Respiratory infections and acute respiratory distress syndrome
1Critical Care Center, Parc Taulí University Hospital, Parc Taulí Research and Innovation Institute I3PT, 08208 Sabadell, Spain
2CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, 28029 Madrid, Spain
3Critical Care Center, Lille University Hospital, F-59000 Lille, France
4Department of Pneumology, Hospital Clinic of Barcelona, August Pi i Sunyer Biomedical Research Institute—IDIBAPS, University of Barcelona, 08036 Barcelona, Spain
Submitted: 17 March 2022 Accepted: 01 June 2022
Online publish date: 20 July 2022
Respiratory infections and acute respiratory distress syndrome (ARDS) are closely related. Pneumonia is the most common cause of ARDS, and patients with ARDS usually develop infectious respiratory complications. Sixty percent of the cases of ARDS are due to pneumonia, but only some patients with pneumonia will develop ARDS. Viral pneumonia is a common cause of ARDS, especially in seasonal outbreaks or pandemics. Patients admitted with ARDS could present a secondary infection, and ventilator-associated pneumonia may impair prognosis. Several conditions that predispose patients with ARDS to respiratory infections are present. Decisions regarding antimicrobial treatment should be based on epidemiology, risk factors and current recommendations. Corticosteroids may be used as adjunctive therapy in both pathologies in selective patients.
Pneumonia; VAP; ARDS
Adrian Ceccato,Elena Campaña-Duel,Aina Areny-Balagueró,Saad Nseir,Antoni Torres. Respiratory infections and acute respiratory distress syndrome. Signa Vitae. 2022.doi:10.22514/sv.2022.054.
 Bellani G, Laffey JG, Pham T, Fan E, Brochard L, Esteban A, et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries. The Journal of the American Medical Association. 2016; 315: 788–800.
 Ferguson ND, Frutos-Vivar F, Esteban A, Fernández-Segoviano P, Aramburu JA, Nájera L, et al. Acute respiratory distress syndrome: underrecognition by clinicians and diagnostic accuracy of three clinical definitions. Critical Care Medicine. 2005; 33: 2228–2234.
 Meduri GU, Kanangat S, Stefan J, Tolley E, Schaberg D. Cytokines IL-1beta, IL-6, and TNF-alpha enhance in vitro growth of bacteria. American Journal of Respiratory and Critical Care Medicine. 1999; 160: 961–967.
 Meduri GU. A paradigm shift: the bidirectional effect of inflammation on bacterial growth. Sepsis and Organ Dysfunction. 2000; 19: 145–154.
 Rouzé A, Martin-Loeches I, Povoa P, Makris D, Artigas A, Bouchereau M, et al. Relationship between SARS-CoV-2 infection and the incidence of ventilator-associated lower respiratory tract infections: a European multicenter cohort study. Intensive Care Medicine. 2021; 47: 188–198.
 Guérin C, Reignier J, Richard J, Beuret P, Gacouin A, Boulain T, et al. Prone positioning in severe acute respiratory distress syndrome. New England Journal of Medicine. 2013; 368: 2159–2168.
 Combes A, Hajage D, Capellier G, Demoule A, Lavoué S, Guervilly C, et al. Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome. New England Journal of Medicine. 2018; 378: 1965–1975.
 Ferrer Monreal M, Cilloniz C, Liapikou A, Garcia-Vidal C, Gabarrus A, Ceccato A, et al. Acute respiratory distress syndrome in mechanically ventilated patients with community-acquired pneumonia. European Respiratory Journal. 2018; 51: 1702215.
 Gajic O, Dabbagh O, Park PK, Adesanya A, Chang SY, Hou P, et al. Early identification of patients at risk of acute lung injury: evaluation of lung injury prediction score in a multicenter cohort study. American Journal of Respiratory and Critical Care Medicine. 2011; 183: 462–470.
 Trillo-Alvarez C, Cartin-Ceba R, Kor DJ, Kojicic M, Kashyap R, Thakur S, et al. Acute lung injury prediction score: derivation and validation in a population-based sample. European Respiratory Journal. 2011; 37: 604–609.
