JPS647790B2 - - Google Patents

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to an artificial heart pump drive device for driving an artificial heart pump, which is an auxiliary circulation device for medical use. (Prior Art) Conventionally, in order to treat diseases of the circulatory system of a living body, devices have been developed that assist the heart of the living body using, for example, an auxiliary artificial heart. As an example of this type of device, a drive device that generates pressure pulses to drive an artificial heart pump is proposed, for example, in a patent application filed in 1983.
-Disclosed in Publication No. 169460. In this type of drive device, a compressor generates positive pressure and a vacuum pump generates negative pressure, the positive pressure and negative pressure are stored in tanks for positive pressure and negative pressure, respectively, and the positive and negative pressures are stored using solenoid valves. By alternately switching the pressure supply, pressure pulses are generated and supplied to the artificial heart pump. (Problems to be Solved by the Invention) In conventional devices, for example, when switching the supply pressure to an artificial heart pump from negative pressure to positive pressure, communication from the negative pressure tank to the artificial heart pump is cut off, and the positive pressure is switched off. Open communication from the tank to the artificial heart pump. When the connection from the positive pressure tank to the artificial heart pump is opened, since negative pressure is accumulated in the artificial heart pump, it takes time until the necessary positive pressure is supplied to the artificial heart pump. The same applies when switching from positive pressure to negative pressure. in this way,
The rising and falling waveforms of the pressure pulses supplied to the artificial heart pump become gentle. Due to this rounding of the waveform, even if the pressure pulses are switched accurately, there will be some fluctuation in the flow rate of fluid supplied to the artificial heart pump when positive pressure is applied. Fluctuations in the flow rate occur not only in the above case but also depending on the wiring between the drive device and the artificial heart pump and the condition of the living body. Variations in the flow rate to the artificial heart pump directly result in variations in the flow rate of blood passing through the artificial heart pump.
A number of problems arise when the flow rate of blood through an artificial heart pump increases or decreases. For example, when right heart support is performed using an artificial heart pump, if the amount of blood ejected by the artificial heart pump is large, blood may accumulate in the lungs because the amount of blood ejected from the left heart is fixed. This can lead to pulmonary edema. In addition, if the flow rate of blood passing through an artificial heart pump is low, for example when an artificial valve is attached to the aortic valve of a living heart, blood clots are likely to form, and blood circulation to other organs cannot be maintained. become unable. In response to this, the applicant has developed a system in which the electronic control means closes the positive pressure switching solenoid valve when the blood ejection flow rate exceeds a set flow rate after the electronic control means opens the positive pressure switching solenoid valve. Patent application for artificial heart drive device 1980-
Proposed in No. 166399. If the actual blood ejection amount is measured and the positive pressure switching solenoid valve is closed when the actual blood ejection amount becomes the same as the set flow rate, the blood ejection amount will be close to the set flow rate. However, even after the positive pressure switching solenoid valve is closed, positive pressure is still present in the artificial heart pump, and the artificial heart pump is ejecting blood, so the ejection flow rate at one time is slightly reduced. An error will occur. Therefore, an object of the present invention is to stabilize the flow rate of blood ejected by an artificial heart pump and to reduce the error thereof. [Structure of the Invention] (Means for Solving the Problem) The means taken in the present invention to solve this problem is to alternately cause the working fluid to flow out and stop the flow to generate pressure pulses, and to generate pressure pulses. pressure pulse generating means for driving the artificial heart pump; setting means for setting the ejection flow rate of the artificial heart pump;
