosocomial pneumonia in adults. By integrating novel diagnostic modalities and refined therapeutic strategies, it aims to standardize care, improve patient outcomes, and enhance antimicrobial stewardship to curb the emergence of resistant pathogens.

Interstitial lung disease (ILD) is a clinical term that refers to a diverse group of non-neoplastic lung diseases. This group includes idiopathic and secondary pulmonary entities that are often associated with progressive pulmonary fibrosis. Currently, therapeutic approaches based on specific structural targeting of pulmonary fibrosis are limited to nintedanib and pirfenidone, which can only slow down disease progression leading to a lower mortality rate. Lung transplantation is currently the only available curative treatment, but it is associated with high perioperative mortality. The pulmonary vasculature plays a central role in physiological lung function, and vascular remodelling is considered a hallmark of the initiation and progression of pulmonary fibrosis. Different patterns of pulmonary fibrosis commonly exhibit detectable pathological features such as morphomolecular changes, including intussusceptive and sprouting angiogenesis, vascular morphometry, broncho-systemic anastomoses, and aberrant angiogenesis-related gene expression patterns. Dynamic cellular interactions within the fibrovascular interface, such as endothelial activation and endothelial-mesenchymal transition, are also observed. This review aims to summarise the current clinical, radiological and pathological diagnostic algorithm for different ILDs, including usual interstitial pneumonia/idiopathic pulmonary fibrosis, non-specific interstitial pneumonia, alveolar fibroelastosis/pleuroparenchymal fibroelastosis, hypersensitivity pneumonitis, systemic sclerosis-related ILD and coronavirus disease 2019 injury. It emphasises an interdisciplinary clinicopathological perspective. Additionally, the review covers current therapeutic strategies and knowledge about associated vascular abnormalities.

The updated S3 guideline on the "Epidemiology, Diagnosis and Treatment of Adult Patients with Nosocomial Pneumonia", published in January 2024, provides evidence- and consensus-based recommendations aimed at improving care for this prevalent hospital-acquired infection. Replacing the 2017 version, the guideline was developed through an interdisciplinary process involving 14 professional societies. It includes 26 recommendations, covering extended diagnostic strategies (including multiplex PCR, biomarkers, and BAL) and tailored antimicrobial therapy. Key innovations include shortened treatment durations, targeted use of combination regimens, integration of viral and fungal pathogens, and a flowchart to guide empirical therapy. Emphasis is placed on antibiotic stewardship, reevaluation strategies, and resistance management. The guideline remains valid until February 2029.

Granulomas are the hallmark of mycobacterial (MB) infections, forming structured immune environments that contain bacteria but also drive disease persistence. However, their spatial and functional organization remains unclear. Using spatial RNA sequencing on 38 patient samples, we identified five distinct granuloma niches: a necrotic core, an immune-activated inner niche, an inflammatory and an extracellular matrix (ECM)-remodeling middle niche, an outer structural niche, and a tertiary lymphoid structure niche supporting antigen presentation. Immune activity peaks in the inner niche, transitioning to fibrosis at the periphery. Lymph node granulomas display reduced fibroblast involvement but stronger JAK-STAT activation. Mycobacterium tuberculosis (MTB) granulomas exhibit heightened JAK-STAT and IFN-γ signaling, while non-tuberculous mycobacteria (NTM) granulomas show increased hypoxia signatures. Compared to sarcoidosis, MB granulomas feature a structured adaptive immune response, marked by the clustering of plasma cells. Our findings, accessible via , define key disease signatures, guiding biomarker discovery and therapeutic targeting in granuloma-related diseases. ### Competing Interest Statement The authors have declared no competing interest. ERC Starting Grant, 948207 Lower Saxony Center for Artificial Intelligence and Causal Methods in Medicine, ZN4257 Deutsche Forschungsgemeinschaft, 390874280 Lower Saxony MWK Sprung Fund, 19777006 Fritz Thyssen Foundation, 10.21.2.021MN Else Kröner-Fresenius Foundation, 2023_EKCS.18

