Transcutaneous oxygen measurement in paediatric respiratory disease

We have measured simultaneous arterial (Pao2) and transcutaneous oxygen tension (tcPo2) in 13 children, aged 8 months to 10 years, with respiratory disease. A Radiometer TCM2 transcutaneous oxygen monitor was used. At an electrode temperature of 44 degrees C the regression equation was tcPo2 = 0.9 Pao2 -10 and at 44.5 degrees C tcPo2 = 0.9 Pao2 -8. The 95% confidence limits were +/- 13 torr at both temperatures. We also studied the usefulness of the method in monitoring trends in oxygenation in individual patients. In six children paired observations were made on five or more occasions and in these tcPo2 followed changes in Pao2 accurately. We conclude that this technique is not sufficiently reliable for predicting arterial values, but in individual patients it accurately reflects trends in oxygenation.