title: Subjects hospitalized with the 2009 pandemic influenza A (H1N1) virus in a respiratory infection unit: clinical factors correlating with ICU admission.
abstract: BACKGROUND
  The 2009 pandemic influenza A (H1N1) virus was accompanied by high morbidity and mortality. The aim of this study was to describe the clinical characteristics of patients with documented 2009 influenza A (H1N1) virus admitted to a reference chest hospital, the disease outcome, and risk factors associated with ICU admission.
  
  
  METHODS
  We assessed 109 subjects admitted to the respiratory infection unit of a hospital for chest disease with signs and symptoms of the 2009 influenza A (H1N1) virus between April 2009 and December 2010. Demographic data, comorbidities, clinical signs and symptoms, laboratory tests, radiographic findings, treatment, and final outcomes were all recorded. Factors associated with severe disease requiring ICU admission were determined.
  
  
  RESULTS
  Ninety subjects (82.5%) had laboratory-confirmed 2009 influenza A (H1N1). Sixty-four percent of these subjects had pneumonia on admission, 26% had respiratory failure, and 11% required care in the ICU. Dyspnea and the presence of infiltrates on chest x-rays were the most common signs among the subjects with H1N1. All subjects were treated with antiviral therapy, and 75% received antibiotic treatment based on their clinical and laboratory findings. The predictive factors of ICU admission were severe hypoxemia and lymphocytosis.
  
  
  CONCLUSIONS
  The outcome of subjects with influenza A (H1N1) virus infection was influenced by the severity of the disease on admission, the subjects' underlying conditions, and complications during hospitalization.
authors.affiliation: Intensive Care Unit, First Department of Respiratory Medicine, Medical School, National and Kapodistrian University of Athens and "Sotiria" Chest Diseases Hospital, Athens, Greece. nikrovina@med.uoa.gr.
authors.forename: Nikoletta
authors.initials: N
authors.lastname: Rovina
authors.affiliation: First Department of Respiratory Medicine, Medical School, National and Kapodistrian University of Athens and "Sotiria" Chest Diseases Hospital, Athens, Greece.
authors.forename: Magdalini
authors.initials: M
authors.lastname: Erifaki
authors.affiliation: Pulmonary Department, Intensive Care Medicine, Evaggelismos Hospital, Medical School, University of Athens, Athens, Greece.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Katsaounou
authors.affiliation: First Department of Respiratory Medicine, Medical School, National and Kapodistrian University of Athens and "Sotiria" Chest Diseases Hospital, Athens, Greece.
authors.forename: Georgia
authors.initials: G
authors.lastname: Lyxi
authors.affiliation: Intensive Care Unit, First Department of Respiratory Medicine, Medical School, National and Kapodistrian University of Athens and "Sotiria" Chest Diseases Hospital, Athens, Greece.
authors.forename: Antonia
authors.initials: A
authors.lastname: Koutsoukou
authors.affiliation: First Department of Respiratory Medicine, Medical School, National and Kapodistrian University of Athens and "Sotiria" Chest Diseases Hospital, Athens, Greece.
authors.forename: Nikolaos G
authors.initials: NG
authors.lastname: Koulouris
authors.affiliation: First Department of Respiratory Medicine, Medical School, National and Kapodistrian University of Athens and "Sotiria" Chest Diseases Hospital, Athens, Greece.
authors.forename: Manos
authors.initials: M
authors.lastname: Alchanatis
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D015897:Comorbidity; D004196:Disease Outbreaks; D005260:Female; D006115:Greece / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology / Q000628:therapy* / Q000821:virology*; D007362:Intensive Care Units; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D012124:Respiratory Care Units; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000628:therapy* / Q000821:virology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000998:Antiviral Agents
keywords: hospitalization outcome; intensive care unit; pandemic H1N1 infection