JP6170603B2 - Circulation device and control method thereof - Google Patents

Description

  The present invention relates to a circulation device and a control method thereof.

  One of the elements constituting the extracorporeal circulation device is an oxygenator. When blood comes into contact with air, it takes in oxygen and discharges carbon dioxide. The artificial lung does not directly contact blood and air, but has a structure in which a gas exchange membrane is interposed between them (for example, Patent Document 1).

JP 2007-289695 A

  When the extracorporeal circulation device is operating, the gas exchange efficiency of the oxygenator, in other words, the blood oxygen concentration fluctuates. This factor includes internal factors such as the material and structure of the gas exchange membrane and external factors such as temperature and humidity. In particular, the gas exchange membrane may have a structure in which a large number of minute holes are arranged. If the humidity is high, the exchange efficiency decreases. Therefore, usually, the display signal of the sensor for detecting the blood oxygen concentration provided on the circulation device is monitored on the display screen, and the supply capability of the gas blender device connected to the artificial lung is adjusted manually if necessary Is done. In general, a gas blender device supplies a mixed gas of 100% oxygen and compressed air. The supply amount can be adjusted manually by opening and closing the valve (opening ratio or valve opening ratio). Is doing. That is, when the blood oxygen concentration becomes low, the opening rate of the valve of the gas blender device is increased to increase the amount of gas supplied per unit time (oxygen concentration). When the blood oxygen concentration exceeds a certain level, an operation of lowering the supply gas amount by lowering the opening ratio of the valve of the gas blender device is performed.

  While the above is done at relatively short time intervals, there is another problem with oxygenator. That is a phenomenon in which plasma fluid oozes out like a droplet on the surface of the gas exchange membrane through which gas passes, as time passes. This phenomenon is called “plasma leak”. If this state is left as it is, a part of the gas exchange membrane will be in a state where it is covered with plasma. In such a state, most of the gas exchange holes are clogged with plasma fluid, resulting in very poor gas exchange efficiency and an accident. Because of such problems, the gas blender device valve gas is increased (or fully opened) for about 3 minutes at intervals of 3 to 6 hours. An operation of passing over the exchange membrane and blowing off the plasma fluid on the gas exchange membrane is performed. This operation is called a flash operation. In addition, even if blood oxygen concentration does not fluctuate for a long time, dew condensation occurs when moisture in the air enters a low-temperature artificial lung. This is called “wet rung”, but it is desirable to remove the condensed moisture by periodically flushing the gas every few hours in order to prevent the adverse effects of this phenomenon.

  However, the flash operation is manually performed at an empirical time interval as described above, and it cannot be denied that an accident has occurred due to forgetting to perform the flash operation. On the other hand, if the flash operation is performed more than necessary, problems such as an increase in gas cylinder consumption will occur.

  The present invention has been made in view of the above problems. In the present specification, it is intended to provide a technique for monitoring an artificial lung in a circulatory device and maintaining it in a safe state without human intervention.

In order to achieve the above object, the circulation device according to the present invention has the following configuration. That is,
A circulation device that circulates the blood of a subject outside the body using a circulation circuit,
A detection means that is located downstream of the oxygenator installed on the circulation circuit, and detects oxygen concentration in blood that has undergone gas exchange in the oxygenator;
Determination means for determining whether the oxygen concentration in the blood detected by the detection means is within a preset target range, exceeds the target range, or falls below the target range;
A gas supply means for supplying a gas containing at least oxygen to the artificial lung, the supply amount per unit time being variable;
Control means for controlling the gas supply amount by the gas supply means according to the determination result of the determination means,
The determination means further determines whether or not the oxygen concentration detected by the detection means is below a threshold value smaller than a lower limit of the target range,
The control means includes
When an oxygen concentration lower than the threshold is detected, it is considered that the gas exchange membrane in the artificial lung is covered with plasma fluid, and a sufficient amount of gas is blown to the gas supply means to blow the plasma fluid. Execute the flash process to supply,
The flush process is also performed when the state where the oxygen concentration is between the lower limit of the target range and the threshold value continues for a predetermined time or longer.

  According to the specification of the present application, it is possible to monitor the oxygenator in the circulatory device and maintain it in a safe state without human intervention.

  Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals.

