[New parameters of oxygen metabolism in clinical practice].

The authors discuss parameters characterizing the oxygen metabolism and their clinical impact: Partial oxygen pressure in arterial and mixed venous blood, lactate and new parameters derived from direct assessment of haemoglobin saturation with oxygen in arterial blood. Oxygen extraction tension (px): partial oxygen pressure in mixed venous blood at which 2.3 mmol oxygen are released from one litre of blood. Extractable oxygen (cx): the amount of oxygen released from on litre of blood when the partial oxygen pressure drops to 5.0 kPa. Oxygen compensation factor (Qx): it is the factor that cardiac output should increase to maintain a normal mixed venous p O2 of 5.0 kPa. Effective haemoglobin: haemoglobin participating in oxygen transmission which determines the oxygen capacity of blood for oxygen. Half the haemoglobin saturation (p50): characterizing the haemoglobin affinity for oxygen and corresponding to the shape and position of the haemoglobin saturation curve. Pulmonary shunts. Advantages, pitfalls and limitations of the mentioned parameters are given.