GB2368286A

GB2368286A - Aspirating sample collection device

Info

Publication number: GB2368286A
Application number: GB0019466A
Authority: GB
Inventors: Sam Chhaya; Geoffrey Cusick
Original assignee: University College London Hospitals NHS Foundation Trust (UCLH)
Current assignee: University College London Hospitals NHS Foundation Trust (UCLH)
Priority date: 2000-08-08
Filing date: 2000-08-08
Publication date: 2002-05-01
Also published as: WO2002011613A3; GB0019466D0; WO2002011613A2; AU2001276523A1

Abstract

An apparatus for aspirating body samples comprising a sample receiving chamber 28 connected to a syringe needle 8 and a source of suction <I>via</I> a valve 36 within the chamber which is controlled by an externally accessible operating mechanism. The suction means may be a disposable, evacuated vessel 20 sealed by a rubber membrane 22 which is pierced by a spike 34 extending from the interior wall 26 as the vacuum container is inserted into the barrel 30 of the device. The conduit 32 connecting the vacuum reservoir and sample chamber outlet is sealed by a biased valve comprising a resilient plug which is supported by rigid, acutely angled rods 38 connecting the valve with the barrel wall, which possesses annular thinning 40 and is compressible. Compression of the barrel by squeezing deflects the spokes, raises the valve from the flow passage and a sample is aspirated into the sample receiving chamber by suction.

Description

2368286 ASPIRATION OF SAMPLES The present invention relates to apparatus

for the aspiration of samples, particularly (but not exclusively) from solid human tissue and fluid samples.

Such samples are used for example in cytological examination.

It is common in medical practice to draw (aspirate) samples of tissue from a patient so that cells within the sample can be analysed to assist in the diagnosis of the patient Typically this is achieved by the use of a hypodermic needle and syringe to withdraw a sample of tissue from the appropriate location.

The technique requires medical staff to insert the needle at the correct location and then withdraw the plunger to create a vacuum within the syringe The whole apparatus is then manipulated back and forth through the region of interest with continual vacuum being applied In the case of a fluid or cystic lesion such manipulation would not be required The aim being that a small sample of cellular material is drawn up (aspirated) into the needle The vacuum is then released and the needle withdrawn from the patient The material can then be sent for cytological examination This technique requires targeting of the needle The target is usually either a visible or palpable mass or lesion seen under some form of radiological imaging One hand is needed to either stabilise the lesion or manipulate the imaging device leaving only one hand free to operate the syringe Ensuring the accurate placement of the needle tip when withdrawing the plunger of the syringe with one hand is difficult.

US-A-2460641 describes a system in which a previously evacuated flask is impaled on a cannula which has been inserted into a vein Thus, the vacuum in the flask withdraws blood from the patient.

The present invention seeks to enable the single handed operation of a device to assist in the fine needle aspiration of cytological specimens This would free the operator's spare hand for other uses, such as manipulation of an imaging device used to ensure that the needle is in the correct location of stabilisation of the lesion or the like In this way, a signal handed operation would be more reliable and accurate.

The present invention therefore provides apparatus comprising a sample receiving chamber connectable to a source of suction via a valve within the chamber, and an externally accessible operating mechanism linked to the valve thereby to permit selective connection between the chamber and the source.

The source of suction is preferably a previously evacuated vessel This will ideally have a wall section made of a penetrable membrane such as rubber.

A cannula or other sharp tipped conduit will thus be able to gain access to the vacuum However, the evacuated vessel could be integrated into the apparatus if desired.

The valve preferably comprises a resilient member normally biased to rest in a sealing fashion against an outlet of the source of suction The operating mechanism is preferably operable by squeezing the apparatus A suitable mechanism is a compressible portion of the apparatus within which at least one substantially rigid rod members is attached at one end to the interior of the compressible portion and at the other to the valve and disposed at an angle to the compression direction This arrangement results in the valve being displaced when the compressible portion is compressed.

Thus, a preferred arrangement is one in which the apparatus is elongate with an annular thinned region thereabout to enable local compression.

The valve can be located within the chamber to selectively seal a conduit leading to the chamber from the source of suction.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which; Figure 1 is a cross section through the example of the invention prior to use; Figure 2 is a cross section corresponding to figure 1, showing the example in use; Figure 3 is a cross section on ll- 11 l of figure 1; and Figure 4 shows the manner of expulsion of a sample from the example.

Referring to the figures, figure 1 shows an apparatus 10 according to the invention which comprises an elongate barrel 12 The barrel has an open rear end 14 and a front end 16 which tapers to a conventional fitting 18 for a hypodermic needle 8, such as a Luer fitting.

