Pulsatile blood pump

Abstract

An extravascular pulsation blood pump possesses a bidirectionally acting pumping system (P, M) having a pump (P) which is connected via a first conduit (L.sub.1) to the left ventricle (LV) and via a second conduit (L.sub.2) to the aorta (AO). By means of a control means (St), the pump (P) is operated alternately in one and the other direction according to a given cardiac rhythm, so that alternately blood is sucked through the first conduit (L.sub.1) and simultaneously blood ejected through the second conduit (L.sub.2) to the same extent, on the one hand, and blood is sucked through the second conduit (L.sub.2) and simultaneously blood ejected through the first conduit (L.sub.1), on the other hand. The pulsation blood pump combines the functions and advantages of an extravascular copulsation pump with those of an extravascular counterpulsation blood pump.

Claims

1. An extravascular pulsation blood pump, comprising a first conduit for connecting the pulsation blood pump to a heart chamber, a second conduit for connecting the pulsation blood pump to a blood vessel, a bidirectional pumping system which is arranged for alternately sucking blood through the first conduit and simultaneously ejecting blood through the second conduit, on the one hand, and sucking blood through the second conduit and simultaneously ejecting blood through the first conduit, on the other hand, and a control means which is provided for operating the pumping system alternately in one and the other direction according to a given cardiac rhythm.

2. The pulsation blood pump according to claim 1, comprising a sensor means coupled with the control means for capturing and transmitting cardiac rhythm data to the control means.

3. The pulsation blood pump according to claim 1, wherein the pumping system has a first pumping chamber with variable volume which is attached to the first conduit, and a second pumping chamber with variable volume which is attached to the second conduit, wherein the first and second pumping chambers are so coupled with each other that when blood is sucked into the first pumping chamber through the first conduit blood is ejected from the second pumping chamber into the second conduit, and vice versa.

4. The pulsation blood pump according to claim 3, wherein the first pumping chamber forms with a first compliance chamber with variable volume a first double chamber, and the second pumping chamber with a second compliance chamber with variable volume a second double chamber, wherein the first pumping chamber is separated from the first compliance chamber and the second pumping chamber from the second compliance chamber by a respective variable partition, and wherein the pumping system comprises a pump which is arranged for pumping a fluid back and forth between the first compliance chamber and the second compliance chamber.

5. The pulsation blood pump according to claim 4, wherein the partitions respectively comprise a flexible membrane.

6. The pulsation blood pump according to claim 4, wherein the fluid is a liquid.

7. The pulsation pump according to claim 1, wherein the pumping system is a differential pumping system.

8. The pulsation blood pump according to claim 1, wherein the pumping system is arranged for being implanted into a patient's body.

9. A method for supporting the pulsation of a heart, comprising the following steps: a) removing a first quantity of blood from the heart and bringing a second quantity of blood into a blood vessel substantially during a diastole of the heart, b) removing a quantity of blood corresponding to the second quantity from the blood vessel and bringing a quantity of blood corresponding to the first quantity into the heart substantially during a systole of the heart following the diastole, and c) repeating the steps a) and b) a plurality of times, characterized in that the first and second quantities of blood are removed and brought in by means of the same pumping system.

10. The method according to claim 9, wherein the blood removed from the heart and the blood vessel is stored temporarily in separate pumping chambers of the pumping system, and the same blood is brought into the heart or blood vessel again with the next systole or diastole.

11. The method according to claim 10, wherein the first pumping chamber is coupled with a first compliance chamber, and the second pumping chamber with a second compliance chamber, and wherein blood flow is effected from the first pumping chamber into the heart and from the second pumping chamber into the blood vessel by alternatingly filling and emptying the first and second compliance chambers.

12. The method according to claim 9, wherein the blood is removed from the heart from the left half of the heart, in particular the left ventricle, and the blood from the blood vessel from the aorta.

13. The method according to claim 9, wherein the blood is removed from the heart from the right half of the heart, in particular the right ventricle, and the blood from the blood vessel from the pulmonary arteries.