 Ichikado K, Kawamura K, Johkoh T, Fujimoto K, Shintani A, Hashimoto S, et al. Clinical phenotypes from fatal cases of acute respiratory distress syndrome caused by pneumonia. Scientific Reports. 2021; 11: 20051.
 Cillóniz C, Ewig S, Polverino E, Marcos MA, Esquinas C, Gabarrus A, et al. Microbial aetiology of community-acquired pneumonia and its relation to severity. Thorax. 2011; 66: 340–346.
 Ceccato A, Torres A, Cilloniz C, Amaro R, Gabarrus A, Polverino E, et al. Invasive disease versus urinary antigen confirmed pneumococcal community-acquired pneumonia. Chest. 2017; 151: 1311–1319.
 Mongardon N, Max A, Bouglé A, Pène F, Lemiale V, Charpentier J, et al. Epidemiology and outcome of severe pneumococcal pneumonia admitted to intensive care unit: a multicenter study. Critical Care. 2012; 16: R155.
 Georges H, Leroy O, Vandenbussche C, Guery B, Alfandari S, Tronchon L, et al. Epidemiological features and prognosis of severe community-acquired pneumococcal pneumonia. Intensive Care Medicine. 1999; 25: 198–206.
 Luyt C, Combes A, Trouillet J, Nieszkowska A, Chastre J. Virus-induced acute respiratory distress syndrome: epidemiology, management and outcome. La Presse MéDicale. 2011; 40: e561–e568.
 Iuliano AD, Roguski KM, Chang HH, Muscatello DJ, Palekar R, Tempia S, et al. Estimates of global seasonal influenza-associated respiratory mortality: a modelling study. The Lancet. 2018; 391: 1285–1300.
 Perez-Padilla R, de la Rosa-Zamboni D, Ponce de Leon S, Hernandez M, Quiñones-Falconi F, Bautista E, et al. Pneumonia and respiratory failure from swine-origin influenza A (H1N1) in Mexico. New England Journal of Medicine. 2009; 361: 680–689.
 Domínguez-Cherit G, Lapinsky SE, Macias AE, Pinto R, Espinosa-Perez L, de la Torre A, et al. Critically ill patients with 2009 influenza A (H1N1) in Mexico. The Journal of the American Medical Association. 2009; 302: 1880–1887.
 Lee N, Qureshi ST. Other Viral Pneumonias: coronavirus, respiratory syncytial virus, adenovirus, hantavirus. Critical Care Clinics. 2013; 29: 1045–1068.
 Hasvold J, Sjoding M, Pohl K, Cooke CR, Hyzy RC. The role of human metapneumovirus in the critically ill adult patient. Journal of Critical Care. 2016; 31: 233–237.
 Wu Z, Zhang R, Liu D, Liu X, Zhang J, Zhang Z, et al. Acute respiratory distress syndrome caused by human adenovirus in adults: a prospective observational study in Guangdong, China. Frontiers in Medicine. 2021; 8: 791163.
 Figueiredo LTM, Souza WMD, Ferrés M, Enria DA. Hantaviruses and cardiopulmonary syndrome in South America. Virus Research. 2014; 187: 43–54.
 Peiris JSM, Yuen KY, Osterhaus ADME, Stöhr K. The severe acute respiratory syndrome. The New England Journal of Medicine. 2003; 349: 2431–2441.
 Zaki AM, van Boheemen S, Bestebroer TM, Osterhaus ADME, Fouchier RAM. Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. New England Journal of Medicine. 2012; 367: 1814–1820.
 Grasselli G, Zangrillo A, Zanella A, Antonelli M, Cabrini L, Castelli A, et al. Baseline characteristics and outcomes of 1591 patients infected with sars-cov-2 admitted to ICUs of the Lombardy Region, Italy. The Journal of the American Medical Association. 2020; 323: 1574–1581.
 Botta M, Tsonas AM, Pillay J, Boers LS, Algera AG, Bos LDJ, et al. Ventilation management and clinical outcomes in invasively ventilated patients with COVID-19 (PRoVENT-COVID): a national, multicentre, observational cohort study. The Lancet Respiratory Medicine. 2021; 9: 139–148.
