ABSTRACT
BACKGROUND: Before the pandemic of coronavirus disease (COVID-19), rapidly improving acute respiratory distress syndrome (ARDS), mostly defined by early extubation, had been recognized as an increasingly prevalent subphenotype (making up 15-24% of all ARDS cases), associated with good prognosis (10% mortality in ARDSNet trials). We attempted to determine the prevalence and prognosis of rapidly improving ARDS and of persistent severe ARDS related to COVID-19. METHODS: We included consecutive patients with COVID-19 receiving invasive mechanical ventilation in three intensive care units (ICU) during the second pandemic wave in Greece. We defined rapidly improving ARDS as extubation or a partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2:FiO2) greater than 300 on the first day following intubation. We defined persistent severe ARDS as PaO2:FiO2 of equal to or less than 100 on the second day following intubation. RESULTS: A total of 280 intubated patients met criteria of ARDS with a median PaO2:FiO2 of 125.0 (interquartile range 93.0-161.0) on day of intubation, and overall ICU-mortality of 52.5% (ranging from 24.3 to 66.9% across the three participating sites). Prevalence of rapidly improving ARDS was 3.9% (11 of 280 patients); no extubation occurred on the first day following intubation. ICU-mortality of patients with rapidly improving ARDS was 54.5%. This low prevalence and high mortality rate of rapidly improving ARDS were consistent across participating sites. Prevalence of persistent severe ARDS was 12.1% and corresponding mortality was 82.4%. CONCLUSIONS: Rapidly improving ARDS was not prevalent and was not associated with good prognosis among patients with COVID-19. This is starkly different from what has been previously reported for patients with ARDS not related to COVID-19. Our results on both rapidly improving ARDS and persistent severe ARDS may contribute to our understanding of trajectory of ARDS and its association with prognosis in patients with COVID-19.
Subject(s)
COVID-19 , Respiratory Distress Syndrome , COVID-19/diagnosis , COVID-19/therapy , Humans , Intensive Care Units , Oxygen , Respiration, Artificial/methods , Respiratory Distress Syndrome/diagnosis , Respiratory Distress Syndrome/epidemiology , Respiratory Distress Syndrome/therapyABSTRACT
Immune deactivation of phagocytes is a central event in the pathogenesis of sepsis. Herein, we identify a master regulatory role of IL-6 signaling on LC3-associated phagocytosis (LAP) and reveal that uncoupling of these two processes during sepsis induces immunoparalysis in monocytes/macrophages. In particular, we demonstrate that activation of LAP by the human fungal pathogen Aspergillus fumigatus depends on ERK1/2-mediated phosphorylation of p47phox subunit of NADPH oxidase. Physiologically, autocrine IL-6/JAK2/Ninein axis orchestrates microtubule organization and dynamics regulating ERK recruitment to the phagosome and LC3+ phagosome (LAPosome) formation. In sepsis, loss of IL-6 signaling specifically abrogates microtubule-mediated trafficking of ERK, leading to defective activation of LAP and impaired killing of bacterial and fungal pathogens by monocytes/macrophages, which can be selectively restored by IL-6 supplementation. Our work uncovers a molecular pathway linking IL-6 signaling with LAP and provides insight into the mechanisms underlying immunoparalysis in sepsis.
Subject(s)
Interleukin-6/metabolism , Microtubule-Associated Proteins/metabolism , Phagocytosis/immunology , Signal Transduction , Aspergillus fumigatus/metabolism , Cytokines/metabolism , Cytoskeletal Proteins/metabolism , Humans , Janus Kinase 2/metabolism , Macrophages , Monocytes , Nuclear Proteins/metabolism , Phagocytes , Phagocytosis/physiology , Sepsis/metabolismABSTRACT
AIM: To describe the response of breathing pattern and inspiratory effort upon changes in assist level and to assesss if changes in respiratory rate may indicate changes in respiratory muscle effort. METHODS: Prospective study of 82 patients ventilated on proportional assist ventilation (PAV+). At three levels of assist (20 %-50 %-80 %), patients' inspiratory effort and breathing pattern were evaluated using a validated prototype monitor. RESULTS: Independent of the assist level, a wide range of respiratory rates (16-35br/min) was observed when patients' effort was within the accepted range. Changing the assist level resulted in paired changes in inspiratory effort and rate of the same tendency (increase or decrease) in all but four patients. Increasing the level in assist resulted in a 31 % (8-44 %) decrease in inspiratory effort and a 10 % (0-18 %) decrease in respiratory rate. The change in respiratory rate upon the change in assist correlated modestly with the change in the effort (R = 0.5). CONCLUSION: Changing assist level results in changes in both respiratory rate and effort in the same direction, with change in effort being greater than that of respiratory rate. Yet, neither the magnitude of respiratory rate change nor the resulting absolute value may reliably predict the level of effort after a change in assist.