Background of the Invention Intravenous administration apparatus ("IV sets") are well known for use in human medicine. They are used to administer many types of fluids and drugs during and post surgery, during recovery, or otherwise as required. They comprise a length of hollow tubing, usually of plastics.

At one end of the tubing (the proximal end) there is provided a drip reservoir and spike extending into the drip reservoir. The needle and drip reservoir are arranged to be connected to a fluid reservoir which is provided separately from the IV set. The fluid reservoir will, in operation, contain any fluid which is desired to be introduced into the patient.

At the distal end of the tubing a catheter connector is provided for mounting a catheter for introduction into an appropriate blood vessel. Located a short distance along the tubing from the catheter connector (usually 100 to 150 mm) is an injection port, to enable additional fluids and drugs to be introduced into the patient.

Positioned at any appropriate point between the drip reservoir and injection point is a flow adjustor, for compressing the tubing and thereby adjusting the rate of flow of fluid.

IV sets may also be used with infusion pumps, which nowadays are usually electronically controlled devices which provide more accurate control of the fluid flow to a

patient.

All present IV sets have been designed for use with human patients, but veterinary medicine also has a significant need for IV sets for use with animal patients.

Unfortunately, presently available human IV sets are not very well suited for use with veterinary medicine. There are a number of reasons for this.

Human beings can generally be relied upon not to interfere with or remove a catheter. They are also able to retain the limb or portion of the body that is catheterised relatively immobile so as to avoid accidental removal or interference with the catheter or kinking of the tubing, affecting fluid flow. This is not the case with animals. In order to ensure the stability of an IV catheter in animals it is necessary to firmly secure the catheter to the animal and prevent access to the catheter by the animal. It is also necessary to secure at least a portion of the tubing in order to prevent kinking in the tubing in response to motion of the animal.

The above are usually achieved by bandaging the catheter to the animal's limb with a relatively large amount of bandaging. The tubing connecting to the catheter is usually looped in a 360 degree loop and bandaged firmly against the patient's limb, in order to prevent accidental kinking. The problem with doing this, however, is that the injection port available in human IV sets is then usually obscured by the bandaging. This can be avoided by using less tubing in the loop, but this leads to a potential kinking problem.

Another problem relates to the length of the available human IV sets. The length is usually approximately 150 centimetres. This is not really long enough for animal medicine, where the patient will not usually remain immobile and will be in a cage, usually some way from the needle and drip reservoir.

Attempts at addressing the problems with length and access to the injection port have been made using

extension sets which are available for human IV sets.

Extension sets include standard diameter tubing and an extra injection port.

The problem with using an extension set, however, is that there is potential for the extension set to come away from the standard IV set at the join, which can result in interruption in fluid flow. Further, because the extension set and standard IV set are separate, there is risk of infection being introduced via the join between them.

Yet a further problem, particularly if used with small animals, is that to introduce fluids or drugs via the extension set injection port it is necessary to flush a significant length of standard diameter tubing before the drugs or other fluids can be injected. Particularly with small animals, flushing can take a very long time leading to problems with timing of introduction of drugs and the additional volume of fluid that is injected into the patient.

Summary of the Invention In accordance with a first aspect, the present invention provides an intravenous administration apparatus comprising a length of tubing having a proximal end and a distal end, a catheter connector at the distal end and a first injection port mounted back from the distal end, wherein a first portion of tubing between the first injection port and the catheter connector is of a smaller diameter than a second portion of tubing between the first injection port and the proximal end.

Preferably, the first injection port is mounted from the distal end at a sufficient distance so that the tubing between the injection port and the catheter can be turned through a 360 degree loop and secured to a patient while still allowing access to the injection port.

The first injection port is preferably set back

between 200 and 300 millimetres from the catheter connector and preferably 250 millimetres back from the catheter connector.

Preferably, the first portion of tubing is of a smaller diameter than the rest of the tubing of the apparatus. This preferably allows for a relatively low volume of the section of tubing between the first injection port and the catheter connector, whereby to minimise the flush volume required when alternative fluids or drugs are to be introduced into the patient via the first injection port. Furthermore, smaller gauge tubing has less tendency to kink when wrapped around the limb of a patient.

