PHYSIOLOGY AND MEASUREMENT OF TISSUE PERFUSION

Sufficient tissue perfusion and oxygenation are vital for all metaboli c processes in cells and the major influencing factor of tissue repair and resistance to infectious organisms. The concept of tissue perfusi on has been aliked with blood flow, oxygen delivery or a combination o f flow and nutritional supply including that of oxygen. A concept cove ring both oxygen delivery, tissue oxygen transport and oxygen consumpt ion of the cells could be named tissue oxygen perfusion. This concept could be useful for clinicians describing tissue perfusion and oxygena tion of the patient. Tissue perfusion must be evaluated on local tissu e level. A single tissue that would represent the situation in all tis sues of the body and be easily available for measurements, would be id eal. Subcutis and mucosa of the gastrointestinal tract are such types of tissue. Many monitoring systems are available for measuring tissue perfusion and oxygenation. However, only measurement of tissue oxygen tension and pH in the gastrointestinal mucosa fulfil the criteria of t issue oxygen perfusion. Future evaluation of tissue perfusion will be of fundamental importance for the outcome of medical treatment. Presen tly measurements of tissue oxygen tension, and in intensive care units also gastrointestinal mucosal pH, seem to be the best monitoring syst ems clinically available for this purpose.