MEDICAL DEVICE FOR BLOOD PERFUSION

Technical field

The present invention relates to a medical device for blood perfusion.

For the purposes of the present description, the expression "blood perfusion" is taken to mean administering of blood, preferably though not necessarily via an artery, in extracorporeal circulation.

Background art

In surgical operations known as "open heart", there is a need for machines that are able to carry out the heart and lung functions, to temporarily replace the respective organs of the patient undergoing the operation.

Regarding the blood, an extracorporeal circulation is established, in which the blood is collected from a venous cannula, purified in special machinery and reintroduced to the patient's body through an arterial cannula.

There are substantially two ways of doing this: one is known as the central way, in which the operation is done directly on the heart and the aorta and venous vessels of the heart; while the other, known as peripheral, involves the vein and the femoral artery.

A parallel medical protocol has been developed for patients who experience acute cardiogenic or cardio-respiratory shock, and where there is therefore a need to keep the patient alive either while he or she recovers from the disease or until a determined therapy has been completed.

To do this, generally the peripheral way is used and the arterial and venous cannulas remain in their operating sites, i.e. inside the respective blood vessels, for hours or even days or weeks. In these cases there is an issue of a certain significance: to maintain the flows that guarantee sufficient general vitality of the organs, such as the brain, heart, lungs, there must be cannulas of a certain diameter, i.e. able to ensure a sufficient blood flow. Cannulas, in particular arterial cannulas, are usually occlusive, meaning for example that injecting blood into the patient from the groin in anti-physiological direction, since the cannula has large dimensions, might lead to the part downstream of the lower limb where the cannula is implanted not receiving blood in sufficient quantities.

Unfortunately, one of the complications in the above-described methodology described is an ischemia, i.e. a partial or total absence of blood flow, a frequent cause of acute or chronic damage, which can be very serious and which can sometimes lead to the amputation of all or part of the limb.

The lack of blood circulation to the cells inhibits the basal metabolism, leading to death and consequent necrosis of the tissues.

It therefore occurs that patients who achieve a positive outcome to their cardiac or cardio-respiratory pathology have, however, neurological deficits in their leg, or indeed need to have toes amputated, or even a significant part of their leg.

With the aim of obviating these issues, recent years have seen the development of bi-directional cannulas which substantially have a hole that can spray blood at the insertion point of the cannula into the artery.

These solutions have not in practice shown themselves able to fully obviate the drawbacks as evidenced in the foregoing.

Aim of the invention

An aim of the present invention is to provide a medical device for blood perfusion which is able to obviate the drawbacks in the prior art by establishing an adequate blood flow in the vessel into which it is introduced.

A further aim of the present invention is to provide a medical device for blood perfusion which is effective in ensuring an adequate blood flow and, at the same time, is practical and simple to use.

A still further aim of the present invention is to provide a medical device for blood perfusion which is practical and economical to make. According to the invention, this aim is achieved by an external fixation device comprising the technical features described in one or more of the appended claims. Brief description of the drawings

The technical features of the invention, according to the above aims, are clearly described in the appended claims and its advantages are apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate non-limiting example embodiments of it, and in which:

- Figure 1 is a schematic view, with some parts in cross section better to illustrate others, of a first embodiment of a medical device for blood perfusion made according to the present invention, applied to an artery;

- Figure 2 is a schematic view, with some parts in cross section better to illustrate others, of a further embodiment of the device of Figure 1;

- Figure 3 is a schematic perspective view with some parts in cross section of a further embodiment of the device of Figure 1;

- Figure 4 is a cross section view along line IV-IV of Figure 2;

- Figure 5 is a schematic perspective view with some parts in cross section to better illustrate others, of the medical device of Figure 1 in a different use configuration.

Detailed description of preferred embodiments of the invention

As illustrated in Figure 1 reference numeral 1 denotes in its entirety a medical device for blood perfusion made in accordance with this invention.

The medical device 1 for blood perfusion, in the following indicated for the sake of brevity only as "perfusion device", comprises a flexible cannula 2 which is designed to be inserted internally of an artery 3.