 Torres A, Motos A, Riera J, Fernández-Barat L, Ceccato A, Pérez-Arnal R, et al. The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients. Critical Care. 2021; 25: 331.
 Lim ZJ, Subramaniam A, Ponnapa Reddy M, Blecher G, Kadam U, Afroz A, et al. Case fatality rates for patients with covid-19 requiring invasive mechanical ventilation. A meta-analysis. American Journal of Respiratory and Critical Care Medicine. 2021; 203: 54–66.
 Wu C, Chen X, Cai Y, Xia J, Zhou X, Xu S, et al. Risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in Wuhan, China. The Journal of the American Medical Association. 2020; 180: 934–943.
 González J, Benítez ID, Carmona P, Santisteve S, Monge A, Moncusí-Moix A, et al. Pulmonary function and radiologic features in survivors of critical COVID-19: a 3-month prospective cohort. Chest. 2021; 160: 187–198.
 Barbeta Viñas ER, Benegas M, Sánchez M, Motos A, Ferrer M, Ceccato A, et al. Risk factors and clinical impact of fibrotic-like changes and the organizing pneumonia pattern in patients with COVID-19- and non-COVID-19-induced acute respiratory distress syndrome. Archivos de Bronconeumologia. 2022; 58: 183–187.
 Ceccato A, Pérez-Arnal R, Motos A, Barbé F, Torres A, Saera MB, et al. One-year mortality after ICU admission due to COVID-19 infection. Intensive Care Medicine. 2022; 48: 366–368.
 Ackermann M, Verleden SE, Kuehnel M, Haverich A, Welte T, Laenger F, et al. Pulmonary vascular endothelialitis, thrombosis, and angiogenesis in Covid-19. New England Journal of Medicine. 2020; 383: 120–128.
 José RJ, Williams A, Manuel A, Brown JS, Chambers RC. Targeting coagulation activation in severe COVID-19 pneumonia: lessons from bacterial pneumonia and sepsis. European Respiratory Review. 2020; 29: 200240.
 Iba T, Warkentin TE, Thachil J, Levi M, Levy JH. Proposal of the definition for COVID-19-associated coagulopathy. Journal of Clinical Medicine. 2021; 10: 191.
 Rouze A, Martin-Loeches I, Povoa P, Metzelard M, Du Cheyron D, Lambiotte F, et al. Early bacterial identification among intubated patients with COVID-19 or influenza pneumonia: a European multicenter comparative cohort study. American Journal of Respiratory and Critical Care Medicine. 2021; 204: 546–556.
 Pickens CO, Gao CA, Cuttica MJ, Smith SB, Pesce LL, Grant RA, et al. Bacterial superinfection pneumonia in patients mechanically ventilated for COVID-19 pneumonia. American Journal of Respiratory and Critical Care Medicine. 2021; 204: 921–932.
 Kao K, Chiu L, Hung C, Chang C, Yang C, Huang C, et al. Coinfection and mortality in pneumonia-related acute respiratory distress syndrome patients with bronchoalveolar lavage: a prospective observational study. Shock. 2017; 47: 615–620.
 Kao K, Hu H, Hsieh M, Tsai Y, Huang C. Comparison of community-acquired, hospital-acquired, and intensive care unit-acquired acute respiratory distress syndrome: a prospective observational cohort study. Critical Care. 2015; 19: 384.
 Barbeta E, Ceccato A, Artigas A, Ferrer M, Fernández L, López R, et al. Characteristics and outcomes in patients with ventilator-associated pneumonia who do or do not develop acute respiratory distress syndrome. An observational study. Journal of Clinical Medicine. 2020; 9: 3508.
 Iregui MG, Kollef MH. Ventilator-associated pneumonia complicating the acute respiratory distress syndrome. Seminars in Respiratory and Critical Care Medicine. 2001; 22: 317–326.
