3 Major Lactate Considerations in Sepsis

SUMMARY

  • Serum lactate measurements have been part of the sepsis bundles since the beginning.
  • The recommendation to use and follow serum lactate concentrations are based on weak and low-quality evidence.
  • Changes in serum lactate concentrations are not solely reflective of changes in production but also based on lactate clearance from multiple sources.

BACKGROUND

  • An association has been established between serum lactate concentrations and:
    • The likelihood of the presence of sepsis
    • Sepsis related mortality
  • Changes in serum lactate concentrations are thought to be related primarily due to increased production associated with tissue hypoxia and circulatory dysfunction.
  • However, to determine true serum lactate concentration changes, one needs to consider the sum of ongoing production and removal of lactate.
  • Although improvements in serum lactate concentrations are considered to be related to decreased production based on improved circulatory status, this cannot be totally proven.
  • Serum lactate concentrations do not correlate with sepsis disease severity

REVIEW

  • Lactate alone is neither sensitive or specific enough to determine a diagnosis of sepsis.
    • Although the Surviving Sepsis Campaign guidelines recommend the measurement of serum lactate concentrations, this remains a weak recommendation with low-quality evidence.
  • Lactate levels greater than or equal to 4 mmol/L had:
    • 50% sensitivity & 73.2% specificity of progression to septic shock
    • 36% sensitivity & 92% specificity for any death
    • 55% sensitivity & 91% specificity for death within 3 days
  • Increases in serum lactate concentrations maybe due to
    • Decreases in Clearance
    • Increases in Production – separate from circulatory hypoperfusion.
  • Lactate is a normal product of glucose and pyruvate metabolism.
    • As glucose metabolism increases or pyruvate metabolism decreases, serum lactate concentrations will increase.
    • The inflammatory process of sepsis is associated with increased glycolysis and impaired pyruvate dehydrogenase, leading to lactate generation
  • Lactate Metabolism
    • Lactate metabolism occurs within the liver (~ 60%) and kidneys (up to 50%) and to a lesser extent in the heart.
    • Lactate metabolism is hindered during circulatory dysfunction seen in sepsis.
  • Other lesser factors affecting serum lactate concentrations are:
    • Large volume fluid administration containing lactate
    • Inhibition of lactate use via specific drugs (i.e. catecholamine’s in septic shock, metformin, etc.)

CONCLUSIONS

  • Sensitivity ranges for serum lactate in sepsis remain in an unimpressive + 65% range and inconsistent.
  • The exact lactate level that should trigger aggressive resuscitation efforts is not known.
  • Increased production of serum lactate concentrations should not be the only consideration is patients with sepsis.
  • Increased production as well as decreased removal of serum lactate all play major roles. Any change in serum concentrations should consider both these factors.

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Erkan Hassan is the Co-Founder & Chief Clinical Officer of Sepsis Program Optimization where he designs & oversees the implementation of solutions to optimize sepsis programs.

To discuss your organization’s Barriers of Effective Sepsis Care, contact Erkan by phone (844) 4SEPSIS (844-473-7747), email (erkan@spo.icu), or video chat.