Electrode device

Claim 1

A potentiometric electrode device is transcutaneous pCO 2 measurement, said device comprising a capsule suited for application on a skin surface with a CO 2 premeable membrane closing one side of said capsule and serving as a contact face against the skin and a pH-sensitive measuring electrode located within said capsule, said electrode arranged behind the membrane, an electrolyte in contact with the measuring area of the said electrode and positioned between said measuring area and the membrane, a reference electrode communicating with the electrolyte, and a heating device in thermal communication with said measuring electrode for thermostating the measuring electrode and thermally stimulating the blood flow in the skin in the measured area, said heating device being capable of providing a heat level sufficient to produce vasodilation and for compensating for the heat loss to the surroundings, the reference electrode being in direct heat-conductive contact with the heating device, and the reference electrode surrounding the measuring electrode and being in heat-conductive contact with the membrane for thermal stimulation of the local bloodflow, said reference electrode having a predetermined shape capable of producing a thermostating exactitude of greater than 0.2° C. for said heat level.