title: Clinical characteristics and outcomes of patients with 2009 influenza A(H1N1) virus infection with respiratory failure requiring mechanical ventilation.
abstract: OBJECTIVE
  The purpose of the study was to describe the clinical characteristics and outcomes of critically ill patients with 2009 influenza A(H1N1).
  
  
  METHODS
  An observational study of patients with confirmed or probable 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation was performed.
  
  
  RESULTS
  We studied 96 patients (mean age, 45 [14] years [mean, SD]; 44% female). Shock and acute respiratory distress syndrome were diagnosed during the first 72 hours of admission in 43% and 72% of patients, respectively. Noninvasive positive pressure ventilation was used in 45% of the patients, but failed in 77% of them. Bacterial pneumonia was diagnosed in 33% of cases, 8% during the first week (due to community-acquired microorganisms) and 25% after the first week (due to gram-negative bacilli and resistant gram-positive cocci). Intensive care unit mortality was 50%. Nonsurvivors differed from survivors in the prevalence of cardiovascular, respiratory, and hematologic failure on admission and late pneumonia. Reported causes of death were refractory hypoxia, multiorgan failure, and shock (50%, 38%, and 12% of all causes of death, respectively).
  
  
  CONCLUSIONS
  Patients with 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation often present with clinical criteria of acute respiratory distress syndrome and shock. Bacterial pneumonia is a frequent complication. Mortality is high and is primarily due to refractory hypoxia.
authors.affiliation: Hospital Universitario de Getafe & CIBER de Enfermedades Respiratorias, Madrid, Spain.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Nin
authors.forename: Luis
authors.initials: L
authors.lastname: Soto
authors.forename: Javier
authors.initials: J
authors.lastname: Hurtado
authors.forename: José A
authors.initials: JA
authors.lastname: Lorente
authors.forename: María
authors.initials: M
authors.lastname: Buroni
authors.forename: Francisco
authors.initials: F
authors.lastname: Arancibia
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ugarte
authors.forename: Homero
authors.initials: H
authors.lastname: Bagnulo
authors.forename: Pablo
authors.initials: P
authors.lastname: Cardinal
authors.forename: Guillermo
authors.initials: G
authors.lastname: Bugedo
authors.forename: Estrella
authors.initials: E
authors.lastname: Echevarría
authors.forename: Alberto
authors.initials: A
authors.lastname: Deicas
authors.forename: Carlos
authors.initials: C
authors.lastname: Ortega
authors.forename: Fernando
authors.initials: F
authors.lastname: Frutos-Vivar
authors.forename: Andrés
authors.initials: A
authors.lastname: Esteban
mesh_terms: D000328:Adult; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D000860:Hypoxia / Q000209:etiology / Q000401:mortality; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000209:etiology / Q000401:mortality; D018410:Pneumonia, Bacterial / Q000150:complications / Q000401:mortality; D011175:Positive-Pressure Respiration; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000401:mortality*; D012720:Severity of Illness Index; D012769:Shock / Q000209:etiology / Q000401:mortality*