Respiration monitor with simplified breath detector

• US 5,611,349 A
• Filed: 05/11/1995
• Issued: 03/18/1997
• Est. Priority Date: 04/26/1993
• Status: Expired due to Fees

• Current Assignee: iLIFE Solutions, Inc.
• Original Assignee: I Am Fine, Inc.
• Inventors: James, Donald N., Halleck, Michael E.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US08/439,505
• Time in Patent Office: 677 Days
• Field of Search: 128/721, 128/722, 128/716, 128/671, 128/782, 310/331
• US Class Current: 600/534
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion

Abstract

A respiration monitor is disclosed which includes a simplified pneumatic breath detector, a pressure sensor connected with the detector, and an active low pass filter for filtering the output of the monitor to reduce signals not indicative of respiration, such as movement of and/or impacts upon the detector. The monitor may be linked with a transmitter for remote subject monitoring, and the entire monitor may be configured to be unobtrusively worn by the subject.

Claims

1. A breath detector for connection with monitoring means including pressure sensing means for monitoring changes in capacity of said detector, said detector comprising:

at least a first hollow tube having a fluid channel defined between first and second ends of said tube, said fluid channel normally having a substantially constant diameter from said first end to said second end and providing said capacity, said tube having an outlet from said channel and having flexibility sufficient to respond, by deformation of said tube, to breathing of a subject when secured adjacent to the subject'"'"'s torso and resiliency sufficient to regain its original shape after deformation without other structural aid;

securing means for securing said tube adjacent to the subject'"'"'s torso; and

connecting means for connecting said outlet of said tube with the pressure sensing means of the monitoring means.

2. The detector of claim 1 wherein said tube is stretchable so that overall volume of said channel increases when a subject having said tube applied adjacent to the subject'"'"'s torso inhales.

3. The detector of claim 1 wherein said flexibility of said tube is insufficient to totally close said channel when said tube is exposed to a variety of external pressures.

4. The detector of claim 1 further comprising at least one additional flexible yet resilient hollow tube having an outlet for a fluid channel defined thereby, and wherein said connecting means includes manifold means for connecting said outlets of said tubes with the monitoring means.

5. The detector of claim 1 wherein said securing means is at said first and second ends of said tube.

6. The detector of claim 1 wherein said tube has a second outlet, said securing means comprising a junction having at least first, second and third access openings, said first access opening providing said connecting means, said outlets of said tube secured to different ones of said second and third access openings of said junction.

7. A respiration monitor comprising:

a respiration detector including stretchable means defining a hollow conduit having a volume for containing a quantity of fluid and an outlet, said conduit having a substantially constant diameter between ends of said stretchable means when said stretchable means is in an unstretched condition, said stretchable means configured so that when stretched said volume of said conduit increases;

means for applying said respiration detector adjacent to the subject'"'"'s torso in a manner allowing stretching of said stretchable means responsive to inhalation by the subject; and

pressure sensing means connectable at said outlet of said stretchable means of said detector for sensing pressure changes at said respiration detector due at least in part to said stretching and having as an output therefrom an electrical signal which is variable with sensed pressure.

8. The monitor of claim 7 further comprising low pass filter means for receiving said signal from said pressure sensing means and reducing artifact in said signal not related to respiration of a subject, said low pass filter means providing an output therefrom indicative of the subject'"'"'s respiration.

9. The monitor of claim 8 further comprising transmitting means for receiving said output from said low pass filter means, said transmitting means including an antenna for transmitting a signal indicative of said received output from said low pass filter means.

10. The monitor of claim 7 wherein said low pass filter means is configured to provide said output therefrom in phase with the subject'"'"'s breathing and has a cutoff between about 2.0 and 2.5 Hz.

11. The respiration monitor of claim 7 wherein said pressure sensing means is an electret microphone transducer.

12. The monitor of claim 11 wherein said electret microphone transducer is exposed to pressure changes exerted from said conduit without intervening structure.

13. The monitor of claim 7 wherein said detector comprises a flexible yet resilient hollow tube of one-piece construction and having said fluid conduit substantially entirely defined by a wall of said tube.

14. A respiration monitor comprising;

a breath detector including stretchable means defining a hollow conduit having a volume for containing a quantity of fluid and an outlet, said conduit having a substantially constant diameter between ends of said stretchable means when said stretchable means is in an unstretched condition, said stretchable means configured so that when stretched said volume of said conduit increases;

means for applying said breath detector adjacent to the subject'"'"'s torso in a manner allowing stretching of said stretchable means responsive to inhalation by the subject;

a pressure transducer connected with said detector for sensing indications of volumetric changes in said detector and providing an electrical signal output indicative thereof; and

an active low pass filter utilizing feedback, said low pass filter receiving said output from said transducer and providing an output indicative of the subject'"'"'s respiration, said filter having a cutoff no greater than about 3 Hz.

15. The monitor of claim 14 wherein said pressure transducer is an electret microphone.

16. The monitor of claim 14 wherein said cutoff of said low pass filter is between about 0.5 and 2.5 Hz.

17. The monitor of claim 14 further comprising transmitting means for receiving said output from said low pass filter, said transmitting means including an antenna for transmitting a signal indicative of said received output from said low pass filter.

18. The monitor of claim 17 wherein said means for applying said breath detector adjacent to the subject'"'"'s torso is configured for mounting of said transducer, said low pass filter and said transmitting means thereto.