The influence of different electrode temperatures on the recorded transcutaneous Po2 level

The technique of transcutaneous monitoring of oxygen partial pressure (PtcO2), first described in 1969, provided a new clinical possibility for continuous and noninvasive surveillance of changes in the oxygenation of the organism. To obtain optimal arterialization of the skin and thus a relieable recording, the electrodes used have been supplied with microheating elements. The electrode temperature used implies the risk of producing burns; this is especially true when the measurements are performed in patients with decreased skin circulation or in immature children with a thin and vulnerable skin. Thus, a careful choice of the electrode temperature is important in PtcO2 recording; a higher temperature is desirable for obtaining adequate arterialization, whereas a lower temperature is preferred for reducing the risk of burns. The electrode temperatures described for PtcO2 measurements range from 42--45 C. A systematic study with the Radiometer TCM 1 equipment showed that changing the electrode temperature influences the OtcO2 in a systematic way within the temperature range 43.0--45.0 C. The study also showed that simultaneous measurements obtained from two electrodes with different temperatures showed a highly parallel course and a comparable oscillating pattern within this temperature range. The results of the present study suggest that an electrode temperature of 44.5 C may be the most appropriate for this equipment in clinical applications with newborns.