Flowmeters
First Claim
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1. A peak expiratory flow meter for determining the expiratory flow rate of a subject, comprising:
- flow passage means for transporting expiratory flow along an expiratory flow passage, said flow passage means having a first end for receiving expiratory air from said subject and a second end through which expiratory flow exits to the environment; and
flow inhibition means connected to said flow passage means normally effective to inhibit expiratory flow through said flow passage means, said flow inhibition means comprising a valve mechanism which normally closes said expiratory flow passage, said valve mechanism opening completely and in a short time relative to the duration of forced expiration from said subject in response to attainment of a predetermined expiratory pressure to allow expiratory flow through said flow passage means and out through said second end to the environment.
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Abstract
Peak expiratory flow meter for measuring the expiratory flow rate of a subject having a flow inhibitory device normally effective to inhibit expiratory flow through the peak expiratory flow meter, the flow inhibitory device being operable in response to attainment of a predetermined expiratory pressure to allow the expiratory flow. From the PEF measured, the airway passage resistance can be determined. Further lung characteristics can be determined from the shape of the decay portion or the expiratory flow curve. The meter has clinical application in the monitoring and diagnosis of asthma and other pulmonary diseases.
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Citations
18 Claims
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1. A peak expiratory flow meter for determining the expiratory flow rate of a subject, comprising:
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flow passage means for transporting expiratory flow along an expiratory flow passage, said flow passage means having a first end for receiving expiratory air from said subject and a second end through which expiratory flow exits to the environment; and flow inhibition means connected to said flow passage means normally effective to inhibit expiratory flow through said flow passage means, said flow inhibition means comprising a valve mechanism which normally closes said expiratory flow passage, said valve mechanism opening completely and in a short time relative to the duration of forced expiration from said subject in response to attainment of a predetermined expiratory pressure to allow expiratory flow through said flow passage means and out through said second end to the environment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11, 12, 13)
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- 9. A meter according to claim 9, and further including a flow measuring means for providing an electrical signal representation of expiratory flow through passage.
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14. A method of measuring pulmonary function in a subject, said method comprising:
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providing a flow meter having an expiratory flow passage means for transporting expiratory flow along an expiratory flow passage, said flow passage means having a first end for receiving expiratory air from a subject and a second end through which expiratory flow exits to the environment and flow inhibition means normally effective to inhibit expiratory flow through said flow passage means, wherein said flow inhibition means comprises a valve mechanism which normally closes said expiratory flow passage, said valve mechanism opening completely and in a short time relative to the duration of forced expiration from the subject in response to attainment of a predetermined expiratory pressure to allow expiratory flow through said flow passage means and out through said second end to the environment; having the subject to attempt expiratory flow through the meter; automatically operating said valve mechanism on attainment of a predetermined expiratory pressure to allow expiratory flow through the flow passage means, such that the subject is induced to produce a peak expiratory flow; measuring the expiratory flow through the meter. - View Dependent Claims (15, 16, 17)
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18. A peak expiratory flow meter for determining the expiratory flow rate of a subject, comprising:
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a flow passage having a first end for receiving expiratory air from a subject and a second end through which expiratory flow exits to the environment; a closure operatively connected to said flow passage and normally effective to inhibit expiratory flow through said flow passage, said closure opening completely and in a short time relative to the duration of forced expiration from said subject in response to attainment of a predetermined expiratory pressure to allow expiratory flow through said flow passage and out through said second end to the environment.
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Specification