Volume variation sensor and method for obstructive sleep apnea monitoring

• US 5,191,893 A
• Filed: 05/12/1992
• Issued: 03/09/1993
• Est. Priority Date: 05/18/1990
• Status: Expired due to Term

• Current Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Original Assignee: CNS Incorporated (GSK plc)
• Inventors: Reiten, Denise M.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): PONTIUS, KEVIN LANE
• Application Number:
  US07/884,853
• Time in Patent Office: 301 Days
• Field of Search: 128/686, 128/687, 128/689, 128/694, 128/716, 128/721, 128/774, 128/782
• US Class Current: 600/534
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

A volume change sensor having an elongated tubular enclosure with a thin deformable wall having a conduit for connection to a pressure monitor, there being an elongated insert material within the tubular enclosure that is wider than it is thick at some locations formed from resiliently deformable open cell foam. An elastic belt against which the tubular enclosure is positioned is used to wrap it about a respirating subject undergoing corresponding changes to measure same.

Claims

1. A first volume change sensor for sensing volume changes in a flexible body subject to such volume changes, said first sensor comprising:

a tubular enclosure formed by a flexible wall about an interior region, said tubular enclosure being airtight except for at least one conduit having a conduit wall about a conduit passsageway therein connected to said flexible wall at an end of said conduit such that said conduit passageway opens to said interior region of said tubular enclosure with said conduit having an opposite end adapted for connection to a pressure monitor, said tubular enclosure being sufficiently elongated so as to be capable of being positioned substantially about a said flexible body, said flexible wall being sufficiently thin so as to be easily deformable;

an elongated insert formed of a unitary body of resiliently deformable, open cell foam and positioned in said interior region of said tubular enclosure; and

an elastic belt with a pair of opposite sides against one of which said tubular enclosure is positioned, said belt having fastening means at opposite ends thereof for being selectively joined together to secure said tubular enclosure about a said flexible body between said belt and that said flexible body;

said insert, if undeformed by external forces at a cross section thereof taken substantially perpendicular to its direction of elongation, having an extent at that cross section in a direction substantially parallel to said belt exceeding its extent there in a direction substantially perpendicular to said belt;

wherein said insert is an entity that, if undeformed, has an area at said cross section thereof that exceeds half that area at its greatest extent of a substantially parallel cross section of said tubular enclosure at that same location.

2. The sensor of claim 1 wherein said cross sectional area of said insert is substantially equal to said cross sectional area of said tubular enclosure.

3. A first volume change sensor for sensing volume changes in a flexible body subject to such volume changes, said first sensor comprising:

a tubular enclosure formed by a flexible wall about an interior region, said tubular enclosure being airtight except for at least one conduit having a conduit wall about a conduit passageway therein connected to said flexible wall at an end of said conduit such that said conduit passageway opens to said interior region of said tubular enclosure with said conduit having an opposite end adapted for connection to a pressure monitor, said tubular enclosure being sufficiently elongated so as to be capable of being positioned substantially about a said flexible body, said flexible wall being sufficiently thin so as to be easily deformable;

an elongated insert formed of resiliently deformable, open cell foam and positioned in said interior region of said tubular enclosure; and

an elastic belt with a pair of opposite sides against one of which said tubular enclosure is secured to said elastic belt by a fabric attached to said belt, said belt having fastening means at opposite ends thereof, for being selectively joined together to secure said tubular enclosure about a said flexible body between said belt and that said flexible body;

said insert, if undeformed at a cross section thereof taken substantially perpendicular to its direction of elongation, having an extent at that cross section in a direction substantially parallel to said belt exceeding its extent there in a direction substantially perpendicular to said belt, said fabric having a weave which can stretch relatively far substantially parallel to the direction of elongation of said tubular enclosure but can stretch relatively little in a direction transverse thereto.

4. A method for determining whether obstructional apneas are occurring in a respirating subject through measurement of volume changes at each of selected regions of that subject undergoing such volume changes because of respiration, said method comprising:

providing a first volume change sensor about said subject'"'"'s torso at a chest location, and providing a second volume change sensor about said subject'"'"'s torso at an abdominal location, said first and second volume change sensors each being capable of providing a varying air pressure in a corresponding conduit extending therefrom as a result of corresponding variations in volume of said subject'"'"'s torso at that sensor'"'"'s location;

comparing over time air pressure changes from said first and second volume change sensor conduits; and

selecting at least some of those occasions in which air pressure in said first volume change sensor is increasing and said air pressure in said second volume change sensor is decreasing, and vice versa, as indications of obstructive apneas.

5. A first volume change sensor for sensing volume changes in a flexible body subject to such volume changes, said first sensor comprising:

a tubular enclosure formed by a flexible wall about an interior region, said tubular enclosure being airtight except for at least one conduit having a conduit wall about a conduit passageway therein connected to said flexible wall at an end of said conduit such that said conduit passageway opens to said interior region of said tubular enclosure with said conduit having an opposite end adapted for connection to a pressure monitor, said tubular enclosure being sufficiently elongated so as to be capable of being positioned substantially about a said flexible body, said flexible wall being sufficiently thin so as to be easily deformable;

an elongated insert formed of a plurality of resiliently deformable, open cell foam pieces each abutting at least one other and positioned in said interior region of said tubular enclosure; and

an elastic belt with a pair of opposite sides against one of which said tubular enclosure is positioned, said belt having fastening means at opposite ends thereof for being selectively joined together to secure said tubular enclosure about a said flexible body between said belt and that said flexible body;

said insert, if undeformed by external forces at a cross section thereof taken substantially perpendicular to its direction of elongation, having an aggregate extent at that cross section in a direction substantially parallel to said belt exceeding its extent there in a direction substantially perpendicular to said belt.

6. The sensor of claim 5 wherein said insert is an entity that, if undeformed, has an area at said cross section thereof that exceeds half that area at its greatest extent of a substantially parallel cross section of said tubular enclosure at that same location.

7. The sensor of claim 6 wherein said cross sectional area of said insert is substantially equal to said cross sectional area of said tubular enclosure.