Material and Method: This was a prospective observational study at the Songklanagarind Hospital Emergency Department. Between April 1 and October 31, 2009, 131 consecutive patients met the enrollment criteria of age older than 18 years and fulfilled the SIRS criteria. Serum venous lactate was obtained in all enrolled patients. The main outcome measurements were development of septic shock, death within 24 hours, and in-hospital mortality at 3- and 28-day of presentation.

Results: Of the 131 patients enrolled, 50 (38.1%) developed septic shock. A lactate level greater than 36 mg/dL was associated with death (odds ratio [OR] = 4.29, 95% confidence interval [CI] = 1.19-15.55) to predict 28-day hospitalization mortality. It was also statistically significant to the progression to septic shock (p = 0.013) with 50.0% sensitivity and 73.2% specificity (OR = 2.73, 95% CI = 1.22-6.13).

Conclusion: For patients presenting to the emergency department with clinical symptoms of SIRS, a single serum venous lactate level measurement of greater than 36 mg/dL provides valuable prognostic predictor information concerning the high-risk group likely to progress to septic shock, more serious disease severity, and death.

Keywords: Septic shock, Serum lactate level, Systemic inflammatory response syndrome