Respiratory analyzer system
First Claim
1. Apparatus for diagnosing possible brain stem disfunction relating to respiration in a patient comprising:
- (a) means for selectively introducing a plurality of known percentages of a test gas into air being inspired by said patient;
(b) means for measuring the inspiratory and expiratory flow of air to and from said patient during time periods related to introduction of each such gas percentage and for developing first electrical signals proportional thereto;
(c) means for measuring the percentage concentration of said test gas in the air expired by said patient during time periods related to introduction of each such gas percentage and for producing second electrical signals proportional thereto;
(d) analyzer means, including a programmable computing means, connected to receive said first and second electrical signals for integrating said first signals over respective predetermined time intervals and for computing from said second signals the respective alveolar partial pressure of carbon dioxide gas in the expiratory air flow from the lungs of said patient, said analyzer means further including means for determining the change in said integrated first signals relative to said respective alveolar partial pressures; and
(e) display means connected to said analyzer means for displaying said relative change, whereby normal and abnormal ventilatory responses may be distinguished.
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Accused Products
Abstract
A system for measuring the ventilatory response of the human respiratory system to increased levels of CO2 and/or decreased levels of O2. Measured concentrations of CO2 are introduced into an infant'"'"'s lungs and the inspired and expired air is passed through a pneumotachograph for developing various electrical analog signals relating to flow. Samples of the expired air are delivered to CO2 and O2 analyzers. The resulting electrical analog signals produced by these devices represent inspiratory and expiratory flow, and the CO2 and the O2 levels in the expired air. They are applied to a waveform analyzer containing an analog to digital converter and a microprocessor system which is programmed to discriminate between normal breathing patterns and irregular patterns. The microprocessor also computes inspiratory and expiratory tidal volume, ventilation (measured in liters per minute), breathing frequency, inspiratory, expiratory and total times of a preceding breath, minimum CO2 and O2, peak CO2 and O2 and volume of expired CO2 and O2 either on a breath-by-breath basis or over a user selected time interval. The results of these computations are provided in digital form to a digital computer having a graphic display capability. When the ventilation rate is plotted as a function of changes in the inspired CO2 concentration, the slope of this linear relation is indicative of abnormal ventilatory response, which is deemed helpful in the diagnosis of a number of disease states, e.g., Sudden Infant Death Syndrome.
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Citations
7 Claims
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1. Apparatus for diagnosing possible brain stem disfunction relating to respiration in a patient comprising:
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(a) means for selectively introducing a plurality of known percentages of a test gas into air being inspired by said patient; (b) means for measuring the inspiratory and expiratory flow of air to and from said patient during time periods related to introduction of each such gas percentage and for developing first electrical signals proportional thereto; (c) means for measuring the percentage concentration of said test gas in the air expired by said patient during time periods related to introduction of each such gas percentage and for producing second electrical signals proportional thereto; (d) analyzer means, including a programmable computing means, connected to receive said first and second electrical signals for integrating said first signals over respective predetermined time intervals and for computing from said second signals the respective alveolar partial pressure of carbon dioxide gas in the expiratory air flow from the lungs of said patient, said analyzer means further including means for determining the change in said integrated first signals relative to said respective alveolar partial pressures; and (e) display means connected to said analyzer means for displaying said relative change, whereby normal and abnormal ventilatory responses may be distinguished. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for diagnosing possible brain stem disfunction relating to respiration in a patient comprising the steps of:
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(a) selectively introducing a plurality of known percentages of test gases into air being inspired by said patient; (b) measuring the inspiratory and expiratory flow of air to and from said patient during time periods related to introduction of each such gas percentage and for developing first electrical signals proportional thereto; (c) measuring the percentage concentration of carbon dioxide gas in the air expired by said patient during time periods related to introduction of each such gas percentage and for producing second electrical signals proportional thereto; (d) computing the integral of said first signals over respective predetermined time intervals; (e) computing from said second signals the respective alveolar partial pressure of carbon dioxide gas in the expiratory air flow from the lungs of said patient; (f) determining the change in said integrated first signals relative to said respective alveolar partial pressures; and (g) displaying said relative change, whereby normal and abnormal ventilatory responses may be distinguished.
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Specification