is an important factor when reporting results in units of conductivity s cm the concept of a cell constant may be leveraged to optimize ceil design for the co2 range of interest those of skill in the art will appreciate that a smaller cell constant relates to a larger magnitude conductance signal for a given concentration the larger magnitude signals allow for finer resolution a resolution of 1 mmhg is acceptable for the reporting of sublingual pco2 and a resolution of 0 1 mmhg is preferable the cell constant has a geometric interpretation of the distance d or the u201c gap u201d between the electrodes divided by the area a of the electrodes thus the shorter the distance between the electrodes the smaller the cell constant in the same manner the larger the area of the electrodes the smaller the cell constant the size of the electrode must be balanced with the need for shorter response times to optimize these somewhat conflicting needs the area of the electrode is maximized while minimizing the resultant volume this size can be modified to fit the size restrictions of the various measurement locations in another aspect of the sensor to maximize the cell length within the limited footprint of the sensor the electrodes may be a serpentine zig zag or similar cell shape in which the two electrodes are in mating relationship separated.