Ventilator/Anaesthetic system with juxtaposed CO.sub.2 meter and expired gas flow meter
First Claim
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1. A ventilator/anaesthetic system comprising:
- a ventilator/anaesthetic unit;
an inspiratory tube connected to said ventilator/anaesthetic unit and adapted for communication with a patient for carrying a breathing gas from said ventilator/anaesthetic unit to a patient;
an expiratory tube connected to said ventilator/anaesthetic system and adapted for communication with a patient for carrying expired breathing gas from a patient to said ventilator/anaesthetic unit;
a patient tube connected to said inspiratory tube and to said expiratory tube and adapted for connection to airways of a patient;
a flow meter disposed downstream of said patient tube for measuring a flow of expired breathing gas and for generating a flow signal corresponding to said flow of expired breathing gas;
carbon dioxide meter means, juxtaposed to said flow meter downstream from said patient tube, for measuring carbon dioxide in expired breathing gas and for generating a measurement signal and a reference signal identifying carbon dioxide in expired breathing gas at respectively different times; and
calculating means, supplied with said measurement signal, said reference signal and said flow signal, for calculating a concentration of carbon dioxide in expired breathing gas from a ratio of said measurement signal and said reference signal and for calculating a parameter related to production of carbon dioxide by a patient from said concentration and said flow signal over at least two respiratory cycles of a patient.
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Abstract
A number of different parameters related to carbon dioxide output of a patient are routinely determined in ventilator/anaesthetic systems. For this purpose, a ventilator/anaesthetic system for determining carbon dioxide parameters includes a ventilator unit in which a first flow meter is arranged to measure an expired flow of gas, and a carbon dioxide meter is arranged to measure the concentration of carbon dioxide in expired gas. Arranging the carbon dioxide meter in the ventilator/anaesthetic unit minimizes the equipment which must be located in the immediate vicinity of patient, and a faster, more sensitive carbon dioxide meter thus can be used.
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Citations
7 Claims
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1. A ventilator/anaesthetic system comprising:
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a ventilator/anaesthetic unit; an inspiratory tube connected to said ventilator/anaesthetic unit and adapted for communication with a patient for carrying a breathing gas from said ventilator/anaesthetic unit to a patient; an expiratory tube connected to said ventilator/anaesthetic system and adapted for communication with a patient for carrying expired breathing gas from a patient to said ventilator/anaesthetic unit; a patient tube connected to said inspiratory tube and to said expiratory tube and adapted for connection to airways of a patient; a flow meter disposed downstream of said patient tube for measuring a flow of expired breathing gas and for generating a flow signal corresponding to said flow of expired breathing gas; carbon dioxide meter means, juxtaposed to said flow meter downstream from said patient tube, for measuring carbon dioxide in expired breathing gas and for generating a measurement signal and a reference signal identifying carbon dioxide in expired breathing gas at respectively different times; and calculating means, supplied with said measurement signal, said reference signal and said flow signal, for calculating a concentration of carbon dioxide in expired breathing gas from a ratio of said measurement signal and said reference signal and for calculating a parameter related to production of carbon dioxide by a patient from said concentration and said flow signal over at least two respiratory cycles of a patient. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification