[The significance of the local oxygen pressure and of the PO2 histogram for the evaluation of the state of oxygen supply to various organs (author's transl)].

Theoretical and experimental investigations have shown that the oxygen pressure field of an organ reflects the state of the oxygen supply of a tissue. Unfortunately it is practically impossible to measure the total oxygen pressure field. Meaurements of arterial and venous PO2 or of the mean tissue PO2 do not reveal the local tissue situation. Measurements together with K. Kunze and M. Kessler lead us to the conclusion, that the oxygen pressure field can be characterized sufficiently well by a PO2-histogram. Under normal conditions the PO2-histogram is bell shaped with a steeper left side. The form and position is rather consistent. In hypoxia low PO2 values increase causing a leftward shift of the histogram; in hyperoxia the bell shaped form is destroyed and the form becomes broader and irregular. The form of the histogram gives also information about the state of the regulation of the microflow. It can be measured by PO2 microelectrodes as well as by multiwire surface electrodes. Both techniques have been applied successfully with patients.