JPH07265414A - Plasma exchanger - Google Patents

Abstract

PURPOSE:To provide a device which can be stably operated by providing an automating device which is capable of automatically controlling the pressure in a blood taking circuit so as not to drop the pressure too much and not to completely close a liquid feed tube according to a condition on the blood taking end and a fluctuation in the posture of a patient. CONSTITUTION:This plasma exchanger is provided with the blood taking circuit 2 for taking the blood from the patient, a pressure gage for detecting the pressure in the blood taking circuit 2 and a blood pump Ml for controlling the pressure in the blood taking circuit 2 so as to maintain the pressure at the prescribed pressure value or above between the blood taking circuit 2 and a blood introducing circuit 3 of a plasma separator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasmapheresis device.

[0002]

2. Description of the Related Art Conventionally, there is a plasma exchange device as one of plasma processing devices for removing blood plasma components containing disease-causing substances from blood and returning the blood. This plasma exchange device is a device that separates a blood cell component and a plasma component from blood, discards the separated plasma component, and replenishes an amount of replacement fluid equivalent to the discarded plasma.

By the way, a particular problem in automating this type of blood processing apparatus is pressure fluctuation in a blood collecting circuit for collecting blood from a patient, and in particular, an injection as a blood collecting end for collecting blood from a patient. It is necessary to have a delicate sensation as to whether the needle is properly inserted so that it cannot be pressed against the inner wall surface of the blood vessel, and whether the number of rotations of the blood pump that determines the pressure in the blood collection circuit is balanced. I was forced to rely on the experience of skilled doctors. For this reason, it is difficult for those who do not have such experience to perform this blood collection operation easily, and it is difficult to provide an automated plasma exchange device over the entire circuit from the blood collection end.

On the other hand, on the other hand, in fact, fairness is 4-44761.
In the plasma exchange device disclosed in Japanese Patent Laid-Open Publication No. 2003-242, in order to perform the same filtering action in the plasma separator even when clogging occurs in the blood introducing part, which is one of the problems of this type, the introduction of the plasma separator A technique is shown in which all pumps in the circuit are driven at low speed while maintaining a constant flow ratio between the discharge side and the discharge side.

[0005]

However, in the technique described in the above-mentioned publication, even when the blood introducing portion is clogged, the rotation speed of the pumps can be controlled without stopping the driving of all the pumps in the circuit. The pump speed changed by the low-speed driving means of the pump is shown in FIG. 6 (because it is characterized in that it is intended to smoothly continue the filtering action of the entire apparatus by controlling the decrease while maintaining a constant flow rate ratio. It was controlled to be gradually lowered with a constant inclination as shown in B). That is, since the pump for controlling the pressure in the blood sampling circuit similarly decreases as shown in FIG. 6 (B), the pressure in the blood sampling circuit becomes negative as shown in FIG. 6 (A). When such a low speed control is performed in the vicinity of the pressure lower limit value, the pressure value gradually decreases, and in some cases, the closing pressure of the liquid feeding tube may be further reduced.

[0006] Therefore, as a result, a doctor or the like has to perform blood collection work while still monitoring the liquid supply tube so as not to be blocked, which is one of the works that cannot be performed without considerable experience. . In view of such a point, the present invention provides a device capable of automatically controlling the blood supply tube so as not to be blocked during blood collection work, simplifies the blood collection work, and as a result, continues safe and stable treatment automatically. It is an object of the present invention to provide a plasmapheresis device that can be used.

[0007]

A plasma exchange apparatus according to claim 1 of the present invention separates blood drawn from the body into blood cell components and plasma components by a plasma separator, and discharges the separated plasma components. Then, in the plasma exchange device for returning the replacement fluid in the same amount as the discharged plasma component to the separated blood cell component and then returning to the body, a pressure detection unit for detecting the pressure of the blood collection circuit for collecting blood from the patient, A control unit for driving and controlling a blood pump provided between the blood collection circuit and the blood introduction circuit of the plasma separator is provided, and the control unit controls the pressure of the blood collection circuit to be equal to or higher than a predetermined pressure value. It is a device.

A blood plasma exchange device according to a second aspect of the present invention is a device in which the pressure detection unit according to the first aspect is a pillow type pressure gauge.

[0009]

In the plasma exchange apparatus, a blood collecting circuit for collecting blood from a patient, a pressure detecting unit for detecting the pressure in the blood collecting circuit, and the blood collecting circuit between the blood collecting circuit and the blood introducing circuit of the plasma separator. Since it has a blood pump that is controlled so that the internal pressure is within a predetermined range, even if the blood pressure is negative, or even if the blood pressure rises or falls near the negative pressure detection point, the pressure of the blood collection circuit Can be controlled to be equal to or higher than a predetermined pressure value that does not completely block the blood sampling tube.