a flow rate measuring means disposed at the output end of the artificial heart pump and measuring the ejection flow rate of the artificial heart pump; an outflow unit for accumulating the measured value of the flow rate measuring means while the outflow of the working fluid of the pressure pulse generating means is stopped; flow rate accumulating means during stop; flow rate accumulating means for accumulating the measured value of the flow rate measuring means during the outflow of the working fluid of the pressure pulse generating means; and a flow rate accumulating means during outflow based on the set value of the setting means The value obtained by subtracting the cumulative value is set as the control target value, and when the cumulative value of the flow rate accumulating means during outflow exceeds the control target value during the next outflow of the working fluid of the pressure pulse generating means, the pressure pulse generating means A control means for stopping the outflow of the working fluid is provided. (Operation) According to the means of the present invention, when the pressure pulse generating means starts outflowing the working fluid, the fluid is delivered to the artificial heart pump and blood is ejected. The outflow flow accumulating means accumulates the measured value of the flow rate measuring means while the working fluid of the pressure pulse generating means is outflowing. When this cumulative value exceeds the control target value, the pressure pulse generating means stops the flow of working fluid to the artificial heart pump.
Therefore, the blood ejection amount of the artificial heart pump during outflow of the working fluid is controlled to be equal to the control target value. Even if the outflow of fluid to the artificial heart pump is stopped, the ejection of blood does not suddenly stop, so blood is ejected from the artificial heart pump even while the outflow of the working fluid of the pressure pulse generating means is stopped. . The flow rate accumulating unit during outflow stop accumulates the ejected blood flow rate measured by the flow rate measuring unit while the outflow of the working fluid from the pressure pulse generating unit is stopped, Find the ejection volume. Then, the value obtained by subtracting the blood ejection amount while the outflow is stopped from the set value is set as the next control target value. During the next outflow of the working fluid from the pressure pulse generating means, the blood ejection amount during outflow of the working fluid is controlled by the updated control target value. Therefore, the next flow rate of blood ejected from the artificial heart pump is calculated by subtracting the flow rate ejected during the previous flow stop from the set value, and then calculating the flow rate ejected during the current flow stop. The value is the sum of The flow rate of blood ejected after the pressure pulse generating means stops the outflow of fluid changes depending on the state of the living body, etc., but this change does not occur suddenly. The flow rate will be approximately the same. For this reason,
The flow rate of blood pumped out from the artificial heart pump at one time is approximately the same as the set value. (Embodiment) A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a circulatory system, which has an artificial heart pump 12 as its main body. artificial heart pump 1
2 is connected to an operating pressure supply system which is a biasing means. The supply system repeatedly supplies operating pressure to operate the artificial heart pump 12.
Furthermore, a probe 19 of an electromagnetic blood flow meter 20 is attached to the outflow side of the artificial heart pump 12. The working fluid supply system includes a gas pulse generator 10 that is a positive pressure generation control device, and a normally open solenoid valve 15 that is an on-off valve that controls the supply of fluid pressure from the control device 10 to an artificial heart pump 12. Solenoid valve 1
5 and the gas pulse generator 10 or the artificial heart pump 12 are connected by pipes 13 and 14. The gas pulse generator 10 operates at a predetermined period TR, and in the first half of one cycle, the working fluid flows out (systole state), and in the second half, the working fluid stops flowing out (diastole state). Note that the period TR can be set as appropriate. In addition, a control unit 11 to be described later
An ejection signal indicating a state in which the outflow of the working fluid is stopped is applied to the pump (see Fig. 2). The above-mentioned circulatory system is controlled and operated by a control device 11. The control device 11 has a microcomputer 17 as a control section, and the microcomputer 17
A set value switch section 16, an electromagnetic valve 15, an electromagnetic blood flow meter 20, a gas pulse generator 10, and a monitor 18 are connected to each via an interface (not shown). The set value switch section 16 sets the outflow flow rate Q1/min for about one minute. The outflow flow rate is input from the electromagnetic blood flow meter 20 every 2 msec. From the gas pulse device 10, the supply state of the working fluid (second
(See figure) A barrel ejection signal is applied. High signal when fluid is supplied, low signal when stopped. Next, the processing flow included in the control unit 11 will be explained. The processing flow is the main flow (Figure 4) and 1m
Timer interrupt flow processed every sec (5th
Figure). Each flow has memory, flags, and counters summarized in the table below.