Preferably a second injection port is provided further back from the catheter than the first injection port. The second injection port may be useful for larger animals which can take faster fluid flow and therefore do not have problems with a large flush volume.

Preferably, the apparatus is relatively long, being at least one and a half to three times as long as a standard human set. The preferred embodiment is approximately 300 to 350 centimetres long and preferably 325 centimetres long from the proximal end to the distal end. This has the advantage of providing plenty of length for use with animal patients, without requiring any extension set. This minimises the risk of infection.

Preferably, the catheter connector includes a catheter mounting portion, arranged to mount a catheter, and a tube connection portion for connection to the tubing, wherein the catheter mounting portion is arranged at an angle to the tube connection portion, the angle being less than 180 degrees and preferably being 90 degrees. This arrangement preferably facilitates the prevention of kinking and blockage of the apparatus.

Because, in use, the catheter mounting portion is at a right angle to the tube, there is less chance of a kink occurring at the tube mounting portion.

Preferably, the catheter connector also incorporates an injection port.

Brief Description of the Drawings Features and advantages of the present invention will become apparent from the following description of an embodiment thereof, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an illustration of a standard prior art IV set; Figure 2 is an illustration of an IV set in accordance with an embodiment of the present invention; and Figure 3 is an illustration of an alternative embodiment of the present invention.

Description of Preferred Embodiment Figure 1 illustrates a standard human IV set, generally designated by reference numeral 1. The IV set comprises a spike and drip reservoir arrangement 2 a first section of hollow tubing 3, an injection port 4, a second section of hollow tubing 5 and a catheter connector 6. It also comprises a flow adjuster 7. In operation, the fluid to be introduced to a patient is introduced to the spike and drip reservoir 2. The fluid is introduced via the spike and drip reservoir 2 to the tubing sections 3 and 5 and (via the flow control device 7 and the injection port 4) to the catheter connector 6. The catheter connector 6, in operation, can be joined to a needle or catheter at a catheter mounting portion 8. A tube connection portion 9 at the catheter connector 6 is connected to the tube section 5. (A needle or catheter (not shown) is introduced in to the blood vessel of the patient thus enabling fluid from the needle and drip reservoir

arrangement 2 to be introduced into the patient).

The injection port 4 includes a cap 10 which has a rubber seal through which a needle can be inserted to enable access to the interior of the injection port 4 so that fluids or drugs can be introduced into the second section of tubing 4 and therefore the patient.

Such human IV sets are well known and have many applications in human medicine. In veterinary medicine, there is a similar requirement in many circumstances for the introduction of drugs and fluids directly into the blood stream of animal patients. To date, standard human IV sets or standard IV sets with extension sets have been utilised. As discussed above under the"Background of the Invention"section, however, there are a number of problems associated with the use of standard human IV sets in veterinary medicine.

For instance, the second section of tubing 5 is relatively short (in the order of 100 to 150 millimetres in most human IV sets). In order to ensure that the catheter remains immobilised in animal patients and the tubing does not kink and obstruct fluid flow, it is generally necessary to heavily bandage the catheter and, a section of the tubing to a patient's limb. The tubing is preferably bandaged to the patient's limb in a 360 degree loop to avoid problems with kinking and to maintain immobility. With such a short length of tubing between the catheter and the injection port, this can result in the injection port being covered in bandages.

Further, the entire length of the human IV set is not long enough for animal applications. Greater length is desirable for animal applications as the animal may need to be free to move about and will be in a cage some distance from the mounting of the needle and reservoir arrangement. As discussed above, it is possible to use extension sets to extend the length of the IV set but this gives rise to potential problems with infection (because of extra joins between the extension set and the IV set).

Also introduction of drugs into an injection port in the extension set which is a relatively long way from the catheter requires a large volume flush through which can cause difficulties in some circumstances.