The accompanying drawings are included in the specification, constitute a part thereof, show an embodiment of the present invention, and are used to explain the principle of the present invention together with the description.
It is a figure which shows the whole structure of the extracorporeal circulation apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of a function structure of the controller of an extracorporeal circulation apparatus. It is a figure for demonstrating the structure of an artificial lung and the principle of gas exchange. It is a flowchart which shows the flow of the control processing of a controller in embodiment. It is a figure which shows the example of transition of the blood oxygen concentration in embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

[First Embodiment]
<1. Overall configuration of extracorporeal circulation device>
First, an overall configuration of an extracorporeal circulation device according to an embodiment of the present invention will be described. 1a of FIG. 1 is a figure which shows an example of the whole structure of the extracorporeal circulation apparatus 100 which concerns on one Embodiment of this invention.

  The extracorporeal circulation device 100 is used not only for extracorporeal circulation during cardiac surgery but also for auxiliary circulation procedures such as PCPS and ECMO, and performs cardiopulmonary assist operations (extracorporeal circulation operation, priming operation). The extracorporeal circulation apparatus 100 has a blood extracorporeal circuit (hereinafter referred to as a circulation circuit) indicated by an arrow in the figure. In the extracorporeal circulation apparatus 100, after performing the priming operation, the blood of the subject 130 is circulated extracorporeally using this circulation circuit.

  Note that the priming operation refers to an operation of removing the bubbles in the circuit by circulating the priming liquid in the circulation circuit in a state where the circulation circuit is sufficiently filled with the priming liquid (for example, physiological saline).

  The extracorporeal circulation device 100 includes a controller 110 that functions as a control device, a drive motor 111, a centrifugal pump 112, an artificial lung 113, a gas blender 117 that is an oxygen supply source, a catheter (vein side) 119, and a catheter ( (Arterial side) 120, bubble sensor 114, flow sensor 115, blood filter 116, branch line 118, clamp 122, and blood oxygen concentration sensor 125. These components are connected by a flexible tube or the like, and the lumen of the tube forms a flow path for blood or priming liquid.

  The catheter (arterial side) 120 sends blood toward the body of the subject 130, and the catheter (venous side) 119 performs blood removal from the body of the subject 130.

  The centrifugal pump 112 is also called a centrifugal artificial heart, drives a rotating body provided inside, applies pressure to the blood, and circulates the blood in the circulation circuit. The drive motor 111 gives a rotational driving force to the rotating body of the centrifugal pump 112. However, the pump is not limited to the centrifugal pump, and a roller pump or the like may be used.

  The artificial lung 113 performs blood circulation and blood gas exchange (oxygen addition, carbon dioxide removal, etc.) (details will be described later). The gas blender 117 connects an oxygen cylinder and an air cylinder, and supplies the mixed gas to the artificial lung 113. The gas blender 117 has a structure capable of adjusting the amount of gas per unit time (hereinafter referred to as gas supply amount) supplied to the artificial lung 113 in accordance with a control signal from the controller 110. For this reason, the gas blender 117 in the embodiment has a drive system and a circuit for adjusting a valve opening rate (opening rate) of a bubble (not shown) in accordance with a signal from the controller 110. Although details will be described later, The valve opening rate of the valve in the gas blender 117 can be adjusted in five stages, and these are expressed as Vmin, V-, V0, V +, and Vmax. Vmin means a fully closed state, and is also a state before functioning as a circulation circuit. V0 indicates the valve opening rate when the blood oxygen concentration is in the normal range. V− is for lowering the supply amount by ΔV than V0, and is applied when the blood oxygen concentration exceeds the normal range. V + increases the supply amount by ΔV more than V0, and is applied when the blood oxygen concentration falls below the normal range. Vmax indicates a valve opening rate at the time of the flash process, and indicates a valve opening rate at which a gas supply sufficient to blow off the plasma fluid that has oozed onto the gas exchange membrane of the artificial lung 113 is supplied. Typically, the valve is in a fully open state, but it is not necessarily required to be fully open as long as the ability to blow off plasma fluid is obtained.

  The bubble sensor 114 detects bubbles contained in the priming liquid or blood flowing in the circulation circuit during the priming operation and the extracorporeal circulation operation by a predetermined detection method (ultrasonic wave, light, etc.). The blood filter 116 filters blood or removes bubbles in the blood. The flow sensor 115 includes, for example, a built-in ultrasonic transceiver, and detects the flow rate of the priming liquid or blood in the circulation circuit. The oxygen sensor 125 is located downstream of the oxygenator 113, and detects the oxygen concentration in the blood (more precisely, the oxygen saturation oxygen saturation SPO2).

