title: Hyperoxemia as a risk factor for ventilator-associated pneumonia.
abstract: BACKGROUND
  Consequences of hyperoxemia, such as acute lung injury, atelectasis, and reduced bacterial clearance, might promote ventilator-associated pneumonia (VAP). The aim of our study was to determine the relationship between hyperoxemia and VAP.
  
  
  METHODS
  This retrospective observational study was performed in a 30-bed mixed ICU. All patients receiving invasive mechanical ventilation for more than 48 hours were eligible. VAP was defined using clinical, radiologic, and quantitative microbiological criteria. Hyperoxemia was defined as PaO2 > 120 mmHg. All data, except those related to hyperoxemia, were prospectively collected. Risk factors for VAP were determined using univariate and multivariate analysis.
  
  
  RESULTS
  VAP was diagnosed in 141 of the 503 enrolled patients (28 %). The incidence rate of VAP was 14.7 per 1000 ventilator days. Hyperoxemia at intensive care unit admission (67 % vs 53 %, OR = 1.8, 95 % CI (1.2, 29), p <0.05) and number of days spent with hyperoxemia were significantly more frequent in patients with VAP, compared with those with no VAP. Multivariate analysis identified number of days spent with hyperoxemia (OR = 1.1, 95 % CI (1.04, 1.2) per day, p = 0.004), simplified acute physiology score (SAPS) II (OR = 1.01, 95 % CI (1.002, 1.024) per point, p < 0 .05), red blood cell transfusion (OR = 1.8, 95 % CI (1.2, 2.7), p = 0.01), and proton pomp inhibitor use (OR = 1.9, 95 % CI (1.03, 1.2), p < 0.05) as independent risk factors for VAP. Other multiple regression models also identified hyperoxemia at ICU admission (OR = 1.89, 95 % CI (1.23, 2.89), p = 0.004), and percentage of days with hyperoxemia (OR = 2.2, 95 % CI (1.08, 4.48), p = 0.029) as independent risk factors for VAP.
  
  
  CONCLUSIONS
  Hyperoxemia is independently associated with VAP. Further studies are required to confirm our results.
authors.affiliation: CHU Lille, Centre de Réanimation, F-59000, Lille, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Six
authors.affiliation: CHU Lille, Centre de Réanimation, F-59000, Lille, France.
authors.forename: Karim
authors.initials: K
authors.lastname: Jaffal
authors.affiliation: CHU Lille, Centre de Réanimation, F-59000, Lille, France.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Ledoux
authors.affiliation: CHU Lille, Centre de Réanimation, F-59000, Lille, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Jaillette
authors.affiliation: CHU Lille, Centre de Biologie et de Pathologie, F-59000, Lille, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Wallet
authors.affiliation: CHU Lille, Centre de Réanimation, F-59000, Lille, France. s-nseir@chru-lille.fr.|Univ Lille, Faculté de Médecine, F-59000, Lille, France. s-nseir@chru-lille.fr.
authors.forename: Saad
authors.initials: S
authors.lastname: Nseir
mesh_terms: D000368:Aged; D001803:Blood Transfusion / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000150:complications* / Q000503:physiopathology; D007362:Intensive Care Units / Q000458:organization & administration; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology / Q000209:etiology*; D012044:Regression Analysis; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D012307:Risk Factors; D000072878:Simplified Acute Physiology Score
keywords: Arterial oxygen tension; Critical care; Hyperoxia; Outcome, Hyperoxemia; Prevention; Ventilator-associated pneumonia