DE2149026A1 - Non-traumatic blood pump - Google Patents

Description

2 HAMBURG 13 Sept. 29, 1971

INNOCENTIASTRASSE 30 TELEPHONE 452139

DIPL-ING. FRANZ WERDERMANN

. . ADVERTISER

T. 71 122 pl. - __

Tecna Corporation,
Berkeley, Caliph. (V.St.A.)

Non-traumatic blood pump,

For this registration, the priority is derived from the corresponding one U.S. application serial no. 77 291 of October 1, 197o taken.

The invention relates generally to a non-traumatic blood or heart pump.

In many cases over the past decade, blood pumping has become more artificial Means in connection with surgical interventions on the heart and on the blood vessels and as a makeshift maintenance aid of the organ functions in certain cases of illness and accidental injuries. Though through this Pumps large blood damage in the form of destruction of red blood cells, loss of platelets (platelets), protein denaturation, the formation of thrombo-embolism and the like., This method is used more often because in many cases the the only alternative would be death. The pump duration is limited by the permissible damage to the blood elements, which must not exceed the upper limit, the

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by, the ability of the body is predetermined with the Coping with blood damage, i.e. the damaged blood to process. The blood pump systems currently available can be used for four to six hours, which is the case for most surgeries where the heart is opened is sufficient. There are, however many cases in which longer pumping times are required, for example when supporting the circuit afterwards heart failure or accident victims with heart or lung injuries. The need for artificial pumping can be given over several days in which the natural healing process slowly allows the heart or the lungs resume their normal activity.

None of the currently known roller pumps and also not the pulsating ones that have recently come onto the market Pumps are able to provide long-lasting circulatory support to cause, which is primarily due to the damage caused by these pumps to the Bluteiemente is. There is therefore a need for a pump, that can pump blood for unlimited periods of time with only minor and physiologically acceptable blood trauma has the consequence.

As far as it has been ascertained so far, there are two different effects for the damage to the blood elements responsible. When certain blood elements come into contact with a foreign, non-biological surface,

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.biochemical reactions are initiated that lead to destruction the blood elements lead. A second type of injury is mechanical and results from the mechanical processes or from the action of shear forces on various Blood elements, especially the red blood cells. The compression or compression of the blood elements between the parts or surfaces of the pump and excessive turbulence are causes of mechanical blood damage. It follows that this is the main consideration in the design and construction of a blood pump must ensure that the surfaces of the pump that come into contact with the blood do not undergo any biological changes in the blood elements bring about, i.e. are not thrombogenic and that the flow dynamics the pump must be designed in such a way that turbulence, shear, stagnation, flow separation and the like, which can lead to mechanical damage, can be avoided.

The invention is therefore based on the object of creating a non-traumatic blood pump in which the with Surfaces that come into contact with the blood cause an accumulation of fibrous materials and cell deposits from the bloodstream favor and a smooth blood flow results through the pump, so that mechanical damage to the blood components are reduced to a minimum.

The proposed blood pump to solve the problem, which has a housing with a first and a

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Having a second open end portion is characterized according to the invention by a pump chamber within the housing forming flexible bladder with one inflow and one Outflow opening, an inflow valve assigned to the inflow opening, an outflow valve assigned to the outflow opening, one valve chamber for the inflow valve and one valve chamber for the outflow valve, one in each Chamber located valve body and a device that creates a seal between the housing and the bladder, as well forms a chamber surrounding the bladder, and through an inlet port located on the chamber.

The inflow and outflow valves each consist of a valve seat, one that interacts with the valve seat Valve body, a guide device through which the valve between the open and the closed position and devices for limiting valve body movement. Each valve body has a central core with a surface portion which can be brought into seating engagement with the valve seat, and to the outside protruding guide vanes serving to guide the valve body between the open and closed positions on, the multiple flow channels for blood flow past the valve body in the form of a smooth and regular flow form. There are no pegs or other protruding holding devices, so that the generation of turbulence is reduced to a minimum

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and consequently mechanical damage to the blood is prevented.