The following case report details the case of a 40-year-old Caucasian patient who presented with dyspnea following a serologically confirmed mild-to-severe pulmonary infection with SARS-CoV-2. Chest computer tomography revealed a solitary ground-glass pulmonary nodule in the lower right lobe, measuring 2.1 cm in diameter. Video-assisted thoracoscopic surgery wedge resection revealed well-circumscribed lymphoid aggregates adjacent to the round, smaller airways, bronchioles, and blood vessels. IgKappa B exhibited a monoclonal polyclonal pattern, in contrast to the behavior exhibited by IgKappa A and IgLambda. In the following discussion, the lymphoid lesion was considered in the context of lymphoid hyperplasia, accompanied by an early infiltration of low-grade extranodal B cell lymphoma of the bronchus-associated lymphoid tissue (BALToma).

Background: Lung transplantation is the treatment of choice for end-stage nonmalignant lung disease. It has become a routine procedure through advances in donor lung preservation, extracorporeal membrane oxygenation, immunosuppression, intensive care medicine, and follow-up care. Methods: This review is based on publications about lung transplantation that were retrieved by a selective literature search, and on the procedures and experience of two large-volume lung transplantation centers. Results: The mean survival time after lung transplantation is six years, which is the shortest after the transplantation of any solid organ. Chronic graft dysfunction is present in 41% of patients at five years and is the main cause of death after lung transplantation, followed by infection and cancer. Conclusion: Despite all the advances in lung transplantation, acute and-above all-chronic graft dysfunction still pose a major challenge for large-volume transplantation centers. Immunosuppression that is individually tailored to prevent both graft rejection and infection is important for these patients' longterm survival. Xenotransplantation and so-called lung bioengineering may become available in the future as alternatives to allotransplantation.

BACKGROUND:Cystic fibrosis is caused by mutations of the cystic fibrosis transmembrane conductance regulator, CFTR, an epithelial anion transport protein, responsible for, inter alia, sputum viscoelasticity in the lung. We previously identified the TNF receptor superfamily 1A TNFRSF1A (TNFR1) as a genetic modifier of CFTR function and disease severity in the CF twin and sibling study population. We aimed to replicate our findings in independent cohorts, assess the role of TNFR1 for patient survival and identify functional changes associated with TNFR1 polymorphisms. METHODS:We incorporated data from three independent long-term mono- and multicentric cohorts of people with cystic fibrosis (pwCF) to confirm the previously described association of TNFR1 with CFTR function and to extend our study to include survival data for our local cohort and a pan-European cohort of pwCF. We studied TNFR1 transcripts obtained from primary airway epithelia grown as air-liquid interface cultures to address possible mechanisms involved in up-stream and down-stream effects of TNFR1. FINDINGS:Survival differed by more than a decade when comparing carriers of contrasting TNFR1 genotypes among unrelated pwCF as well as among CF siblings pairs. The presence of the TNFR1 transcript variant TNFR1delEx2 in primary airway epithelia was associated with TNFR1 genotype. INTERPRETATION:The association of the TNFR1 transcript variant TNFR1delEx2 associates with the TNFR1 genotype, possibly mediating the genotype-survival association we found regarding TNFR1 genotype and patient survival in cystic fibrosis. FUNDING:Supported by the German Ministry for Education and Research (BMBF) (82DZL009B1 to MAM and 82DZL002A1, to GH, BT, AMD, FS) and the Mukoviszidose Institut gGmbH (MI-2002, to LN, AMD, FS).

