These monitors provide a non-invasive means of measuring the partial pressure of oxygen (pao2) in arterialized capillaries through the skin. Transcutaneous oxygen (tco2) monitors have electrodes which are heated and placed on an area of thin skin e.g. The abdomen. The heating produces a superficial erythema so that the PaO2 in the dilated capillaries can be assessed by the machine and displayed on a visual monitors. Normal values are 8-12 kPa (60-90mmhg). Accuracy is checked by regular comparison with the arterial blood gases.
Electrodes need to be moved to a different position every 4 hours in order to prevent burning. In order to remain accurate,the electrodes need careful positioning and calibration.