| CPC A61M 16/203 (2014.02) [A61M 16/0003 (2014.02); A61M 16/0051 (2013.01); A61M 16/06 (2013.01); A61M 16/122 (2014.02); A61M 2016/0027 (2013.01); A61M 2016/0036 (2013.01); A61M 2205/15 (2013.01); A61M 2205/581 (2013.01); A61M 2205/583 (2013.01)] | 15 Claims |
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1. An apparatus (40) for supplying therapeutic gas, comprising:
a source (3) of a gas comprising at least one therapeutically active compound at an initial concentration (Cini),
a gas delivery apparatus (1) fed with the gas by said gas source (3), and
a respiratory interface (10) provided with at least one exhalation port (11) which is fed with the gas by said gas delivery apparatus (1), wherein the gas delivery apparatus (1) comprises:
an internal gas passage (100) in fluidic communication with a deformable reservoir (27) configured for and adapted to feed the deformable reservoir (27) with the gas,
a valve (22) arranged on the internal gas passage (100), upstream of the deformable reservoir (27), configured for and adapted to control a flow rate of the gas circulating in the internal gas passage (100) (Qalim),
a control unit (50) with a microprocessor (51) which is configured for and adapted to control the valve (22) to thereby control the flow rate of the gas passing through the valve (22) and feed the deformable reservoir (27) with the gas,
a pressure sensor (55) configured for and adapted to perform one or more gas pressure measurements (Pmask) of a gas pressure at the respiratory interface (10) and to supply said one or more gas pressure measurements (Pmask) to the control unit (50),
a flow rate sensor (60) arranged in the internal gas passage (100) configured for and adapted to measure the flow rate of supplied gas (Qalim) circulating in said internal gas passage (100) and to supply said gas flow rate measurement (Q) to the control unit (50), and
an acoustic and/or visual alarm,
further characterized in that:
the gas delivery apparatus (1) additionally comprises a data storage device for storing a concentration threshold value (Cmin) of the at least one therapeutically active compound, and
the control unit (50) is specifically programmed and thereby configured for and adapted to:
i) determine an exhaled flow rate (Qexp) escaping through the exhalation port (11) of the respiratory interface (10) on the basis of the gas pressure (Pmask) measured at the respiratory interface (10), during at least one expiratory phase of said patient,
ii) determine, on the basis of the flow rate of supplied gas (Qalim) during an inspiratory phase of the patient and of the exhaled flow rate (Qexp) during the expiratory phase following said inspiratory phase of the patient, a volume of the gas supplied (Valim) and a volume of an exhalation gas exhaled (Vexp),
iii) determine, on the basis of the volumes of gas supplied (Valim) and exhaled (Vexp), from the integral of the gas pressure (Pmask) during the inspiratory phase and the integral of the gas pressure (Pmask) during the expiratory phase, at least one leakage volume (Vleak) entering the respiratory interface (10) during said inspiratory phase,
iv) determine, on the basis of the leakage volume (Vleak) and the volumes of gas supplied (Valim) and exhaled (Vexp), a rate of dilution of the gas (D %),
v) calculate the actual concentration (Cactual) of said at least one therapeutically active compound in the respiratory interface (10) on the basis of the initial concentration (Cini) of said at least one therapeutically active compound and of the determined rate of dilution of the gas,
vi) compare the calculated actual concentration (Cactual) to the concentration threshold value (Cmin) of the at least one therapeutically active compound, stored by the data storage device, and
vii) trigger an acoustic and/or visual alarm when the calculated actual concentration (Cactual) is below said stored concentration threshold value (Cmin) of the at least one therapeutically active compound.
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