title: The prognostic value of tissue oxygen saturation in emergency department patients with severe sepsis or septic shock.
abstract: OBJECTIVE
  To determine the derangement of muscle tissue oxygen saturation (StO(2)) in the early phase of emergency department (ED) sepsis management and its relationship to 30-day mortality in patients with severe sepsis or septic shock.
  
  
  METHODS
  A prospective cohort study conducted in the ED of a university hospital. Patients were included if they had a clinical diagnosis of severe sepsis or septic shock. Thenar muscle tissue StO(2) on arrival in the ED and its change with usual ED sepsis management was measured using near-infrared spectroscopy. A follow-up measurement was obtained after 24 h of treatment. All patients were followed for 30 days.
  
  
  RESULTS
  49 patients were included, of which 24 (49%) died. There was no difference in mean StO(2) on arrival in the ED between survivors and non-survivors (72% vs 72%; p=0.97). Following ED treatment the mean StO(2) of survivors improved significantly to 78% (p<0.05) while StO(2) remained persistently low in non-survivors (p=0.94). Persistently low StO(2) (<75%) despite initial resuscitative treatment was associated with a twofold increase in mortality (RR of death 2.1%; 95% CI 1.2% to 3.5%).
  
  
  CONCLUSIONS
  Patients with severe sepsis/septic shock have abnormal muscle tissue StO(2) upon arrival in the ED. Inability to normalise StO(2) with ED sepsis management is associated with a poor outcome. The role of StO(2) as an early prognostic and potential therapeutic biomarker in severe sepsis or septic shock warrants further exploration.
authors.affiliation: Emergency Department, Queen Alexandra Hospital, Portsmouth PO6 3LY, UK. ciss@doctors.org.uk
authors.forename: Christiane
authors.initials: C
authors.lastname: Vorwerk
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Coats
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D015331:Cohort Studies; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012772:Shock, Septic / Q000175:diagnosis / Q000378:metabolism* / Q000401:mortality*; D019265:Spectroscopy, Near-Infrared
chemical_list: D015415:Biomarkers