The invention also aims to provide a valve for a blood pump or an artificial heart. To this Purpose is proposed a central core with a seat and several outwardly protruding Form guide vanes that form a plurality of blood flow channels, past which the blood over the Core can flow away and keep it free from deposits.

The invention is explained in more detail below with the aid of several exemplary embodiments.

fig. 1 is a partial elevational cross-section of a blood pump according to the invention.

fig. Figure 2 is an end elevation of the valve, taken along the line 2-2 of fig. 1.

fig. 3 is a cross section taken along line 3-3 of FIG. 1 and shows the bladder, soft the pump chamber forms.

fig. Figure 4 is a section through the bladder when folded State.

fig. Figure 5 is a cross section through another embodiment of the invention.

fig. Figure 6 is a cross-section through a single use blood pump according to the invention.

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In the embodiment shown in Fig. 1, "forms a "flexible bladder 11" forms the pump chamber. At each end of the bladder there is a bead 12 which can be inserted into a groove 15 is, which is each formed in a holding member 14 serving as a valve stop. The bead is inside the groove 13 held by means of a disc 16, which is placed on a member 17, which with the holding member 14 cooperates and holds this. The member 17 forms the inflow port 18. Several screws 19 are used to secure the disc 16 to the member 17 and thus to hold the bladder within the member 14, which is in turn held on the member 17. The discharge nozzle is of the same construction and the same parts are used each denoted by the same reference numerals.

The disks 16 arranged at a mutual distance from one another each have a circular groove 21 to Receiving the end of a cylinder 22 which is provided with a groove 23 and an O-ring 24, which a Seal between the cylinder end and the associated one Disc forms. The bladder 11, the cylinder 22 and the disc 16 form a chamber 25 which surrounds the bladder and is in communication with an inlet port 26, via which the chamber 25 is supplied with compressed air or to this Vacuum can be applied, whereby the bladder is compressed or expanded for the purpose of pumping. When assembled, the pump chamber is through

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several spacers 28 given, which are between the spaced-apart disks 16 extend and nuts 29 screwed onto them are.

In the chambers 33 formed by the opposing, inclined sections of the parts 14 and 17 and 34 there is a valve 31 and 32, respectively.

The valves 31 and 32 each have a core section 36 with guide vanes protruding outward therefrom or flanges 37. The leading edge 38 of the wings 37 forms a continuous surface with the front 39 of the core 36. The outer edges 41 of the vanes lie on a rotating surface which is coaxial with the valve body extends and is designed to interact with the cylindrical portion 42 of the valve chambers 33 and 34, respectively is. The other end of the wings merges with the end of the valve body. The rear edges 44 of the wings are rounded, with the wings tapering towards the downstream end, so that a smoother Transition results for the blood flow past the wings. The downward sloping surface of the surrounding Housing 14 or 17 serves as a valve stop, whereas the upstream end serves as a valve seat. As can be seen the inflow and outflow valves are identical to each other and therefore are identical parts

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also designated in each case with the same reference numerals. At the Inlet valve "is the valve seat on the 51 designated point on the member 17 »while the valve seat is located at the discharge valve at 52 on the member 14. The valve core or body and the vanes are designed so that a substantially constant Cross-sectional area for the flow between the valve bodies and the associated chamber results, so that ! Turbulence is largely eliminated.

Due to the streamlined shape of the pump and the chamber, the formation of stagnant blood sumps will occur prevented inside the pump. The valve body and the valve housing are, as already stated, with a executed almost constant flow cross-section, whereby an acceleration and an associated emergence turbulence in the blood flowing through the various flow channels on the valve body can be prevented. Preferably, the angle of the valve seats 51 and 52 is less than 50 °, and this angle has been found experimentally Proven necessary to prevent detachment and circulation of blood in this area. The blood, that flows through between the channels formed by the wings, flushes the as it flows through central core 36. As a result of the guide vanes and the inclined surface serving as a valve stop, a smooth shape, which means greater accelerations,

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Turbulence and a flow separation prevented and to replace the valve guide struts used in known designs or other protrusions with which less satisfactory results are obtained.