Sepsis and septic shock, defined by a profound immune dysregulation, are among the leading causes of death in the intensive care unit (ICU). Despite advances in understanding the underlying pathophysiology, evidence for specific immunomodulatory treatment does not exist to date. Therapeutic plasma exchange (TPE) represents an adjunctive treatment approach to rebalance immune homeostasis. In the EXCHANGE-1 trial, we recently demonstrated a rapid hemodynamic improvement, possibly caused by the removal of harmful mediators and the replacement of protective plasma proteins. The aim of this secondary analysis is to further characterize the underlying immunomodulatory effects and to identify biomarkers that may predict treatment response. This secondary analysis included patients in early septic shock (< 24 h duration) and a norepinephrine (NE) dose of ≥ 0.4 μg/kg/min. Patients were randomized 1:1 to receive standard of care (SOC) or SOC + one single TPE and plasma samples were collected before and after TPE. Within-group and between group effects of circulating levels of acute-phase proteins [CRP and Pentraxin3 (PTX3)], inflammatory mediators (IL-4, IL-6, IL-8, IL-10, TNF-α, IL-2Rα/CD25) and damage-associated molecular pattern (DAMP) [cell-free DNA (cfDNA)] were analyzed via paired t test or Wilcoxon signed-rank test and a mixed-effects model. Multivariate mixed‐effects modeling of NE and lactate reduction was performed to investigate if cfDNA could be associated with treatment response to TPE. TPE led to a significant reduction in circulating acute-phase protein levels (CRP p = 0.00976, PTX3 p = 0.0001). Pro-inflammatory cytokines, such as circulating TNF-α-, IL-6- und IL-8-levels, were significantly reduced in both groups with no significant difference between treatment groups except for IL-2Rα/CD25 (p ≤ 0.0001). In a multivariate mixed-effects model, rising cfDNA levels over the first 6 h indicated refractoriness to SOC treatment regarding NE (p = 0.004) and lactate (p = 0.001), whereas those receiving TPE demonstrated sustained reductions in both parameters. In this secondary analysis of the EXCHANGE-1 trial adjunctive TPE is associated with the reduction of acute-phase proteins and IL-2Rα/CD25, however not with the reduction of pro-inflammatory cytokines. This phenomenon could contribute to the observed enhancement in hemodynamics among patients with septic shock. Furthermore, TPE may be particularly beneficial for patients with septic shock who exhibit rising levels of cfDNA.

Hintergrund Die nosokomiale Pneumonie, die sowohl die im Krankenhaus erworbene (HAP) als auch die beatmungsassoziierte Pneumonie (VAP) umfasst, ist nach wie vor eine Hauptursache für Morbidität und Mortalität bei hospitalisierten Erwachsenen. Bei sich verändernden Erregerprofilen und aufkommenden Resistenzmustern bietet die vorliegende aktualisierte S3-Leitlinie (AWMF-Register-Nr. 020-013) eine evidenzbasierte Empfehlung zur Verbesserung der Diagnose, Risikostratifizierung und Behandlung der nosokomialen Pneumonie. Methoden Die Aktualisierung der Leitlinie wurde von einem multidisziplinären Gremium entwickelt, in dem die wichtigsten deutschen Fachgesellschaften vertreten waren. Es wurde eine systematische Literaturrecherche mit anschließender kritischer Bewertung nach der GRADE-Methode durchgeführt. Strukturierte Konsensuskonferenzen stellten sicher, dass die Empfehlungen klinisch relevant und methodisch fundiert sind und den aktuellen Grundsätzen des Antibiotic Stewardship entsprechen. Ergebnisse Bei der Behandlung nosokomialer Pneumonien sollten die Patienten in solche mit und solche ohne Risikofaktoren für multiresistente Erreger und/oder Pseudomonas aeruginosa unterteilt werden. Die bakterielle Multiplex-Polymerase-Kettenreaktion (PCR) sollte nicht routinemäßig eingesetzt werden. Die bronchoskopische Diagnose wird im Hinblick auf die wichtigsten Ergebnisse nicht als besser angesehen als die nicht bronchoskopische Probenahme. Eine Antibiotika-Kombinationstherapie ist Patienten mit septischem Schock und hohem Risiko für multiresistente Erreger vorbehalten, während die anderen Patienten mit einer Monotherapie (z. B. Meropenem) behandelt werden können. Bei klinisch stabilisierten Patienten sollte die Antibiotikatherapie deeskaliert und fokussiert sowie die Dauer auf 7–8 Tage verkürzt werden. Bei kritisch kranken Patienten sollte eine prolongierte Applikationsdauer geeigneter Betalaktam-Antibiotika bevorzugt werden. Bei Patienten auf der Intensivstation (ICU) besteht das Risiko einer invasiven pulmonalen Aspergillose (IPA). Die Diagnostik auf Aspergillus sollte mit einem Antigentest aus Bronchiallavageflüssigkeit erfolgen. Schlussfolgerung Diese aktualisierte S3-Leitlinie bietet einen umfassenden, multidisziplinären Ansatz für die Behandlung der nosokomialen Pneumonie bei Erwachsenen. Durch die Integration neuer diagnostischer Verfahren und verfeinerter therapeutischer Strategien zielt sie darauf ab, die Behandlung zu standardisieren, die Ergebnisse für die Patienten sowie das antimikrobielle Stewardship zu verbessern, um das Auftreten resistenter Erreger einzudämmen.

