Transcutaneous monitoring of oxygen tension during progressive hypoxia and sleep

Transcutaneous O2 monitoring (PtcO2) was studied in 16 adult subjects suspected of having sleep-related breathing disorders, by comparison with arterial O2 measurements (PaO2). At rest the mean difference (+/- SD) between PaO2 and PtcO2 was 3.6 (+/- 1.5) kPa. During progressive hypoxia 74 simultaneous measurements showed a mean decrease in PtcO2 from the beginning to the end of the hypoxic tests of 6.6 (+/- 1.4) kPa for PtcO2 and 7.1 (+/- 1.5) kPa for PaO2. The decrease in PtcO2 was slower than that in PaO2 during the first minute (p less than 0.001), but for the whole hypoxic period there was no difference in the rate of decrease between the two methods. Continuous PtcO2 monitoring has been found useful in detecting respiratory abnormalities during sleep.