〔Effect of the invention〕

As explained above, the artificial heart drive device of the present invention includes the pressure pulse generating means 10 that alternately causes the working fluid to flow out and stop flowing, generates pressure pulses, and drives the artificial heart pump 12 with the pressure pulses; Setting means 16 for setting the ejection flow rate of the artificial heart pump; flow rate measuring means 19 disposed at the output end of the artificial heart pump and measuring the ejection flow rate of the artificial heart pump; Flow rate accumulating means during outflow stop for accumulating the measured value of the flow rate measuring means while outflow is stopped (step S62 in the flowchart of the microcomputer 17, cumulative value is qc); Outflow flow rate accumulating means for accumulating the measured values of the flow rate measuring means (step S6 in the flowchart of the microcomputer 17)
1. The cumulative value is q); and the setting value of the setting means
The value obtained by subtracting the cumulative value qc of the flow rate accumulating means during outflow stop from qi is set as the control target value qs (step S32 in the flowchart), and the flow rate during the outflow during the next outflow of the working fluid of the pressure pulse generating means is set as the control target value qs. When the cumulative value q of the cumulative totaling means exceeds the control target value qs (step S7 in the flowchart), the outflow of the working fluid from the pressure pulse generating means is stopped (the pressure pulse generating means is disposed between the pressure pulse generating means and the artificial heart pump). Control means 1 (closes the solenoid valve 15)
7; Therefore, even if the artificial heart pump pumps out blood while the outflow of the working fluid from the pressure pulse generating means is stopped, the flow rate of the blood pumped out by the artificial heart pump remains constant and stable each time it pumps out. . At this time, the set value and the actual ejection amount are almost the same. Therefore, it becomes possible to recover the heart of the living body without affecting other organs. For example, when using an artificial heart pump to assist the right heart, if the amount of blood ejected by the artificial heart pump is large, blood may accumulate in the lungs because the amount of blood ejected from the left heart is fixed. If the flow rate of blood passing through the artificial heart pump is too low, blood clots are likely to form if an artificial valve is attached to the aortic valve of the living heart. In addition, blood circulation to other organs may not be maintained, but with the present invention, the amount of blood ejected can be accurately controlled.
The above problem does not occur. ,

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the system of the drive device according to the present invention, FIG. 2 is a timing chart showing the operating state of the drive device according to the present invention, FIG. 3 is an explanatory diagram showing a method for measuring the outflow flow rate, and 4 and 5 are a main flow and an interrupt flow showing the operation of the control section. 10... Gas pulse generator (pressure pulse generating means), 12... Artificial heart pump, 15... Solenoid valve, 16... Setting switch section (setting means), 17
. . . Control unit (control means), 19 . . . Blood flow meter (flow rate measuring means), S32 .
...Means for accumulating flow rate during outflow stoppage.

Claims (1)

[Scope of Claims] 1. Pressure pulse generating means for generating pressure pulses by alternately causing and stopping the flow of working fluid and driving an artificial heart pump using the pressure pulses; setting an ejection flow rate of the artificial heart pump; setting means; a flow rate measuring means disposed at the output end of the artificial heart pump and measuring the ejection flow rate of the artificial heart pump; a flow rate accumulating means for accumulating the flow rate during outflow stop; a flow rate accumulating means for accumulating the measured value of the flow rate measuring means during the outflow of the working fluid of the pressure pulse generating means; and a flow rate during outflow stop based on a set value of the setting means. The value obtained by subtracting the cumulative value of the cumulative totaling means is set as the control target value,
Control means for stopping the outflow of the working fluid from the pressure pulse generating means when the cumulative value of the flow rate accumulating means during outflow exceeds the control target value during the next outflow of the working fluid from the pressure pulse generating means; Artificial heart pump drive device.