DE2165648B2 - Auxiliary system for blood circulation - Google Patents

Description

The invention relates to a circulatory auxiliary system for sequential actuation of a blood pump in which the Fluid pressure for the pump is controlled.

These systems fall into two groups. One group works with a mechanical device to support the heart function, such as an auxiliary device for the left ventricle. In this system to support the heart function, a device comes into contact with the blood standing membrane pressure exerted.

The blood is displaced by creating controlled changes in pressure that reduce the stress on the heart and systematically pumped. The membrane that is used to drive the gas or liquid separates from the blood, is subject to repeated bending stresses in these devices and therefore requires excellent mechanical properties. The second group comprises the diffusion systems. These include the membrane oxygen generator the artificial lung and hemodialysis with artificial skin. In these devices, the membrane is which separates the blood from the diffusion gas or the diffusion liquid, permeable to the substances, which are exchanged between the fluid and the blood. The separating membrane must be in Be extremely thin in relation to their surface area. The occurrence of both system groups is dangerous of gas leaks and the embolization of fluid into the bloodstream. In such a case the

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physiological consequences of the type and the and when exceeding a predetermined second

Amount of embolized fluid. The tolerance value is released into the open.

limit of the body to foreign fluids in In one embodiment of the system, the larger amount is small. A major leak comes from an intra-arterial pump or a gas pressure

therefore mostly like a catastrophe, before the 5 intra-aortic pump during the rest period between

it is imperative that the patient be protected. see the pump pulses measured and the pressure

The object of the invention is thus to create filled or slowly deflated when the system

an improved circulatory support system that keeps blood pressure in the safe range for compliance with the

flow is supported during diastole and the ideal working pressure is. If the pressure is outside

If the myocardial load during systole falls below this safe range, the system will

wrestles. immediately deflated so that the balloon collapses

So far one has to rely on a mechanical lower and only a minimal resistance for the

Provides support for the failing heart by venous blood flow. The surveillance system

arterial pumping, vented by artery-artery pumping and also then collapses the balloon

and on various counter-pulsation methods if the filling to maintain the desired

Finally, intra-arterial balloon pumping occurs when pressure is too frequent or when inflation occurs

restricts. With counter-pulsation, the pump has to be too long to maintain the normal operating pressure

synchronized with the patient's heart. take. This indicates an impermissibly large leak

Most systems use one through a fluid in the pressure system.

driven pump. The fluid, usually gas, 20 For a more detailed explanation of the invention

exercises on a flexible element, e.g. B. erne membrane, reference is made to the drawing. In it shows

Pressure, which is transferred from this to the blood. Fig. 1 is a block diagram with a pneumatic

will. The fluid or gas of the pressure pump is a gas pressure system, an intra-aortic pump and

separated from the blood, taking care to use an electronic control and monitoring

that there is no leakage of gas in the system, which, for example, on an electrocardio-

Blood or blood can enter the gas pressure system. graph monitor responds to the patient,

The invention provides an automatic Fig. 2 is a block diagram of the logic circuit

Pressurized fluid or gas monitoring for these systems for quick venting and filling of the over-

created. By developing a monitor surveillance system and

systems for operationally reliable heart pumps, the 30 F i g. 3 waveforms of the monitoring system

The risk to the patient is further reduced. with a representation of the working pressure in the system

One type of heart pump that has intra-arterial and various values that are safer or unsafe

Balloon pump and in particular the intra-aortic baler mode of operation correspond.

