Physiologic analyzer
First Claim
1. A physiologic analyzer comprising:
- means continuously sensing the flow rate of expired breath and providing an expired flow signal proportional thereto;
means continuously sensing the proportion of oxygen in inspired and expired breath and providing an oxygen concentration signal proportional thereto;
means continuously sensing the proportion of carbon dioxide in inspired and expired breath and providing a carbon dioxide concentration signal proportional thereto;
an expiratory flow integrator enabled only during expiratory breath and having its input connected to said expiratory flow signal and which samples and integrates said expiratory flow signal at intervals of t seconds and provides at its output a series of signals V0 through Vn where Vn is proportional to the volume expired during the time elapsed between tn-1 and tn ;
an expiratory oxygen concentration sampler which is enabled only when oxygen concentration deviates from the inspired value and which samples oxygen concentration every t seconds and provides at its output a series of signals X0 through Xn proportional to successive instantaneous values of said oxygen concentration;
an expiratory carbon dioxide concentration sampler which is enabled only when carbon dioxide concentration deviates from the inspired value and which samples carbon dioxide concentration every t seconds and provides at its output a series of signals ZO through Zn proportional to successive instantaneous values of said carbon dioxide concentrations.
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Abstract
A physiologic analyzer is disclosed for continuous measurement of a subject'"'"'s metabolic functions in which signals from ventilatory flow rate sensors and gas analyzers are processed to provide continuous measurement of the subject'"'"'s ventilatory volume, carbon dioxide production, oxygen consumption, respiratory exchange ratio, and other metabolic functions of interest. An expiratory oxygen concentration sampler is enabled only when oxygen concentration deviates from the inspired value. When enabled, the sampler provides at its output a series of discrete signals proportional to successive instantaneous values of oxygen concentration in expired breath. A similar sampler is used in the processing of the carbon dioxide concentration signals. A respiratory cycle timer measures elapsed time between successive inspirations and provides a breath duration signal which is used for rate computations. Interpretation and analysis of test results is greatly facilitated by displaying all metabolic measurements as a function of oxygen consumption.
102 Citations
11 Claims
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1. A physiologic analyzer comprising:
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means continuously sensing the flow rate of expired breath and providing an expired flow signal proportional thereto; means continuously sensing the proportion of oxygen in inspired and expired breath and providing an oxygen concentration signal proportional thereto; means continuously sensing the proportion of carbon dioxide in inspired and expired breath and providing a carbon dioxide concentration signal proportional thereto; an expiratory flow integrator enabled only during expiratory breath and having its input connected to said expiratory flow signal and which samples and integrates said expiratory flow signal at intervals of t seconds and provides at its output a series of signals V0 through Vn where Vn is proportional to the volume expired during the time elapsed between tn-1 and tn ; an expiratory oxygen concentration sampler which is enabled only when oxygen concentration deviates from the inspired value and which samples oxygen concentration every t seconds and provides at its output a series of signals X0 through Xn proportional to successive instantaneous values of said oxygen concentration; an expiratory carbon dioxide concentration sampler which is enabled only when carbon dioxide concentration deviates from the inspired value and which samples carbon dioxide concentration every t seconds and provides at its output a series of signals ZO through Zn proportional to successive instantaneous values of said carbon dioxide concentrations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a physiologic analyzer having means continuously sensing the flow rate of expired breath, means continuously sensing the concentration of oxygen in inspired and expired breath, and means continuously sensing the concentration of carbon dioxide in inspired and expired breath, the method comprising:
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sampling and integrating the expiratory flow rate at intervals of t seconds to provide a series of values of expiratory volume V0 through Vn where Vn is the volume expired during the time elapsed between tn-1 and tn ; sampling, upon detecting oxygen concentration which deviates from the inspired value, the oxygen concentration every t seconds to provide a series of oxygen concentration values X0 through Xn proportional to successive instantaneous values of expired oxygen concentration; sampling, upon detecting carbon dioxide concentration which deviates from the inspired value, the carbon dioxide concentration every t seconds to provide a series of carbon dioxide concentration value Z0 through Zn proportional to successive instantaneous values of carbon dioxide concentration in expired breath. - View Dependent Claims (11)
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Specification