title: Outcomes of patients ventilated with synchronized intermittent mandatory ventilation with pressure support: a comparative propensity score study.
abstract: BACKGROUND
  Few data are available regarding the benefits of one mode over another for ventilatory support. We set out to compare clinical outcomes of patients receiving synchronized intermittent mandatory ventilation with pressure support (SIMV-PS) compared with assist-control (A/C) ventilation as their primary mode of ventilatory support.
  
  
  METHODS
  This was a secondary analysis of an observational study conducted in 349 ICUs from 23 countries. A propensity score stratified analysis was used to compare 350 patients ventilated with SIMV-PS with 1,228 patients ventilated with A/C ventilation. The primary outcome was in-hospital mortality.
  
  
  RESULTS
  In a logistic regression model, patients were more likely to receive SIMV-PS if they were from North America, had lower severity of illness, or were ventilated postoperatively or for trauma. SIMV-PS was less likely to be selected if patients were ventilated because of asthma or coma, or if they developed complications such as sepsis or cardiovascular failure during mechanical ventilation. In the stratified analysis according to propensity score, we did not find significant differences in the in-hospital mortality. After adjustment for propensity score, overall effect of SIMV-PS on in-hospital mortality was not significant (odds ratio, 1.04; 95% CI, 0.77-1.42; P = .78).
  
  
  CONCLUSIONS
  In our cohort of ventilated patients, ventilation with SIMV-PS compared with A/C did not offer any advantage in terms of clinical outcomes, despite treatment-allocation bias that would have favored SIMV-PS.
authors.affiliation: Hospital de Santa Clara (Dr Ortiz), Bogotá, Colombia.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Ortiz
authors.forename: Fernando
authors.initials: F
authors.lastname: Frutos-Vivar
authors.forename: Niall D
authors.initials: ND
authors.lastname: Ferguson
authors.forename: Andres
authors.initials: A
authors.lastname: Esteban
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Raymondos
authors.forename: Carlos
authors.initials: C
authors.lastname: Apezteguía
authors.forename: Javier
authors.initials: J
authors.lastname: Hurtado
authors.forename: Marco
authors.initials: M
authors.lastname: González
authors.forename: Vinko
authors.initials: V
authors.lastname: Tomicic
authors.forename: José
authors.initials: J
authors.lastname: Elizalde
authors.forename: Fekri
authors.initials: F
authors.lastname: Abroug
authors.forename: Yaseen
authors.initials: Y
authors.lastname: Arabi
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Antonio
authors.initials: A
authors.lastname: Anzueto
mesh_terms: D018806:APACHE; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation / Q000379:methods* / Q000401:mortality; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009656:North America; D012372:ROC Curve; D012131:Respiratory Insufficiency / Q000401:mortality / Q000628:therapy*; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D015300:Ventilator Weaning