 Torres A, Niederman MS, Chastre J, Ewig S, Fernandez-Vandellos P, Hanberger H, et al. International ERS/ESICM/ESCMID/ALAT guide-lines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia: guidelines for the management of hospital-acquired pneumonia (HAP)/ventilator-associated pneumonia (VAP) of the European Respiratory Society (ERS), European Society of Intensive Care Medicine (ESICM), European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and Asociación Latinoamericana del Tórax (ALAT). European Respiratory Journal. 2017; 50: 1700582.
 Kalil AC, Metersky ML, Klompas M, Muscedere J, Sweeney DA, Palmer LB, et al. Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clinical Infectious Diseases. 2016; 63: e61–e111.
 Salluh JIF, Souza-Dantas VC, Póvoa P. The current status of biomarkers for the diagnosis of nosocomial pneumonias. Current Opinion in Critical Care. 2017; 23: 391–397.
 Póvoa P, Martin-Loeches I, Ramirez P, Bos LD, Esperatti M, Silvestre J, et al. Biomarker kinetics in the prediction of VAP diagnosis: results from the BioVAP study. Annals of Intensive Care. 2016; 6: 32.
 Chastre J, Trouillet J, Vuagnat A, Joly-Guillou M, Clavier H, Dombret M, et al. Nosocomial pneumonia in patients with acute respiratory distress syndrome. American Journal of Respiratory and Critical Care Medicine. 1998; 157: 1165–1172.
 Forel J, Voillet F, Pulina D, Gacouin A, Perrin G, Barrau K, et al. Ventilator-associated pneumonia and ICU mortality in severe ARDS patients ventilated according to a lung-protective strategy. Critical Care. 2012; 16: R65.
 Ayzac L, Girard R, Baboi L, Beuret P, Rabilloud M, Richard JC, et al. Ventilator-associated pneumonia in ARDS patients: the impact of prone positioning. A secondary analysis of the PROSEVA trial. Intensive Care Medicine. 2016; 42: 871–878.
 Wu Z, Liu Y, Xu J, Xie J, Zhang S, Huang L, et al. A ventilator-associated pneumonia prediction model in patients with acute respiratory distress syndrome. Clinical Infectious Diseases. 2020; 71: S400–S408.
 Meduri GU, Kohler G, Headley S, Tolley E, Stentz F, Postlethwaite A. Inflammatory cytokines in the BAL of patients with ARDS: persistent elevation over time predicts poor outcome. Chest. 1995; 108: 1303–1314.
 Headley AS, Meduri GU, Tolley E. Infections and the inflammatory response in acute respiratory distress syndrome. Chest. 1997; 111: 1306–1321.
 Song M, Liu Y, Lu Z, Luo H, Peng H, Chen P. Prognostic factors for ARDS: clinical, physiological and atypical immunodeficiency. BMC Pulmonary Medicine. 2020; 20: 102.
 Kyo M, Nishioka K, Nakaya T, Kida Y, Tanabe Y, Ohshimo S, et al. Unique patterns of lower respiratory tract microbiota are associated with inflammation and hospital mortality in acute respiratory distress syndrome. Respiratory Research. 2019; 20: 246.
 Zakharkina T, Martin-Loeches I, Matamoros S, Povoa P, Torres A, Kastelijn JB, et al. The dynamics of the pulmonary microbiome during mechanical ventilation in the intensive care unit and the association with occurrence of pneumonia. Thorax. 2017; 72: 803–810.
 Fromentin M, Ricard J, Roux D. Respiratory microbiome in mechanically ventilated patients: a narrative review. Intensive Care Medicine. 2021; 47: 292–306.
 Luyt C, Bouadma L, Morris AC, Dhanani JA, Kollef M, Lipman J, et al. Pulmonary infections complicating ARDS. Intensive Care Medicine. 2020; 46: 2168–2183.
 Manzano F, Fernández-Mondéjar E, Colmenero M, Poyatos ME, Rivera R, Machado J, et al. Positive-end expiratory pressure reduces incidence of ventilator-associated pneumonia in nonhypoxemic patients. Critical Care Medicine. 2008; 36: 2225–2231.
