From the Guidelines
Lactate clearance rate is a critical marker for assessing treatment effectiveness in critically ill patients, and a normal lactate clearance rate is approximately 30% reduction within the first 6 hours of treatment for critically ill patients, as suggested by the Surviving Sepsis Campaign guidelines 1. To measure lactate clearance, obtain a baseline lactate level and then repeat measurements at intervals (commonly 2-6 hours) to calculate the percentage decrease. Inadequate lactate clearance (less than 10-20% in the first 6 hours) is associated with higher mortality in sepsis and shock states, as demonstrated by several studies, including a meta-analysis of 647 patients that showed a significant reduction in mortality with lactate-guided resuscitation compared to resuscitation without lactate monitoring 1. When treating patients with elevated lactate levels, focus on addressing the underlying cause while optimizing tissue perfusion through:
- Fluid resuscitation
- Vasopressors if needed
- Ensuring adequate oxygenation Serial lactate measurements should guide ongoing resuscitation efforts. Lactate accumulates when oxygen delivery to tissues is insufficient, forcing cells to shift from aerobic to anaerobic metabolism. Therefore, improving lactate clearance indicates restoration of adequate tissue perfusion and oxygen delivery, making it a valuable marker for assessing treatment effectiveness in critically ill patients, as supported by the guidelines and studies 1. It is essential to note that lactate clearance is not a direct measure of tissue perfusion, but rather a surrogate marker, and its interpretation should be considered in the context of the patient's overall clinical picture, as highlighted in the guidelines 1.
From the Research
Lactate Clearance Rate
- Lactate clearance rate is a useful indicator of outcome in patients with septic shock, as shown in studies 2, 3, 4, 5, 6
- A high lactate clearance rate is associated with improved outcome and decreased mortality rate in severe sepsis and septic shock 3, 5
- Lactate clearance can be calculated as the percent decrease in lactate from initial measurement to a subsequent measurement, typically 6 hours later 2, 3, 4, 5
Association with Mortality
- Studies have shown that lactate clearance is inversely related to mortality, with higher lactate clearance associated with lower mortality rates 2, 3, 4, 5
- A lactate clearance rate of <10% has been shown to be a predictor of in-hospital mortality in pediatric septic shock patients 5
- Norepinephrine dosage has been shown to be associated with lactate clearance, with higher doses associated with lower lactate clearance and higher mortality rates 4
Clinical Utility
- Lactate clearance can be used as a target for fluid resuscitation therapy in patients with septic shock, in combination with other parameters such as central venous oxygen saturation 6
- Serial lactate measurements can be used to predict outcome in pediatric septic shock patients 5
- Lactate clearance may serve as an index in confirming the endpoint of fluid resuscitation for patients with septic shock 6