14. The method according to claim 9, wherein a greater quantity of blood is removed from the heart than from the blood vessel.

15. The method according to claim 9, wherein a greater quantity of blood is removed from the blood vessel than from the heart.

Description

(1) Hereinafter the invention will be explained by way of example with reference to the accompanying drawings. Therein are shown:

(2) FIG. 1 the basic principle of a pulsation blood pump according to the invention by the example of support for the left ventricle,

(3) FIG. 2 a first modification of the basic principle,

(4) FIG. 3 a second modification of the basic principle, and

(5) FIG. 4 the basic principle by the example of supporting the right ventricle.

(6) With reference to the schematic representation according to FIG. 1, the basic principle of the pulsation blood pump according to the invention will be explained hereinafter. The pulsation blood pump consists substantially of a bidirectional pumping system which is connected via a first conduit L.sub.1 and a second conduit L.sub.2 to a blood vessel, here the aorta AO, on the one hand, and to a heart chamber, here the left ventricle LV, on the other hand. The bidirectional pumping system consists substantially of a pump P and a motor M driving the pump P. How the pump and/or the motor are concretely constituted and coupled with each other in the particular case is of minor importance to the invention. What is essential to the basic principle represented in FIG. 1 is that the pump P is configured in the manner of a double-acting piston-cylinder arrangement wherein the piston K is moved in a direction back and forth within a cylinder Z. This changes the volumes V.sub.1 and V.sub.2 in the mutually opposing pumping chambers 1 and 2 separated by the piston K.

(7) The motor M and thus the pump P is operated alternately in one and the other direction according to a given cardiac rhythm via a control means St. The cardiac rhythm data for controlling the pumping system (e.g. pressure, ECG, contraction, PPS, etc.) can be captured by means of a sensor means S coupled with the control means St and be transmitted to the control means St. This is indicated in FIG. 1 only schematically by a sensor S lying in the atrium of the left ventricle LV, which may be a pressure sensor.

(8) The energy necessary for operating the pumping system can be made available from an energy storage device E, which is accordingly charged for example contactlessly either continually or preferably temporarily via a transmitter T.

(9) Employing this energy and with consideration of the cardiac rhythm data processed by the control means St, the piston K is now displaced according to the cardiac rhythm such that during systole the volume V.sub.1 of the pumping chamber 1 is reduced and blood is accordingly pumped out of the pumping chamber 1 via the conduit L.sub.1 into the left ventricle LV. Thus, blood is simultaneously sucked out of the aorta AO through the conduit L.sub.2 into the increasing volume V.sub.2 of the second pumping chamber 2. The left ventricle LV thus works against a reduced aortic pressure, and also the blood volume displaced out of the pumping chamber 1 flows through the left ventricle LV and the aortic valve into the aorta AO. During the following diastole the piston K is moved in the opposite direction, so that blood is sucked out of the left ventricle LV through the conduit L.sub.1 into the pumping chamber 1, and simultaneously a corresponding quantity of blood is pumped out of the second pumping chamber 2 through the conduit L.sub.2 into the aorta AO. This minimizes the expansion of the left ventricle LV and counteracts a dilatation of the heart, so that the heart can recover. Simultaneously, the blood pumped into the aorta AO so increases the blood pressure in the aorta AO that the blood flows reliably into the organs, i.e. also in the heart, and the peripheral blood vessels. Reduction of the diastolic ventricular size enables the wall stress of the myocardium to be minimized and thus the heart to be supplied with blood more efficiently.