 Six S, Rouzé A, Pouly O, Poissy J, Wallet F, Preau S, et al. Impact of hyperoxemia on mortality in critically ill patients with ventilator-associated pneumonia. Annals of Translational Medicine. 2018; 6: 417.
 Povoa P, Martin-Loeches I, Nseir S. Secondary pneumonias in critically ill patients with COVID-19: risk factors and outcomes. Current Opinion in Critical Care. 2021; 27: 468–473.
 Fumagalli J, Panigada M, Klompas M, Berra L. Ventilator-associated pneumonia among SARS-CoV-2 acute respiratory distress syndrome patients. Current Opinion in Critical Care. 2022; 28: 74–82.
 Nseir S, Martin-Loeches I, Povoa P, Metzelard M, Du Cheyron D, Lambiotte F, et al. Relationship between ventilator-associated pneumonia and mortality in COVID-19 patients: a planned ancillary analysis of the coVAPid cohort. Critical Care. 2021; 25: 177.
 Martin-Loeches I, Motos A, Menéndez R, Gabarrús A, González J, Fernández-Barat L, et al. ICU-acquired pneumonia is associated with poor health post-COVID-19 sndrome. Journal of Cinical Mdicine. 2021; 11 224.
 Verweij PE, Rijnders BJA, Brüggemann RJM, Azoulay E, Bassetti M, Blot S, et al. Review of influenza-associated pulmonary aspergillosis in ICU patients and proposal for a case definition: an expert opinion. Intensive Care Medicine. 2020; 46: 1524–1535.
 Koehler P, Bassetti M, Kochanek M, Shimabukuro-Vornhagen A, Cor-nely OA. Intensive care management of influenza-associated pulmonary aspergillosis. Clinical Microbiology and Infection. 2019; 25: 1501–1509.
 Koehler P, Bassetti M, Chakrabarti A, Chen SCA, Colombo AL, Hoenigl M, et al. Defining and managing COVID-19-associated pulmonary aspergillosis: the 2020 ECMM/ISHAM consensus criteria for research and clinical guidance. The Lancet Infectious Diseases. 2021; 21: e149–e162.
 Rouzé A, Lemaitre E, Martin-Loeches I, Povoa P, Diaz E, Nyga R, et al. Invasive pulmonary aspergillosis among intubated patients with SARS-CoV-2 or influenza pneumonia: a European multicenter comparative cohort study. Critical Care. 2022; 26: 11.
 Ranzani OT, Motos A, Chiurazzi C, Ceccato A, Rinaudo M, Li Bassi G, et al. Diagnostic accuracy of Gram staining when predicting staphylococcal hospital-acquired pneumonia and ventilator-associated pneumonia: a sys-tematic review and meta-analysis. Clinical Microbiology and Infection. 2020; 26: 1456–1463.
 Peiffer-Smadja N, Bouadma L, Mathy V, Allouche K, Patrier J, Reboul M, et al. Performance and impact of a multiplex PCR in ICU patients with ventilator-associated pneumonia or ventilated hospital-acquired pneumonia. Critical Care. 2020; 24: 366.
 Monard C, Pehlivan J, Auger G, Alviset S, Tran Dinh A, Duquaire P, et al. Multicenter evaluation of a syndromic rapid multiplex PCR test for early adaptation of antimicrobial therapy in adult patients with pneumonia. Critical Care. 2020; 24: 434.
 Fagon J. Diagnosis and treatment of ventilator-associated pneumonia: fiberoptic bronchoscopy with bronchoalveolar lavage is essential. Semi-nars in Respiratory and Critical Care Medicine. 2006; 27: 034–044.
 Blot SI, Taccone FS, Van den Abeele A, Bulpa P, Meersseman W, Brusselaers N, et al. A clinical algorithm to diagnose invasive pulmonary aspergillosis in critically ill patients. American Journal of Respiratory and Critical Care Medicine. 2012; 186: 56–64.