The guide vane sections 41 of the valve body specify its position in the pump axis by being with the cooperate cylindrical portion 42 of the passage. The wings are with respect to the axis of the valve body inclined at a small angle so that with each movement of the valve body from left to right, i.e. at Opening and closing of the same, the same about a certain one Amount is rotated. This ensures that the valve body and valve seat are in uniform mutual contact come and no uneven wear on the surface of the valve seat or the walls holding the valve body or deformation occurs. The shape of the guide vanes used to guide the valve and the central one Core sections lead to sufficient rinsing of the valve body, bo that prevents the formation of thrombus will. In addition, turbulent eddies and the like are reduced to a minimum. The ones described above Precautions are required as the valve is not coated with a material that would allow the Would allow the formation of a biological coating.

The bladder itself is essentially a straight cylinder in its central section, which is attached to the two

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The ends are tapered and provided with the beads 12. the cylindrical walls preferably have two reinforced sections 61 and 62 diametrically opposite one another along the length Sides up, so that the cylinder is preferred according to the illustration of Pig. 4 folded will. Because of these reinforced sections, even and reproducible folding of the Bubble assured. This is an important feature that ensures that a maximum Displacement volume is obtained without affecting the There is a risk that the opposite sides of the bladder surface touch each other and that Damage blood.

The sloping sections 63 of the bladder are formed in such a thickness that the formation of excessive stresses is avoided, which can lead to fractures and fatigue permanent deformation.

It has been found that the angle of inclination is preferably selected to be about 40 °. In general, the bowing takes place the bladder in the first place during the collapse Line at the point designated by the reference numeral 64 instead, so that too high a concentration of stresses is avoided.

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According to a further feature of the invention, the bladder, the valve housing and the inflow and Outflow-side parts preferably coated with a material that is compatible with the blood and a It has a multitude of microwells, which allow the anchoring of fibrin and cellular deposits from the bloodstream favor, so that within a short time a complete coverage with biological material results. These deposits gradually lead to the formation of a pseudointimal coating that is sufficiently thin is to retain its adherence and flexibility and is nourished by the blood flowing by.

A covering which is preferred for this purpose contains a large number of micro-depressions such as, for example can be produced in accordance with a method that is described in a further patent application by the same applicant the file number with the

Title "blood- or tissue-compatible surface or coating and manufacturing process" is described.

When the pump is in operation, compressed air is fed to the chamber 25 through the inlet port 26, through which the bladder is conveyed squeezed, the inlet valve is closed and the outlet valve is opened, allowing blood to flow out of the chamber flows outwards. The amount of compressed air supplied to the chamber 25 is precisely controlled so that the walls 61 and 62 coincide and for the purpose of a maximum volume

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crowding into a closely adjacent position, yourself but do not touch each other, so that there is no damage to the blood elements. Then the pressure removed and a negative pressure applied to chamber 25 to expand the bladder and blood into the pump chamber suck in.

The one in Pig. The blood pump shown in FIG. 5 works in essentially the same way as that based on the figures 1-4- described pump, the same reference numerals being used for the same parts. The chamber 25 consists of an oval-shaped housing 71 with end threads 72 and 73 and an inlet port 26. The end threads 72 and 73 each serve to receive couplings 74 and 76, respectively. Those for a single use Specific, i.e. disposable, bladder 11 is located within chamber 21 and is provided with retaining flanges 77 and 78 provided. The bladder 11 extends beyond the flanges and is shaped such that valve chambers 33 and 34 are formed with inlet and outlet ports 79 and 81 which are directly connected to the patient can be connected. In this way only one material comes into contact with the blood. This material is covered in a suitable manner and has, for example, a covering in the aforementioned further patent application mentioned quality.

