GB2333964A

GB2333964A - Intravenous coagulation catheter for treatment of varicose veins

Info

Publication number: GB2333964A
Application number: GB9904976A
Authority: GB
Inventors: Falah Hasan Ali
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-04
Filing date: 1999-03-04
Publication date: 1999-08-11
Anticipated expiration: 2019-03-04
Also published as: GB2333964B; GB9904976D0

Abstract

A long catheter has a metallic head 1 connected by a glass tube 2 to a plastics insulating cover 4. A spiral wire 3 couples the head 1 to a tail 5 for connection to a high frequency electrosurgical supply. The catheter is introduced into a vein using a cannula. In operation, coagulation of the vein is produced by electrocautery.

Description

INTRAVENOUS COAGULATION CATHETER FOR TREATMENT OF VARICOSE VEINS This invention relates to I.V. coagulation catheter for treatment of primary (simple) varicose Veins.

Primary varicose veins are usually treated either surgically by stripping of the saphenous vein and the connected varicosities, or by sclerotherapy inducing thrombophlebitis through the use of irritant chemical compound.

Electrocautery is used to coagulate and eventually obliterate the vein, in this new method, avoiding the use of the knife and the drawbacks of the chemical method.

High voltage radio frequency current initiates electrical spark which heats the tissues rapidly.

On - off control is instantaneous. This sort of current is carried on surfaces of conductors, rather than passing through them i.e. there is no risk of causing cardiac arrhythmias or thermal damage to the internal organs. The generated heat by an electrical current is proportional to the current density, The use of small ( active) electrode at the site of surgical field will allow current density and heat production to be maximised. In contrast, by using a large (return) electrode i.e. the pad,the current is dispersed over a wide area. Indeed we can apply the active electrode at almost any point in the body to cauterise it.

The idea behind the application of this catheter is to use the intravenous route to treat the varicose veins by coagulation of high fiequency current electrocautery. This method may be helpful to treat other vascular disorders. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which, Figure 1 in perspective, is the intravenous coagulation catheter.

Figure 2 illustrates the intravenous cannula which is used to introduce the catheter intravenously.

Referring to the drawing, fig 1 shows the i.v. coagulation catheter which comprises a metal head 1 that conveys the current from the spiral wire 3 to the points of coagulation. It is 1 cm in length, apart from its narrow base which is fitted firmly insidethe glass tube 2. This head is conical in shape for easy introduction into the vein and its circumference is equal to that of the catheter. The heat resistant glass (or porcelain) tube 2 is lcm in length and serves to prevent the near end of the plastic insulator 4 from being damaged by direct effect of heat . The spiral flexible metal wire 3 connects the catheter head 1 to its tail 5 It has a suitable electrical resistance. The plastic cover 4 (current insulator) covers the spiral wire 3 right from the beginning of the tail 5 to to the end of the glass tube 2 and it is completely adherent to the latter, to prevent current leakage. It has o.5 - 1 mm thickness. The glass tube 2 is of the same thickness and size of that of the plastic insulator 4.

The metal tail 5 is used to connect the catheter to the electro surgical unit as it is touched by the clamp of electrocautery. It is narrower than the catheter to allow easy removal ofthe cannula after i.v. introduction of the catheter. It is about 2cm in length.

Fig 2 shows the i.v. coagulation catheter 6 introduced into the metal tube 7 of the cannula which is attached to its plastic wings 8.

This catheter is disposable and sterilised by gamma radiation. It is about Imeter in length and of3 sizes, French Gauge 8, 10 & 12.

The patient is preferably put on non steroidal anti inflammatory drug if possible starting the day before coagulation and continued for few days.

The varicose veins are labelled during clinical examination. The catheter is being introduced intravenously through the cannula which is applied at the lower end of the vein e.g. long saphenous v. In general the catheter can be introduced at any point along the course of the vein . Venography is done to avoid accidental introduction of the catheter into the external iliac vein, if coagulation is to be applied at a high level a long the course of the vein.

The catheter head is better to be few cms away from the sapheno femoral junction to avoid thermal injury to the femoral vein. After the catheter is being adjusted it should be fixed firmly to the skin by adhesive tape to prevent its displacement . The catheter should be introduced under aseptic technique.

Normal saline solution which contains 0.2 % lignocaine is prepared in order to; a. provide local anaesthesia. b. push the skin apart from the site of coagulation c. protect the surrounding tissues from thermal injury.

The electro surgical unit is checked before being applied to the patient . The limb is raised so that the collapsed (empty) vein will be in an intimate contact with the head of the catheter for effective coagulation. A tourniquet can be used in this procedure The patient is connected perfectly to the return electrode (the pad) which is placed at the contra lateral side of the body The labelled points on the course of the vein are injected subcutaneously with the prepared normal saline solution before coagulation is being applied Up to 100 ml can be used in normal adult patient. Apiece of gauze soaked with cold saline can be applied on the skin at these points before and after coagulation to protect the skin from thermal injury. Coagulation should be started from upper part going downward a long the course of the vein with gradual pulling of the catheter.

After coagulation is being finished, what is left of the catheter is withdrawn to the outside. The limb is supported by elastic pressure bandage for few days The following points can help in the assessment of the integrity of the circuit & the intensity of coagulation a. Fast and short touch to the catheter tail by the electro cautery clamp produces a spark indicating the integrity of the circuit. Its size gives a clue for the intensity of coagulation. b. Palpation of the skin over the point of coagulation help in the same way by feeling the crepitation of coagulation. A stethoscope can be used as well Cutting electro cautery is better not to be used to avoid unnecessary extensive damage.

Claims

CLAIMS The intravenous coagulation catheter provides an alternative to the available methods of the treatment of primary varicose veins including sclerotherapy and surgery This is achieved by using coagulation of high frequency current electrocautery The tissue damage induced by coagulation and subsequent replacement with adhesion and fibrosis will obliterate the veins . A long catheter is used, to be introduced intravenously so that the active electrode is brought about in direct contact with the points needed to be coagulated along the course of the vein e.g long saphenous vein.

These points are labelled previously during clinical examination The procedure is done with local anaesthesia under aseptic technique.