 Fan E, Del Sorbo L, Goligher EC, Hodgson CL, Munshi L, Walkey AJ, et al. An Official American Thoracic Society/European Society of Intensive Care Medicine/society of critical care medicine clinical practice guideline: mechanical ventilation in adult patients with acute respiratory distress syndrome. American Journal of Respiratory and Critical Care Medicine. 2017; 195: 1253–1263.
 Gainnier M, Roch A, Forel J, Thirion X, Arnal J, Donati S, et al. Effect of neuromuscular blocking agents on gas exchange in patients presenting with acute respiratory distress syndrome. Critical Care Medicine. 2004; 32: 113–119.
 Papazian L, Forel J, Gacouin A, Penot-Ragon C, Perrin G, Loundou A, et al. Neuromuscular blockers in early acute respiratory distress syndrome. New England Journal of Medicine. 2010; 363: 1107–1116.
 Moss M, Huang DT, Brower RG, Ferguson ND, Ginde AA, Gong MN, et al. Early neuromuscular blockade in the acute respiratory distress syndrome. New England Journal of Medicine. 2019; 380: 1997–2008.
 Chang W, Sun Q, Peng F, Xie J, Qiu H, Yang Y. Validation of neuromuscular blocking agent use in acute respiratory distress syndrome: a meta-analysis of randomized trials. Critical Care. 2020; 24: 54.
 Watling SM, Dasta JF. Prolonged paralysis in intensive care unit patients after the use of neuromuscular blocking agents: a review of the literature. Critical Care Medicine. 1994; 22: 884–893.
 Metlay JP, Waterer GW, Long AC, Anzueto A, Brozek J, Crothers K, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. American Journal of Respiratory and Critical Care Medicine. 2019; 200: e45–e67.
 Ekren PK, Ranzani OT, Ceccato A, Li Bassi G, Muñoz Conejero E, Ferrer M, et al. Evaluation of the 2016 Infectious Diseases Society of America/American Thoracic Society guideline criteria for risk of multidrug-resistant pathogens in patients with hospital-acquired and ventilator-associated pneumonia in the ICU. American Journal of Respiratory and Critical Care Medicine. 2018; 197: 826–830.
 Rhen T, Cidlowski JA. Antiinflammatory action of glucocorticoids—new mechanisms for old drugs. New England Journal of Medicine. 2005; 353: 1711–1723.
 Bernard GR, Luce JM, Sprung CL, Rinaldo JE, Tate RM, Sibbald WJ, et al. High-dose corticosteroids in patients with the adult respiratory distress syndrome. New England Journal of Medicine. 1987; 317: 1565–1570.
 Steinberg KP, Hudson LD, Goodman RB, Hough CL, Lanken PN, Hyzy R, et al. Efficacy and safety of corticosteroids for persistent acute respiratory distress syndrome. The New England Journal of Medicine. 2006; 354: 1671–1684.
 Villar J, Ferrando C, Martínez D, Ambrós A, Muñoz T, Soler JA, et al. Dexamethasone treatment for the acute respiratory distress syndrome: a multicentre, randomised controlled trial. The Lancet Respiratory Medicine. 2020; 8: 267–276.
 ARDS Definition Task Force, Ranieri VM, Rubenfeld GD, Thompson BT, Ferguson ND, Caldwell E, et al. Acute respiratory distress syndrome: the Berlin definition. The Journal of the American Medical Association. 2012; 307: 2526–2533.
 Prina E, Ceccato A, Torres A. New aspects in the management of pneumonia. Critical Care. 2016; 20: 267.
 Ceccato A, Ferrer M, Barbeta E, Torres A. Adjunctive therapies for community-acquired pneumonia. Clinics in Chest Medicine. 2018; 39: 753–764.
 Torres A, Sibila O, Ferrer M, Polverino E, Menendez R, Mensa J, et al. Effect of corticosteroids on treatment failure among hospitalized patients with severe community-acquired pneumonia and high inflammatory response: a randomized clinical trial. The Journal of the American Medical Association. 2015; 313: 677–686.
 Blum CA, Nigro N, Briel M, Schuetz P, Ullmer E, Suter-Widmer I, et al. Adjunct prednisone therapy for patients with community-acquired pneumonia: a multicentre, double-blind, randomised, placebo-controlled trial. The Lancet. 2015; 385: 1511–1518.
