Why order POC (Point of Care) lactate versus serum lactate?

From the Guidelines

Lactate should be ordered over procalcitonin when trying to assess tissue perfusion and guide resuscitation efforts in septic patients, as it is a more direct marker of tissue hypoperfusion and anaerobic metabolism. According to the Surviving Sepsis Campaign guidelines 1, lactate-guided resuscitation has been shown to reduce mortality in patients with septic shock. The guidelines suggest guiding resuscitation to normalize lactate in patients with elevated lactate levels as a marker of tissue hypoperfusion 1. Lactate is a standard laboratory test that can serve as a marker of tissue hypoxia, accelerated aerobic glycolysis, or other causes of increased lactate levels, which are associated with worse outcomes 1.

Some key points to consider when ordering lactate over procalcitonin include:

• Lactate is a more direct marker of tissue perfusion and anaerobic metabolism, making it better suited for guiding resuscitation efforts in septic patients 1
• Lactate-guided resuscitation has been shown to reduce mortality in patients with septic shock, with a significant reduction in mortality seen in lactate-guided resuscitation compared to resuscitation without lactate monitoring (RR 0.67; 95% CI 0.53–0.84; low quality) 1
• Procalcitonin, on the other hand, is more specific for bacterial infections and can be used to guide antibiotic therapy decisions, but it is not a direct marker of tissue perfusion 1
• The use of lactate and procalcitonin can be complementary in critically ill patients, with lactate providing information on tissue perfusion and procalcitonin providing information on the presence of bacterial infection 1

In terms of specific scenarios where lactate may be preferred over procalcitonin, consider the following:

• Patients with septic shock who require close monitoring of tissue perfusion and resuscitation efforts 1
• Patients with elevated lactate levels who require guided resuscitation to normalize lactate levels 1
• Patients who are at risk of tissue hypoperfusion or anaerobic metabolism, such as those with shock, seizures, or liver dysfunction 1

From the Research

Fluid Resuscitation in Sepsis

• The choice of fluid for resuscitation in sepsis is a topic of debate, with crystalloids being the most commonly recommended type of fluid 2, 3, 4.
• The Surviving Sepsis Campaign guidelines recommend the use of crystalloids as the primary fluid for resuscitation, but the optimal type and amount of fluid are still unclear 2, 4.
• Some studies suggest that balanced crystalloids may be a safer alternative to normal saline, which has been associated with increased mortality and kidney injury 5.
• The use of albumin is also a topic of debate, with some studies suggesting that it may be similar to crystalloids in terms of outcomes, but at a higher cost 5.
• Hydroxyethyl starches are no longer recommended for use in critically ill patients due to their association with increased mortality and kidney injury 5.

Procal vs Lactate

• There is no direct evidence in the provided studies to support the use of Procal vs lactate in fluid resuscitation.
• However, the studies suggest that the choice of fluid and the amount of fluid administered can have a significant impact on patient outcomes, with excessive fluid administration potentially worsening shock and increasing mortality 2, 6.
• The optimal approach to fluid resuscitation is likely to be individualized and guided by the patient's physiologic response to treatment, rather than a one-size-fits-all approach 2, 4.