Agent gas analyzer and method of use
First Claim
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1. An agent gas analyzer for simultaneously determining concentrations of N gases in a respiratory gas stream, where N>
- 1, said agent gas analyzer comprising;
an optical bench includingat least one light source mounted to irradiate a portion of said respiratory gas stream with radiation,means for separating said radiation into N different bands of wavelengths of said radiation, andmeans for detecting the amount of radiation received, after passing through said portion of said respiratory gas stream, in each of said N different bands of wavelengths of said radiation;
means, coupled to said optical bench, for generating N electrical absorption signals representative of said amount of received radiation in said N bands; and
means, coupled to said means for generating, for computing simultaneously the concentrations of each of said N gases in the respiratory gas stream using matrix equations with a dimension of the matrix equal to N, and including said N electrical absorption signals as variables which are at least second order variables in said matrix equations.
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Abstract
An agent gas analyzer that will determine the types and measure simultaneously the concentrations of a plurality of agent gases in a respiratory gas stream of an anesthetized patient, with the analyzer self-determining the agent gas types and concentrations each time gas measurements are made.
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Citations
21 Claims
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1. An agent gas analyzer for simultaneously determining concentrations of N gases in a respiratory gas stream, where N>
- 1, said agent gas analyzer comprising;
an optical bench including at least one light source mounted to irradiate a portion of said respiratory gas stream with radiation, means for separating said radiation into N different bands of wavelengths of said radiation, and means for detecting the amount of radiation received, after passing through said portion of said respiratory gas stream, in each of said N different bands of wavelengths of said radiation; means, coupled to said optical bench, for generating N electrical absorption signals representative of said amount of received radiation in said N bands; and means, coupled to said means for generating, for computing simultaneously the concentrations of each of said N gases in the respiratory gas stream using matrix equations with a dimension of the matrix equal to N, and including said N electrical absorption signals as variables which are at least second order variables in said matrix equations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 1, said agent gas analyzer comprising;
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11. An agent gas analyzer for determining concentrations of N agent gases in a respiratory gas stream, said agent gas analyzer comprising:
an optical bench including at least one light source mounted to irradiate a portion of said respiratory gas stream with radiation, means for separating said radiation into a reference band, corresponding to absorption by a reference gas indicative of inspired and expired events in a breath cycle of said respiratory gas stream, and N different agent bands of wavelengths of said radiation, and means for detecting the absorption of radiation from radiation received, after passing through said portion of said respiratory gas stream, in said reference band;
means, coupled to said optical bench, for determining the occurrence of an inspired or expired event from the amount of received radiation detected in said reference band;means for detecting the amount of radiation absorbed by said respiratory gas stream in said N different agent bands; and means for computing and displaying said concentrations from said amounts of radiation in said agent bands absorbed for a period of time corresponding to one of said inspired and expired events wherein the rate of change of absorption by said reference gas is within a predetermined range.
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12. An agent gas analyzer for determining concentrations of N gases in a respiratory gas stream, said agent gas analyzer comprising:
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an optical bench including at least one light source mounted to irradiate a portion of said respiratory gas stream with radiation, means for separating said radiation into N different bands of wavelengths of said radiation, and means for detecting the absorption of radiation from radiation received, after passing through said portion of said respiratory gas stream, in as many of said N bands of wavelengths of said radiation as is possible during each of a plurality of measurement periods; means, coupled to said optical bench, for interpolating a value from values for absorption in one of said bands from previous and subsequent periods to determine the absorption in said one band when absorption is not detected in one of said measurement periods and computing the concentrations of each of said N gases using detected and interpolated absorptions with multiple simultaneous equations. - View Dependent Claims (13, 14)
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15. An agent gas analyzer for determining concentrations of N gases in a respiratory gas stream, where N>
- 1, said agent gas analyzer comprising;
an optical bench including at least one light source mounted to irradiate a portion of said respiratory gas stream with radiation, means for separating said radiation into N different bands of wavelengths of said radiation, and means for detecting the absorption of said radiation from radiation received, after passing through said portion of said respiratory gas stream, in said N bands of wavelengths of said radiation; means, coupled to said optical bench, for comparing a detected absorption in one of said N bands to criteria for one of an inspired and an expired event of a breath cycle; means for determining whether said absorption for said one band is within said event; and means for computing the concentrations of each of said N gases during said event using detected absorptions with multiple simultaneous equations. - View Dependent Claims (16, 17, 18, 19, 20, 21)
- 1, said agent gas analyzer comprising;
Specification