title: The use of the pulse oximetric saturation/fraction of inspired oxygen ratio for risk stratification of patients with severe sepsis and septic shock.
abstract: OBJECTIVE
  Our aims were to determine whether the pulse oximetric saturation/fraction of inspired oxygen (S/F) can be used for the early identification of patients with sepsis who are at increased risk for death and to compare the S/F ratio with the Pao2/fraction of inspired oxygen (P/F) ratio.
  
  
  METHODS
  This is a retrospective cohort study in 260 patients admitted to 2 tertiary mixed intensive care units (ICUs) with severe sepsis or septic shock. We studied the association between tertiles of S/F ratio and ICU mortality using Cox regression. Subsequently, we compared corresponding measurements of S/F ratio and P/F ratio upon ICU admission using Pearson correlation coefficient (r).
  
  
  RESULTS
  We observed an overall case fatality of 72 (28%) of 260. After adjustment for severity of the illness, the lowest tertile (S/F, <164) at ICU admission was associated with increased mortality (hazard ratio, 1.87 [95% confidence interval, 1.02-3.41]) comparing to the highest tertile (S/F, >236). The S/F ratio was correlated with P/F ratio (r=0.48; P<.0001).
  
  
  CONCLUSIONS
  A low S/F at ICU admission is associated with increased risk of death in patients with severe sepsis or septic shock.
authors.affiliation: Department of Critical Care Medicine, ABC Medical School (FMABC), Santo André, Brazil; Department of Critical Care Medicine, Hospital Israelita Albert Einstein (HIAE), São Paulo, Brazil. Electronic address: aryserpa@terra.com.br.
authors.forename: Ary
authors.initials: A
authors.lastname: Serpa Neto
authors.forename: Sérgio O
authors.initials: SO
authors.lastname: Cardoso
authors.forename: David S Y
authors.initials: DS
authors.lastname: Ong
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Espósito
authors.forename: Victor G M
authors.initials: VG
authors.lastname: Pereira
authors.forename: José A
authors.initials: JA
authors.lastname: Manetta
authors.forename: Arjen J C
authors.initials: AJ
authors.lastname: Slooter
authors.forename: Olaf L
authors.initials: OL
authors.lastname: Cremer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D018805:Sepsis / Q000401:mortality* / Q000503:physiopathology*; D012720:Severity of Illness Index; D012772:Shock, Septic / Q000401:mortality / Q000503:physiopathology
keywords: Risk factor; Sepsis; Septic shock; SpO(2)