AU727386B1 - Multistage intravascular catheter placement unit - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT MULTI-STAGE INTRAVASCULAR CATHETER PLACEMENT UNIT The following statement is a full description of this invention, including the best method of performing it known to me: MULTI-STAGE INTRAVASCULAR CATHETER PLACEMENT UNIT This invention relates to improvements in devices used for the purpose of gaining access to the vascular system of the physical human or animal body. The object of such access is various and includes the aspiration of fluids from the body and the provision of the means whereby medications, drugs and or solutions may be introduced into the body. (Figure 1) The unit comprises of a flexible tube, (hereafter called a catheter), one end of which is designed to accommodate a range of accessories associated with typical devices in current use.

Within the catheter is a stiff sharp -pointed needle (hereafter called a trocar) which serves to introduce and guide the catheter into the body and blood vessel after piercing both the skin and the blood vessel. (Figure 2) As the trocar is removed the catheter is usually left in place allowing fluids to pass from the body to the outside of the body, and or, medications drugs or solutions may be passed from the outside into the body through the vascular system, or through in some instances some other tissue.

Such procedures are carried out either routinely, or within the context of a medical emergency, or where a perceived possibility of a medical emergency of any sort may arise.

The procedure requires a degree of skill in the person using the device. Sometimes it is difficult to successfully complete the procedure for various reasons such as the physical state of the body and or blood vessels of the recipient of the procedure.

The bore of the trocar must be of sufficient size to facilitate the flow of blood from its vessel to the outside of the body. Even small gauge units (21 g -23g) are sometimes resisted as they are pressed into some skin surfaces, particularly the skin of some geriatric patients, or patients with skin hardened by any combination of factors from genetics to the adverse effects of life style.

When a catheter placement unit is pressed into such skin it tends to compress the surface of the skin sufficiently to flatten or dislodge the vessel beneath it, making placement of the unit difficult or in some instances impossible. (Figure 3) To select a unit small enough in its diameter and point to minimise this distortion is often not practical for the purpose of blood collection or the placement of a suitable catheter. In many applications a large catheter is required.

Further to this, to immobilise the vessel to some extent prior to puncture, a finger is often employed, the same pressing the vessel upstream in relation to blood flow to the heart.

Prob ms associited with unsuccessful placement include: Increased risk of injury or death of the patient should the device be required urgently.

Increased discomfort or trauma to the patient should the patient be conscious at the time.

Frustration of medical staff Time wasted as alternative sites for placement are explored and attempted.

Delays in attending other patients requiring medical attention.

Waste of materials.

Much of the placement problems may be overcome by the present invention which incorporates improvements in the design of the trocar and catheter.

It is proposed therefore that the trocar be of a two-stage design The design and machining of the point of the trocar provides a projection which serves to introduce the larger diameter after having first pierced the skin with minimal confrontation and stabilised the blood vessel. (Figure 4 and Conventional designs present a comparatively blunt point of entry which often disturbs underlying vessels, flattening or pushing them to one side.

The trocar could be made of any suitable material for the purpose. The trocar hub is made of any suitable material for the purpose and would provide the user with a means of holding the device when placement is attempted. The catheter could be made of any suitable material.

A second problem encountered with conventional devices is produced by the catheter itself upon entry into the vessel. The conventional catheter has a single point of entry for fluids to pass either from the body or into the body. This is sufficient for the latter, but often presents difficulties when blood is required to pass from the vessel into the catheter to establish correct placement. As mentioned, the catheter is a hollow tube and as such incorporates a single point of fluid entry at its forward end.

This point of entry is sometimes blocked by the blood vessel prohibiting flow through the unit. (Figure 6) In some instances, for instance, where the vessel is of small diameter, the point of entry being upstream from the flow of blood back to the heart, it is difficult for blood to move around the catheter to enter it.

For this reason the invention incorporates a series of ports at the forward end of the catheter, greatly increasing the prospect of successful placement. Blood may enter the catheter from the top, sides and bottom of the tube as well as at the forward end.

(Figure 7) These auxiliary ports at the top and bottom are staggered. The side ports may fall anywhere along the sides, close to the forward end, and may be considered as optional.

Claims (4)

1. A multi-stage intravascular catheter placement unit comprising of a two-stage trocar of hollow section situated within a catheter of round hollow section containing auxiliary ports.

2 The multi-stage intravascular catheter placement device of claim 1 wherein the trocar incorporates an introducer of smaller dimensions, projecting from the forward end.

3 The multi-stage intravascular catheter placement device of claim 1 wherein the trocar is made of metal or any suitable material for the purpose.

4 The multi-stage intravascular placement device of claim 1 wherein the catheter features a number of auxiliary ports at its front end. The multi-stage intravascular catheter placement device of claim 1 wherein the catheter is made of any suitable material for the purpose. 6 The multi-stage intravascular catheter placement devise is substantially as herein described, with accompanying drawings. AN APPLICANT 21 FEBRUARY 2000