(10) FIG. 2 shows a first modification of this basic principle. The piston K is configured here as a differential piston with two piston areas of different size. Accordingly, the volumes V.sub.1 and V.sub.2 do not change to the same extent upon a motion of the piston K in the direction R. In the concretely represented exemplary embodiment, a smaller quantity of blood is pumped back and forth between the left ventricle LV and the pumping chamber 1 due to the differential piston K than between the aorta AO and the second pumping chamber 2. Depending on which heart function is to be mainly supported by the pulsation blood pump, the greater piston area of the differential piston can lie on the side of either the heart or the blood vessel. However, the differential piston K requires on the side of the smaller piston area an additional compliance chamber C, which is connected to the pump P via a conduit L.sub.3. The compliance chamber C takes up the difference resulting from the volume displacement V.sub.2 and V.sub.1, which is positive or negative depending on the displacement direction of the differential piston K. The compliance chamber C is placed at a location within the patient where it is only subjected to low ambient pressure, for example in the abdomen, and is connected to the pump P via a conduit L.sub.3. In the conduit L.sub.3 and the compliance chamber C there is preferably located a liquid, i.e. in particular no blood.

(11) FIG. 3 shows a second modification of the basic principle. Here, the first pumping chamber 1 forms with a first compliance chamber C.sub.1 a first double chamber, and the second pumping chamber 2 with a second compliance chamber C.sub.2 a second double chamber. The pumping chambers 1 and 2 are separated from the compliance chambers C.sub.1 and C.sub.2 by a respective membrane M.sub.1 and M.sub.2, so that the volume V.sub.1 and V.sub.2 of the pumping chambers 1 and 2 is respectively variable. By means of a pump P, which is rendered here only schematically and may be a bidirectional rotation pump by way of example, a fluid is then pumped back and forth between the compliance chambers C.sub.1 and C.sub.2 according to the cardiac rhythm such that the variable volumes V.sub.1 and V.sub.2 of the two pumping chambers 1 and 2 change in the manner described hereinabove with reference to FIG. 1. For this purpose, the pump P is connected to the compliance chambers C.sub.1 and C.sub.2 via the conduits L.sub.4 and L.sub.5. In the conduits L.sub.4, L.sub.5 and the compliance chambers C.sub.1, C.sub.2 there is located a hydraulic fluid, i.e. in particular no blood. The pump P is thus reliably shielded from the blood circulation by means of the membranes M.sub.1 and M.sub.2. This is favorable for the structure and the effectiveness of the pumps P usable for the pumping system. Likewise, it considerably improves the fatigue strength of the pumping system.

(12) An additional compliance chamber C.sub.V can be provided to take up volume fluctuations when the blood quantities V.sub.1 and V.sub.2 vary in size. FIG. 3 shows such an additional compliance chamber C.sub.V for taking up a part of the fluid pumped between the compliance chambers C.sub.1 and C.sub.2. This additional compliance chamber C.sub.V is optional and preferably adjustable variably with regard to its compliance properties. For adjusting the compliance properties, the control valve StV is used. The adjustment can be effected either prior to implantation or preferably for example by remote control also after implantation either as needed or continually. This enables the blood volumes received in the pumping chambers 1 and 2 to be varied, also dynamically, where applicable. A reason for such a measure may be for example that problems arise upon filling of one or the other of the two pumping chambers 1 and 2, or that the available volumes of the pumping chambers 1 and 2 are to be varied intentionally. Thus, it is possible that different volumes are pumped between the appurtenant compliance chambers C.sub.1 and C.sub.2 in spite of the common pump P for both pumping chambers 1 and 2, with the differential volume being taken up by the additional compliance chamber C.sub.V. By means of the control valve StV it is thus possible to control the suction volumes and ejection volumes of the pumping chambers 1 and 2 variably. However, the volume reduction must not have the result that so much blood continually remains in one of the pumping chambers that successive agglutination of the blood is to be feared.

(13) Instead of the additional compliance chamber C.sub.V being attaching to the conduit L.sub.5, it can also be attached to the conduit L.sub.4.

(14) FIG. 4 finally shows yet a further modification of the basic principle represented in FIG. 1. Here, the conduits L.sub.1 and L.sub.2 of the pulsation blood pump are not connected to the left ventricle LV and the aorta AO, but instead to the right ventricle RV and the pulmonary arteries PA.

(15) There is also the possibility to operate two separate pulsation blood pumps of the above-described type simultaneously for the left half of the heart, on the one hand, and for the right half of the heart, on the other hand.