Ion pump, consists of a balloon on a The block diagram of FIG. 1 shows a pneumatic catheter attached to the femoral artery 35 matic system and an electronic control and The patient is introduced and placed in the descending monitoring system, which together is an intra-aorta is brought and so control a mild heart aid aortic balloon 1 on a catheter 2, which is in educates for the patient. To ensure the femoral artery of the patient is inserted and correct inflation and deflation of the balloon, which is used to mildly support the heart function of the Positioned in the descending aorta via a volumeter to increase and decrease 40 patients. The pneumatic system mainly comprises two components constant amount of pressurized gas in the system. Through separate, pneumatic systems, through the meme leaks, Diffusion and failure function 3 separately in the insulating flask 4. About the Arbeitsneller Gas can escape from the system. piston, in particular the membrane 3 in this, ge-Zum Protection of the patient must be an escape 45 long pressure pulses from the pneumatic Inadmissibly large amounts of gas in the blood of the patient's initial system 6 for pneumatic pump printing be prevented. Likewise, excessive verses are 7. As a result of the different to which Loss of the gas system outside the body of the system is required in the Patients facing significant failure. of systems 6 and 7 can be different gases. Example system point out to prevent. In contrast, 50 may wisely contain the pump pressure system, which is about minor leaks due to osmosis through the intra-aortic balloon 1 into the patient's body the balloon or catheter, minor th extends, preferably helium, which extends without System leaks outside the body adversely affect the patient's blood of the patient or a slight increase in pressure. Other, practically harmless gases, such as from the constriction of the catheter line with carbon dioxide and oxygen, for example, which are heavier filling or venting the gas pressure and are, can also be used because .the blood so keep the right working pressure. the patient has a certain tolerance in the resolution

The gas monitoring system has one of these gases. On the other hand, nitrogen can result

Intra-aortic balloon pump according to a suitable low tolerance limit of the blood

Embodiment of the invention fulfills this safety- 60 nitrogen lead to harm to the patient

safety regulations. This is with consideration of the possible exit

The circulatory system according to the invention with a gas from the catheter or the balloon into the

working sequentially and to pay attention to the fluid pressure of the patient's blood. Compared to the

controlled blood pump is marked by working gas in the pneumatic initial system 6 are

a pressure measuring device for the fluid pressure of the 65 such considerations are not necessary because the

Pump and by a probability on the pressure measuring device that this is in the bloodstream

appealing device that gets the pressure when the patient goes down, is extremely low.

fall below a specified first value increases the patient's tolerance limit for gas,

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that feeds the pneumatic pumping system 7 is one of the control signal is amplified by the amplifier 11 of the factors to be determined when the exit and feeds the magnetic development 12 of the pneumativon gas from the system dangerous for the patient see system 6. This valve connects the isolation could be, lead to failure and the piston 4 could require a pressure source 13 or a Va shutdown or venting. The in 5 kuumquelle 14 and thereby expands the membrane 3 Fig. 1 shown electronic control and monitoring in the insulating piston, whereby pressure pulses for the monitoring system fulfills a double purpose. It pumping work released in the pneumatic system 7 firstly triggers the pneumatic initial system 6, which are. The pressure pulses arrive from the piston 4, which drives the insulating piston 4 and, secondly, it speaks via the catheter 2 to the intra-aortic balloon pump 1. In the pump pressure system 7 to the gas pressure in the io supplies a signal for the pneumatics of the pressure transducer 15, which is in contact with the catheter, which controls the pressure within the specified range. The electrical signal of the transducer holds limits, the system refills if an electronic leakage, not dangerous for the patient, has occurred via an amplifier 16 monitoring system 17. This signal from the system is or the system is vented and switches off when 15 pressure shows the curve » System pressure «in Fig. 3. the leak is impermissibly large or if the pressure in the monitoring system is above the specified pressure limits, which in the interval of the in Fig. 3 also indicates a serious malfunction of the system. query pulses queried or investigated. By venting this, the system is switched off and impulses are folded up by a mnostable tipper 18 of the intra-aortic balloon. The heart-pump synchronization system 10, which is generated depending on control signal pulses from the folded balloon, obstructs the blood flow.
very little left in the aorta. During operation, the pneumatic

