Microdialysis is a minimally invasive technique allowing continuous monitoring of the composition of extracellular fluid and local changes of tissue metabolism in vivo (concentration of glucose, glycerol, lactate, pyruvate, glutamate, urea, catecholamines, aminoacids, etc.). The microdialysis unit is a biluminal probe which is perfused at a constant rate with microdialysis solution (perfusate). This solution is separated from interstitial space by a semipermeable membrane. Substances diffuse through the membrane in the direction of the concentration gradient. Therefore, the composition of the solution acquired (dialysate) reflects the composition of the extracellular fluid. It is important to note that numerous factors can affect the composition of dialysate such as: length of membrane, blood flow, perfusion rate. At present, microdialysis has not only experimental but also clinical applications in different groups of patients (patients with nutrition disorders, endocrine disease, critically ill patients, patients after transplantation and reconstruction surgery).

        Key words: microdialysis – interstitial fluid – local metabolism.