  The clamp 122 is a member for closing the tube so as to forcibly stop blood feeding toward the body of the subject 130 during the extracorporeal circulation operation. Based on the output signal from the bubble sensor 114, the clamp 122 can automatically perform a closing operation in conjunction with it when it is determined that an abnormality that immediately stops blood feeding has occurred.

  The branch line 118 switches the flow path of the circulation circuit. Specifically, during an extracorporeal circulation operation in which the blood of the subject 130 is circulated extracorporeally, a circulation circuit passing through the body of the subject 130 is constructed as shown in FIG. Circulate blood. During the priming operation, as shown in 1b of FIG. 1, the circuit of the circulation circuit to the inside of the subject 130 by the branch line 118 is blocked by the branch line 118 (in other words, the circulation circuit passing through the outside of the subject 130 (in other words, the subject) A circulation circuit that does not pass through the body of the person 130 is constructed, and the circulation circuit is filled with the priming liquid (without passing through the body of the subject) to circulate the priming liquid. On the circulation circuit, one or a plurality of bubble discharge ports (not shown) for discharging bubbles are provided. By circulating a plurality of priming liquids in the circulation circuit, the bubbles in the circulation circuit are circulated. It will be discharged from the bubble discharge port.

  The controller 110 controls the extracorporeal circulation operation and the priming operation in the extracorporeal circulation device 100. In the controller 110, for example, the centrifugal motor 112 is driven by controlling the drive motor 111. Further, the bubble sensor 114 is controlled to acquire an output signal from the bubble sensor 114, or the flow rate sensor 115 is controlled to acquire a flow rate value. Further, in the extracorporeal circulation operation mode, the clamp 122 is closed when an abnormality that requires blood supply to be stopped is detected based on the output signal from the bubble sensor 114. Further, the controller 110 also performs a process of adjusting the gas supply amount to the gas blender 117 according to the oxygen concentration detected by the oxygen sensor 125.

  Next, the flow of processing when performing a cardiopulmonary assist operation (extracorporeal circulation operation, priming operation) using the extracorporeal circulation device 100 shown in FIGS. 1a and 1b will be briefly described.

  When the cardiopulmonary assist operation is started, the controller 110 controls the execution of the priming operation. During the priming operation, a circulation circuit that does not pass through the body of the subject 130 is constructed by the branch line 118 as shown in 1b of FIG. At this time, the priming liquid supply source 121 is connected to the branch line 118, and the priming liquid is supplied from the priming liquid supply source 121 into the circulation circuit. As a result, the circulation circuit is filled with the priming liquid.

  Then, the centrifugal pump 112 is driven under the control of the controller 110, and the priming liquid circulates a plurality of times in the circulation circuit. Bubbles in the circulation circuit are discharged from the bubble discharge port or the like with this circulation. Further, the bubble sensor 114 may detect the presence or absence of bubbles flowing in the circulation circuit during the priming operation.

  The user who confirms that the priming is completed stops the driving of the centrifugal pump, switches the branch line 118, and constructs a circulation circuit passing through the body of the subject 130 as shown in 1a of FIG. Thereafter, the user operates the controller 110 to set a target flow rate and inputs an instruction to start extracorporeal circulation. As a result, the controller 110 drives the pump 112 based on the set information, so that the blood of the subject 130 is circulated extracorporeally. Further, the controller 110 sets the gas supply amount V0 as an initial value in order to start the gas supply to the gas blender 117.

  When the extracorporeal circulation operation starts, blood that has been removed from the catheter (vein side) 119 enters the oxygenator 113 via the centrifugal pump 112. As described above, the oxygenator 113 performs gas exchange, that is, gas exchange processing such as oxygen addition and carbon dioxide removal according to the gas supplied from the gas blender 117, and supplies the blood after gas exchange downstream. Thereafter, the filtered blood is sent from the catheter (arterial side) 120 into the body of the subject 130 through the blood filter 116 and the like. The blood flow of the subject 130 from the catheter (vein side) 119 to the catheter (arterial side) 120 is continuously performed. In the extracorporeal circulation operation mode, processing according to signals from various sensors is performed. For example, when the bubble sensor 114 detects bubbles in the circulation circuit and it is necessary to stop blood supply, the clamp 122 is closed. Further, the controller 110 is controlled according to the oxygen concentration detected by the oxygen sensor 125 to adjust the gas exchange efficiency of the oxygenator 113 (details will be described later).