The flexible cannula 2 is inserted in the artery 3 in a first flow direction VI of the artery, which does not necessarily coincide with the physiological flow of blood internally of the artery 3. In other words, as indeed occurs in the majority of cases, for procedural reasons the blood is returned into the artery with a reverse flow direction, i.e. an opposite direction to the physiological circulation direction of the patient. The flexible cannula 2, in the portion thereof inserted in the artery 3, is arranged substantially parallel thereto.

The flexible cannula 2 is in fluid connection with a blood treatment machine, schematically illustrated in Figure 1 by a block 4.

The blood treatment machine 4 is of known type and does not form an object of the present invention.

The flexible cannula 2 is designed to inject blood treated by the machine 4 internally of the artery 3.

The insertion methodology of the flexible cannula 2 in a blood vessel is of substantially known type and will not therefore be described further during the course of the present description.

We mention only that, with only the purpose of exemplification, a very widely used technique is the one known as the Seidinger technique, in which a guide wire is inserted through a hollow needle, which hollow needle has previously been used to perforate the wall of the vessel. The needle is then retracted while the guide wire remains positioned internally of the blood vessel. The guide wire thus defines a guide element for the following insertion of a flexible cannula 2, directly or following a prior introduction of appropriate dilators, also not illustrated.

As illustrated in Figure 1, the flexible cannula 2 has a first distal opening 2a designed to enable inlet of blood into the artery 3 according to the first direction VI.

The flexible cannula 2 has a second median opening 2b configured so as to be positioned internally of the artery 3 facing towards the portion of artery 3 where the flexible cannula 2 is not present.

Once more with reference to Figure 1, the perfusion device 1 comprises a catheter 5 arranged internally of the flexible cannula 2 and slidably movable with respect to the flexible cannula 2.

The catheter 5 is slidably movable internally of the flexible cannula 2 at least between a first retracted position, visible in Figure 5, in which it is completely internal of the flexible cannula 2, and a second advanced position, visible in Figure 1, in which at least a distal end portion 5a thereof is arranged internally of the artery 3 and exits from the above-mentioned second median opening 2b made in the flexible cannula 2.

As clearly illustrated in Figure 1, the distal end portion 5a of the catheter 5 is designed to be partially advanced in the artery 3 according to a second direction V2 that is opposite said first direction VI, i.e. in a distancing direction from the flexible cannula 2, in order to spray blood internally of the artery 3 with a flow coinciding with the second direction V2.

The perfusion device 1 comprises sliding means 6 of the catheter 5 with respect to the flexible cannula 2, configured to move the catheter 5 between the two abovedescribed positions.

With reference to Figure 1, the sliding means 6 have been schematically illustrated with a block fitted on the flexible cannula 2.

The sliding means 6 are configured to move the catheter 5 with respect to the cannula 2 as the health operator using the device 1 wishes and, advantageously, are activated manually by the operator him or herself.

Embodiments of the sliding means 6, not illustrated, include friction couplings or even electrically-controlled motor-driven actuating mechanisms.

In the embodiment illustrated in Figure 1, the catheter 5 is configured so as to adopt, at the distal end portion 2a thereof, a curved conformation having a hook conformation.

According to the embodiment illustrated in Figure 2 and in detail in Figure 4, the perfusion device 1 comprises, fashioned internally of the cannula 2, a tubular cavity 7 for housing the catheter 5.

The tubular cavity 7 advantageously extends from the sliding means 6 and opens at the second median opening 2b.

In other words, an exit mouth of the tubular cavity 7 defines said second median opening 2b.

The tubular cavity 7 defines a sliding channel of the catheter 5. The tubular cavity 7 has a curved portion at the second median opening 2b, so as to direct the distal end portion 5a of the catheter 5 according to said second direction V2.

According to what is illustrated in Figure 1, the perfusion device 1 comprises a directing element 8 arranged at the second median opening 2b of the cannula 2 and configured to engage with the distal end portion 5a of the catheter 5 to direct the portion 5a in said second direction V2 in exiting from the cannula 2 and at the same time entering the artery 3.

