[The clinical assessment of tissue oxygenation. The significance of hemodynamic and oxygen transport-related parameters]

Abstract

Adequate matching of the tissue O2 supply to the cellular O2 demands depends on the integrity of all components of the O2 transport system. The quality of O2 uptake by the lungs as well as O2 transport to the tissues can be assessed nowadays in the clinical setting. However, even if O2 uptake by the lungs and O2 transport to the tissues are normal cellular O2 supply may nevertheless be inadequate, if gas and substrate exchange are impaired on the tissue level. This may occur when nutritive blood flow is disturbed, as in patients with sepsis and ARDS. The hemodynamic monitoring parameters that are available in the clinical setting (i.e. systemic blood pressure, heart rate, cardiac filling pressures and art. blood gases) are only poor reflectors of the adequacy of tissue oxygenation. This review attempts to evaluate the extent to which the commonly measured hemodynamic variables relate to O2 transport and tissue oxygenation.