  The above is the description of the overall configuration of the extracorporeal circulation device 100 according to the present embodiment and an example of the flow of the cardiopulmonary assist operation. Note that the configuration of the extracorporeal circulation device 100 shown in FIGS. 1a and 1b is merely an example, and the configuration may be changed as appropriate.

<2. Functional configuration of controller>
Next, an example of a functional configuration of the controller 110 illustrated in 1a and 1b of FIG. 1 will be described with reference to FIG.

  The controller 110 includes, as its functional configuration, a control unit 201, an operation unit 202, a display unit 203, a timer unit 204, a storage unit (computer-readable recording medium) 205, an I / F unit 206, a communication unit, Unit 207.

  The control unit 201 performs control of the controller 110 and control of the circulation circuit, and is configured by a CPU (Central Processing Unit).

  The operation unit 202 is realized by various buttons, for example, and inputs an instruction from a medical worker. The display unit 203 is realized by, for example, a display such as a monitor (including an output unit that outputs an alarm sound), and displays various types of information (including a message) to the user. Note that a part or all of the operation unit 202 and the display unit 203 may be realized as a touch panel with an audio speaker, for example.

  The timer unit 204 measures various times. The storage unit 205 is realized by, for example, a ROM and a RAM, and a control program 210 for realizing an extracorporeal circulation operation mode for operating as a circulation device, and a detection for storing detection results detected by each sensor It has a data storage area 211. When the control program related to the continuous operation mode is executed, the control unit 201 executes the priming process described above, and subsequently inputs the target flow rate setting from the operation unit 202, and the I / F unit 206. Thus, the drive control of the pump 112 and the extracorporeal circulation process corresponding to the detection results of various sensors are executed.

  The communication unit 207 performs communication with the communication unit 220 attached to the medical staff. The communication between the communication unit 207 and the communication unit 220 may be short-range wireless communication such as Bluetooth (registered trademark) or wireless communication using a wireless LAN such as Wi-Fi.

  The above is an example of the functional configuration of the controller 110. Note that the functional configuration shown in FIG. 2 is merely an example, and a new configuration may be added, or unnecessary configuration may be omitted as appropriate.

  A feature of the present embodiment is a process for satisfactorily maintaining gas exchange of the artificial lung 113 during execution of the extracorporeal circulation operation mode after the priming process. Therefore, in the following, the extracorporeal circulation operation mode will be described focusing on this point.

<3. Outline of extracorporeal circulation operation mode based on output signal from oxygen sensor>
An important factor for processing in the extracorporeal circulation apparatus is to circulate blood at a target flow rate. However, the feature of the extracorporeal circulation device in the embodiment is that the processing capability of the oxygenator 113 is evaluated by the oxygen sensor 125, and the gas blender 117 is controlled to maintain the gas exchange efficiency of the oxygenator 113 in a good state. There is in point to do. Therefore, the following description will focus on that point.

  As described above, the artificial lung 113 has a property of ingesting oxygen and discharging carbon dioxide (carbon dioxide) when blood touches air, but coagulates when blood directly touches air. Therefore, generally a gas exchange membrane is interposed. FIG. 3 is a conceptual diagram of the artificial lung 113. The artificial lung 113 has a structure in which a portion through which blood flows and a portion through which gas supplied from the gas blender 117 flows are separated by a gas exchange membrane. By the action of the gas exchange membrane, oxygen contained in the gas supply path is taken into the blood and carbon dioxide in the blood is discharged to the gas supply path. Usually, in order to increase the efficiency of this gas exchange, a structure having a large number of the illustrated structures is formed.

  The controller 110 in the embodiment determines whether or not this gas exchange is normally performed based on the oxygen concentration detected by the oxygen sensor 125 located downstream of the oxygenator 113. Then, the controller 110 controls the gas blender 117 according to the oxygen concentration, thereby maintaining normal gas exchange of the artificial lung 113.