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In the embodiments shown in FIGS. 5 and 6, a single piece is in contact It uses a coating standing with the blood, which is applied to both the flexible bladder and the valves. This one-piece structure represents an improvement over the interface in Pig. 1 shown pump represents, which is composed of several segments. The improvement is because hydrodynamic Effects on small irregularities such as gaps or differences in height at connection points between the parts to create localized turbulence, can lead to flow separation or stasis, i.e. blood congestion. These effects in turn lead to thrombus formation or for the formation of a thick pseudointimal coating at these points. A second benefit that is results from a coating that is continuous in one piece, the continuity of the microporous blood interface is due to which prevents the formation of ridges or fibrin deposits, which occur preferentially at discontinuities. Holders 82 and 83 held by the clutches hold the lining in place by flanges 77 and 78 between, respectively the surfaces 86, 87 or, 88 and 89 are clamped in between. The brackets have such a shape, that they can accommodate the bladder and form a housing for the valve chambers 33 and 34. The valves 31 and 32 are formed in the manner described above.

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The pump can also be made with a disposable housing. An embodiment of this kind is shown in Fig. 6. The housing "consists in this Pali of two plastic parts 91 and 92, which are hooked together at the point marked 95. The bladder, which is also intended for single use, ie is disposable, has the valve chambers 5f> and 54, which are designed in this way are that the housing ends each have an end wall 94 or 96 and the bladder is provided with a bead 97 or 98, which in each case forms the other wall of a valve chamber sealed so that an adhesive is applied to the bladder and the housing in areas 1o1 and 1o2 The valves 31 and 52 can be of the type described above, The bladder is coated in the manner described above.

The invention thus creates a non-traumatic blood pump in which the coating the Deposition and permanent anchoring of a psudointimal Covering allowed, through which contact between the blood elements and non-blood surfaces is prevented will. The construction of the pump chamber and the valves result in a substantially constant flow rate for the blood with the slightest acceleration, deceleration and the resulting turbulence, as well as without

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stagnant zones. The valve is designed in such a way that that it favors the formation of a steady speed and is supported by the blood flowing past continuous, washed. The valve body is rotated by the flow, so that a substantially uniform wear of the pseudointimal covering results on the valve body and the valve seat.

- patent claims -

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Claims (9)

- 16 claims 1J blood pump, consisting of a housing with a first and a second open end portion characterized by one inside the housing (H, 17, 22) Flexible bladder (11) which forms the pump chamber and has an inflow opening and an outflow opening, one of the inflow opening assigned inflow valve (51), an outflow valve (52) assigned to the outflow opening, each one valve chamber (53) for the inflow valve and a valve chamber (34) for the discharge valve, a valve body located in each chamber and a device that creates a seal between the housing and the bladder, as well as a chamber surrounding the bladder, and by one located on the chamber Inlet port (26). 2. Blood pump according to claim 1, characterized in that each valve body (31, 52) has a central core (36) with a surface portion which can be brought into seat engagement with a valve seat, and protruding outward, for valve guidance and for the formation of several flow channels has guide vanes (37) serving for the flow of blood on the valve body. 3. Blood pump according to claim 2, characterized in that the guide vanes (37) are inclined in the axial direction and the valve is rotatable by the blood flow and can be repositioned with respect to the seat (51, 52). 209815 / 112S 4. Blood pump after. Claim. 1, characterized, that a cylindrical portion of the bladder along diametrically opposed sides reinforced portions (61, 62). 5. Blood pump after. Claim 1, characterized in that that the inner surface of the bladder has microwells, which are designed to prevent fibrin and cellular sedimentation and formation favor a psudointimal covering. 6. Blood pump after. Claim 1, characterized in that that the bladder (11) extends beyond the open housing ends (94, 96). 7. Blood pump according to claim 1, characterized in that the housing consists of first and second to form a cylindrical Housing interconnectable housing sections (91, 92) and the sealing device with means is provided for attaching the bladder to the housing ends. 8. Blood pump according to claim 1, characterized in that that the housing ends (94ι 96) and the bladder in such Are designed so that they form the valve chambers. 9. Valve for a blood pump or an artificial heart, characterized by a core (36) with a seat and several outwardly protruding 209815/1125 2H9026 Guide vanes (37) which form a plurality of blood flow channels past which the blood flows over the core and keeps it free from deposits. 1o. Valve according to Claim 9, characterized in that the guide flightsJ. (37) are inclined in the axial direction, so that the valve can be set in rotation by the blood flowing past. 209815/1125