Appliance for cannulation of a blood vessel

Abstract

The present invention relates to an appliance for cannulation of a blood vessel with a cannula which, after introduction into the vessel, is in fluidic communication with the vessel. At least one means is also provided to permit a controlled division of the blood into a first subsidiary stream which leaves the vessel through the cannula, and a second subsidiary stream which continues to flow through the vessel.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to an appliance for cannulation of a blood vessel with a cannula which, after introduction into the vessel, is in fluidic communication with the vessel, and also to the use of the appliance and to a method for cannulation of blood vessels.[0003] 2. Related Prior Art[0004] Such appliances are already known in the medical field and are used in many different medical indications.[0005] For example, they are used in extracorporeal blood circuits, for example for extracorporeal lung assist. This is necessary when a patient's pulmonary function is impaired and the body's oxygen supply is at risk. In this connection, apparatuses have now been used for some time which, like a heart-lung machine in open-heart surgery, can temporarily take over the function of the diseased lung.[0006] In temporary extracorporeal lung assist (ECLA), extracorporeal membrane oxygenation (ECMO) has for many years been an established treatment pr...

AI Technical Summary

Benefits of technology

[0021] With the present invention, it is possible to ensure that blood guided in a vessel is not removed in its entirety from the body via a cannula, but instead only a defined proportion of the blood flowing in the vessel is removed. At the same time, means provided according to the invention ensure that another portion of the blood is continued in a controlled manner through the vessel. In this way, the supply of blood and oxygen to areas situated below the cannulation site is guaranteed.

[0079] The appliance according to the invention is also particularly advantageous in pumpless arterio-venous lung assist. In this method, blood trauma can be minimized by omission of a blood pump and by means of a very short connection and low filling volumes. Moreover, this pumpless lung assist has the advantage that no additional machines are needed for maintaining the circulation. When appropriate cannulas are used, the patient's mean arterial pressure ensures a sufficient throughflow, the blood in the lung assist device being saturated with oxygen and having the carbon dioxide in it washed out. An important condition here is that the action of the heart is sufficient and only the pulmonary function is impaired.

Problems solved by technology

However, as a result of the overall trauma triggered, for example, by high doses of medication, blood transfusions, septic reactions, etc., there may be severe contractions of the arteries in particular.

In this way, all of the blood guided in the artery flows into the cannula and, via the cannula, into the femoral vein of the other leg, which means that blood supply to the distal areas of the leg with the arterial cannula is no longer guaranteed.

However, these techniques have the disadvantages that the insertion of the two further cannulas additionally damages and thus irritates the vessels.

Moreover, the method is made very complicated by the use of four cannulas.

However, in extracorporeal lung assist, for example, such balloon catheters are not suitable because they completely close the artery, as a result of which the flow of blood into the lower extremities or into the areas below the cannulation site is blocked, which, as has been mentioned above, may lead to ischaemia and, consequently, to ischaemic tissue necrosis.

When using air, for example, or other solutions, there is a danger that, if these fluids escape from the balloon into the blood, embolisms or immunological reactions may be produced and thus cause considerable damage within the human body.

This supply can be achieved locally via a collateral circulation, however, so that with these appliances it is not possible to measure whether a specific flow of blood is actually present in the cannulated vessel and whether the oxygen supply to all the areas below is thus guaranteed.

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