A DEVICE FOR INDICATING THE PRESENCE OF CARBON DIOXIDE IN A PATIENT'S EXHALED AIR

摘要

PCT No. PCT/SE93/00554 Sec. 371 Date Feb. 10, 1994 Sec. 102(e) Date Feb. 10, 1994 PCT Filed Jun. 22, 1993 PCT Pub. No. WO94/00756 PCT Pub. Date Jan. 6, 1994.A device for indicating the presence of CO2 in a patient's inhaled air comprises a CO2 detector including an indicator element (14) which undergoes a reversible color change in response to exposure thereof to air containing CO2 in concentrations of the same order of magnitude as the CO2 concentration of air exhaled by a human being, and also comprises a heat-moisture exchanger (12) including a housing (13) with a first connecting port (15) adapted to be connected to the trachea of a patient, and a second connecting port (15) adapted for connection to a ventilator or an anesthetic machine, for example. In a flow-through passage (P) extending between the connecting ports (15, 16) there is mounted an element (18) for the regenerative exchange of heat and moisture between, on the one hand, air flowing through the flow-through passage (P) in one direction and, on the other hand, air flowing through the flow-through passage (P) in the opposite direction. The indicator element (14) is disposed in the flow-through passage on the side of the heat-moisture exchanger element (18) remote from the first connecting port (15) and is viewable from outside the housing, and its response time for the color change is sufficiently short to enable it to change color upon each breath.