Apparatus and method for the identification of gases
First Claim
1. Apparatus for the identification of one or more anesthetic or other gases included in the respiratory air of a patient, said apparatus comprising:
- a source of radiation (4);
a chamber (1) for receiving the gas or gases to be examined and through which radiation from said source passes;
an optical interference filter means (7) for receiving and transmitting radiation passing through said chamber, said optical interference filter means having a transmission band within a range of 1.5%-0.4% of the mean transmission wavelength of incoming radiation, said optical interference filter means receiving the radiation at an angle of incidence within a range of 10°
-60°
;
optical focusing means (12) for the radiation transmitted by said optical interference filter means;
a radiation detector (10) for receiving radiation from said optical focusing means; and
measuring means (19) coupled to said radiation detector for analyzing the properties of the detected radiation obtained at more than two angles of incidence within said range of angles of incidence to identify the gas or gases.
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Accused Products
Abstract
An apparatus and method for the identification of one or more anesthetic or other gases included in the respiratory air of a patient, said identification being effected within the infrared range 3-4 μm. The appratus comprises a radiation source (4), a chamber (1) for receiving therein a gas or gases to be examined, an optical filter (7) for passing the radiation exiting the chamber therethrough, an optical focusing device (12) through or via which the incoming radiation travels, a radiation detector (10) and a measuring processor (19) which performs the measuring and identification. The transmission band of the optical filter (7) or a combination of successive filters is within a range of 1.5%-0.4% of the mean transmission wavelength and the ray arriving at filter (7) has an angle of incidence between 10°-60°, the measuring effected within this range being performed at more than two angles. A measured spectrum is compared with a prior known spectrum by means of correlation algorithm to carry out the ientification. In a monitor for anesthetic gases, the content of gases is measured by means of a rapid-response sensor breath by breath. The quality or mixing ratio of an anesthetic gas is, in turn, measured by means of a slower sensor of the type described above.
36 Citations
25 Claims
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1. Apparatus for the identification of one or more anesthetic or other gases included in the respiratory air of a patient, said apparatus comprising:
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a source of radiation (4); a chamber (1) for receiving the gas or gases to be examined and through which radiation from said source passes; an optical interference filter means (7) for receiving and transmitting radiation passing through said chamber, said optical interference filter means having a transmission band within a range of 1.5%-0.4% of the mean transmission wavelength of incoming radiation, said optical interference filter means receiving the radiation at an angle of incidence within a range of 10°
-60°
;optical focusing means (12) for the radiation transmitted by said optical interference filter means; a radiation detector (10) for receiving radiation from said optical focusing means; and measuring means (19) coupled to said radiation detector for analyzing the properties of the detected radiation obtained at more than two angles of incidence within said range of angles of incidence to identify the gas or gases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for the identification of one or more anesthetic or other gases included in the respiratory air of a patient, said method comprising the steps of:
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passing infrared radiation through the respiratory air; applying the radiation after it has passed through the respiratory air to an optical interference filter means at an angle of incidence within a range of 10°
-60°
, the transmission band of the optical interference filter means shifting, as a function of the angle of incidence through a range of 1.5%-0.4% of the mean transmission wavelength of the radiation;focusing the radiation transmitted through the optical interference filter means; detecting the focused radiation at more than two angles of incidence within said range of angles of incidence to obtain a measured spectrum of radiation properties; and comparing the measured spectrum to a known spectrum to identify the gas or gases. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A monitor for determining the amount at type of a anesthetic gas contained in the respiratory air of a patient, said monitor comprising:
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a passageway along which the respiratory air of the patient flows; first sensor means in communication with said passageway, said first sensor means having rapid response characteristics for determining the amount of anesthetic gas in the respiratory air on a breath by breath basis; and second sensor means in communication with said passageway at a location downstream, in the flow direction of the respiratory air, from said first sensor means, said second sensor means having slower response characteristics than said first sensor means for identifying the type of anesthetic gas in the respiratory air from an accumulation of respiratory air obtained form a plurality of breaths of the patient. - View Dependent Claims (19, 20)
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21. A method for determining the amount and type of an anesthetic gas contained in the respiratory air of a patient, said method comprising the steps of:
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passing the respiratory air of the patient along a flow path; determining the amount of anesthetic gas in the respiratory air, said determination being carried out sufficiently rapidly as to enable same to be made on a breath by breath basis, said determination being carried out at a first point along the flow path; and identifying the type of anesthetic gas in the respiratory air of the patient from an accumulation of respiratory air obtained from a plurality of breaths of the patient, said identification requiring a time period greater than that used to analyze respiratory air in an individual breath of the patient, said identification being carried out at a second point along the flow path downstream from the first point in the flow direction of the respiratory air. - View Dependent Claims (22, 23, 24, 25)
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Specification