GB2274991A

GB2274991A - Embryo replacement catheter

Info

Publication number: GB2274991A
Application number: GB9302682A
Authority: GB
Inventors: Sara Kinal; Harry Hodgkins
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-02-11
Filing date: 1993-02-11
Publication date: 1994-08-17
Anticipated expiration: 2013-02-11
Also published as: WO1994017743A1; GB9302682D0; GB2274991B

Abstract

An embryo replacement catheter has a bi-lumen tube with segregated access to each lumen so that the embryo pick-up and subsequent replacement of the embryo in the patient is carried out via one lumen 10, 12 and the other lumen 11 may be used to control the flexibility of the catheter and to modify its shape to facilitate insertion into the patient or subsequent control of the catheter. For instance, a stylet (15, Figs. 2, 3) is inserted into lumen 11 via access aperture 8 to control and modify the catheter. <IMAGE>

Description

EMBRYO REPLACEMENT CATHETER This invention relates to a catheter for picking up a human embryo from the petri dish in which it has grown and subsequently enabling the embryo to be inserted into the prospective mother.

One of the procedures used for the treatment of infertility is known as in-vitro fertilisation (I.V.F.). During this procedure the human egg is extracted from a female and fertilised outside the body by means of semen obtained from a male. The fertilised egg (embryo) is incubated and growth is promoted. When the embryo reaches the correct level of development it must be transferred into the female where it is hoped the embryo will develop and grow such that the female parent will from that time have a normal pregnancy and give birth approximately nine months later.

A critical part of the IVF procedure is the transfer or replacement of the embryo from the dish, in which it was growing, to the female recipient. The transfer is normally achieved by drawing the embryo into a catheter lumen by applying suction via a syringe - to draw fluid, in which the embryo is suspended, into the lumen of the catheter shaft. The catheter would then be inserted into the patient until the clinician considers that the tip of the catheter is correctly positioned. The embryo would then be expelled from the shaft and into the patient via syringe pressure to the hub of the catheter. The success of the procedure depends critically on the ease of use of the catheter in respect of insertion into and ease of location within the patient and also ease of manipulation and handling of the embryo during the procedure.The nature of the procedure means that the catheter has to be sufficiently flexible not to damage the patient and cause possible rejection of the embryo but sufficiently stiff to be inserted into the patient to the correct site.

According to the present invention there is provided a catheter comprising a bi-lumen tube with segregated access to each tube.

One lumen is designed to take a stylet, normally plastic or metal, the other is designed to allow carriage and transfer of fluid containing the embryo. The stylet would act as a stiffener for all or part of the catheter portion which is introduced into the patient. In addition, if a malleable stylet is used, it may be pre-formed either before or after entry into the catheter in order to modify the shape of the catheter. If, during use the stylet is withdrawn relative to the catheter, then the catheter will recover its original shape and flexibility. The stylet also provides the possibility of the tip. of the catheter being visualised by the clinician after insertion into the patient with the use of ultrasound. This invention can also be applied to multi-lumen catheters.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:- Figure 1 shows an embryo replacement catheter in section to illustrate the two lumens 10 and 11; Figure 2 shows an embryo replacement catheter in section with the stylet 15 inserted; Figure 3 shows the catheter and stylet 15 with the stylet preformed to modify the catheter shape; Figure 4 shows an example of possible lumen configuration.

Referring to the drawings, the catheter comprises of a bi-lumen tube with a hub 7 at one end. The internal surface of the hub should be tapered in accordance with recognised international standards to provide a leak-proof fit when attached to syringes conforming to the same standards. The tip of the catheter is shown as being open for one lumen 10 andl2 and sealed at the tip of the other lumen 6.

The lumen intended for insertion of the stylet is sealed 6 to produce a more rounded and less traumatic tip for insertion into a patient and to prevent entry of fluid or body tissue.

To provide stiffness to the catheter while picking up the embryo and on initial insertion into the patient the stylet 15 may be inserted into the catheter via 8 as shown in Figure 2. The separating membrane 9 between the lumens means that the stylet cannot damage the embryo by impact or accidentally expelling it from the shaft, also syringe pressure can be used to control the position of the embryo irrespective of the stylet position.

If the clinician chooses, and if the stylet is malleable, the stylet may be bent as shown in Figure 3 to assist with insertion into the patient. Withdrawal of the stylet allows the catheter to return to its original shape or, if flexible enough, to follow the contours of the vessel into which it has been inserted.

Claims

1 An embryo replacement catheter comprising a bi-lumen tube with segregated access at one end to each lumen.

2 An embryo replacement catheter as claimed in claim 1 where means is provided to vary the flexibility of the catheter along part or all of its length.

3 An embryo replacement catheter as claimed in claim 1 and claim 2 in which the flexibility of the catheter may be varied during the period of use of the catheter.

4. An embryo replacement catheter substantially as described with reference to, or as shown in, the drawings.

4 An embryo replacement catheter as claimed in claim 2 or claim 3 wherein the flexibility may be varied after the catheter has been pre-loaded with the embryo.

5 An embryo replacement catheter as claimed in claim 1 wherein the external shape of the shaft may be varied in a controlled manner during use.

6 An embryo replacement catheter as claimed in claim 1 in which means is provided to enhance the visibility of the catheter under ultrasound after insertion into the patient.

7 An embryo replacement catheter substantially as described herein with reference to Figures 1-4 of the accompanying drawings.

Amendments to the claims have been filed as follows 1. An embryo replacement catheter, comprising a bi-lumen tube with separate access to each lumen at one end thereof and a stylet slidably extending in one lumen, characterised in that the stylet is formed of a malleable material whereby it may be bent to a predetermined shape.

2. An embryo replacement catheter according to Claim 1, wherein the lumen containing the stylet is closed at the other end thereof.

3. An embryo replacement catheter according to Claim 1 or 2, comprising more than two lumens.