The intra-aortic balloon pump must first be synchronized with the cardiac system 7 via a valve 21 from one stroke of the patient. In particular, the tank 22 with helium gas via a pressure regulator 23 must be filled with gas during the diastolic 35. The compressed gas reservoir 24 can be inflated with pressure in the isolation phase in the cardiac cycle. piston 4 is up to a maximum measuring pressure As already mentioned, during this phase the 15 mm, set on the gas pressure regulator 23, is filled, the left ventricle, which supplies the aorta, is stretched. The value of this initial pressure of the gas in the aortic valve is closed and the aorta normal voir can be dilated depending on the size of the used. At this point the balloon is inflated, the type of compressed gas and the catheter inflated and thereby supports the aorta, the length of the blood is varied. If the balloon does not pump, through the capillaries and other vessels of the body, it is deflated and the pressure in the catheter presses on pers. The curve "system pressure" kept within safe operating limits of the system, FIG. 3 shows the pressure impulses for the balloon. For example, with helium between +7 and -5 mm. The duration / one impulse of this waveform represents pressure. When the system is pumping, the pumping interval and the point S between the monitoring system 17 examines the pressure between the pulses, gives an interrogation or test point pumping pulses and gives corrective commands. At Aban, in which the balloon pressure from monitoring questions is within the limits of +7 to -5 mm, the system is removed and examined to determine nothing. If, however, the query does not ask whether it is within the predetermined limits 40 limits, the correct one is used to ensure that there is a danger of a dangerous malfunction. The proper functioning of the point S in the body in the pumping cycle represents the resting or patient introduced cardiac device a zero pressure for the pump initiated between the pumping intercorrection procedures. If present, vallen. a no longer safe overpressure, for example

At 77 heart beats per second, a query 45 to the pressure comprises +20 mm or more, the pumping interval is about ^{_2/3 of} the entire cycle. If helium is used, the overinterval can be reduced to about half of the entire monitoring system 17, the rapid venting valve 25, pump cycle, if the pulse - that immediately ventilates the pneumatic pump system in the stroke of the patient between 100 and 120 per atmosphere and thereby the whole in the second. An electrical system that allows gas stored on the 50 insulating flasks to escape. Through the output of an electrocardiogram unit (EKG), devices not shown in detail are also switched off for monitoring the heartbeat of the patient, responds, delivers an electrical drive or if the pressure is in the range of + 7 or + 20 mm control signal for the pneumatic System 6, which is one, initiates a slow vent valve 26 pressure pulse for the balloon and also 55 opens and pressure triggers the excess gas to be vented to the atmosphere with a controlled interrogation pulse to examine the balloon deflation rate. This heart-pump synchronization until a pressure of less than +7 mm is reached. system 10 generates a control pulse in the diasto- The safe operating state is usually restored after the heart's lischen phase, depending on the pulse rate of a few heartbeats. If the patient falls. A suitable cardiac pump synchronization pressure from, for example, to values between -5 nization system of this type is in the USA the gas pressure in the pneumatic system was restored to the legal successor to the present invention. The monitoring system 17 asks, however, to go. The output signal of the EKG shows the curve before filling, whether the time from the last, high form EKG input in Fig. 3. The output control 65 normal pressure of +5 mm, to which the system on the signal of the cardiac pump synchronization system 10 was filled, has stepped through the curve "drive signal" (control signal) within the last minute. Shown for a time greater than one minute. the filling valve 27 is opened and the gas pressure

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brought to the normal pressure of + 5 mm. score the system. After remedying the deficiency If, however, the filling valve is set back for longer than 10 seconds and the flip-flops 44, 45 are continuously open, it can be assumed that there is a leak in the system for renewed rapid ventilation. The filling - when the pressure exceeds the limit values,
valve 27 is closed and the rapid ventilation 5 The outputs of gates 39 and 40 trigger the valve 25 and the system is also switched off logic circuits 50 for rapid ventilation and for an overpressure of more than +20 mm. Fill up. On the other hand, if the filling valve 27 is less than circuit 46 signals to the rapid ventilation booster is open for 10 seconds, the system is brought to the ker 47 for rapid venting of the system to a high, normal operating pressure of 5 mm. io men with the logic circuit already described. The system can continue pumping. If the pressure drops and the logic circuitry also allows the system to drop to -20 mm or less, a decision is made as to whether the system should be refilled. The Rapidventil25 is also open, as this indicates a malfunction and the patient is at risk. a signal from the circuits 50 via the filling

