Three Part Question
In [a patient presenting to the emergency department with infection] is [serum lactate] a [predictor of mortality]?
A 40 year old male presents to the emergency department with a 4 day history of cellulitis of the lower extremity, fever and chills. How useful is an initial serum lactate concentration drawn in the ED as a predictor of mortality?
Medline 1950-2007 April Week 1 using the OVID interface.
Cochrane Database of Systematic Reviews and Cochrane Central register of Controlled Trials, April 2007
[(lactic acid.mp. or exp Lactic Acid/) OR (lactate.mp.) OR (exp Acidosis, Lactic/)] AND [(exp Infection/ or infection.mp.) OR (sepsis.mp. or exp Sepsis/) OR (septic shock.mp. or exp Shock, Septic/ OR severe sepsis.mp.)] AND [(emergency medical services.mp. or exp Emergency Medical Services/) OR (exp Emergency Service, Hospital/ or emergency department.mp.)]
18 papers were found on Medline, of which 2 were relevant.
No additional papers were found in the Cochrane Library.
|Author, date and country
||Study type (level of evidence)
|Shapiro et al.|
|1278 patients in an urban academic medical center: 18 years or older, admitted to the hospital with a suspected infection-related diagnosis, having had serum lactate level drawn at initial presentation in the ED.
Patients stratified according to lactate. Low (L) <2.5 mmol/L, medium (M) 2.5-3.99 mmol/L, high (H) >/= 4 mmol/L.||Prospective cohort study. Level IIb evidence.||Death at 28 days||L=43/877 (4.9%) (95% CI 3.5%-6.3%), M=24/267 (9.0%) (95% CI 5.6%-12.4%), H=38/134 (28.4%) (95% CI 21%-36%)||Patients without lactate drawn at presentation were not included. Only patients admitted to the hospital were inlcuded. No patient demographics or measures of illness severity provided.|
|Sensitivity (Sn) and specificity (Sp) for death at 28 days||Lactate >/= 2.5 Sn=59% (95% CI 50%-68%), Sp=71% (95% CI 69%-74%), lactate>/= 4, Sn=36% (95% CI 27%-45%), Sp=92% (95% CI 90%-93%)|
|Death within 3 days||L = 13/877 (1.5%) (95% CI 0.7%-2.3%), M = 12/267 (4.5%) (95% CI 2.0%-7.0%), H = 30/134 (22.4%) (95% CI 15%-29%)|
|Sensitivity (Sn) and specificity (Sp) for death within 3 days||Lactate >/= 2.5 Sn=76% (95% CI 65%-88%), Sp=71% (95% CI 68%-73%), lactate>/= 4, Sn=55% (95% CI 41%-68%), Sp=91% (95% CI 90%-93%)|
An initial serum lactate may be useful in risk stratification in patients presenting to the emergency department with infections. Conversely, it may be a covariate of another clinical marker. There appears to be an increasing trend of mortality with elevated initial lactate levels. 22.4% patients with an initial lactate level > 4.0 mmol/L died within 3 days.
Clinical Bottom Line
Initial serum lactate levels drawn in the ED may serve as an overall marker of mortality in patients admitted to the hospital with an infection-related diagnosis.
- Shapiro NI. Howell MD. Talmor D. et al. Serum Lactate as a Predictor of Mortality in Emergency Department Patients With Infection Annals of Emergency Medicine 2005,45:524-528.