[0010]

Embodiments of the plasma exchange apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is an overall circuit diagram showing a plasmapheresis apparatus according to the present invention. The overall circuit diagram here means the route to circulate the blood collected from the patient out of the body and return it to the patient after performing a predetermined process. Since the flow rate is changed by the introduction side (primary side) and the discharge side (secondary side) of the pumps M1 and M2, which are the flow rate controllers provided in the above, the circuits before and after these pumps M1 and M2 are respectively separated circuits. Constitute. Further, in the following, the upstream side and the downstream side are referred to as the upstream side on the blood collecting side with respect to the plasma separator, and the downstream side is the blood returning side.

In FIG. 1, the blood pump M is drawn from the blood collecting end 1.
The circuit leading to the introduction side of 1 is a blood collection circuit 2 for collecting blood from a patient with an appropriate blood pressure. Then, the blood of the patient taken out by the blood collecting circuit 2 is introduced into the plasma separator 4 via the blood introducing circuit 3. Plasma separator 4
Is for separating blood cell components and plasma components by the sieving action of the pores of the filtration membrane 5 made of hollow fiber or the like.

A plasma component derivation circuit 6 which is a derivation circuit from the plasma separator 4 is provided with a plasma discharge / replacement fluid pump M2,
One of the outlet sides of the pump M2 is a replacement fluid introduction circuit 8 for introducing a replacement fluid corresponding to the plasma component stored in the storage container 7.

The blood cell component derived from the blood cell component derivation circuit 9 on the downstream side of the plasma separator 4 is mixed with the replacement fluid introduced through the replacement fluid introduction circuit 8 and then returned to the blood through the warmer 10. It is returned to the inside of the blood vessel (blood return end 12) of the patient through the circuit 11. On the other hand, the plasma component that has passed through the plasma component deriving circuit 6 is pushed out to the other outlet side of the pump M2, and is stored in the storage container 13 and then discarded.

The pump M2 in this embodiment uses a roller pump in which a so-called plasma pump and a replacement fluid pump are linked to drive a machine so that the amount of plasma discharged and the amount of replacement fluid supplemented are equal. Is done by
Of course, these pumps may be installed separately.

By the way, in the circuit shown in FIG. 1, the blood collecting circuit 2, the blood introducing circuit 3, the plasma component deriving circuit 6, the replacement fluid introducing circuit 8, and the blood returning circuit 11 have drip chambers for removing bubbles in the blood. And a pressure gauge for detecting the pressure of the air chamber in the drip chamber is provided, and the pressure values of P1 to P5 are detected by these pressure gauges.

The rotational speeds of the pumps M1 and M2 described above are controlled by a microcomputer in accordance with a predetermined procedure based on the detected values P1 to P5 of the pressure gauge. FIG. 2 is a block diagram showing the hardware configuration of the pump control unit 14. In FIG. 2, the analog signals detected by the pressure gauges P1 to P5 are input in parallel to the multiplexer 15, and the signals selected according to the instruction of the CPU 16 are input to the A / D converter 17 and converted into digital signals. , Are input to the CPU 16. On the other hand, C
The PU 16 outputs a control signal of the rotation speed of each pump M1, M2 according to a fixed procedure, and the signal is the D / A converter 1
At 8, the signal is converted into an analog signal for pump control and output. In the drawings, for convenience of the following description, only the blood pump M1, which is a characteristic control in the present invention, is shown.

Specifically, the blood pump M1 is designed so that the blood sampling pressure P1 is equal to or higher than the set pressure value so that the blood sampling pressure does not become a negative pressure and the liquid delivery pipe is crushed. Plasma separator 4 depending on the rotation difference
The filtration membrane 5 is controlled so as not to be clogged.

The feature of the present invention is that
This is pump control of the blood pump M1, and the control procedure of the pump M1 is shown in the flowchart of FIG. In the figure, the rotational speed of the blood pump M1 is controlled by the control variable R based on the pressure value P1.
Shows a procedure for controlling the motor. As shown in FIG. 4, the control characteristic of this rotation speed is determined by a predetermined lower limit pressure P.
When the pressure is P _min or higher, with _min as the threshold,
Rotate at the maximum speed R _max that allows stable operation, and
When the pressure is less than or equal to _min , the rotation is controlled so as to have a linear decrease characteristic 20 that linearly decreases with the decrease in pressure, but the rotation speed is set so as not to be lower than a preset base rotation speed R0. . The base rotation speed R0 here is a rotation speed at a limit at which the liquid feeding tube of the blood sampling circuit 2 is not blocked.