An embodiment of an intravenous administration apparatus in accordance with the present invention is illustrated in figure 2.

The apparatus is generally designated by reference numeral 20 and comprises a length of tubing 21 which extends from a proximal end 22 to a distal end 23. In this embodiment, the tubing 21 is divided into first 26, second 25 and third 24 sections.

The IV set of this embodiment 20 also comprises a catheter connector 27 at the distal end of the tubing 21.

The catheter arrangement 27 includes a catheter mounting portion 28 which is arranged to connect to a needle or catheter (not shown). The catheter mounting portion 28 is illustrated in proximity to a cap 29 through which a needle can be inserted. The catheter connector 27 also includes a tube connection portion 30 which is mounted to the section of the tubing 26. The angle between the tubing connection portion and catheter mounting portion 28 is less than 180 degrees and in this example is approximately 90 degrees. The needle extends in use, therefore, from the catheter mounting portion 28 at approximately a right angle from the extending direction of the tubing 26 mounted to the tubing mounting portion 30 of the catheter connector 27. This has the advantage of facilitating stable securing of the catheter connector 27 to a patient without kinking of the tubing 26.

The catheter connector 27 also includes an integral injection port 31 having a cap 32 which a needle can be passed so that fluids and/or drugs can be injected into the patient via the integral injection port 31. An advantage of having an injection port as part of the catheter connector at the distal end of the IV set 20 is that the fluids and/or drugs can be injected into the

patient with virtually no flushing.

The IV set 20 also comprises a first injection port 33 mounted to the tubing sections 25 and 26, respectively.

The length of the section 26 of the tubing between the first injection point 33 and the catheter connector 27 is relatively long compared with that of the equivalent section of tubing in standard IV sets. The length of the section 26 is preferably between 200 and 300 millimetres and in this example is 250 millimetres. This gives plenty of room for looping the section 26 of tubing so that it can be secured under bandages to an animal patient, without risking kinking and fluid obstruction.

When a patient is bandaged, it is likely that the catheter connector 27 (with the integral injection port) will be obscured. With the extra length of the section of tubing 26, however, the first injection point 33 is available for injection of alternative fluids and/or drugs, via removal of the first injection port 33 cap 34.

In order to minimise the flushing volume required, the section of tubing 26 is of a relatively small diameter, being smaller than the diameter of the other tubing sections 24 and 25. This leads to a relatively low volume section of tubing 26 which minimises the amount of flushing that is required to introduce substances via the first injection port 33. In this embodiment, the tubing of sections 24 and 25 has an inner diameter of approximately 2 millimetres and an outer diameter of approximately 4 millimetres, whereas the tubing of section 26 has an inner diameter of approximately 1.5 millimetres and an outer diameter of approximately 3 millimetres.

In this embodiment, the IV set also includes a second injection port 35 joining the sections of tubing 24 and 25. This second injection point 35 is optional. It may be useful for large animals where flushing volume is not critical.

The IV set of this embodiment also includes a flow control arrangement 36.

The overall length of this IV set is much greater than that of the standard IV set, and is preferably between one and a half and three times the length of a standard IV set. In this embodiment, the IV set is just over twice the length of the standard IV set, in this embodiment being 3250 millimetres, wherein sections 24 and 25 are each approximately 1500 millimetres, and section 26 is 250 millimetres long.

The apparatus also includes a spike and drip reservoir arrangement 40 at the proximal end of the apparatus.

Please note that the dimensions shown in figure 2 are illustrative only and the IV set of the present invention is not limited by those dimensions.

The tubing used in this embodiment is standard NIPRO tubing, but the tubing maybe of any convenient material.

Figure 3 illustrates an embodiment wherein section 26 is provided as an attachment having the catheter connector 27 at one end and a female luer lock 42 protected by a cap 41. The remainder of the IV set (not shown) includes a male luer lock adjacent the first injection port 33. Thus the IV set can be provided with alternative attachments having the T shaped catheter connector 27 as shown in Figure 3, and having a standard straight catheter connector similar to that illustrated in Figure 1.

Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.