title: Occult hypoperfusion and mortality in patients with suspected infection.
abstract: OBJECTIVE
  To determine, in the early stages of suspected clinically significant infection, the independent relationship of the presenting venous lactate level to 28-day in-hospital mortality.
  
  
  METHODS
  Prospective, observational cohort study.
  
  
  METHODS
  Urban, university tertiary-care hospital.
  
  
  METHODS
  One thousand two hundred and eighty seven adults admitted through the emergency department who had clinically suspected infection and a lactate measurement.
  
  
  RESULTS
  Seventy-three [5.7% (95% CI 4.4-6.9%)] patients died in the hospital within 28 days. Lactate level was strongly associated with 28-day in-hospital mortality in univariate analysis (p<0.0001). When stratified by blood pressure, lactate remained associated with mortality (p<0.0001). Normotensive patients with a lactate level >or=4.0 mmol/l had a mortality rate of 15.0% (6.0-24%). Patients with either septic shock or lactate >or=4.0 mmol/l had a mortality rate of 28.3% (21.3-35.3%), which was significantly higher than those who had neither [mortality of 2.5% (1.6-3.4%), p<0.0001. In a model controlling for age, blood pressure, malignancy, platelet count, and blood urea nitrogen level, lactate remained strongly associated with mortality. Patients with a lactate level of 2.5-4.0 mmol/l had adjusted odds of death of 2.2 (1.1-4.2); those with lactate >or=4.0 mmol/l had 7.1 (3.6-13.9) times the odds of death. The model had good discrimination (AUC=0.87) and was well calibrated.
  
  
  CONCLUSIONS
  In patients admitted with clinically suspected infection, the venous lactate level predicts 28-day in-hospital mortality independent of blood pressure and adds significant prognostic information to that provided by other clinical predictors.
authors.affiliation: Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Medicine, KB-23, 330 Brookline Avenue, Boston, MA 02215, USA. mhowell@bidmc.harvard.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Howell
authors.forename: Michael
authors.initials: M
authors.lastname: Donnino
authors.forename: Peter
authors.initials: P
authors.lastname: Clardy
authors.forename: Daniel
authors.initials: D
authors.lastname: Talmor
authors.forename: Nathan I
authors.initials: NI
authors.lastname: Shapiro
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D042241:Early Diagnosis; D005260:Female; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D020896:Hypovolemia; D019344:Lactic Acid / Q000032:analysis / Q000097:blood; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012772:Shock, Septic / Q000175:diagnosis*; D014218:Triage; D014481:United States / Q000453:epidemiology
chemical_list: D019344:Lactic Acid