myocardial lactate extraction
The difference between arterial and coronary sinus lactate concentrations, indicating myocardial metabolic state and oxygen supply-demand balance.
Full Definition
Myocardial lactate extraction measures the heart's ability to metabolize lactate, calculated as the difference between systemic arterial and coronary sinus lactate levels. Normal myocardium extracts lactate from the blood for energy production, but during ischemia or metabolic stress, the heart may switch to anaerobic metabolism and actually produce lactate. A negative extraction (lactate production) indicates inadequate oxygen delivery relative to demand. During cardiac anesthesia, monitoring lactate extraction through coronary sinus sampling provides early detection of myocardial ischemia and helps guide interventions to optimize myocardial oxygen balance.
Usage
Usage note: Report as percentage or absolute difference; negative values indicate lactate production.
In Context
- "Negative myocardial lactate extraction indicated ongoing ischemia despite apparently adequate coronary perfusion." — Research protocol
- "Normal lactate extraction resumed following optimization of coronary perfusion pressure." — Intensive care consultation