 Confalonieri M, Urbino R, Potena A, Piattella M, Parigi P, Puccio G, et al. Hydrocortisone infusion for severe community-acquired pneumonia: a preliminary randomized study. American Journal of Respiratory and Critical Care Medicine. 2005; 171: 242–248.
 Snijders D, Daniels JMA, de Graaff CS, van der Werf TS, Boersma WG. Efficacy of corticosteroids in community-acquired pneumonia: a ran-domized double-blinded clinical trial. American Journal of Respiratory and Critical Care Medicine. 2010; 181: 975–982.
 Marti C, Grosgurin O, Harbarth S, Combescure C, Abbas M, Rutschmann O, et al. Adjunctive corticotherapy for community acquired pneumonia: a systematic review and meta-analysis. PLoS One. 2015, 10: e0144032.
 Siempos II, Vardakas KZ, Kopterides P, Falagas ME. Adjunctive therapies for community-acquired pneumonia: a systematic review. Journal of Antimicrobial Chemotherapy. 2008; 62: 661–668.
 Nie W, Zhang Y, Cheng J, Xiu Q. Corticosteroids in the treatment of community-acquired pneumonia in adults: a meta-analysis. PLoS One. 2012; 7: e47926.
 Siemieniuk RAC, Meade MO, Alonso-Coello P, Briel M, Evaniew N, Prasad M, et al. Corticosteroid therapy for patients hospitalized with community-acquired pneumonia: a systematic review and meta-analysis. Annals of Internal Medicine. 2015; 163: 519–528.
 Horita N, Otsuka T, Haranaga S, Namkoong H, Miki M, Miyashita N, et al. Adjunctive systemic corticosteroids for hospitalized community-acquired pneumonia: systematic review and meta-analysis 2015 update. Scientific Reports. 2015; 5: 14061.
 Wan Y, Sun T, Liu Z, Zhang S, Wang L, Kan Q. Efficacy and safety of corticosteroids for community-acquired pneumonia: a systematic review and meta-analysis. Chest. 2016; 149: 209–219.
 Briel M, Spoorenberg SMC, Snijders D, Torres A, Fernandez-Serrano S, Meduri GU, et al. Corticosteroids in patients hospitalized with community-acquired pneumonia: systematic review and individual patient data metaanalysis. Clinical Infectious Diseases. 2018; 66: 346–354.
 Stern A, Skalsky K, Avni T, Carrara E, Leibovici L, Paul M. Corticos-teroids for pneumonia. Cochrane Database of Systematic Reviews. 2017; 12: CD007720.
 Wu W, Fang Q, He G. Efficacy of corticosteroid treatment for severe community-acquired pneumonia: a meta-analysis. The American Journal of Emergency Medicine. 2018; 36: 179–184.
 Bi J, Yang J, Wang Y, Yao C, Mei J, Liu Y, et al. Efficacy and safety of adjunctive corticosteroids therapy for severe community-acquired pneumonia in adults: an updated systematic review and meta-analysis. PLoS One. 2016; 11: e0165942.
 Ceccato A, Russo A, Barbeta E, Oscanoa P, Tiseo G, Gabarrus A, et al. Real-world corticosteroid use in severe pneumonia: a propensity-score-matched study. Critical Care. 2021; 25: 432.
 Moreno G, Rodríguez A, Reyes LF, Gomez J, Sole-Violan J, Díaz E, et al. Corticosteroid treatment in critically ill patients with severe influenza pneumonia: a propensity score matching study. Intensive Care Medicine. 2018; 44: 1470–1482.
 Lansbury LE, Rodrigo C, Leonardi-Bee J, Nguyen-Van-Tam J, Shen Lim W. Corticosteroids as adjunctive therapy in the treatment of influenza: an updated Cochrane systematic review and meta-analysis. Critical Care Medicine. 2020; 48: e98–e106.
