Patent ID: 11864881
Assignee: COVIDIEN LP
Field: Measurement (Instruments)
Classification: CPC A  G | IPC A  G

Claim 0:
1. A method for determining a volume of exhaled CO2 as a function of time using side-stream capnography, the method comprising:
obtaining, by a processing unit, flow dynamics measurements of a subject from a flow sensor;
obtaining, by the processing unit, CO2 concentration measurements of the subject from a side-stream CO2 monitor;
determining, by the processing unit, a duration of time (ΔTs1) for a sample of gas to flow from a side-stream reference point to the side-stream CO2 monitor, wherein determining the ΔTs1 is performed based on a time from on-start of inhalation (Ti) until a notch in the CO2 concentration measurement, the notch resulting from a bolus of clean air or a bolus of air having a known CO2 concentration introduced between the side-stream reference point and the side-stream CO2 monitor at Ti;
synchronizing, by the processing unit, in time the CO2 concentration measurement with the flow dynamics measurement, based on the determined ΔTs1; and
determining, by the processing unit, a volume of CO2 exhaled as a function of time, based on the flow dynamics measurement and the synchronized CO2 concentration measurement.