Colorimetric capnography: a misnomer worth correcting.

The treatment of Coronavirus disease 2019 (Covid-19) includes endotracheal intubation in patients with respiratory failure. Capnography, defined as the graphical display of exhaled carbon dioxide concentration over time, is best suited to corroborate endotracheal intubation. However, a time-limited colorimetric test, which uses a pH-sensitive chemical indicator that changes color when carbon dioxide is detected, can also be used. The term “colorimetric capnography” is often used to describe this chemical detection of carbon dioxide [1-3]. Considering that the chemical indicator color change only provides qualitative information without a continuous waveform, the terms “colorimetric capnography” and “colorimetric capnometry” should be discouraged as they undermine the intended meaning of “capnography.” Instead, the terms “carbon dioxide colorimetry", "colorimetric carbon dioxide detection”, and "chemical colorimetric analysis" seem more appropriate.