 Arabi YM, Mandourah Y, Al-Hameed F, Sindi AA, Almekhlafi GA, Hussein MA, et al. Corticosteroid therapy for critically ill patients with Middle East respiratory syndrome. American Journal of Respiratory and Critical Care Medicine. 2018; 197: 757–767.
 Horby P, Lim WS, Emberson JR, Mafham M, Bell JL, Linsell L, et al. Dexamethasone in hospitalized patients with Covid-19. New England Journal of Medicine. 2021; 384: 693–704.
 Sterne JAC, Murthy S, Diaz JV, Slutsky AS, Villar J, Angus DC, et al. Association between administration of systemic corticosteroids and mortality among critically ill patients with COVID-19: a meta-analysis. The Journal of the American Medical Association. 2020; 324: 1330–1341.
 Reyes LF, Rodriguez A, Bastidas A, Parra-Tanoux D, Fuentes YV, García-Gallo E, et al. Dexamethasone as risk-factor for ICU-acquired respiratory tract infections in severe COVID-19. Journal of Critical Care. 2022; 69: 154014.
 Ranzani OT, Ferrer M, Esperatti M, Giunta V, Li Bassi G, Carvalho CRR, et al. Association between systemic corticosteroids and outcomes of intensive care unit-acquired pneumonia. Critical Care Medicine. 2012; 40: 2552–2561.
 Calfee CS, Delucchi K, Parsons PE, Thompson BT, Ware LB, Matthay MA. Latent class analysis of ARDS subphenotypes: analysis of data from two randomized controlled trials. The Lancet Respiratory Medicine. 2014; 2: 611–620.
 Gautam S, Sharma L, Dela Cruz CS. Personalizing the management of pneumonia. Clinics in Chest Medicine. 2018; 39: 871–900.
 Matthay MA, Arabi YM, Siegel ER, Ware LB, Bos LDJ, Sinha P, et al. Phenotypes and personalized medicine in the acute respiratory distress syndrome. Intensive Care Medicine. 2020; 46: 2136–2152.
 Ware LB, Matthay MA, Mebazaa A. Designing an ARDS trial for 2020 and beyond: focus on enrichment strategies. Intensive Care Medicine, 2020; 46: 2153–2156.
Science Citation Index Expanded (SciSearch) Created as SCI in 1964, Science Citation Index Expanded now indexes over 9,200 of the world’s most impactful journals across 178 scientific disciplines. More than 53 million records and 1.18 billion cited references date back from 1900 to present.
Journal Citation Reports/Science Edition Journal Citation Reports/Science Edition aims to evaluate a journal’s value from multiple perspectives including the journal impact factor, descriptive data about a journal’s open access content as well as contributing authors, and provide readers a transparent and publisher-neutral data & statistics information about the journal.
Chemical Abstracts Service Source Index The CAS Source Index (CASSI) Search Tool is an online resource that can quickly identify or confirm journal titles and abbreviations for publications indexed by CAS since 1907, including serial and non-serial scientific and technical publications.
IndexCopernicus The Index Copernicus International (ICI) Journals database’s is an international indexation database of scientific journals. It covered international scientific journals which divided into general information, contents of individual issues, detailed bibliography (references) sections for every publication, as well as full texts of publications in the form of attached files (optional). For now, there are more than 58,000 scientific journals registered at ICI.
Geneva Foundation for Medical Education and Research The Geneva Foundation for Medical Education and Research (GFMER) is a non-profit organization established in 2002 and it works in close collaboration with the World Health Organization (WHO). The overall objectives of the Foundation are to promote and develop health education and research programs.
Scopus: CiteScore 0.5(2021) Scopus is Elsevier's abstract and citation database launched in 2004. Scopus covers nearly 36,377 titles (22,794 active titles and 13,583 Inactive titles) from approximately 11,678 publishers, of which 34,346 are peer-reviewed journals in top-level subject fields: life sciences, social sciences, physical sciences and health sciences.
Embase Embase (often styled EMBASE for Excerpta Medica dataBASE), produced by Elsevier, is a biomedical and pharmacological database of published literature designed to support information managers and pharmacovigilance in complying with the regulatory requirements of a licensed drug.