JP4290106B2 - Blood purification equipment - Google Patents

Description

The present invention relates to a blood purification equipment for purifying, while the patient's blood is extracorporeally circulated.

  In general, in blood purification therapy such as dialysis treatment, a blood circuit composed of a flexible tube is used to circulate a patient's blood extracorporeally. This blood circuit is mainly composed of an arterial blood circuit in which an arterial puncture needle for collecting blood from a patient is attached to the tip, and a venous blood circuit in which a venous puncture needle for returning blood to the patient is attached to the tip. The dialyzer is interposed between the arterial blood circuit and the venous blood circuit to purify blood circulating outside the body.

  In such a dialyzer, a plurality of hollow fibers are arranged inside, and blood passes through the inside of each hollow fiber, and on the outside thereof (between the outer peripheral surface of the hollow fiber and the inner peripheral surface of the housing). It is set as the structure which can flow a dialysate. The hollow fiber has a blood purification membrane with micropores (pores) formed in the wall surface, and waste products of blood passing through the hollow fiber permeate the blood purification membrane and are discharged into the dialysate. At the same time, waste blood is discharged and purified blood is returned to the patient's body.

  By the way, when the arterial puncture needle that has punctured the patient is removed for some reason or disconnected from the arterial blood circuit during dialysis treatment, air is sucked from the arterial puncture needle to cause an air lock in the dialyzer. Or when the venous puncture needle is removed for some reason or disconnected from the venous blood circuit, the patient's blood introduced from the arterial puncture needle flows out without returning to the patient's body. Therefore, in order to detect the removal of the puncture needle from the patient and the disconnection from the blood circuit, the blood pressure of the patient flowing through the venous blood circuit is monitored. That is, when the puncture needle is removed from the patient, the puncture needle is opened to the atmosphere, and the pressure of blood flowing through the venous blood circuit is reduced. By detecting this, the removal of the venous puncture needle from the patient can be detected. is there.

  Specifically, a tube for monitoring is extended from the air layer side of the venous drip chamber disposed in the venous blood circuit and connected to a pressure sensor, so that the patient flowing through the venous blood circuit during dialysis treatment Always detect blood pressure. Then, it is determined whether or not the pressure detected by the pressure sensor exceeds a lower limit width as a preset alarm value. If the lower limit width is exceeded, there is a possibility that the puncture needle has come off. As an alarm. In addition, since this prior art does not relate to the literature known invention, there is no prior art document information to be described.

However, the conventional blood purification apparatus has the following problems.
That is, during dialysis treatment, the pressure (venous pressure) detected by the pressure sensor usually changes as shown in FIG. 5 due to clogging of the dialyzer or changes in the blood state of the patient. When the upper limit value K1 and the lower limit value K2 at which an alarm is given are set as shown in the figure, the venous pressure approaches the upper limit value K1 while moving away from the lower limit value K2 as the treatment time elapses.

  For this reason, there is a case where an alarm is issued despite the fact that the upper limit value K1 has been exceeded and there is no abnormality at time t1 in the figure, while the puncture needle has left the patient and the venous pressure has dropped as shown by the two-dot chain line in the figure. However, there is a problem that the lower limit width K2 is not exceeded and no alarm is given. In particular, when the puncture needle is withdrawn, the flow resistance when introduced into the vein in the patient's body disappears, but the flow resistance in the puncture needle remains generated, so the decrease in venous pressure remains small. Therefore, it is difficult to detect such a small decrease in venous pressure. Therefore, in the prior art, there has been a problem that it is difficult to accurately detect the removal of the puncture needle.

The present invention has been made in view of such circumstances, to provide a blood purification equipment that can transect accurately detect from omission or blood circuit from patient puncture needle during blood purification treatment There is.

