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GB2318869A - Device for analysing blood gases - Google Patents

Device for analysing blood gases Download PDF

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Publication number
GB2318869A
GB2318869A GB9622571A GB9622571A GB2318869A GB 2318869 A GB2318869 A GB 2318869A GB 9622571 A GB9622571 A GB 9622571A GB 9622571 A GB9622571 A GB 9622571A GB 2318869 A GB2318869 A GB 2318869A
Authority
GB
Grant status
Application
Patent type
Prior art keywords
gas
tube
cell
blood
plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9622571A
Other versions
GB9622571D0 (en )
Inventor
Michael Ernest Garrett
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BOC Group Ltd
Original Assignee
BOC Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/145Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D63/00Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/02Hollow fibre modules
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D63/00Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/02Hollow fibre modules
    • B01D63/027Twinned or braided type modules
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by the preceding groups
    • G01N33/48Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/483Physical analysis of biological material
    • G01N33/487Physical analysis of biological material of liquid biological material
    • G01N33/49Blood
    • G01N33/4925Blood measuring blood gas content, e.g. O2, CO2, HCO3

Abstract

A device to be placed in the body of a patient for use in blood gas analysis comprises at least one hollow tubular fibre (3) of membrane material having a tube plate (6 and 8) at each end. Preferably, a plurality of hollow tubular fibres (3) are provided which are spun together to define a gas separation cell (4).

Description

MEDICAL DEVICES The present invention relates to medical devices and in particular medical devices adapted to be placed in the body of a patient for use in blood gas analysis.

Oximetry equipment is used for the non-invasive blood gas analysis of patients.

However, oximetry equipment is limited to analysing the presence and concentration of oxygen only and is not sufficiently accurate in certain circumstances.

It is an aim of the present invention to provide apparatus for analysing blood gases on a relatively continuous basis using invasive techniques.

Throughout this specification the expression "membrane material" is intended to embrace semi-permeable membranes, for example, polycarbonates, silicones and polysulphones which can be used as a means for separating different gases because of the different rates of permeation of the gases through the membrane material.

According to the present invention, a medical device adapted to be placed in the body of a patient for use in blood gas analysis, comprises at least one hollow tubular fibre of membrane material having a tube plate at each end.

In a preferred embodiment, a plurality of hollow tubular fibres are provided which are spun together to define a gas separation cell, the gas separation cell being terminated at each end by a tube plate.

In one embodiment, a needle is releasably connected to the distal tube plate for piercing the body of a patient. In an alternative embodiment, the gas separation cell may be contained initially within a hollow needle having a sharpened distal tip for piercing the skin of a patient.

An embodiment of the invention will now be described, by way of example, reference being made to the Figures of the accompanying diagrammatic drawing in which: Figure 1 is a schematic view of a medical device according to the present invention; and Figure 2 illustrates the device when placed in the body of a patient and connected to a carrier gas supply and a gas analyser.

As shown, a medical device 1 for placement in the body 2 of a patient for use, for example, in the blood gas analysis of the patient comprises a plurality of hollow tubular fibres 3 all made from membrane material which are spun or plaited together to form a gas separation cell 4. The cell 4 terminates at each end in a tube plate 6, 8. The proximal tube plate 6 is connected via an elastomeric tube 10 to a source 12 of carrier gas, for example nitrogen or krypton. As shown, the distal tube plate 8 is releasably connected to a needle 14 having a sharpened distal tip 16 for piercing the skin of the patient.

In use, the needle 14 is used to pierce the body 2 of the patient so that the gas separation cell 4 is located in a pre-selected area of the body, for example, a vein.

The needle 14 is then removed from the tube plate 8 and an elastomeric tube 18 is subsequently fitted to the tube plate 8, which elestomeric tube 18 is already connected to a gas analyser 20 known per se.

Next, an inert carrier gas for example nitrogen or krypton is then passed from the source 12 through the elastomeric tube 10 and into the cell 4 via the tube plate 6.

