PULMONARY INFORMATION TRANSMISSION SYSTEM

• US 3,726,270 A
• Filed: 09/20/1971
• Issued: 04/10/1973
• Est. Priority Date: 09/20/1971
• Status: Expired due to Term

• Current Assignee: Sensormedics Corporation (Becton, Dickinson & Co)
• Original Assignee: Rauterkus L. Thomas, Roy A. Griffis, Terence Torzala
• Inventors: Griffis, Roy A., Rauterkus, L. Thomas, Torzala, Terence
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/182,053
• Time in Patent Office: 568 Days
• Field of Search: 128/2.08,2.07,2.1A 23/254R,254E 73/23,421.5
• US Class Current: 600/532
• CPC Class Codes: A61B 5/0878 using temperature sensing means
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A system by which signals pertaining to the pulmonary condition of a patient are transmitted to a location which is remote from the location of the patient. The signals are transmitted as the patient is being tested. pulmonary information in the form of spirometry data and total lung capacity volume are transmitted by means of telephone lines or the like to a location remote from the patient, and at the remote location the transmitted information may be studied by a person who is well acquainted in the art of analysis of such information. Patients at various locations provide information to a central location at which studies of the information are conducted. Thus, a specialist in the art of such studies is in a position to receive information from various patients who may be located at numerous widespread places and who may be many miles from the specialist.

Claims

1. A pulmonary testing system for providing an electrical signal indicating the peak percent nitrogen expired by a person in a breath and the total nitrogen volume expired by said person during repetitious breathing comprising:

means responsive to said person'"'"''"'"'s repetitious breathing for providing a first electrical signal proportional to the gas flow in each expired breath, analyzer means responsive to the repetitious exhaling of said person for providing a second electrical signal indicating the percent of nitrogen during each exhalation, integrating means responsive to said first and second electric signals for providing a third electrical signal indicating the total volume of nitrogen exhaled by said person, pulse generator means responsive to said second signal for providing a series of pulse signals, each pulse signal indicating the peak percent of nitrogen during a single exhalation, and means for providing a system electrical signal by superimposing said series of pulse signals upon said third signal such that said series of pulse signals occur during the time an inhalation occurs.

2. The invention according to claim 1 wherein said integrating means includes multiplying means fOr multiplying said first and second electrical signals prior to integrating the product thereof.

3. The invention according to claim 1 wherein said pulse generator means includes memory means for storing a value equal to the peak percent of nitrogen during each exhalation and delay means for providing said pulse generator means signal during the next inhalation.

4. The invention according to claim 3 wherein said next exhalation is detected by means determining that said second signal is below a certain value.

5. The invention according to claim 3 wherein said second signal is an analog signal having an instantaneous magnitude related to the instantaneous percent of nitrogen during each exhalation and wherein said memory means includes a capacitor which is charged to a voltage related to the maximum magnitude of said second signal.

6. The invention according to claim 5 wherein said pulse generating means include means for discharging said capacitor by determining that the instantaneous magnitude of said second signal is below a certain value.

7. The invention according to claim 1 wherein said system further includes minimum flow detector means for determining when said first signal is below a predetermined value and minimum percent nitrogen detector means for determining when said second signal is below a predetermined value, said integrating means being inhibited from providing a signal whenever said first or said second signals are less than said predetermined values therefor, and said pulse generating means being inhibited from providing a signal whenever said second signal is below said predetermined value therefor.

8. The invention according to claim 7 wherein said integrating means includes multiplying means for multiplying said first and second signals prior to integrating the product thereof.

9. The invention according to claim 8 wherein said integrating means further includes inhibiting means for inhibiting said integrating means from integrating the product of said first and second signals whenever either of said first or second signals is less than said predetermined value therefor.

10. A pulmonary testing system for providing an electrical signal capable of being transmitted over a single pair of telephone lines to a recording device for causing, in response to said transmitted signal, a graphic representation of the peak percent of nitrogen expired by a person during each one of a plurality of successive breaths, and the total volume of nitrogen expired by said person during said plurality of breaths, said person, during said plurality of breaths, inhaling a gaseous mixture containing negligible nitrogen and exhaling a gaseous mixture containing a decreasing percent of nitrogen, said system comprising:

means responsive to said plurality of successive breaths for providing a first electrical signal having an instantaneous magnitude proportional to the instantaneous gas flow resulting from said breaths, analyzer means responsive to said plurality of successive breaths for providing a second electrical signal having an instantaneous magnitude proportional to the instantaneous percent of nitrogen contained in each exhalation, multiplying means responsive to said first and second signals for multiplying said first signal times said second signal to provide a nitrogen flow signal, integrating means responsive to said nitrogen flow signal for integrating said nitrogen flow signal to provide a signal indicating the total volume of nitrogen expired by said person, pulse generating means responsive to said second signal for providing one pulse for each exhalation, said pulse having a magnitude proportional to the largest magnitude of said second signal during that exhalation, said pulse being provided during the inhalation immediately following that exhalation, and output means to which is applied said pulse generating means signal and said integrating means signal for adding said signals applied thereto, thereby proviDing said system electrical signal.