In the monitoring system 17 compare signal i ₅ amplifier 51, the Auffülldruckventil 27th
Comparison circuits 31 to 35, e.g. B. commercially available- In Fig. 2, the logic circuits 50 are shown as one

Liche voltage comparators, the voltage of the fold block diagram with logic elements Darge pressure signal from amplifier 16 with the set represents. A one minute timer 52 responds to voltages defining the pressure limits. If the output of the gate 39 to generate a pressure signal is greater or less than this defined ₂ o pulse of one minute duration, if the pulse and the limit queried by the comparison circuit, the output of the gate 39 is positive and a high then the circuit generates a Output signal. Which indicates normal pressure of +5 mm. Circuit 31 also provides an output signal when the output of gate 40 initiates a pulse at a low pressure signal, a normal pressure of -5 mm representing + 7 mm pressure. The reference value exceeds. The circuit 32 supplies a logic circuit of the circuits 54 with an AND signal when the pressure signal asks a reference 55, 56 first of all whether the lower pressure limit value for +20 mm pressure exceeds. The limit -5 mm, which requires padding, is reached by circuit 33, providing an output if there is a reference and asks whether, after the last oversignal representing -20 mm, the pressure signal exceeds the pressure +5 mm Minute passed. The circuit 34 provides an output which is 30. If both answers are no, then if the pressure signal exceeds the reference signal, this indicates that the system is printing pressure too quickly at the 5 mm pressure, and the circuit 35 says that there is a dangerous leak, produces an output if a reference signal, that and the system must be switched off. The off - 5 mm represents the pressure signal exceeds. The output of the AND circuit 55 feeds via the OR outputs of the circuits 31 to 35, the rapid ventilation valve 25 is switched via circuit 46 to the gate circuits 36 to 40, which are switched off by the system. If, on the other hand, the answer is question gate pulses according to FIG. 3 (generated by the tipper 18 is yes, meaning that replenishment is required). The outputs of the gates and the pressure during the last minute are not binary signals that indicate the presence of the for over +5 mm, so the output of the AND-rend of the interrogation gate intervals generated event circuit 56 a fill signal for the flip-flop 59 , and represent nisse. The intervals lie between a delay pulse of ten seconds from the pressure pulses of the system according to the curve timer 53 are formed by the AND circuit 57 in FIG. 3. combined. After the answer of the circuit 54 is yes

The output of the gate 36 is a negative one asks the logic circuit "is the system after voltage pulse, which the presence of the through 45 ten seconds still filled?" If the state determined by the circuit 31 represents. The answer to this is yes, it means that negative impulse occurs with this condition, both the system is not yet ready for operation again and for example if a pressure has to be switched off a reference pressure of. A yes answer exceeds +7 mm. The negative pulse leads the AND circuit 57 gives the system a control signal for slow venting from the 50 command for venting and switching off, since the open pulse shaper 41 off, amplified by the filling, takes too long. If, however, the pressure boosting circuit 48, which controls the vent valve 26 within ten seconds, a high normal value. This control signal for slow venting reaches +5 mm, so the filling is stopped, is stopped when the output of gate 36 The logic circuit also contains a flip-flop switch is positive when the system is below +7 mm, 55 device 59 with double input. One stage of the determined by an AND circuit 42. The valve via the AND circuit 56 controlled flip-flops 26 for slow venting thus vents the feeds via the OR circuit 46 to the rapid venting system after the initiation continuously as long as the valve 25 and the others over the filling until the system pressure is below +7 mm and an amplifier 51 the filling valve 27.
Interrogation gate pulse disappears. 60 The above timers can be used together

