Serum lactate as a predictor of mortality in patients with infection.
OBJECTIVE
To determine the utility of an initial serum lactate measurement for identifying high risk of death in patients with infection.


METHODS
Post-hoc analysis of a prospectively compiled registry in an urban academic hospital.


METHODS
Patients with (a) a primary or secondary diagnosis of infection and (b) lactate measurement who were admitted over the 18 months following hospital-wide implementation of the Surviving Sepsis Campaign guideline for lactate measurement in patients with infection and possible severe sepsis. There were 1,177 unique patients, with an in-hospital mortality of 19%.


RESULTS
Outcome measures included acute-phase (<or=3 days) death and in-hospital death. We defined lactate ranges a priori (low, 0.0-2.0; intermediate, 2.1-3.9; high, 4.0 mmol/l or above)--and tested for linear associations with mortality by one-way analysis of variance. We determined sensitivity/specificity, odds ratios, and likelihood ratios for a lactate >or=4.0 mmol/l and performed a Bayesian analysis to determine its impact on a full range (0.01-0.99) of hypothetical pretest probability estimates for death. In-hospital mortality was 15%, 25%, and 38% in low, intermediate, and high lactate groups, respectively. Acute-phase deaths and in-hospital deaths increased linearly with lactate. An initial lactate >or=4.0 mmol/l was associated with sixfold higher odds of acute-phase death; however, a lactate level less than 4 mmol/l had little impact on probability of death.


CONCLUSIONS
When broadly implemented in routine practice, measurement of lactate in patients with infection and possible sepsis can affect assessment of mortality risk. Specifically, an initial lactate >or=4.0 mmol/l substantially increases the probability of acute-phase death.
Trzeciak
Stephen
S
UMDNJ-Robert Wood Johnson Medical School at Camden, Cooper University Hospital, Division of Cardiovascular Disease and Critical Care Medicine, One Cooper Plaza, Camden 08103, NJ, USA. trzeciak-stephen@cooperhealth.edu
Dellinger
R Phillip
RP
Chansky
Michael E
ME
Arnold
Ryan C
RC
Schorr
Christa
C
Milcarek
Barry
B
Hollenberg
Steven M
SM
Parrillo
Joseph E
JE
D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D001499:Bayes Theorem; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000032:analysis* / Q000097:blood; D008297:Male; D008875:Middle Aged; D009515:New Jersey / Q000453:epidemiology; D011446:Prospective Studies; D012042:Registries; D018805:Sepsis / Q000401:mortality*; D012720:Severity of Illness Index
D019344:Lactic Acid