Cardiogenic Shock

The clinical indicator of metabolic distress has been lactate monitoring. Quantitative waveform capnography can be a reliable surrogate for lactate monitoring in detecting metabolic distress.

When organ hypoperfusion occurs, serum lactate levels rise precipitously, and lactic acidosis follows soon thereafter. The body’s physiologic response is to increase the respiratory rate to attenuate the metabolic acidosis. There is an inverse relationship between serum lactate levels and end-tidal CO2 (ETCO2); as lactate rises, carbon dioxide levels fall.  Research has found that ETCO2 levels less than 25 mm Hg are strongly associated with serum lactate levels > 4 mmol/L.

Lactate Levels:

• Normal lactate levels (below 2 mmol/L) are generally considered a good sign, indicating adequate tissue perfusion. 
• Lactate levels between 2 and 4 mmol/L are considered elevated and should prompt further investigation, including a careful assessment of the patient's clinical status and hemodynamic parameters. 
• Lactate levels above 4 mmol/L are strongly suggestive of severe tissue hypoxia and are associated with increased mortality.