The outputs of gates 37 and 38 represent high normal with the comparator circuit the presence of an extreme condition, at- (+5 mm) is omitted if the application of a For example, a pressure above or below +20 mm, analog refill system is desired and / which requires immediate venting of the system. or if the elimination of the time functions for a These gates trigger flip-flops 44 and 45, 65 minutes and ten seconds as described above Via the OR gate 46 the amplifier 47 exercise together with the pressure functions for high control that feeds the rapid vent valve 25. Normal value is intended. Such a circuit This switches when the danger is exceeded - is always activated when the pressure is below

falls the lower normal value of -5 mm. This automatically leads to the actuation of the filling pressure valve. The filling speed is at least approximately the same as the speed at which the human body can safely absorb the compressed gas used. Is the filling speed for Compliance with normal operating pressure is unsuitable and the system falls below the safe pressure limit of - 20 mm, the system, as described above, causes immediate venting and shut-off. When the filling speed is sufficient to bring the system into the safe working area to be able to, so the patient is not endangered, since the added gas from the human body is safely absorbed. When the top-up speed increases the pressure to the upper limit of the System brings, so a feedback loop or the like switches the filling function at the desired, high normal pressure of, for example, +5 mm.

That described above in terms of general and specific function and construction Exemplary embodiment of the invention enables its best possible utilization. In addition, the Invention can also be used for pressure monitoring and control in other auxiliary circulation pumps, that are inside or outside the human body.

1 sheet of drawings

Claims (16)

Patent claims: 1. Circulatory system with a sequentially working and controlled by the fluid pressure Blood pump, characterized by a pressure measuring device for the fluid pressure of the pump and by a pressure measuring device for the pressure measuring device appealing facility that keeps the pressure below a predetermined level increases the first value and discharges into the open when a predetermined second value is exceeded. 2. System according to claim 1, characterized in that the pressure is also undercut a predetermined third value is drained. 3. System according to claim 1, characterized by releasing the pressure when a predetermined fourth value is not exceeded during a predetermined first interval. 4. System according to claim 1, characterized by releasing the pressure when the pressure in a predetermined second interval after a predetermined fourth value has been exceeded drops below the specified first value. 5. System according to claim 2, characterized in that the predetermined third value is smaller is than the predetermined first value, which is smaller than the predetermined second value. 6. System according to claim 4, characterized in that the predetermined fourth value is greater is than the predetermined first value and smaller than the predetermined second value. 7. System according to claim 4, characterized in that the predetermined first interval is longer than the specified second interval. 8. System according to claim 1, characterized by devices which act on the pressure measuring devices respond and change the pressure when it goes from a normal value to a predetermined one Pressure range deviates between the predetermined first value and a predetermined fifth value lies. 9. System according to claim 8, characterized in that the pressure change as a function from exceeding the normal pressure value within the specified pressure range takes place relatively slowly to atmospheric pressure, compared to the venting speed, when the working pressure exceeds the specified second value. 10. System according to claim 3, characterized in that responsive to the measuring device Facilities are in place for changing the pressure when it is from normal Value in a predetermined pressure range between the predetermined first and fourth Value deviates, the last-mentioned change in pressure depending on whether it is exceeded the normal value through the working pressure within the specified pressure range Relatively slow venting into the environment takes place compared to the venting speed, when the working pressure exceeds the specified second value. 11. System according to claim 8, characterized in that the predetermined fifth value is greater is than the predetermined first value and smaller than the predetermined second value. 12. System according to claim 2, characterized in that the device for increasing pressure contains a slow fill valve whose fill rate does not significantly affect absorption of the fluid used by the blood in vivo exceeds. 13. System according to claim 1, characterized in that the venting device is one each Contains valve for relatively slow and relatively fast venting and that the valve for relatively quick venting for use above and below a specified working pressure range is provided in which a first control device, the venting device and a second control device controls the device for increasing the pressure. 14. System according to claim 13, characterized in that the first and the second Control device connected to the venting device and the device for increasing pressure are so that the pressure is vented when it is within a first predetermined Interval falls below the specified first working pressure range. 15. System according to claim 14, characterized in that the means for connecting also used for pressure venting, if the to increase the pressure to the specified Working pressure range required time exceeds a predetermined second interval. 16. System according to claim 15, characterized in that the predetermined first interval is longer than the second interval.