  According to the first aspect of the present invention, there is provided a blood circuit including an arterial blood circuit and a venous blood circuit in which an arterial puncture needle and a venous puncture needle are attached to a distal end in order to circulate a patient's blood extracorporeally; A blood pump disposed in a circuit; blood purification means connected between the arterial blood circuit and the venous blood circuit; for purifying blood flowing through the blood circuit; and for blood of a patient flowing through the blood circuit In a blood purification apparatus comprising a detection means capable of detecting pressure, a blood pump control means for appropriately changing a blood flow rate by the blood pump, a detection value by the detection means, a blood circuit and a blood passing through the puncture needle Deriving an approximate expression showing the relationship between flow resistance, blood flow rate through the blood circuit, and access intravascular pressure as static pressure in the puncture needle as parameters And calculating means for calculating the access blood pressure based on the approximate expression, the blood flow rate changed by the blood pump control means and the detection value by the detection means, and the access blood pressure calculated by the calculation means Based on the above, it is detected that the puncture needle is removed from the patient or disconnected from the blood circuit.

  The invention according to claim 2 is the blood purification apparatus according to claim 1, further comprising monitoring means for issuing an alarm when the pressure detected by the detection means exceeds a set lower limit width, and The lower limit width of the monitoring means is set corresponding to the access intravascular pressure calculated by the calculating means.

  According to a third aspect of the present invention, in the blood purification apparatus according to the first or second aspect, the blood flow resistance of the blood is calculated by the calculating means, and a change in blood concentration is obtained based on the flow resistance. And

According to the first aspect of the present invention, the removal of the puncture needle from the patient or the disconnection from the blood circuit is detected based on the access intravascular pressure as a static pressure in the puncture needle (including the arterial puncture needle and the vein puncture needle). Therefore, it is possible to accurately detect the puncture needle from the patient and the disconnection from the blood circuit during the blood purification treatment as compared with the blood pressure that is easily influenced by disturbance.

According to the invention of claim 2, since the lower limit width of the monitoring means is set corresponding to the access blood pressure as the static pressure in the puncture needle, the lower limit width is set based on the blood flow pressure that is easily affected by disturbance. In comparison with this, it is possible to accurately detect the puncture needle being removed from the patient and the disconnection from the blood circuit during the blood purification treatment.

According to the invention of claim 3, since the blood flow resistance is calculated and the change in the blood concentration is obtained based on the flow resistance, the blood can be obtained without using a separate means for detecting the blood concentration, such as a hematocrit sensor. It is possible to measure changes in concentration.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The blood purification apparatus according to the present embodiment is for purifying a patient's blood while circulating it extracorporeally, and is applied to a dialysis apparatus used in dialysis treatment. As shown in FIG. 1, such a dialysis machine is mainly composed of a blood circuit 1 to which a dialyzer 2 as blood purification means is connected, and a dialysis machine body 6 for removing water while supplying dialysate to the dialyzer 2. . As shown in the figure, the blood circuit 1 is mainly composed of an arterial blood circuit 1a and a venous blood circuit 1b made of a flexible tube. The arterial blood circuit 1a and the venous blood circuit 1b A dialyzer 2 is connected between them.

  An arterial puncture needle a is connected to the distal end of the arterial blood circuit 1a, and an iron-type blood pump 3 is disposed in the middle, while the venous blood circuit 1b is disposed at the distal end. A vein-side puncture needle b is connected, and a drip chamber 4 for removing bubbles is connected midway.

  When the blood pump 3 is driven while the patient is punctured with the arterial puncture needle a and the venous side puncture needle b, the blood of the patient reaches the dialyzer 2 through the arterial blood circuit 1a. As a result, blood purification is performed, and defoaming is performed in the drip chamber 4 to return to the patient's body through the venous blood circuit 1b. That is, the blood of the patient is purified by the dialyzer 2 while circulating outside the body by the blood circuit 1.

  The dialyzer 2 is formed with a blood introduction port 2a, a blood outlet port 2b, a dialysate inlet port 2c, and a dialysate outlet port 2d in the casing. Among these, the blood inlet port 2a has an arterial blood circuit 1a. The base end of the venous blood circuit 1b is connected to the blood outlet port 2b. The dialysate introduction port 2c and the dialysate lead-out port 2d are connected to a dialysate introduction line L1 and a dialysate discharge line L2 extending from the dialyzer body 6, respectively.

