Early lactate clearance is associated with improved outcome in severe sepsis and septic shock.
OBJECTIVE
Serial lactate concentrations can be used to examine disease severity in the intensive care unit. This study examines the clinical utility of the lactate clearance before intensive care unit admission (during the most proximal period of disease presentation) as an indicator of outcome in severe sepsis and septic shock. We hypothesize that a high lactate clearance in 6 hrs is associated with decreased mortality rate.


METHODS
Prospective observational study.


METHODS
An urban emergency department and intensive care unit over a 1-yr period.


METHODS
A convenience cohort of patients with severe sepsis or septic shock.


METHODS
Therapy was initiated in the emergency department and continued in the intensive care unit, including central venous and arterial catheterization, antibiotics, fluid resuscitation, mechanical ventilation, vasopressors, and inotropes when appropriate.


RESULTS
Vital signs, laboratory values, and Acute Physiology and Chronic Health Evaluation (APACHE) II score were obtained at hour 0 (emergency department presentation), hour 6, and over the first 72 hrs of hospitalization. Therapy given in the emergency department and intensive care unit was recorded. Lactate clearance was defined as the percent decrease in lactate from emergency department presentation to hour 6. Logistic regression analysis was performed to determine independent variables associated with mortality. One hundred and eleven patients were enrolled with mean age 64.9 +/- 16.7 yrs, emergency department length of stay 6.3 +/- 3.2 hrs, and overall in-hospital mortality rate 42.3%. Baseline APACHE II score was 20.2 +/- 6.8 and lactate 6.9 +/- 4.6 mmol/L. Survivors compared with nonsurvivors had a lactate clearance of 38.1 +/- 34.6 vs. 12.0 +/- 51.6%, respectively (p =.005). Multivariate logistic regression analysis of statistically significant univariate variables showed lactate clearance to have a significant inverse relationship with mortality (p =.04). There was an approximately 11% decrease likelihood of mortality for each 10% increase in lactate clearance. Patients with a lactate clearance> or =10%, relative to patients with a lactate clearance <10%, had a greater decrease in APACHE II score over the 72-hr study period and a lower 60-day mortality rate (p =.007).


CONCLUSIONS
Lactate clearance early in the hospital course may indicate a resolution of global tissue hypoxia and is associated with decreased mortality rate. Patients with higher lactate clearance after 6 hrs of emergency department intervention have improved outcome compared with those with lower lactate clearance.
Department of Emergency Medicine (HBN), Loma Linda University and Medical Center, 11234 Anderson Street, Loma Linda, CA 92354, USA. hbnguyen@ahs.llumc.edu
H Bryant
HB
Nguyen
Emanuel P
EP
Rivers
Bernhard P
BP
Knoblich
Gordon
G
Jacobsen
Alexandria
A
Muzzin
Julie A
JA
Ressler
Michael C
MC
Tomlanovich
D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D004632:Emergency Medical Services / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000097:blood / Q000209:etiology; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies; D018805:Sepsis / Q000097:blood* / Q000150:complications / Q000401:mortality* / Q000628:therapy; D012772:Shock, Septic / Q000097:blood / Q000150:complications / Q000401:mortality / Q000628:therapy; D016019:Survival Analysis
D015415:Biomarkers; D019344:Lactic Acid