Transcutaneous measurement of arterialized capillary blood PCO2 by a new mass spectrometer inlet system

A new mass spectrometer inlet system for transcutaneous measurement of capillary blood PCO2 is described. The system is constructed to allow calibration in a gas mixture of known composition. The accuracy and precision of the system is demonstrated in human experiments, in which the PCO2 measured by the new probe is shown to be highly correlated with arterialized capillary PCO2 measured by Astrup's equilibration technique.