System and method for determining airway obstruction
First Claim
1. A system for diagnosing the presence of abnormal respiratory function, comprising:
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a breathing tube through which a subject may take one or more breaths over a predetermined time period;
a flow meter connected to said tube;
an oxygen meter connecter to said tube;
a carbon dioxide meter connected to said tube; and
a microprocessor connected to said flow meter, said oxygen meter, said carbon dioxide meter, and said pulse oximeter, wherein said microprocessor is programmed to calculate the ratio of carbon dioxide to oxygen in said breaths in real-time.
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Accused Products
Abstract
A method and system for detecting the presence of restriction to expired airflow in humans or animals by analyzing the expired capnogram and oxygram, as well as the geometric analysis of the real-time plot of the waveform that depicts the instantaneous ratio of CO2 to O2 (the carboxygram ratio). Airway obstructions causes an increase in the Q-angle between the slope of phase 11 and slope of phase III in the expired carboxygram. The diagnostic accuracy of the detection of airways obstruction is further enhanced by measuring the ratio of time spent in exhalation (Te) versus inhalation (Ti). The system uses the combination of an increased carboxygram Q-angle, and a prolonged Te/Ti to detect presence of airways obstruction.
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Citations
25 Claims
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1. A system for diagnosing the presence of abnormal respiratory function, comprising:
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a breathing tube through which a subject may take one or more breaths over a predetermined time period;
a flow meter connected to said tube;
an oxygen meter connecter to said tube;
a carbon dioxide meter connected to said tube; and
a microprocessor connected to said flow meter, said oxygen meter, said carbon dioxide meter, and said pulse oximeter, wherein said microprocessor is programmed to calculate the ratio of carbon dioxide to oxygen in said breaths in real-time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of diagnosing the presence of abnormal respiratory function, said method comprising:
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providing a patient with a device adapted for measuring inspired and expired carbon dioxide and oxygen and flow rate;
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measuring the flow rate and partial pressures of carbon dioxide and oxygen in tidal breaths over a predetermined time period;
computing the ratio of carbon dioxide to oxygen in real-time;
visually plotting the computed ratios of carbon dioxide to oxygen; and
determining the presence of abnormal respiratory function based on the slope of predetermined portions of the plot of the computed ratios of carbon dioxide to oxygen. - View Dependent Claims (20, 21, 22)
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23. A method of diagnosing the presence of abnormal respiratory function, said method comprising:
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providing a patient with a device adapted for measuring inspired and expired carbon dioxide and oxygen and flow rate;
measuring inspired and expired carbon dioxide and oxygen and flow rate;
determining the start of inspiration and the start of expiration based upon predetermined absolute thresholds and the measured flow rates;
calculating the average inspiration time and expiration time over a predetermined period of time;
calculating the ratio of the average inspiratory time divided by the expiratory time over the predetermined period of time; and
displaying the calculated ratio of the average inspiratory time divided by the expiratory time over the predetermined period of time. - View Dependent Claims (24, 25)
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Specification