From the Guidelines
The best indicator of adequate resuscitation in septic shock is decreased lactate level (option E). When treating septic shock, monitoring lactate clearance provides the most reliable evidence that tissue perfusion is improving and that resuscitation efforts are effective. During septic shock, tissues experience hypoperfusion and switch to anaerobic metabolism, producing lactate. As resuscitation improves oxygen delivery to tissues, lactate levels decrease, indicating restoration of aerobic metabolism. While normal blood pressure, pulse, urine output, and improved mental status are important clinical parameters to monitor, they may normalize before tissue perfusion is fully restored. Lactate clearance (typically aiming for >10-20% reduction within the first few hours) directly reflects improvement at the cellular level and has been shown to correlate with improved outcomes, as demonstrated by a significant reduction in mortality in lactate-guided resuscitation compared to resuscitation without lactate monitoring (RR 0.67; 95% CI 0.53–0.84; low quality) 1. Serial lactate measurements should be obtained during resuscitation, with decreasing levels confirming that the interventions are effectively addressing the underlying tissue hypoxia that characterizes septic shock. Some studies suggest guiding resuscitation to normalize lactate in patients with elevated lactate levels as a marker of tissue hypoperfusion (weak recommendation, low quality of evidence) 1. However, the most recent and highest quality study supports the use of lactate clearance as a key indicator of adequate resuscitation 1. Key points to consider when using lactate clearance as an indicator of adequate resuscitation include:
- Lactate levels should be monitored serially during resuscitation
- A decrease in lactate levels indicates improvement in tissue perfusion
- Lactate clearance should be used in conjunction with other clinical parameters, such as blood pressure, pulse, and urine output, to guide resuscitation efforts.
From the Research
Indicators of Adequate Resuscitation in Septic Shock
- The best indicator of adequate resuscitation in septic shock is a topic of ongoing research and debate 2, 3, 4, 5, 6.
- According to some studies, decreased lactate level is a key indicator of adequate resuscitation, as it reflects improved tissue perfusion and oxygen delivery 2, 4.
- However, other studies suggest that lactate is an unreliable indicator of tissue hypoxia in injury or sepsis, and that its levels may not correlate with traditional indicators of perfusion 5.
- Other potential indicators of adequate resuscitation include:
- A multimodal approach to perfusion monitoring, incorporating multiple variables and parameters, may be necessary to optimize resuscitation in septic shock patients 3, 6.
- The use of parameters such as central venous pressure (CVP), mean arterial pressure (MAP), and cardiac output/index, as well as microcirculatory resuscitation endpoints like lactate, central venous oxygen saturation (ScvO2), and central venous-arterial CO2 gradient, can provide a more comprehensive understanding of the patient's response to therapy 3.