  A plurality of hollow fibers are accommodated in the dialyzer 2, the inside of the hollow fibers is used as a blood flow path, and the flow of dialysate is between the hollow fiber outer peripheral surface and the inner peripheral surface of the housing. It is considered a road. A hollow fiber membrane is formed in the hollow fiber by forming a large number of minute holes (pores) penetrating the outer circumferential surface and the inner circumferential surface, and impurities in the blood are passed through the membrane in the dialysate. It is comprised so that it can permeate.

  On the other hand, as shown in FIG. 2, the dialysis machine body 6 bypasses the dual pump 11 formed across the dialysate introduction line L1 and the dialysate discharge line L2, and the dual pump 11 in the dialysate discharge line L2. It is mainly composed of a connected bypass line L3 and a water removal pump 8 connected to the bypass line L3. One end of the dialysate introduction line L1 is connected to the dialyzer 2 (dialyte introduction port 2c), and the other end is connected to a dialysate supply device 7 for preparing a dialysate having a predetermined concentration.

  One end of the dialysate discharge line L2 is connected to the dialyzer 2 (dialysate outlet port 2d), and the other end is connected to a waste fluid means (not shown). The dialysate supplied from the dialysate supply device 7 After reaching the dialyzer 2 through the dialysate introduction line L1, it is sent to the waste fluid means through the dialysate discharge line L2 and the bypass line L3. In the figure, reference numerals 9 and 10 denote a heater and a deaeration means connected to the dialysate introduction line L1.

  The dewatering pump 8 is for removing water from the blood of the patient flowing through the dialyzer 2. That is, when the dewatering pump 8 is driven, since the duplex pump 11 is a fixed type, the volume of liquid discharged from the dialysate discharge line L2 is larger than the amount of dialysate introduced from the dialysate introduction line L1. Thus, water is removed from the blood by the large volume. In addition, you may make it remove a water | moisture content from a patient's blood by means other than this water removal pump 8 (for example, what utilizes what is called a balancing chamber etc.).

  Here, a monitor tube H is extended from the air layer side of the drip chamber 4, and a venous pressure sensor 5 (detection means) is connected to the tip of the monitor tube H. The venous pressure sensor 5 is composed of a sensor disposed in the dialysis machine body 6 and is configured to detect in real time the blood pressure (venous pressure) of the patient flowing through the venous blood circuit 1b during dialysis treatment. Has been.

  The venous pressure sensor 5 is electrically connected to the venous pressure monitoring means 12 and the calculation means 15, and the venous pressure monitoring means 12 and the calculation are performed using the venous pressure detected by the venous pressure sensor 5 as an electrical signal. It is configured to be able to transmit to the means 15. The venous pressure monitoring means 12 causes the alarm means 13 to issue an alarm when the pressure detected by the venous pressure sensor 5 exceeds a predetermined alarm value. For example, the venous pressure monitoring means 12 controls various operations and displays in the hemodialysis apparatus. It consists of a microcomputer and so on.

  The alarm means 13 is for urging attention to surrounding medical personnel when the venous pressure monitoring means 12 determines that the venous pressure exceeds a predetermined alarm value, which will be described later. An alarm is configured by blinking or lighting of a warning lamp, display by a display unit (both not shown), or the like.

  Further, a blood pump control means 14 for controlling the driving of the blood pump 3 is disposed in the dialyzer body 6, and the blood pump control means 14 and the blood pump 3 are electrically connected via a wiring W. Connected. The blood pump control means 14 in the present embodiment is set so as to appropriately change the blood flow rate by the blood pump 3 at a predetermined timing during dialysis treatment, and is detected by the blood flow rate Qb and the venous pressure sensor 5 at each timing. The venous pressure Pv can be transmitted to the calculation means 15.