The directing element 8 extends internally of the cannula 2 and has a curved surface designed to accompany the movement of the catheter 5 in the step in which it adopts the hook configuration thereof.

According to possible embodiments of the perfusion device 1, compatible for example with what is illustrated in Figure 1, the distal end portion 5a of the catheter 5 is realised in such a way as to deform and maintain a curved conformation imposed by the directing element.

In other words, by virtue of the material used for the realisation of the distal end portion 5a of the catheter 5, the portion 5a is able to maintain the curved hook shape which it adopts by engaging slidingly with the directing element 8.

The above-mentioned tubular cavity 7 and directing element 8 define, for the perfusion device 1 according to the invention, respective guiding means of the catheter 5 configured to orientate the distal end portion 5a thereof according to said second direction V2.

The perfusion device 1 according to the invention further comprises a detector member, not illustrated in the appended drawings, of the presence of blood internally of the catheter 5.

The detector member is advantageously defined by a transport portion of the catheter 5 configured so as to enable the operator to see that the catheter is in the filled condition with the blood coming from the artery 3. Alternatively, said detector member is advantageously defined internally of said sliding means 6 through a transparent zone that enables viewing that the catheter 5 has been filled by the blood coming from the artery 3.

According to a further possible embodiment, the detector member comprises a different conduit, not illustrated, distinct from the catheter 5 and originating in proximity of the second median opening 2b, which is capable of filling with blood and transmitting, with its filling, a visual signal at an upper point of the device, visible by the operator.

The above-mentioned and not-illustrated detector member defines, for the device 1 according to the invention, detection means of the entry of the second median opening 2 b of the cannula 2 internally of the artery 3, i.e. the reaching of the correct operating position thereof.

In fact, with reference to Figure 1, the circumstance that the blood flows internally of the catheter 5, rising towards the sliding means 6, is an unequivocal sign that the opening 2b has penetrated internally of the artery 3 and it is therefore possible to proceed with the inserting of the distal end portion 5a of the catheter 5 in the artery 3 according to the second direction V2.

The use of the perfusion device 1 according to the invention operatively includes percutaneous insertion of the flexible cannula 2 internally of the artery 3, for example according the above-described Seidinger technique, with the distal portion of the cannula 2 introduced into the artery 3 according to the first direction VI.

As mentioned in the foregoing, the first direction VI is advantageously a reverse direction, i.e. opposite the physiological circulation direction of the blood internally of the artery 3.

Once the health operator has verified the correct positioning of the second median opening 2b internally of the artery 3, by means of said detection means or by means of radiographic techniques of known type, the operator can proceed to inserting the catheter 5 internally of the artery. The inserting of the catheter 5 internally of the artery 3 takes place via said sliding means 6, by means of which the operator can advance the catheter 5 internally of the cannula 2, maintained stationary with respect to the artery 3.

In other words, by means of the sliding means 6, the operator moves the catheter 5 forward from its first withdrawn position, shown in Figure 5, in which it is completely inside the flexible cannula 2, to its second advanced position, shown in Figure 1, in which the distal end portion 5a thereof is arranged internally of the artery 3 facing in the opposite direction with respect to the first distal opening 2a of the flexible cannula 2, and is designed to spray blood internally of the artery 3 in the second direction V2, opposite the first direction VI.

In this way, once blood is sent from the treatment machine 4 towards the artery 3, the perfusion device 1 injects blood into the artery 3 in two different directions: from the first distal opening 2a of the cannula 2 blood exits with a flow directed according to the first direction VI while from the catheter 5 blood exits and flows, directed according to the second direction V2.

In this way the perfusion device 1 according to the invention attains the prefixed aim of spraying the peripheral part of the patient's limb.

In other terms, the perfusion device according to the invention enables obtaining, at the same time, a reverse blood flow, i.e. in direction VI, which sprays the organs, but also an anterograde flow, i.e. a distal perfusion via the catheter 5, able to ensure that the tissues of the leg remain vital.