The fibres 3 exposed in the vein will be permeable to dissolve gases which will enter the gas separation cell 4 in accordance with Henry's Law provided that the flow rate is sufficiently low to enable the gases to reach equilibrium. The inert carrier gas then carries this blood gas mixture through the tube 18 to the gas analyser 20 where the gases can be monitored using conventional techniques such as paramagnetism and infrared absorption for oxygen and carbon dioxide respectively.

In the manner described, the medical device 1 should provide no more discomfort than a flexible cannula as currently used in attaching a drip feed to a patient. The membrane material can be chosen to provide adequate strength and compatibility with body tissue and will provide several hours of useful samples before becoming blocked by tissue reaction.

It will be appreciated that to be effective, the membrane material thickness must be very small and the available area for exposure to blood gases very large if the process is to work with an acceptable efficiency. This is achieved by spinning the fibres 3 to form the gas separation cell 4.

In a modification, the cell 4 could be contained within a hollow needle prior to use rather than attached to one end of the needle as described in the embodiment illustrated in Figure 1.

Claims (7)

1. A medical device adapted to be placed in the body of a patient for use in blood gas analysis, comprising at least one hollow tubular fibre of membrane material having a tube plate at each end.
2. A medical device as claimed in Claim 1, in which a plurality of hollow tubular fibres are provided which are spun together to define a gas separation cell, the gas separation cell being terminated at each end by a tube plate.
3. A medical device as claimed in Claim 2, in which a needle is releasably connected to the distal tube plate for piercing the body of a patient.
4. A medical device as claimed in Claim 2, in which the gas separation cell is initially located within a hollow needle for piercing the body of a patient.
5. A medical device as claimed in any one of Claims 2 to 4, in which the proximal tube plate is connectable to a tube for communication with a source of inert carrier gas.
6. A medical device constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the Figures of the accompanying drawing.
7. A method of blood gas analysis comprising the steps of placing the gas separation cell in the blood to be analysed, allowing blood gases to permeate into the cell, passing an inert carrier gas through the cell, thereby to drive the blood gases which have permeated through the cell towards a gas analyser for analysis.
GB9622571A 1996-10-30 1996-10-30 Medical devices Withdrawn GB9622571D0 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9622571A GB9622571D0 (en) 1996-10-30 1996-10-30 Medical devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9622571A GB9622571D0 (en) 1996-10-30 1996-10-30 Medical devices

Publications (2)

Publication Number Publication Date
GB9622571D0 GB9622571D0 (en) 1997-01-08
GB2318869A true true GB2318869A (en) 1998-05-06

Family

ID=10802156

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9622571A Withdrawn GB9622571D0 (en) 1996-10-30 1996-10-30 Medical devices

Country Status (1)

Country Link
GB (1) GB9622571D0 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2100859A (en) * 1981-06-18 1983-01-06 Instrumentarium Oy Method of and apparatus for determining and controlling the gas content of the blood
US4832034A (en) * 1987-04-09 1989-05-23 Pizziconi Vincent B Method and apparatus for withdrawing, collecting and biosensing chemical constituents from complex fluids
EP0549341A1 (en) * 1991-12-24 1993-06-30 W.R. Grace & Co.-Conn. Hollow fiber plasma sampler
EP0585614A2 (en) * 1992-08-03 1994-03-09 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Hollow fiber permeator with tubesheet preform

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2100859A (en) * 1981-06-18 1983-01-06 Instrumentarium Oy Method of and apparatus for determining and controlling the gas content of the blood
US4832034A (en) * 1987-04-09 1989-05-23 Pizziconi Vincent B Method and apparatus for withdrawing, collecting and biosensing chemical constituents from complex fluids
EP0549341A1 (en) * 1991-12-24 1993-06-30 W.R. Grace & Co.-Conn. Hollow fiber plasma sampler
EP0585614A2 (en) * 1992-08-03 1994-03-09 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Hollow fiber permeator with tubesheet preform

Also Published As

Publication number Publication date Type
GB9622571D0 (en) 1997-01-08 grant

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)