A disposable reservoir 20 is pre-evacuated and in the form of a cylinder sized to fit within the barrel One end of the reservoir is sealed with a membrane 22 which extends across that end and attaches to the outer face of the cylinder Sealing fins 24 extend outwardly to take up the tolerance between the outside of the reservoir and the inside of the barrel.

Within the barrel, an interior wall 26 divides the interior of the barrel into a sample region 28 and a reservoir-receiving region 30 The interior wall 26 is solid except for a central flow passage 32 extending into the reservoir- receiving region 30 and ending in a spike 34.

A valve member 36 is located in the sample region 28 and has a tapered tip adapted to fit into the flow passage 32 in a sealing manner The valve member 36 is held in place by a plurality of substantially rigid rod members 38 which are attached at another end to internal faces of the barrel These rod members are shown in more detail in figure 3 and form spokes about the valve member 36 in order to support it without preventing fluid flow in its vicinity.

The rod members are disposed within the barrel 12 at an acute angle to the radial dimension.

The barrel wall is locally thinned in the region 40 where the rod members 38 are attached This allows the barrel to be compressed in this region, deflecting the rod members due to the angle between them and the radial compression direction This lifts the valve member 36 from the flow passage 32.

The use of the apparatus 10 is illustrated in figure 2 A hypodermic needle 8 is fitted onto the fitting 18 The reservoir is pushed home onto the spike 34, piercing the membrane 22 At this point, the valve member 36 prevents loss of the vacuum within the reservoir The operator holds the apparatus as in the manner of a pencil, with thumb and forefinger lying gently on the locally thinned region 40, and the hypodermic is inserted into the appropriate area of the patient When it is located correctly, the operator squeezes with thumb and forefinger, lifting the valve member from the passage 32 and allowing fluid communication between the reservoir 20 and the sample region 28 This evacuates the sample region 28 and a sample from the patient is drawn in the manner of US 2,460,641 When an adequate sample has been drawn, the pressure on the thinned region 40 is relaxed allowing the valve member to return to the a sealing position on the passage 32 Flow then stops and the hypodermic can be removed from the patient.

To expel the sample, the hypodermic 8 can (if desired) be removed, and the reservoir is removed and re-inserted in the barrel in a reversed orientation as shown in figure 4 The rear end of the reservoir is for this purpose formed with a sealing ring 42 about its outer edge to seal against the interior of the barrel 12, and a recess 44 adapted to accommodate the spike 34 when fully home.

As the reservoir travels along the barrel, an air pressure will build up in front of it which will lift the valve member 36 and expel the sample through the fitting 18 or hypodermic 8 A suitably positioned receptacle can then be employed to collect the sample.

Thus, the present invention permits the extraction of a sample from a patient with only single-handed operation at all material times.

Many variations could be made to the above-described apparatus without departing from the present invention For example, the reservoir could be replaced with a switchable source of vacuum or gas.

Claims

CLAIMS:

1 Apparatus for aspirating a sample comprising a sample-receiving chamber connectable to a source of suction via a valve within the chamber, and an externally accessible operating mechanism linked to the valve thereby to permit selective connection between the chamber and the source.

2 Apparatus as claimed in claim 1, wherein the source of suction is a previously evacuated vessel.

3 Apparatus as claimed in claim 2, wherein the evacuated vessel is integrated into the apparatus.

4 Apparatus as claimed in any preceding claim, wherein the source of suction comprises a wall section made of a penetrable membrane such as rubber.

Apparatus as claimed in any preceding claim, wherein the valve comprises a resilient member.

6 Apparatus as claimed in claim 5, wherein the resilient member is biased to rest in a sealing fashion against an outlet of the source of suction.

7 Apparatus as claimed in any preceding claim, wherein the operating mechanism is operable by squeezing the apparatus.

8 Apparatus as claimed in any preceding claim, wherein the operating mechanism is a compressible portion of the apparatus within which at least one substantially rigid rod members is attached at one end to the interior of the compressible portion and at the other to the valve and disposed at an angle to the compression direction.

9 Apparatus as claimed in any preceding claim, wherein the apparatus is elongate with an annular thinned region thereabout to enable local compression.

Apparatus as claimed in any preceding claim, wherein the valve is located within the chamber to selectively seal a conduit leading to the chamber from the source of suction.

11 Apparatus for aspirating a sample substantially as hereinbefore described with reference to, and/or as illustrated by, the accompanying drawings.