In step S1 of FIG. 3, the pressure value P1
To P5 are selected and fetched, and in step S2, the pressure value P1 in the blood sampling circuit 2 is compared with the value of the lower limit pressure P _min , and if the former is smaller, step S3
Moving to the step of setting the rotational speed of the blood pump M1, the rotational speed is set here according to the linear decrease characteristic 20 shown in FIG. Whether the rotation speed set in this way is less than or equal to the base rotation speed R0 is determined in the following step S4.
Check in S5. Specifically, in step S4, the current rotation speed of the blood pump M1 is set to the base rotation speed R.
When it is smaller than 0, the base rotation speed R0 is set in the control variable R in step S5.

On the other hand, when the pressure value P1 in the blood sampling circuit 2 is not less than the threshold value P _min in the step S2,
In step S6, the maximum rotation speed R _max is set. And finally, in step S7, output the number of revolutions,
Return to step S1. Through the above procedure, the blood pump M
The rotation speed of 1 can be maintained so as not to be lower than the base rotation speed R0 at which the liquid feeding tube of the blood sampling circuit 2 may be blocked, and the rotation speed is linearly reduced.
Since it is set to 0, it is possible to speed up the processing speed because the rotation can be quickly returned without being lowered all at once.

Instead of the pressure gauge P1 and other pressure gauges, as described in JP-A-3-254754, a bag shape made of an elastic material such as vinyl chloride inserted in the middle of the liquid feeding pipe. It is preferable to use a so-called pillow type pressure gauge, which is a pressure sensor that detects the amount of deformation of the pressure reaction jig by the electric output of a load cell type load sensor. By using such a pillow type pressure gauge for a part or all of the pressure gauge using the pillow type pressure gauge, the structure of the circuit becomes simple and the handling at the time of attachment / detachment of the circuit becomes easy.

The blood collecting circuit 2 is provided with the pressure gauge P1 for detecting the blood collecting pressure, and the blood pump M1 is controlled so that the blood collecting pressure becomes a predetermined pressure value or more. That is, in the state where the blood sampling pressure deviates from the predetermined pressure, the pump M1 is controlled and changes its rotation speed according to the characteristic shown in FIG. 4 so that the blood flow rate is preset according to the blood sampling pressure. The rotation speed of the blood pump M1 does not become lower than the base rotation speed R0 at which the liquid feeding tube of the blood collection circuit 2 may be blocked. Specifically, FIG.
Since the pump speed can be changed as shown in (B) with respect to the change in blood sampling pressure in (A), the liquid feeding tube is not blocked.

The pumps M1 and M2 may be valves, screw cocks or the like as long as they can stably circulate blood outside the body, but in the drawing, a plurality of squeezing rollers attached to the rotating body are used. The pipe is used that rotates while crushing the liquid delivery pipe in sequence and the flow rate can be controlled by controlling the number of revolutions.

[0024]

As described above, according to the present invention, the pressure inside the blood sampling circuit is too low and the liquid delivery tube is completely blocked due to the situation of the blood sampling end and the posture change of the patient. Since it does not have any, the blood collection work is simplified and can be effectively used as an automated device. In addition, even if the blood pressure becomes negative pressure or the blood pressure rises or falls near the negative pressure detection point, the rotation of the pump is smoothly controlled, and there is no problem that the drive means is switched unnecessarily frequently. Is stable.

[Brief description of drawings]

FIG. 1 is an overall circuit diagram showing an embodiment of a plasmapheresis apparatus according to the present invention.

FIG. 2 is a block diagram showing a hardware configuration of a pump control unit.

FIG. 3 is a flowchart illustrating a control procedure of a blood pump.

FIG. 4 is a graph showing control characteristics of a blood pump.

FIG. 5 is a graph showing a control result by the blood pump.

FIG. 6 is a graph showing conventional control characteristics.

[Explanation of symbols]

 1 ... Blood collection end 2 ... Blood collection circuit 3 ... Blood introduction circuit 4 ... Plasma separator 6 ... Plasma component derivation circuit 8 ... Replacement fluid introduction circuit 9 ... Blood cell component derivation circuit 14 ... Pump control unit M1 ... Blood pump M2 ... Plasma discharge and supplement fluid pump

Claims (2)

[Claims] 1. A blood cell derived from the body is separated into a blood cell component and a plasma component by a plasma separator, the separated plasma component is discharged, and an equivalent amount of the replacement fluid as the discharged plasma component is separated into the blood cells. In a plasma exchange device that returns to the body after mixing with components, it is provided between a pressure detection unit that detects the pressure of a blood collection circuit that collects blood from a patient, and the blood collection circuit and the blood introduction circuit of the plasma separator. A plasma exchange apparatus comprising: a control unit for driving and controlling a blood pump, the control unit controlling the pressure of the blood collection circuit to be equal to or higher than a predetermined pressure value. 2. The plasmapheresis apparatus according to claim 1, wherein the pressure detection unit is a pillow type pressure gauge.