  The calculation means 15 includes a detection value (venous pressure) Pv detected by the venous pressure sensor 5, a flow resistance Rn of blood flowing through the blood circuit 1 and the venous puncture needle b, a blood flow rate Qb flowing through the blood circuit 1, and a venous puncture needle b. An approximate expression using the shunt internal pressure (access blood pressure) Ps as a static pressure as a parameter is calculated, and the approximate expression and the blood flow rate Qb changed by the blood pump control means 14 and the detection value Pv by the venous pressure sensor 5 are calculated. Based on this, the shunt internal pressure Ps is calculated.

  A shunt is a portion where a artery and a vein previously formed in a patient's body in order to obtain a sufficient extracorporeal blood volume, and a static pressure generated between the shunt and the puncture needle. Is called shunt internal pressure. In the present embodiment, the shunt internal pressure is the access intravascular pressure, but instead of this, the access intravascular pressure generated between the puncture needle and the blood vessel in a patient who does not form the shunt may be used.

For example, when the venous pressure Pv is approximated by a quadratic expression, the following approximate expression can be obtained.
Pv = Rn1 × Qb ² + Rn2 × Qb + Ps
(However, Rn1 and Rn2 are constants)

  Here, each timing in the process of changing the blood flow rate by the blood pump control means 14 is, for example, as shown in FIG. Each blood flow rate is changed so that each blood flow rate is Qb1 (for example, 200 (mL / min)), Qb2 (for example, 180 (mL / min)) and Qb3 (for example, 160 (mL / min)). If the venous pressure is Pv1, Pv2 and Pv3, the following three equations are obtained. The blood flow rates Qb1 to Qb3 are known by obtaining a control signal from the blood pump control means 14, and the venous pressures Pv1 to Pv3 are known from the detection values of the venous pressure sensor 5.

Pv1 = Rn1 × Qb1 ² + Rn2 × Qb1 + Ps (1)
Pv2 = Rn1 × Qb2 ² + Rn2 × Qb2 + Ps (2)
Pv3 = Rn1 × Qb3 ² + Rn2 × Qb3 + Ps (3)
(However, the blood flow rates Qb1 to Qb3 and the venous pressures Pv1 to Pv3 are known as described above.)

  The blood flow rate is obtained from the control signal from the blood pump control means 14, but the control signal is based on the driving speed of the blood pump 3, and there is a possibility that an error occurs with the actual blood flow rate. . In order to suppress such an error, a sensor for measuring the pressure of the part, such as a blood pressure removal sensor, is disposed in the middle of the arterial blood circuit 1a between the arterial puncture needle a and the blood pump 3. When the arterial pressure measured by such a sensor is normal, the error is determined to be small, and if abnormal, the error is determined to be large, and a procedure for correcting the error (re-puncture of the puncture needle, etc.) ) Can be performed. Further, since the venous pressure Pv is not stabilized immediately after the blood flow rate is changed, it is preferable to average the data for a predetermined time in the second half of each timing (for example, 20 seconds in the latter half of each timing) to obtain the venous pressure Pv.

  From the above formulas (1) to (3), Ps (shunt internal pressure as static pressure) which is one of the unknowns can be obtained, and the obtained shunt internal pressure Ps is transmitted to the venous pressure monitoring means 12. Then, as shown in FIG. 3, the venous pressure monitoring means 12 has a lower limit width D1 to D8 (alarm range) (for example, an alarm range) corresponding to the transmitted shunt internal pressure Ps with respect to the detection value detected by the venous pressure sensor 5. Ps = D) is sequentially set, and the removal of the venous puncture needle b from the patient or the disconnection from the venous blood circuit 1b is monitored.

  That is, when the horizontal axis is the treatment time (h) and the vertical axis is the venous pressure (mmHg) detected by the venous pressure sensor 5, the venous pressure gradually increases with time as shown in FIG. Since the graph of the detected value A is obtained, the lower limit width (D1) corresponding to the shunt internal pressure Ps obtained by the calculation means 15 is sequentially set and updated every time a predetermined time elapses. And when the detection value by the venous pressure sensor 5 exceeds the said lower limit width | variety (D1-), the warning by the warning means 13 is performed.

