Abstract: A measurement arrangement for measuring carbon dioxide partial pressure of exhaled air from a person includes a calculation unit, a carbon dioxide analyser device, and a gas conduit assembly. A perturbation volume member is provided, defining a predetermined known perturbation volume, and configured to be selectively connected and disconnected to a person such that both inspiratory and expiratory air flows can pass either through the perturbation volume member or not, thereby introducing a variation of the determined end-tidal carbon dioxide. The perturbation volume member is either a gas conduit, or a perturbation space conduit which is configured to be connected to and disconnected from the gas conduit. The calculation unit is configured to calculate the effective pulmonary blood flow (EPBF) and the effective lung volume (ELV) based upon these induced variations of the determined end-tidal carbon dioxide partial pressure, the known perturbation volume, and a respiratory rate.

Abstract: A device for detecting breathing of a subject, includes a colorimetric CO2 detector. A method for determining whether a subject is breathing and a method for verifying proper placement of an endotracheal tube when using a resuscitation bag are also described.

Abstract: A fast-response colorimetric carbon dioxide indicator device which is substantially insensitive to humidity and comprises a chemically inert substrate and an indicator composition supported by the substrate and responsive to exposure to carbon dioxide in expired respiratory air to undergo a color changing reaction. The indicator composition includes a pH sensitive dye and a basic substance having the general formula in which X is a nitrogen or phosphorus atom, each of R1, R2, R3 and R4 is an alkyl, Y− is an anion selected from the group consisting of hydroxide, fluoride, chloride, bromide, iodide, carbonate, and tetrafluoroborate, at least one of the alkyls R1, R2, R3 and R4 having at least 13 carbon atoms and at least one of the other alkyls having from 6 to 8 carbon atoms, the remaining alkyls, if any, having from 1 to 12 carbon atoms.