Patent attributes
A method for determining the consumption of a CO2 absorber (8) in a respirator with a rebreathing system, with a fresh gas mixer (1) and with a computing and control unit (10). The rebreathing system has a respiration drive (2), a volume flow sensor (3) located in the inspiratory branch, a CO2 absorber (8) located in the expiratory branch, whose output, combined with that of the fresh gas mixer (1), is fed into the inspiratory branch, a breathing gas escape valve (7) and a breathing gas reservoir (9). The computing and control unit (10) is connected to the fresh gas mixer (1), to the respiration drive (2) and to the volume flow sensor (3) in order to receive signals and send control commands. The fresh gas volume flow FG discharged from the fresh gas mixer (1) and the inspiration volume flow I flowing into the inspiratory branch are determined in the method in the computing and control unit (10). A value for the purified rebreathing volume flow abs admitted from the CO2 absorber (8) is determined from the difference I−FG of those values, and a rate of CO2 absorption is determined herefrom on the basis of a preset CO2 concentration value or from a CO2 concentration value measured with a gas sensor in the expiratory branch and integrated over time in order to determine the quantity of CO2 absorbed in the CO2 absorber (8).