  Thus, for example, when the venous puncture needle b is removed from the patient at time t1 and the venous pressure is changed as shown in the graph A ′, the change can be accurately detected, and the puncture needle is removed from the patient. Can be detected quickly. Further, since the shunt internal pressure Ps is a static pressure in the venous puncture needle b, the venous puncture during dialysis treatment is compared with a case where the lower limit is set based on the blood flow pressure (dynamic pressure) that is easily affected by disturbance. The removal of the needle b from the patient or the disconnection from the venous blood circuit 1b can be accurately detected.

  That is, when the venous puncture needle b is removed from the patient during dialysis treatment, the venous puncture needle b is released to the atmosphere, and theoretically, the venous pressure is only the shunt internal pressure Ps that is the static pressure in the venous puncture needle b. Therefore, the lower limit width D as an alarm value by the venous pressure monitoring means 12 is made to correspond to the shunt internal pressure Ps (that is, the lower limit width D is substantially the same as the shunt internal pressure Ps), so that it is more accurate. The removal of the venous puncture needle b from the patient or the disconnection from the venous blood circuit 1b can be detected.

  In the figure, reference symbols a and b indicate an upper limit value and a lower limit value for the venous pressure set as a fixed value. Since the upper limit value and the lower limit value are constant during dialysis treatment, and the width is set to be relatively large, the following effects can be obtained. That is, even when the venous pressure increases despite no abnormality in extracorporeal circulation, such as when the patient changes from a lying position to a sitting position, the upper limit value a is prevented from exceeding. Accordingly, there is no abnormality in the extracorporeal circulation, and it is possible to prevent an erroneous alarm from being caused simply by an increase in venous pressure based on a change in the patient's posture.

  According to the embodiment, since the shunt internal pressure Ps is calculated and the removal of the venous puncture needle b from the patient is monitored, the pressure drop width when the venous puncture needle b is removed from the patient is theoretically determined. Can do. In addition to the control software of the blood pump control means 14 for changing the flow rate of the blood pump 3, no special means can be required and applied to an existing hemodialysis apparatus (blood purification apparatus). Is easy.

  In addition to the automatic follow-up by calculating the shunt internal pressure Ps every predetermined time and setting the lower limit width D sequentially as described above, the following configuration may be adopted. For example, in the dialysis treatment process, the shunt internal pressure Ps is calculated at predetermined time intervals as described above, and the shunt internal pressure Ps is monitored. When the shunt internal pressure Ps approaches 0, it is determined that the venous puncture needle b has been removed from the patient, and an alarm is issued by the alarm means 13. According to such a configuration, since the shunt internal pressure Ps is directly monitored, it is possible to quickly detect the removal of the venous puncture needle b from the patient or the disconnection from the venous blood circuit 1b.

  Furthermore, in the above, the shunt internal pressure Ps, which is an unknown, is calculated from the approximate expression. In addition to this, other unknowns, R1 and R2 (the blood flowing through the blood circuit 1 and the venous puncture needle b) (Flow resistance) may be calculated, and a change in blood concentration may be obtained based on the flow resistance. That is, the calculated flow resistance is a function of blood viscosity, and the blood viscosity correlates with hematocrit (the volume fraction of red blood cells in the blood) (the hematocrit value increases due to water removal during dialysis treatment). Therefore, the change in hematocrit can be easily detected by obtaining the value of the flow resistance with time. If the change in the hematocrit value can be detected, the change in the circulating blood volume (BV: blood volume) in the body can be obtained.

  Accordingly, the blood flow resistance is calculated and the change in blood concentration is obtained based on the flow resistance. For example, the blood concentration change can be measured without using a separate means for detecting the blood concentration such as a hematocrit sensor. is there. As long as it correlates with the flow resistance, a parameter indicating a blood concentration (for example, hemoglobin concentration, etc.) different from the hematocrit may be obtained.