  Specifically, thresholds for determining that gas exchange is normally performed are defined as T1 and T2 (where T1 <T2), and the oxygen concentration detected by the oxygen sensor 125 is defined as D. And

  When T1 ≦ D ≦ T2, it is determined that the oxygenator 113 is normally performing gas exchange, and the controller 110 sets the gas supply amount of the gas blender 117 to V0. When D <T1, the oxygen concentration is below the lower limit of the normal range. Therefore, the controller 110 causes the gas blender 117 to set the gas supply amount to V +, which is larger by ΔV, in order to increase the gas exchange rate. On the other hand, when D> T2, the oxygen concentration exceeds the upper limit of the normal range. Therefore, the controller 110 causes the gas blender 117 to set the gas supply amount to V−, which is smaller by ΔV, in order to lower the gas exchange rate. In any case, when the oxygen concentration D falls within the normal range, the gas blender 117 is set to V0 again. The gas blender 117 drives a valve drive circuit (not shown) according to a signal from the controller, and adjusts the valve opening rate of the valve.

  The oxygen sensor 125 detects the oxygen concentration in the blood at intervals of about 50 ms. However, since the detection result includes a measurement error, it slightly fluctuates with respect to the time axis. In order to suppress this fluctuation, the controller 110 in the embodiment stores the detected oxygen concentration in the detection data storage area 211 in order to hold the latest ten oxygen concentrations obtained by the oxygen sensor 125, and the average value thereof. Is calculated as the current oxygen concentration D.

  As a result, even if the gas exchange rate of the oxygenator 113 fluctuates due to internal or external factors, it can be made to act within the normal range. If the circulation circuit is used for a patient's surgery and the period of use thereof is relatively short, the above processing is sufficient.

  However, as gas exchange by the artificial lung 113 is continued, droplets of plasma fluid are gradually formed on the gas exchange membrane as shown in FIG. As the gas exchange membrane is covered with plasma fluid, the gas exchange rate naturally decreases. As the gas exchange rate decreases, the blood oxygen concentration decreases as a result, and the controller 110 continues to output a signal for increasing the gas supply amount to V + and supplying it to the gas blender 117. Even so, the blood oxygen concentration D cannot be reduced. This is because even if the gas supply amount is set to V +, there is no momentum to blow off the plasma. When such a state is reached, it is determined that flash processing should be performed. Therefore, in the embodiment, when the threshold value T0 lower than the lower limit threshold value T1 for determining the normal range is set, and the blood oxygen concentration D falls below the threshold value T0, the controller 110 determines that the flash process should be executed, The gas supply amount Vmax is set in order to inject the gas blender 117 with a gas sufficient to blow off the plasma fluid in the artificial lung 113.

  In the embodiment, even when the oxygen concentration D is equal to or higher than the threshold T0 and lower than the threshold T1, the flash process is performed even when the period is equal to or longer than a preset period. This is because it can be determined that a certain amount of plasma leak has occurred in the gas exchange membrane in the oxygenator 113 that the oxygen concentration D is continued from the threshold value T0 to less than T1.

  Since a normal manual flash operation period is about 3 minutes, in this embodiment, Vmax is continuously set for 3 minutes. In addition, the decrease in the gas exchange rate due to the plasma exchange on the gas exchange membrane is improved by the flush operation, and then the flush operation is performed after at least 3 hours have elapsed. Further, the flash operation means that a high gas pressure is applied to the oxygenator, and there is a concern that the oxygenator 113 is burdened and the product life is shortened. Furthermore, if a gas pressure higher than necessary is continuously applied, there is a high possibility that bubbles are generated in the blood, and the gas tank of the gas blender 117 is consumed quickly.

  Therefore, in this embodiment, the flash operation is not performed again until a predetermined time (3 hours) elapses from the previous flash process, as in manual operation. In other words, if the blood concentration D falls below the threshold T0 before the predetermined time has elapsed since the previous flush process was executed, the gas cylinder connected to or contained in the gas blender 117 is in a state of no remaining gas, Since an abnormal state such as gas leakage somewhere between the blender 117 and the artificial lung 113 is assumed, a warning alarm is generated in such a case. The warning alarm may be either a sound or a warning message display, or both.

<4. Flow of extracorporeal circulation operation mode processing>
Based on the above description, the processing contents of the extracorporeal circulation operation mode of the controller 110 in the extracorporeal circulation apparatus 100 according to the embodiment will be described according to the flowchart of FIG. This figure represents a part of the control program 210 of FIG. Hereinafter, in order to simplify the description, the processing based on the oxygen concentration detected by the oxygen sensor 125 will be described.

