Transcutaneous oxygen tension during exercise in patients with pulmonary emphysema.

Transcutaneous PO2 (tcPO2) and arterial PO2 (PaO2) were compared during exercise in six patients with pulmonary emphysema. For calibration purposes, the tcPO2 electrode was first attached to the skin and after stabilisation its reading was adjusted to correspond to the PO2 of an initial arterial blood sample. It was shown that tcPO2 measurement could follow accurately the rapid changes in PaO2 occurring during exercise. Sixty-eight paired comparisons of PaO2 and tcPO2 were available and the regression equation was given by: tcPO2 (mmHg) = 0.98 PaO2 + 0.7 (correlation coefficient, 0.985; 95% confidence limits, 5.7 mmHg).