  Although the present embodiment has been described above, the present invention is not limited to this. For example, the venous pressure Pv is approximated by a linear expression, and the venous puncture needle is easily removed from the patient without obtaining accuracy. Can be detected. In this case, if the fluctuation range of the blood flow rate by the blood pump 3 is narrowed, the error can be suppressed even if the venous pressure change is linearly approximated. Specifically, since the approximate expression can be expressed as Pv = R1 × Qb + Ps, the shunt internal pressure Ps can be calculated by changing the blood flow rate Qb between two points. The approximate expression may be a linear expression or a quadratic expression, a cubic expression or an exponential function, or the like, and the blood flow rate Qb may be changed according to the order of the approximate expression.

  In this embodiment, the approximate expression is applied using the venous pressure detected by the venous pressure detecting means as a parameter. Instead of this, the means for detecting the arterial pressure (the arterial puncture needle and the blood pump The arterial pressure detected by an anti-blood pressure sensor or the like disposed between them may be applied to the approximate expression as a parameter. In this case, the blood flow resistance is a resistance flowing through the blood circuit and the artery side puncture needle, and the access blood vessel internal pressure is an internal pressure as a static pressure in the artery side puncture needle a.

  Furthermore, in the present embodiment, the dialysis device body 6 is composed of a dialysis monitoring device that does not incorporate a dialysate supply mechanism, but may be applied to a personal dialysis device that incorporates a dialysate supply mechanism. . The present invention can be applied to other blood purification apparatuses such as hemofiltration therapy and hemofiltration dialysis therapy in addition to hemodialysis therapy as in the embodiment.

  Any blood purification device provided with a monitoring means for updating an alarm value based on the pressure detected by the detection means every predetermined time may be applied even if it has a different appearance or is provided with other functions. Can do.

Schematic diagram showing a hemodialysis apparatus according to an embodiment of the present invention. Schematic showing the dialysis machine body in the hemodialysis machine Graph for showing monitoring control of venous pressure by venous pressure monitoring means in the hemodialysis apparatus Graph for showing monitoring control of venous pressure by venous pressure monitoring means in the hemodialysis apparatus (graph showing each timing in the process of changing blood flow rate by blood pump control means) Graph for showing monitoring control of venous pressure by venous pressure monitoring means in a conventional hemodialysis apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blood circuit 1a Arterial blood circuit 1b Venous blood circuit 2 Dialyzer (blood purification means)
3 Blood pump 4 Drip chamber 5 Vein pressure sensor (detection means)
6 Dialysis machine body 7 Dialysate supply device 8 Dewatering pump 9 Humidifier 10 Deaeration means 11 Duplex pump 12 Vein pressure monitoring means (monitoring means)
13 Alarm means 14 Blood pump control means 15 Calculation means a Arterial puncture needle b Vein side puncture needle

Claims (3)

A blood circuit composed of an arterial blood circuit and a venous blood circuit each having an arterial puncture needle and a venous puncture needle attached to the tip of the patient for extracorporeal circulation;
A blood pump disposed in the arterial blood circuit;
Blood purification means connected between the arterial blood circuit and the venous blood circuit and purifying blood flowing through the blood circuit;
Detection means capable of detecting the blood pressure of the patient flowing through the blood circuit;
In the blood purification apparatus comprising
Blood pump control means for appropriately changing the flow rate of blood by the blood pump;
Approximate expression indicating the relationship between the detection value by the detection means, the flow resistance of blood flowing through the blood circuit and the puncture needle, the blood flow rate through the blood circuit, and the access intravascular pressure as the static pressure in the puncture needle as parameters. And calculating means for calculating the access intravascular pressure based on the approximate expression, the blood flow rate changed by the blood pump control means and the detection value by the detection means,
The blood purification apparatus is characterized in that the removal of the puncture needle from the patient or the disconnection from the blood circuit is detected based on the access intravascular pressure calculated by the calculation means.   A monitoring means for giving an alarm when the pressure detected by the detection means exceeds a set lower limit, and a lower limit of the monitoring means corresponding to the access intravascular pressure calculated by the calculation means; The blood purification apparatus according to claim 1, wherein a width is set.   The blood purification apparatus according to claim 1 or 2, wherein the blood flow resistance of the blood is calculated by the calculating means, and a change in blood concentration is obtained based on the flow resistance.

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