Admission serum lactate levels do not predict mortality in the acutely injured patient.
BACKGROUND
The conventional view that admission lactate levels predict outcome in trauma patients stems from simple comparisons of mean blood levels between groups and small sample sizes. To better address this question, we performed more rigorous statistical analyses of lactate in a larger patient sample.


METHODS
We prospectively collected data on admission lactate and outcomes in 5,995 patients admitted to an urban, university-based trauma center. The ability of admission lactate to predict mortality was assessed by logistic regression, calculation of positive predictive values (PPV), and measurement of areas under receiver operating characteristic (ROC) curves.


RESULTS
Differences between survivors and nonsurvivors in means of most proposed prognosticators was again demonstrated. However, the large overlap in these variables between survivors and nonsurvivors prevented clinically useful predictions. The overall PPV of elevated lactate was only 5.4%. Even in severely injured patients (Injury Severity Score >20; mortality 23%), elevated admission lactate level was a poor predictor of outcome. ROC analyses found no useful sensitivity threshold overall or after stratification by age, sex, Glasgow Coma Scale score, revised trauma score, or mechanism of injury.


CONCLUSIONS
This large retrospective examination of admission lactate levels failed to show useful predictive accuracy for hospital death. Serum lactate levels need not be obtained routinely but can be reserved for patients who will be admitted to the intensive care unit and/or require an emergency operation.
Pal
Jay D
JD
Department of Surgery, University of California, San Francisco-East Bay, Oakland, California 94602, USA.
Victorino
Gregory P
GP
Twomey
Patrick
P
Liu
Terrence H
TH
Bullard
M Kelley
MK
Harken
Alden H
AH
D000328:Adult; D002140:California; D003627:Data Interpretation, Statistical; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015601:Injury Severity Score; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D010343:Patient Admission; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012042:Registries; D012044:Regression Analysis; D013223:Statistics as Topic; D014947:Wounds and Injuries / Q000097:blood / Q000401:mortality*
D019344:Lactic Acid