title: Epidemiology of mechanical ventilation: analysis of the SAPS 3 database.
abstract: OBJECTIVE
  To evaluate current practice of mechanical ventilation in the ICU and the characteristics and outcomes of patients receiving it.
  
  
  METHODS
  Pre-planned sub-study of a multicenter, multinational cohort study (SAPS 3).
  
  
  METHODS
  13,322 patients admitted to 299 intensive care units (ICUs) from 35 countries.
  
  
  METHODS
  None.
  
  
  RESULTS
  Patients were divided into three groups: no mechanical ventilation (MV), noninvasive MV (NIV), and invasive MV. More than half of the patients (53% [CI: 52.2-53.9%]) were mechanically ventilated at ICU admission. FIO2, VT and PEEP used during invasive MV were on average 50% (40-80%), 8 mL/kg actual body weight (6.9-9.4 mL/kg) and 5 cmH2O (3-6 cmH2O), respectively. Several invMV patients (17.3% (CI:16.4-18.3%)) were ventilated with zero PEEP (ZEEP). These patients exhibited a significantly increased risk-adjusted hospital mortality, compared with patients ventilated with higher PEEP (O/E ratio 1.12 [1.05-1.18]). NIV was used in 4.2% (CI: 3.8-4.5%) of all patients and was associated with an improved risk-adjusted outcome (OR 0.79, [0.69-0.90]).
  
  
  CONCLUSIONS
  Ventilation mode and parameter settings for MV varied significantly across ICUs. Our results provide evidence that some ventilatory modes and settings could still be used against current evidence and recommendations. This includes ventilation with tidal volumes >8mL/kg body weight in patients with a low PaO2/FiO2 ratio and ZEEP in invMV patients. Invasive mechanical ventilation with ZEEP was associated with a worse outcome, even after controlling for severity of disease. Since our study did not document indications for MV, the association between MV settings and outcome must be viewed with caution.
authors.affiliation: ICU 13I1, Dept. of Anesthesiology and General Intensive Care, Medical University of Vienna, Vienna, Austria.
authors.forename: Philipp G H
authors.initials: PG
authors.lastname: Metnitz
authors.forename: Barbara
authors.initials: B
authors.lastname: Metnitz
authors.forename: Rui P
authors.initials: RP
authors.lastname: Moreno
authors.forename: Peter
authors.initials: P
authors.lastname: Bauer
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Del Sorbo
authors.forename: Christoph
authors.initials: C
authors.lastname: Hoermann
authors.forename: Susana Afonso
authors.initials: SA
authors.lastname: de Carvalho
authors.forename: V Marco
authors.initials: VM
authors.lastname: Ranieri
mesh_terms: D000368:Aged; D015331:Cohort Studies; D016638:Critical Illness / Q000453:epidemiology; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial / Q000706:statistics & numerical data*