  When the priming process is finished and the extracorporeal circulation operation mode is started, the control unit 201 first causes the gas blender 117 to set the gas supply amount to “V0” in step S401. That is, in the state immediately before operating as a circulation circuit, the gas supply amount of the gas blender 117 is “Vmin”, and therefore, processing for setting it to “V0” is performed. As a result, the gas blender 117 starts supplying oxygen-containing gas to the oxygenator 113 with the set gas supply amount V0.

  Next, the control unit 201 proceeds to step S402 and determines whether or not there has been an operation on the operation unit 202 by the user. If it is determined that an instruction is input to the operation unit 202 by the user, the process proceeds to step S403, and processing according to the instruction is performed. The processing in step S403 includes an operation for stopping the warning alarm.

  If it is determined that there is no user operation, the process proceeds to step S404, and the blood oxygen concentration D by the oxygen sensor 125 is detected. As described above, this detection is performed at 50 ms intervals. Further, as described above, the latest average value of about 10 including the current detection value of the oxygen sensor 125 is obtained as the current oxygen concentration D.

  In step S405, it is determined whether the obtained oxygen concentration D exceeds the threshold value T2. If it is determined that the gas has been exceeded, it indicates that the gas exchange has been performed more than necessary, and therefore, the process proceeds to step S406 and the gas supply amount is set to “V−” for the gas blender 117.

  On the other hand, if it is determined that the oxygen concentration D is less than or equal to the threshold T2, it is determined in step S407 whether or not the oxygen concentration is below the threshold T1. If not, it indicates that the oxygen concentration D is within the target range, so the process proceeds to step S408, and the gas supply amount “V0” is set to the gas blender 117. When the gas supply amount set this time is the same as the previous supply amount, the setting for the gas blender 117 may not be performed. The same applies to the following description.

  On the other hand, if it is determined that the oxygen concentration D is lower than the threshold value T1, it can be determined that the gas exchange rate has decreased, so the process proceeds to step S409, and the gas supply amount “V +” is set for the gas blender 117. .

  In step S410, it is determined whether the oxygen concentration has fallen below the threshold value T0. If this determination is NO, the process proceeds to step S411, and it is determined whether or not the state of T0 <D <T1 has passed for a preset time. When no plasma leak occurs in the artificial lung 113, the oxygen concentration rises after an appropriate time when the gas supply amount is set to V +. Therefore, the determination in step S411 is No.

  The above is the processing in the case where no plasma leak occurs in the artificial lung 113 or the amount of generation is small.

  FIG. 5 shows an example of the transition of blood oxygen concentration D. As shown in the figure, the gas supply amount is set to “V0” when the blood oxygen concentration D is not less than the threshold value T1 and not more than T2, and when D exceeds the threshold value T2, the gas supply amount is set to “V−”. , D is below the threshold value T1, the gas supply amount is set to “V +”. As a result of the above processing, the blood oxygen concentration D on the downstream side of the artificial lung 113 can be shifted within the range even if it slightly deviates from the target threshold values T1 and T2. .

  Now, when an extracorporeal circuit is configured and operated for several hours, the gas exchange membrane of the artificial lung 113 begins to be covered with plasma droplets and the gas exchange rate decreases. In this case, even if the gas supply amount is “V +”, the oxygen concentration cannot be increased, and the oxygen concentration D is maintained at a low level or continues to decrease, and finally falls below the threshold value T0. In this embodiment, the situation is determined in steps S410 and S411.

  When the oxygen concentration D falls below the threshold value T0, in step S410, it is determined whether or not a predetermined time (3 hours in the embodiment) has elapsed since the previous flash process. When the operation as an extracorporeal circulation device is started, the operation start time is authorized as the time of the previous flash processing. If it is determined that a predetermined time has elapsed since the last flush process, the oxygen concentration D is considered to have fallen below the threshold T0 because the gas exchange membrane of the artificial lung 113 is covered with plasma fluid. Since it is also scheduled, a flash process is executed in step S414. In this step S414, it is the same as the manual flash operation, and the gas supply amount is continuously set to “Vmax” for about 3 minutes. A period Pf in FIG. 5 is a period during which the flash process is performed.

  On the other hand, if it is determined in step S413 that the period Pi (see FIG. 5) from the previous flush process to the detection of the oxygen concentration D below the current threshold T0 is less than the predetermined time, the circulation circuit In particular, it may be considered that there is some abnormality in the artificial lung 113 and its surroundings. Therefore, the process proceeds from step S413 to step S415, and a warning alarm is issued.

