Carbon Dioxide Sensing—Biomedical Applications to Human Subjects

Carbon dioxide (CO [Formula: see text]) monitoring in human subjects is of crucial importance in medical practice. Transcutaneous monitors based on the Stow-Severinghaus electrode make a good alternative to the painful and risky arterial “blood gases” sampling. Yet, such monitors are not only expensive, but also bulky and continuously drifting, requiring frequent recalibrations by trained medical staff. Aiming at finding alternatives, the full panel of CO [Formula: see text] measurement techniques is thoroughly reviewed. The physicochemical working principle of each sensing technique is given, as well as some typical merit criteria, advantages, and drawbacks. An overview of the main CO [Formula: see text] monitoring methods and sites routinely used in clinical practice is also provided, revealing their constraints and specificities. The reviewed CO [Formula: see text] sensing techniques are then evaluated in view of the latter clinical constraints and transcutaneous sensing coupled to a dye-based fluorescence CO [Formula: see text] sensing seems to offer the best potential for the development of a future non-invasive clinical CO [Formula: see text] monitor.