11. The invention according to claim 10 wherein said output means further includes transmitting means which, in response to said added signals, provides a modulated signal as said system electrical signal.

12. The invention according to claim 10 wherein said system further includes minimum detector means for determining whether said first signal is above a first minimum magnitude and whether said second signal is above a second minimum magnitude, said minimum detector means including means causing said multiplying means to be inhibited from providing a signal whenever either of said first or second signals has a magnitude below said respective first and second minimum magnitudes.

13. The invention according to claim 12 wherein said minimum detector means includes means for inhibiting said pulse generating means from providing a signal whenever said second signal has a magnitude below said second minimum magnitude.

14. The invention according to claim 10 wherein said system further includes means for providing a second system electrical signal which represents the spirometry data of a single breath of said person.

15. The invention according to claim 14 wherein said system further includes switching means to select between said first and second system electrical signals, and wherein said system further includes transmitter means to which the selected one of said first and second system electrical signals is applied for providing a modulated signal representative of said selected signal to a single pair of telephone lines.

16. The invention according to claim 10 wherein said pulse generating means includes a storage capacitor for storing electrical energy having a voltage proportional to the highest magnitude of said second signal during each breath, and logic means responsive to said second signal being below a certain magnitude to cause said pulse to be provided during said immediately following inhalation.

17. The invention according to claim 16 wherein said pulse generating means further includes switching means responsive to said logic means for causing said capacitor to discharge after said pulse is provided and before the immediately following exhalation.

18. Circuitry for transmission of pulmonary information from a test location to a remote location by means of a telephone circuit comprising:

a conduit adapted for communication with the respiratory system of a patient, a flowmeter joined to the conduit, the flowmeter having an electrical output, a percent nitrogen analyzer joined to the conduit and having an electrical output, a multiplier connected to the electrical output of the flowmeter, a minimum flow detector connected to the output of the flowmeter, a peak percent nitrogen follower, a minimum percent nitrogen detector, means connecting the output of the percent nitrogen analyzer to the multiplier and to the peak percent nitrogen follower and to the minimum percent nitrogen detector, a gate member, means connecting the outputs of the multiplier and the minimum flow detector and the minimum percent nitrogen detector to the gate member, a percent nitrogen pulse generator including time delay means, means connecting the output of the minimum percent nitrogen detector to the peak percent nitrogen follower and to the percent nitrogen pulse generator, a transmitter, means connecting the time delay means to the transmitter and to the peak percent nitrogen follower, an integrator, means connecting the output of the gate member to the integrator, means connecting the output of the integrator to the transmitter, a central unit including a demodulator and a recorder, means for connecting the transmitter and the demodulator to a telephone circuit at opposite portions thereof, means connecting the output of the demodulator to the recorder, the transmitter thus transmitting to the central unit signals represeNtative of the peak percent nitrogen expired by a patient in each breath and the nitrogen volume in each breath of the patient.

19. The system of claim 10 in which the analyzer means comprises:

a high output impedance circuit which includes first operational amplifying means, the first operational amplifying means being an inverting amplifying means and having an input and an output, means including first unidirectional current conducting means for coupling from the output thereof to the input of said first operational amplifying means, second unidirectional current conducting means, second operational amplifying means, the second operational amplifying means being high input impedance operational amplifying means and having a noninverting input and an output, said output being coupled to the input of said first amplifying means, and means for connecting the input of said first operational amplifying means through said second unidirectional current conducting means to the output of said first operational amplifying means so that current flows from the input of said second operational amplifying means to the output of said first operational amplifying means.

20. The invention according to claim 19 wherein each of said first and second unidirectional current conducting means is the base-emitter junction of a transistor.

21. The invention according to claim 19 wherein said second operational amplifying means further has an inverting input coupled to the output of said second operational amplifying means.

22. The invention according to claim 19 wherein the output of said circuit is the junction of said second operational amplifying means and said second unidirectional current conducting means.