  Furthermore, if the state in which the oxygen concentration D is T0 <D <T1 continues for a preset time or longer, there is a strong suspicion of plasma leak, and thus the flash process is executed in step S412. .

  As described above, according to the extracorporeal circulation apparatus 100 according to the present embodiment, it is possible to monitor the oxygenator in the circulation apparatus and maintain it in a safe state without human intervention. In addition, even if the plasma fluid causes a decrease in the gas exchange rate due to covering the gas exchange membrane of the oxygenator, it becomes possible to automatically perform the flush process, and the oxygenator can be returned to a normal state. It becomes possible. Furthermore, according to the embodiment, when it is determined that the flash processing is performed, if the elapsed time from the previous flash processing is shorter than the scheduled time interval, it is determined that there is an abnormality and a warning alarm is generated. It is possible to prompt the user to check the circulation circuit, particularly around the oxygenator.

  In the above-described embodiment, the gas blender 117 has been described as being capable of five-stage control including the fully closed state of the bubble. However, a gas blender 117 that can be adjusted with a larger number of stages may be used. Therefore, the present invention is not limited.

[Other Embodiments]
In the said embodiment, it functions by the program which the control part 201 in the controller 110 which functions as a control apparatus of the extracorporeal circulation apparatus 100 performs. Therefore, it is clear that the present invention includes such a program as its category. In addition, since the program is normally stored in a computer-readable storage medium such as a CDROM or a memory card and can be executed by installing it in the system, such a storage medium is also within the scope of the present invention. It is also clear that there is.

  The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

Claims (6)

A circulation device that circulates the blood of a subject outside the body using a circulation circuit,
A detection means that is located downstream of the oxygenator installed on the circulation circuit, and detects oxygen concentration in blood that has undergone gas exchange in the oxygenator;
Determination means for determining whether the oxygen concentration in the blood detected by the detection means is within a preset target range, exceeds the target range, or falls below the target range;
A gas supply means for supplying a gas containing at least oxygen to the artificial lung, the supply amount per unit time being variable;
Control means for controlling the gas supply amount by the gas supply means according to the determination result of the determination means,
The determination means further determines whether or not the oxygen concentration detected by the detection means is below a threshold value smaller than a lower limit of the target range,
The control means includes
When an oxygen concentration lower than the threshold is detected, it is considered that the gas exchange membrane in the artificial lung is covered with plasma fluid, and a sufficient amount of gas is blown to the gas supply means to blow the plasma fluid. Execute the flash process to supply,
The circulation device, wherein the flush process is executed even when a state where the oxygen concentration is between the lower limit of the target range and the threshold value continues for a predetermined time or longer.   When the control means executes the flash process due to detection of an oxygen concentration below the threshold, the elapsed time since the previous flash process is less than a preset time 2. The circulating apparatus according to claim 1, further comprising means for issuing a warning error. An oxygenator, and a gas supply means for supplying a gas containing at least oxygen and having a variable supply amount per unit time to the oxygenator, and circulating the blood of the subject outside the body using a circulation circuit A method for controlling a circulation device,
Based on a signal from a detection means for detecting an oxygen concentration located downstream of the oxygenator installed on the circulation circuit, a detection step of detecting an oxygen concentration in blood that has undergone gas exchange in the oxygenator;
A determination step of determining whether the oxygen concentration in the blood detected in the detection step is within a preset target range, exceeds the target range, or falls below the target range;
A control step of controlling a gas supply amount by the gas supply means according to a determination result of the determination step,
In the determination step, it is further determined whether or not the oxygen concentration detected by the detection step is below a threshold value smaller than a lower limit of the target range,
In the control step,
When an oxygen concentration lower than the threshold is detected, it is considered that the gas exchange membrane in the artificial lung is covered with plasma fluid, and a sufficient amount of gas is blown to the gas supply means to blow the plasma fluid. Execute the flash process to supply,
The method for controlling a circulation device, wherein the flush process is executed even when a state where the oxygen concentration is between the lower limit of the target range and the threshold value continues for a predetermined time or longer.   When the control process executes the flash process due to the detection of an oxygen concentration below the threshold, the elapsed time since the last flash process is less than a preset time The method for controlling a circulating apparatus according to claim 3, further comprising a step of issuing a warning error.   The program which makes the computer in a circulation apparatus perform each step of the method of Claim 3.   A computer-readable recording medium storing the program according to claim 5.

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