Introduction: The underlying causes of exertional dyspnoea and exercise limitation in post-COVID syndrome remain uncertain. We performed deep-phenotyping of post-COVID patients to evaluate limitations of ventilation, gas exchange and cardiopulmonary circulation in a multicentre, cross-sectional study. Methods: The dyspnoea index and aerobic exercise performance (peakVO2) were determined by questionnaires and cardiopulmonary exercise testing, respectively, in a cohort of 86 post-COVID patients and 12 controls. Lung function, gas exchange and ventilation-perfusion mismatch were evaluated. Cardiac parameters were measured by echocardiography and, in a subgroup, systemic vascular characteristics by pulse wave analysis. Results: Post-COVID patients showed low ventilation at peak exercise [VE(peak)], ventilatory inefficiency, low right heart dimensions and low basal oxygen uptake. In a multivariate regression analysis, ventilatory parameters - high breathing frequency at peak exercise (β=0.15, p=0.004) and low forced expiratory volume in 1 s (β=-0.33, p=0.007) - and right atrial end-systolic area index (RA ESAi; β=-0.34, p<0.001) were independent predictors of dyspnoea, while low VE(peak) (β=0.46, p<0.001) and low aerobic capacity (β=0.51, p<0.001) independently predicted low peakVO2. Low RA ESAi was associated with a low diffusion coefficient (r=0.36), low end-tidal pCO2 (r=0.39) and high heart rate (r=-0.31). Subgroup analysis of patients showed specific associations between dyspnoea and diastolic and bronchial function, low blood pressure, hyperventilation or oxygen uptake. Conclusion: Preload insufficiency associated with gas exchange disturbances contributes to the sensation of dyspnoea in post-COVID patients, as well as ventilatory limitations, while peakVO2 was predominantly associated with aerobic capacity. Three phenotypes were defined, indicating the need for tailored interventions. ### Competing Interest Statement All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; K. Lo has received research grants from DFG and was supported under JLU-CAREER- program; K. Krueger has received payment honorariums from Amgen; Amicus Therapeutics; AstraZeneca; Bayer; Novartis; Takeda; Boehringer Ingelheim; Bristol Myers-Squibb; Pfizer; Amgen; Daichii-Sankyo; DGK and for leadership/fiduciary role in the working group Sports Cardiology of the german cardiac society (DGK); K. Milger has received a grant from Bundesministerium fuer Bildung und Forschung BMBF. C. Tabeling has received honorariums from AstraZeneca, Berlin-Chemie, he was was supported for attedning meetings at AstraZeneca, GlaxoSmithKline and participated on data safety monitoring board at AstraZeneca, GlaxoSmithKline; I. Pink has received grant from DZL (Deutsches Zentrum fuer Lungenforschung), COFONI (COVID-19-Research Network of the State of Lower Saxony) and honorariums from GAIA GmbH, AstraZeneca, and Streamedup. I. Pink also participated on Advisory Board at BioNTech. N. Kremer has received consulting fees from MSD and OrphanCare and got payment from MSD. N.Kremer was also supported for attending meetings at AOP. M- Hecker has received grants from Bundesministerium fuer Bildung und Forschung BMBF and consulting fees from Olympus; S. Kuhnert has received consulting fees from AstraZeneca, GSK and Sanofi and gpt honorariums from AstraZeneca, GSK, Sanofi and BerlinChemie. S. Kuhnert also received payment for expert testimony at Sanofi; S. Herold has received research grants from German Research Foundation: KFO309, Hessen State Ministry of Higher Education, Research and the Arts (HMWK): Pandemic Network Hessen, Landes-Offensive zur Entwicklung Wissenschaftlich-oekonomischer Exzellenz, LOEWE, German Center for Lung Research (DZL), German Center for Infection