Early Lactate Clearance as an Independent Predictor of Survival in Patients with Presumed Sepsis

Abstract or Introduction

This paper tries to answer the research question: Is the early clearance of lactate related to outcome and prognosis of patients of sepsis?

The aim of the study comprises measurement of serial serum lactate levels in patients presenting with sepsis and correlating: early lactate clearance with mortality, early lactate clearance versus first (baseline) lactate level in mortality prediction, early lactate clearance versus APACHE II score in mortality prediction and early lactate clearance versus non lactate clearance in mortality prediction.

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Clinical organ dysfunction [presumed sepsis] can be represented by an increase in the Sequential [Sepsis-related] APACHE II score of 12 points or more, which is associated with in-hospital mortality greater than 10%. Sepsis is the most common cause of lactic acidosis, and septic patients with lactic acidosis show a higher mortality rate. The etiology of lactic acidosis in sepsis is complex. It may result from either impaired lactate clearance or increased lactate production. Therefore, increased or sustained lactate levels represent severe sepsis or septic shock. Lactate level has also been used as a prognostic indicator for mortality. In particular, the patients with an initial lactate level ≥ 3.0 mmol/L had higher mortality risks, and the probability of death was substantially increased with a high initial lactate level. Some studies reported that lactate clearance, derived from calculating the change in lactate levels at different times, may have potential prognostic value. These studies have proved that a decrease in these markers within the first several hours may be predictive of a favorable outcome. However, no study has yet examined which factor is the most important mortality risk factor among initial lactate, lactate clearance, or inflammatory markers in severe sepsis patients with lactic acidosis. Lactate elevation is an important marker of impaired tissue perfusion in patients with sepsis and is often elevated even in the absence of arterial hypotension. Blood lactate concentrations ≥3 mmol/L are unusual in normal and non critically ill hospitalized patients, regardless of their underlying comorbidities.