Patent ID: 9572518
Date: 2017-02-21
CPC Classifications: A61B,G01N

Claim:
1. A system configured to monitor respiration of a subject, the system comprising: a subject interface appliance having a sampling interface including a gas inlet and a gas outlet, the subject interface appliance being configured to be installed at or near the airway of the subject such that gas from the airway of the subject is drawn into the gas inlet, the gas outlet being arranged near the gas inlet; a sampling chamber in fluid communication with the subject interface appliance such that gas drawn from the airway of the subject that is drawn into the gas inlet flows into the sampling chamber; a sensor configured to generate an output signal conveying information related to the carbon dioxide content of gas in the sampling chamber; a processor configured to determine, from the output signal generated by the sensor, one or more parameters of the respiration of the subject and to distinguish between breaths and other anatomical events that cause fluctuations in carbon dioxide content in the airway of the subject based solely on the output signal of the sensor; and a diluting flow generator configured to generate a diluting flow of gas, the diluting flow generator being in fluid communication with the subject interface appliance such that the diluting flow of gas is emitted from the gas outlet at or near the gas inlet, wherein: the diluting flow of gas is substantially free of carbon dioxide, and is emitted by the gas outlet with a flow rate and directionality (i) that dilutes gas from the airway of the subject prior to the gas being drawn into the gas inlet of the subject interface appliance such that the processor is able to distinguish between (i)(a) the breaths and (i)(b) the other anatomical events that cause fluctuations in the carbon dioxide content in the airway of the subject based solely on the output signal of the sensor, and (ii) that does not impact the respiration of the subject, and the diluting flow of gas is further configured (iii) such that (iii)(a) during anatomical events that cause the carbon dioxide content of gas at or near the airway of the subject to fluctuate, the diluting flow of gas has a much larger impact on the carbon dioxide of gas drawn into the gas inlet than (iii)(b) during actual breaths.