US 11,864,881 B2
Side-stream volumetric capnography
Joshua Lewis Coleman, Jerusalem (IL); and Michal Ronen, Givat Brenner (IL)
Assigned to COVIDIEN LP, Mansfield, MA (US)
Filed by Covidien LP, Mansfield, MA (US)
Filed on Sep. 28, 2021, as Appl. No. 17/487,393.
Application 17/487,393 is a continuation of application No. 15/595,212, filed on May 15, 2017, granted, now 11,147,472.
Claims priority of provisional application 62/336,663, filed on May 15, 2016.
Prior Publication US 2022/0007963 A1, Jan. 13, 2022
Int. Cl. A61B 5/08 (2006.01); A61B 5/083 (2006.01); A61B 5/087 (2006.01); A61B 5/097 (2006.01); A61B 5/00 (2006.01); G01N 33/497 (2006.01); A61B 5/091 (2006.01); G01N 1/22 (2006.01); A61M 16/08 (2006.01)
CPC A61B 5/082 (2013.01) [A61B 5/087 (2013.01); A61B 5/0836 (2013.01); A61B 5/097 (2013.01); A61B 5/7246 (2013.01); G01N 33/497 (2013.01); A61B 5/091 (2013.01); A61M 16/085 (2014.02); A61M 16/0833 (2014.02); A61M 2230/432 (2013.01); G01N 1/2247 (2013.01); G01N 2001/2297 (2013.01); G01N 2033/4975 (2013.01)] 19 Claims
OG exemplary drawing
 
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.