Abstract: A device for the combined measurement of the arterial oxygen saturation and the transcutaneous CO2 partial pressure on an ear lobe comprises a sensor. The sensor has means for pulse oximetric measurement of the arterial oxygen saturation, means for measurement of the transcutaneous CO2 partial pressure and means for warming a sensor contact surface intended for contact with the ear lobe. The device makes simple and reliable measurement of the arterial oxygen saturation and the transcutaneous CO2 partial pressure possible on an ear lobe.

Abstract: A combined sensor for sensing partial O.sub.2 pressure and partial CO.sub.2 pressure and comprising measuring electrodes, a reference electrode, a diaphragm covering the electrodes and an electrolyte layer between the electrodes and the diaphragm wherein the reference electrode has disposed around it a screening of gold which is at the same potential as the reference electrode and the electrolyte contains a defined concentration of a soluble silver compound or of a silver complex.

Abstract: Calibration of sensors of the type used for the cutaneous determination of blood oxygen and carbon dioxide levels is facilitated by providing separate sensor units, alternatively and removably connectable to a calibration device and to the measuring devices with which they are used for such determinations. The sensor units contain, in addition to a sensor electrode, a data memory in which is stored calibration data generated when the sensor unit is connected to the calibration device. The calibration device can provide a plurality of calibration stations, each capable of supplying a standard gas to a connected sensor and, in response to signals from the sensor exposed to the standard gas, generating data signals representing the calibration of the sensor, which signals are transmitted to the data memory of the sensor unit. Upon connection of the sensor unit to the measuring device, the calibration data from the data memory of the sensor unit are used as a calibration base for measurements by the sensor.