US 10,136,837 B2
Device and method for the analysis of the air exhaled by a subject in order to measure the basal metabolism thereof
Paolo Brugnoli, Pavona di Albano (IT); Alberto Di Pietro, Pavona di Albano (IT); Marco Ragusa, Pavona di Albano (IT); and Domenico Celentano, Pavona di Albano (IT)
Assigned to COSMED S.r.l., Roma (IT)
Filed by COSMED S.R.L., Rome (IT)
Filed on Oct. 21, 2016, as Appl. No. 15/299,510.
Claims priority of application No. 102015000064894 (IT), filed on Oct. 23, 2015.
Prior Publication US 2017/0112413 A1, Apr. 27, 2017
Int. Cl. A61B 5/08 (2006.01); A61B 5/083 (2006.01); A61B 5/087 (2006.01); A61B 5/097 (2006.01); G01N 33/497 (2006.01)
CPC A61B 5/0833 (2013.01) [A61B 5/083 (2013.01); A61B 5/087 (2013.01); A61B 5/0836 (2013.01); A61B 5/097 (2013.01); G01N 33/497 (2013.01); A61B 5/0803 (2013.01); A61B 2505/03 (2013.01); A61B 2560/029 (2013.01); A61B 2560/0223 (2013.01); G01N 2033/4977 (2013.01)] 14 Claims
OG exemplary drawing
 
1. Device for the analysis of the air exhaled by a subject in order to measure basal metabolism of the subject, the device comprising:
a main line, for passage of a sampling flow of the air exhaled by the subject,
a suction pump having a substantially constant flow rate, said pump being arranged downstream of the main line, for drawing said sampling air flow into the main line,
a mixing mini-chamber interposed in the main line upstream of the suction pump for accumulating or mixing with each other a plurality of air sampling flows exhaled by the subject within a number of respiratory cycles,
a by-pass line arranged in parallel to the mixing mini-chamber through which the air flow can flow without passing through said mixing mini-chamber,
a by-pass valve interposed in the main line downstream of the mixing mini-chamber and selectively displaceable in two different positions for causing the airflow through the main line to flow either through the mixing mini-chamber or through said by-pass line,
first sensor means for sensing the oxygen concentration and second sensor means for sensing the carbon dioxide concentration, said first and second sensor means being arranged in the main line between said by-pass valve and the suction pump, for measuring the oxygen concentration and the carbon dioxide concentration within the air flow through the main line downstream of the mixing mini-chamber,
a first switching valve for switching the suction inlet of the suction pump between a condition of connection to said first and second sensor means and a condition in which this connection is interrupted,
flow measuring means for detecting the flow rate of the air inhaled or exhaled by the subject, and
an electronic controller configured for:
receiving and processing signals emitted by said first sensor means of the oxygen concentration, by said second sensor means of the carbon dioxide concentration and by said flow measuring means so as to obtain a measurement of oxygen consumption and carbon dioxide production by the subject within a number of respiratory cycles,
wherein said device further comprises:
a first inlet connector connected to a system for taking a flow of air exhaled by a subject who breathes spontaneously,
a second inlet connector connected through a sampling line to a system for taking a flow of air exhaled by a subject undergoing assisted pulmonary ventilation,
a selection valve interposed in the main line upstream of the mixing mini-chamber for selectively connecting said first connector or said second connector to said main line,
said selection valve having an outlet connected to the main line, a first inlet connected to said first connector and the second inlet for connection to said second connector,
a calibration line, which receives a calibration flow, to be used for calibrating said first and second sensor means for sensing the oxygen concentration and the carbon dioxide concentration,
a second switching valve adapted to be switched between a sampling state and a calibration state, said switching valve being controlled by said electronic controller for selectively connecting said second inlet of said selection valve to said sampling line connected to said second connector or to said calibration line,
a plurality of selector valves distributed in series along said calibration line for selectively connecting the calibration line each time to one only among a plurality of auxiliary lines adapted to provide respective calibration data,
said electronic controller being configured so that, during normal operation of the device, the selection valve is switched for feeding to the main line either a sampling flow of the air exhaled by a subject who breathes spontaneously or by a subject which undergoes assisted pulmonary ventilation, said by-pass valve being in a position causing the airflow to pass through said mixing mini-chamber so that said electronic controller is able to perform said processing in order to obtain said measurement of the oxygen consumption and the carbon dioxide production by the subject within a number of respiratory cycles,
said electronic controller being further programmed for automatically starting, upon switching on the device, a self-calibration stage of the device in which:
the second switching valve communicates said second connector of said selection valve to said calibration line while the selection valve communicates its second inlet to said main line, so that the main line enters into communication with said calibration line,
said electronic controller being configured so that in said self-calibration stage the by-pass valve is in a position which causes said sampling flow of the air exhaled by the subject to flow through said by-pass line, without passing through said mixing mini-chamber, whereby the self-calibration stage can be carried out immediately on the basis of the flow coming from said calibration line, without requiring a filling of said mixing mini-chamber.