Canadian Journal of Anesthesia, Vol 31, 664-677, Copyright © 1984 by Canadian Anesthesiologists' Society

Review Article: Transcutaneous PO₂ Measurement

¹ Department of Anaesthesiology, University of California, Irvine, Medical Center, Orange, California 92668

Transcutaneous PO₂ sensors have been developed over the past ten years from the same basic electrodes used in conventional blood gas machines. The skin is heated to enable the skin surface sensors to respond quickly to the gas tensions beneath them. PtCO₂ is a variable which reflects the PO₂ in the peripheral tissue. PtCO₂ has its own range of normal values and it responds to cardiopulmonary changes which affect tissue oxygenation

In the majority of patients, those without decreased cardiac output, PtCO₂ follows the trend of the arterial gas tension, and the PtCO₂ value decreases relative to PaO₂ with increasing patient age (Table II). When there is severely reduced cardiac output and peripheral perfusion, the PtcO₂ values will deviate from their relationship with the arterial tensions and become blood flow dependent, thus providing quantitative information regarding blood flow. It is likely that the technique of transcutaneous PO₂ monitoring will gain wider acceptance because it is a noninvasive and continuous monitor which provides useful information regarding tissue oxygenation.

Key Words: MEASUREMENT TECHNIQUES: transcutaneous PO₂ • COMPLICATIONS: hypoxia • OXYGEN: blood levels, tension