Method of conveying breathing gases to or from a patient

• US 7,958,891 B2
• Filed: 05/06/2009
• Issued: 06/14/2011
• Est. Priority Date: 06/21/2000
• Status: Expired due to Fees

• Current Assignee: Fisher & Paykel Healthcare Limited
• Original Assignee: Fisher & Paykel Healthcare Limited
• Inventors: Smith, Daniel John, Baldwin, David Peter
• Primary Examiner(s): Bianco; Patricia M
• Assistant Examiner(s): PATEL, NIHIR B
• Application Number:
  US12/436,486
• Publication Number:
  US 20090211579A1
• Time in Patent Office: 769 Days
• Field of Search: 128/201.13, 128/203.16, 128/203.17, 128/203.26, 128/203.27, 128/204.17, 128/911, 392/479, 392/480, 392/481, 392/485, 392/486, 392/487, 392/488, 392/489, 392/490, 392/491, 392/492, 392/493
• US Class Current: 128/203.16
• CPC Class Codes: A61M 16/08 Bellows; Connecting tubes having means for taking samples G01N1/22; Water traps; Patient circuits
• CPC Class Codes: A61M 16/0808 Condensation traps
• CPC Class Codes: A61M 16/0816 Joints or connectors
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/0875 Connecting tubes
• CPC Class Codes: A61M 16/0883 Circuit type
• CPC Class Codes: A61M 16/0891 Closed circuit, e.g. for anaesthesia
• CPC Class Codes: A61M 16/1045 Devices for humidifying or heating the inspired gas by using recovered moisture or heat from the expired gas
• CPC Class Codes: A61M 16/1075 by influencing the temperature A61M16/1045 takes precedence
• CPC Class Codes: A61M 16/1095 in the connecting tubes
• CPC Class Codes: A61M 16/142 with semi-permeable walls separating the liquid from the respiratory gas
• CPC Class Codes: A61M 2205/0238 the material being a coating or protective layer
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: A61M 2205/7527 liquophilic, hydrophilic
• CPC Class Codes: A61M 2207/10 Device therefor
• CPC Class Codes: B29D 23/00 Producing tubular articles B29D24/00 takes precedence

Abstract

A method of conveying humid breathing gases from a patient through a breathable breathing tube. The breathing tube includes a heater associated, at least in part, with a portion of hydrophilic material. The purpose of the heater is to evaporate any condensed liquid collecting in the conduit, which is first sucked up by the hydrophilic material. The heated wick reduces the risk of collected water being passed to the patient and causing choking fits or discomfit. It is preferred that the heated wick lies freely in the conduit to settle at low points in the conduit where condensation may collect.

Claims

1. A method of conveying humid breathing gases from a patient comprising:

providing a flexible breathing tube having a first end and a second end, wherein said tube is connected to a patient interface at said first end, said tube comprising;

an enclosing outer wall defining a flexible gases passageway between said first end and said second end, and

at least a region of said enclosing outer wall being of a material that allows the transmission of water vapour without allowing the transmission of liquid water or respiratory gases through said enclosing outer wall, and wherein said at least a region and said second end are separate from each other;

conveying said breathing gases from said patient through said tube;

heating said gases in said tube;

transmitting at least some water vapour from said humid breathing gases through the enclosing outer wall of said tube.

2. A method of conveying humid breathing gases as claimed in claim 1, wherein said gases are heated by an elongate heater wire located in said breathing tube.

3. A method of conveying humid breathing gases as claimed in claim 2, wherein said heater wire lies freely within said passageway, such that heater wire settles over at least some of its length at low points in said passageway where condensed water vapour may collect.

4. A method of conveying humid breathing gases as claimed in claim 2, wherein said heater wire is covered with an inner hydrophobic insulating layer and at least partially covered with an outer hydrophilic layer, there being no direct supply of water to said hydrophilic layer from outside said tube.

5. A method of conveying humid breathing gases as claimed in claim 4, wherein said heater wire lies freely within said passageway, such that heater wire settles over at least some of its length at low points in said passageway where condensed water vapour may collect.

6. A method of conveying humid breathing gases as claimed in claim 1, wherein said breathing tube further including at least one helically wound polymer tape or strip, part or all of said strip being of a material that allows the passage of water vapour without allowing the passage of liquid water or respiratory gases, respective edges of adjacent turns of said strip being adjoining or overlapping and bonded.

7. A method of conveying humid breathing gases as claimed in claim 1, wherein said breathing tube including said material is extruded.