Research (DZIF) Excellence Cluster Cardio-Pulmonary System/Cardio- Pulmonary Institute (CPI), The Network of University Medicine (NUM, Collaborative Immunity Platform of the NUM (COVIM), NUM Study Network Infections German National Pandemic Cohort Network (NAPKON) and VolkswagenStiftung; J. Wilhelm has received payment for leadership and participation on data safety monitoring at PRVi GoDeep; M. Witzenrath has received research grants from Bundesministerium fuer Bildung und Forschung (BMBF; Federal Ministry of Education and Research), Deutsche Forschungsgemeinschaft (DFG; German Research Foundation), Gemeinsamer Bundesausschuss (G-BA; The Federal Joint Committee), Bundesministerium fuer Gesundheit (BMG; Federal Ministry of Health) Grant Biotest, Pantherna, Aptarion and consulting fees at Biotest, Pantherna, Aptarion and got honorariums from Astra Zeneca, Chiesi, Insmed, Gilead, Pfizer and Boehringer; N. Weissmann has received received research grants from German Research Foundation, Excellence Cluster Cardiopulmonary Institute (CPI); H.-A. Ghofrani has received support, consulting fees, honoararium, payment for expert testimony, participation on data safety monitoring and leadership at Gosasamer Bio, Inc., Aerovate, Altavant, Attgeno, Bayer AG (ended 16 Nov 2023), CSL Behring, Janssen/Actelion, Insmed, MSD/Acceleron, Pfizer, Keros, Morphic Therapeutics, Pulmovant; W. Seeger has received consulting fees from United Therapeutics, Tiakis Biotech AG, Lung Biotechnology, Pfizer and Resyca BV. K. Tello has received research grants from Gossamer, Msd, Aop, OMT, Orphanet, Boehringer nad consulting fees from Gossamer. K. Tello got honorariums from MSD, Boehringer, AOP, OMT and was supported for attending meetings at AOP; N. Sommer has received research grants from German Research Foundation and Network of University Medicine (NUM, Collaborative Immunity Platform of the NUM, COVIM) and consulting fees from Janssen, Deloitte and got honorarium from Charite Berlin for lecture. ### Funding Statement The study was funded by the Federal Ministry of Education and Research (BMBF) (AZ: 01EP2102A). K. Lo was funded by the Justus Liebig University (JLU) CAREER Programm, number GU 405/14-1. C. Tabeling received honoraria for lectures and advisory from AstraZeneca, Berlin-Chemie, GlaxoSmithKline, and for non-financial support from AstraZeneca and GlaxoSmithKline. S. Herold was supported by the German Research Foundation grant KFO309 (reference number 284237345, projects P2, P8); Hessen State Ministry of Higher Education, Research and the Arts (HMWK, Pandemic Network Hessen and Landes-Offensive zur Entwicklung Wissenschaftlich-oekonomischer Exzellenz, LOEWE, Foerderlinie 4a project ID III L7-519/05.00.002 and CoroPan P2); the German Center for Lung Research (DZL, reference number 82DZL005B1 and 82DZLT85C1), the German Center for Infection Research (DZIF); the Excellence Cluster Cardio-Pulmonary System/Cardio- Pulmonary Institute (EXC 2026, reference number 390649896); and the Network of University Medicine (NUM, Collaborative Immunity Platform of the NUM (COVIM), NUM Study Network Infections, German National Pandemic Cohort Network (NAPKON), reference number 01KX2121); VolkswagenStiftung (project Swarm Learning). N. Sommer was supported by the German Research Foundation grant KFO309 (reference number 284237345, project P10), the Excellence Cluster Cardio-Pulmonary System/Cardio- Pulmonary Institute (EXC 2026, reference number 390649896) and the Network of University Medicine (NUM, Collaborative Immunity Platform of the NUM, COVIM). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the local ethics committee (Justus-Liebig University Giessen, reference number AZ 28/22). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript.