JP2017217296A - Cardiac output measuring apparatus, cardiac output measuring method, and cardiac output measuring program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for easily measuring the output of the heart of a patient during cardiopulmonary bypass surgery.SOLUTION: A cardiac output measuring apparatus according to one aspect of the present invention calculates the value of a cardiac output of a patient by: obtaining the value of a carbon dioxide discharge quantity of the lungs of the patient measured from exhaled air of the patient attached with an artificial heart lung apparatus comprising an artificial lung and a blood pump, the value of carbon dioxide discharge quantity of the artificial lung measured from gas discharged from a gas outlet of the artificial lung, and the value of output of the blood pump; and then substituting the obtained value of the carbon dioxide discharge quantity of the artificial lung, the obtained value of the carbon dioxide discharge quantity of the lungs of the patient, and the obtained value of the output of the blood pump into a relational expression which assumes that the ratio of the carbon dioxide discharge quantity of the artificial lung to the carbon dioxide discharge quantity of the lungs of the patient is equal to the ratio of the output of the blood pump to the cardiac output of the patient.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a cardiac output measuring device, a cardiac output measuring method, and a cardiac output measuring program.

  When it is necessary to artificially circulate a patient's blood, such as when performing cardiac surgery, an artificial heart-lung machine is used. A heart-lung machine has a blood pump (artificial heart) that performs the function of the heart and an oxygenator that performs the function of the lung, circulates blood throughout the body by extracorporeal circulation, and gas exchange of the circulated blood ( That is, it is an apparatus that performs discharge of carbon dioxide and provision of oxygen. For example, Patent Document 1 proposes an artificial cardiopulmonary device that can be used for percutaneous cardiopulmonary support (PCPS).

JP2015-205056 A

Conventionally, during the cardiopulmonary surgery, it has been difficult to monitor or measure the amount of stroke from the heart of the patient (that is, the amount of blood discharged from the heart: cardiac output). Therefore, there was no clear management standard and withdrawal index for the oxygenator during the operation, and it was only enough to refer to the mixed venous oxygen saturation (SvO ₂ ). Therefore, the actual situation is that each medical facility relies on experience.

  In one aspect, the present invention has been made in consideration of such points, and an object of the present invention is to provide a technique for easily measuring the amount of stroke from a patient's heart during cardiopulmonary surgery.

  The present invention employs the following configuration in order to solve the above-described problems.

  That is, the cardiac output measuring device according to an aspect of the present invention is a value of the carbon dioxide emission of the patient's lung measured from the exhaled breath of the patient wearing the oxygenator including the oxygenator and the blood pump, An information acquisition unit that acquires the value of carbon dioxide emission of the oxygenator measured from the gas discharged from the gas outlet of the oxygenator and the value of the stroke volume of the blood pump, and is discharged from the oxygenator The relational expression that the ratio of the carbon dioxide output and the carbon dioxide output discharged from the patient's lungs is equal to the ratio of the blood pump output and the patient's heart output is obtained in the relational expression By substituting the value of carbon dioxide output of the artificial lung, the value of carbon dioxide output of the patient's lung, and the value of the stroke volume of the blood pump, the value of the cardiac output of the patient is calculated. A stroke volume calculating unit.

  In the above configuration, the ratio of the amount of carbon dioxide discharged from the patient's lung to the amount of carbon dioxide discharged from the artificial lung is determined by the stroke volume from the patient's heart and the blood pump (ie, artificial heart). Using the same ratio to the stroke volume, the stroke volume from the patient's heart is measured. Here, the carbon dioxide emission of the patient's lungs can be easily measured by using, for example, a known respiratory monitor. Similarly, the carbon dioxide emission from the artificial lung can be easily measured by using, for example, a known carbon dioxide concentration meter. Moreover, since the stroke volume of a blood pump is prescribed | regulated by the operation setting of a blood pump, it is a known value. Therefore, other values excluding the stroke volume from the patient's heart can be easily obtained. Therefore, according to the said structure, the amount of strokes from a patient's heart can be easily measured during a cardiopulmonary operation.

  Further, as another form of the cardiac output measuring device according to the above aspect, the cardiac output measuring device includes the calculated cardiac output together with the value of the blood pump output. You may further provide the display control part which displays a value on a display apparatus. According to this configuration, since the stroke volume from the patient's own heart is displayed together with the stroke volume of the blood pump, it is possible to easily check the pulsation state of the patient's heart compared to the operation of the heart-lung machine. Will be able to.

  As another form of the cardiac output measuring device according to each of the above embodiments, an information processing system, an information processing method, or a program that realizes each of the above configurations may be used. Alternatively, it may be a storage medium that can be read by a computer, a device, a machine or the like in which such a program is recorded. Here, the computer-readable recording medium is a medium that stores information such as programs by electrical, magnetic, optical, mechanical, or chemical action.

  For example, in the cardiac output measuring method according to one aspect of the present invention, the computer calculates the carbon dioxide emissions of the patient's lungs measured from the exhaled breath of the patient wearing a cardiopulmonary apparatus including an artificial lung and a blood pump. Obtaining a value, a value of the carbon dioxide emission of the oxygenator measured from the gas discharged from the gas outlet of the oxygenator, and a value of the stroke volume of the blood pump; The ratio of the amount of carbon dioxide discharged and the amount of carbon dioxide discharged from the patient's lung is obtained as a relational expression that is equal to the ratio of the volume of the blood pump and the volume of the heart of the patient. By substituting the value of carbon dioxide output of the artificial lung, the value of carbon dioxide output of the patient's lung, and the value of stroke volume of the blood pump, the value of the cardiac output of the patient is obtained. And a step for calculating It is a processing method.

  In addition, for example, the cardiac output measurement program according to one aspect of the present invention is a computer program for measuring carbon dioxide excretion in a lung of the patient measured from exhaled breath of a patient who is equipped with a heart-lung machine including an artificial lung and a blood pump. Obtaining the value of the amount, the value of carbon dioxide emission of the oxygenator measured from the gas discharged from the gas outlet of the oxygenator, and the value of the stroke volume of the blood pump; The relational expression that the ratio of the carbon dioxide excreted and the carbon dioxide excreted from the patient's lungs is equal to the ratio of the blood pump output and the patient's heart output is: By substituting the acquired value of the carbon dioxide output of the artificial lung, the value of the carbon dioxide output of the patient's lung, and the value of the stroke volume of the blood pump, the cardiac output of the patient Calculating a value; Is a program for executing.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which measures easily the amount of strokes from a patient's heart during cardiopulmonary surgery can be provided.

FIG. 1 schematically shows an example of a scene to which the present invention is applied. FIG. 2 illustrates an example of a hardware configuration of the cardiac output measuring device according to the embodiment. FIG. 3 illustrates an example of a functional configuration of the cardiac output measuring device according to the embodiment. FIG. 4 illustrates an example of a processing procedure of cardiac output measurement by the cardiac output measuring device according to the embodiment. FIG. 5 shows an example of a screen display according to the embodiment.

  Hereinafter, an embodiment according to an aspect of the present invention (hereinafter, also referred to as “this embodiment”) will be described with reference to the drawings. However, this embodiment described below is only an illustration of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. That is, in implementing the present invention, a specific configuration according to the embodiment may be adopted as appropriate. Although data appearing in the present embodiment is described in a natural language, more specifically, it is specified by a pseudo language, a command, a parameter, a machine language, or the like that can be recognized by a computer.

§1 Application scene First, the scene where the present invention is applied will be described with reference to FIG. FIG. 1 schematically illustrates an application scene of the cardiac output measuring device 1 according to the present embodiment. FIG. 1 illustrates a scene during cardiopulmonary surgery, where a patient has a blood pump 21 (which may be referred to as “artificial heart”) that performs the function of the heart and an oxygenator 22 that performs the function of the lung. And a cardiopulmonary apparatus 2 is mounted. The cardiac output measuring device 1 is an information processing device that measures the cardiac output of a patient during such an artificial cardiopulmonary operation (that is, the amount of blood discharged from the heart: cardiac output).

  Specifically, carbon dioxide has a diffusibility approximately 20 times that of oxygen and easily passes through the alveoli. Therefore, the carbon dioxide partial pressure in the alveoli is almost the same as the carbon dioxide partial pressure in arterial blood. In other words, with respect to the patient's carbon dioxide excretion during the cardiopulmonary surgery, the alveolar membrane or the artificial lung membrane is not almost a barrier, and the carbon dioxide excretion is determined by the amount of blood sent to the patient's lung or oxygenator. The Therefore, as shown in the following equation (1), the ratio of the carbon dioxide exhausted from the patient's lungs to the carbon dioxide exhausted from the artificial lungs is the amount of stroke from the patient's heart. It is the same as the ratio with the stroke volume from the blood pump.

なお、ＣＯａｈｌは血液ポンプの拍出量を示し、ＣＯｐｔは患者の心臓の拍出量を示し、ＶＣＯ₂ａｈｌは人工肺の二酸化炭素排出量を示し、ＶＣＯ₂ｐｔは患者の肺の二酸化炭素排出量を示す。上記数１の関係式は、本発明の「人工肺から排出される二酸化炭素排出量及び患者の肺から排出される二酸化炭素排出量の比が、血液ポンプの拍出量及び患者の心臓の拍出量の比に等しいとする関係式」に相当する。

COahl represents the stroke volume of the blood pump, COpt represents the stroke volume of the patient's heart, VCO ₂ ahl represents the carbon dioxide emissions of the artificial lung, and VCO ₂ pt represents the carbon dioxide emissions of the patient's lungs. Indicates the amount. The relational expression of the above formula 1 is that the ratio of the carbon dioxide exhausted from the oxygenator and the carbon dioxide exhausted from the patient's lung is the ratio of the blood pump output and the heart rate of the patient. This corresponds to a relational expression that is equal to the ratio of the amount of output.

  Therefore, the cardiac output measuring device 1 according to the present embodiment uses this relational expression to measure the cardiac output from the patient's heart. That is, the cardiac output measuring apparatus 1 according to the present embodiment is based on the value of carbon dioxide emission from the patient's lungs measured from the patient's breath, from the gas outlet of the artificial lung 22 (a gas outflow port 224 described later). The value of the carbon dioxide discharge amount of the artificial lung 22 and the value of the stroke amount of the blood pump 21 measured from the discharged gas are acquired. The cardiac output measuring device 1 then adds the obtained value of the carbon dioxide emission of the artificial lung 22, the value of the carbon dioxide emission of the patient's lung, and the blood pump 21 to the relational expression shown in the above equation 1. The value of the cardiac output of the patient is calculated by substituting the value of the cardiac output.

  The amount of carbon dioxide discharged from the lungs of the patient can be easily measured by using, for example, a known respiration monitor or the like (respiration monitor 3 in FIG. 1). Similarly, the carbon dioxide emission amount of the artificial lung 22 can be easily measured by using, for example, a known carbon dioxide concentration meter or the like (in FIG. 1, the carbon dioxide concentration meter 4). Moreover, since the stroke volume of the blood pump 21 is prescribed | regulated by the operation | movement setting of the said blood pump 21, it is a known value.

  Therefore, according to the present embodiment, it is possible to specify the cardiac output of the patient based on easily obtainable information. Therefore, if the cardiac output measuring device 1 according to the present embodiment is used, the cardiac output of the patient can be easily measured during the cardiopulmonary surgery. Further, by using the measured value of the cardiac output of the patient as an index, the timing of detachment of the heart-lung machine 2 can be determined and the stroke volume of the blood pump 21 can be adjusted without depending on experience. Can be done properly.

§2 Configuration example [Hardware configuration]
Next, an example of the hardware configuration of the cardiac output measuring device 1 will be described with reference to FIG. FIG. 2 schematically illustrates an example of a hardware configuration of the cardiac output measuring device 1 according to the present embodiment. As illustrated in FIG. 2, in the cardiac output measuring device 1 according to the present embodiment, the control unit 11, the storage unit 12, the external interface 13, the input device 14, the display device 15, and the drive 16 are electrically connected. It is a connected computer. However, in FIG. 2, the external interface is described as “external I / F”.

  The control unit 11 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and controls each component based on a program 8 or the like stored in the storage unit 12, A series of information processing is executed. The storage unit 12 includes a storage device such as a hard disk drive or a solid state drive, and stores a program 8 executed by the control unit 11 and the like.

  The external interface 13 is used to connect to external devices such as the heart-lung machine 2, the respiratory monitor 3, and the carbon dioxide concentration meter 4. The standard of the external interface 13 may be appropriately selected according to the external device to be connected. The input device 14 is, for example, a button, a mouse, a keyboard, or the like, and is used for inputting. The display device 15 is, for example, a general-purpose display, a number display that displays numbers, and the like, and is used to display information. The drive 16 is used for reading a program stored in the storage medium 9.

  The program 8 stored in the storage unit 12 is a program for causing the control unit 11 of the cardiac output measuring device 1 to control each component and executing each process related to the measurement of cardiac output to be described later. This program 8 corresponds to the “cardiac output measurement program” of the present invention. This program 8 may be stored in the storage medium 9.

  The storage medium 9 stores information such as a program by an electrical, magnetic, optical, mechanical, or chemical action so that information such as a program recorded by a computer or other device or machine can be read. It is a medium to do. In FIG. 2, as an example of the storage medium 9, a disk type storage medium such as a CD (Compact Disk) or a DVD (Digital Versatile Disk) is illustrated. However, the type of the storage medium 9 is not limited to the disk type and may be other than the disk type. Examples of the storage medium other than the disk type include a semiconductor memory such as a flash memory. Further, the type of the drive 16 may be appropriately selected according to the type of the storage medium 9.

  It should be noted that regarding the specific hardware configuration of the cardiac output measuring device 1, the components can be omitted, replaced, and added as appropriate according to the embodiment. For example, the control unit 11 may include a plurality of processors. The cardiac output measuring device 1 may be a general-purpose information processing device such as a personal computer in addition to an information processing device designed exclusively for the service to be provided. For example, the cardiac output measuring device 1 may be a computer (or console) connected to the oxygenator 2 or the respiratory monitor 3. In this case, the cardiac output measuring device 1 is appropriately configured to control the operation of the heart-lung machine 2 or the respiratory monitor 3. Furthermore, the cardiac output measuring device 1 may be configured by one or a plurality of information processing devices.

(Artificial cardiopulmonary device)
Next, an example of the hardware configuration of the heart-lung machine 2 will be described. As illustrated in FIG. 1, the heart-lung machine 2 has an extracorporeal circuit constituted by a blood removal line 23 and a blood delivery line 26, and between the blood removal line 23 and the blood delivery line 26. A blood pump 21 and an artificial lung 22 are arranged.

  The blood removal line 23 is composed of, for example, a flexible tube, and is connected to a blood removal vessel (catheter) inserted into the upper and lower vena cava. Thereby, the blood removal line 23 guides the blood returning from the whole body to the blood pump 21 arranged outside the body. Further, a blood flow sensor 24 is disposed in the blood removal line 23 so that an abnormality in blood flow in the extracorporeal circuit can be detected. An abnormal blood flow occurs, for example, due to twisting of a tube constituting the extracorporeal circuit, a decrease in the rotational speed of a centrifugal pump or a drive motor constituting the blood pump 21, or the like. The type of blood flow sensor 24 is not particularly limited as long as it is a sensor capable of measuring the flow rate of blood passing through the blood removal line 23, and may be appropriately selected according to the embodiment. For example, the blood flow sensor 24 may be a known blood flow sensor using ultrasonic waves.

  The blood pump 21 is appropriately configured to play the role of an artificial heart, and sends blood supplied from the blood removal line 23 so as to circulate through the patient's whole body via the artificial lung 22 and the blood supply line 26. For example, the blood pump 21 includes a centrifugal pump having a rotor that transfers blood by centrifugal force, a drive motor that drives the centrifugal pump, and a console that controls these operations. However, the type of blood pump 21 is not limited to such an example, and may be appropriately selected according to the embodiment. For example, the blood pump 21 may be configured with a roller pump.

  The artificial lung 22 is appropriately configured to play the role of a lung, and performs gas exchange of blood sent from the blood pump 21. In other words, the artificial lung 22 discharges carbon dioxide from the blood passing through the extracorporeal circuit and adds oxygen to the blood. The type of the artificial lung 22 is not particularly limited, and may be appropriately selected according to the embodiment. For example, the oxygenator 22 may be a bubble lung that directly mixes vesicular gas in blood, or a model lung that contacts blood and gas through a gas-permeable membrane. Good. When the artificial lung 22 is a model lung, for example, a film membrane or a hollow fiber membrane can be used as a gas permeable membrane.

  The oxygenator 22 includes a blood inflow port 221 and a blood outflow port 222 as blood flow entrances and exits. The blood inflow port 221 is an inlet for blood before gas exchange, and is connected to the blood pump 21 through, for example, a flexible tube. On the other hand, the blood outflow port 222 is an outlet for blood after gas exchange with the artificial lung 22 and is connected to the blood supply line 26. The blood sent from the blood pump 21 enters the artificial lung 22 through the blood inflow port 221, undergoes gas exchange in the artificial lung 22, and is supplied to the blood supply line 26 through the blood outflow port 222.

  The oxygenator 22 includes a gas inflow port 223 and a gas outflow port 224 as gas inlets and outlets. The gas inflow port 223 is an inlet for gas used for gas exchange, and is connected to the gas supply line 25. The gas supply line 25 is composed of, for example, a flexible tube, a tank filled with a gas containing oxygen, an oxygen blender for adjusting the oxygen concentration, and a console for controlling the flow rate of the gas supplied to the oxygenator 22. Etc. (not shown). Thereby, the sufficiently oxidized gas is supplied into the artificial lung 22 through the gas inflow port 223. On the other hand, the gas outflow port 224 is an outlet for the gas after the gas exchange, and corresponds to the “gas outlet for the artificial lung” of the present invention. The gas used for gas exchange in the oxygenator 22 is discharged out of the apparatus via the gas outflow port 224.

  As described above, the oxygenator 22 performs the gas exchange of the blood sent from the blood pump 21 with the gas supplied from the gas supply line 25, supplies the blood after the gas exchange to the blood supply line 26, and performs the gas exchange. It is configured to discharge the used gas to the outside. The configuration of the oxygenator 22 may not be limited to the above example, and may be appropriately selected according to the embodiment. For example, the oxygenator 22 can further include a heat exchanger for regulating body temperature in addition to the above.

  The blood supply line 26 is composed of, for example, a flexible tube, and is connected to a blood supply vessel (catheter) inserted into the aorta. As a result, the blood supply line 26 is pulsated by the blood pump 21 and sends the blood gas exchanged by the artificial lung 22 to the whole body. In addition, a pressure sensor 27 is disposed in the blood supply line 26 so that an abnormality in blood pressure can be detected. The abnormal blood pressure is caused by, for example, twisting of a tube constituting the extracorporeal circuit, clogging in the blood pump 21, that is, clogging in the oxygenator 22, or the like. The type of the pressure sensor 27 is not particularly limited as long as it is a sensor capable of measuring the pressure of blood passing through the blood supply line 26, and may be appropriately selected according to the embodiment.

  Note that the configuration of the heart-lung machine 2 is not limited to such an example, and may be appropriately selected according to the embodiment. For example, each console may be omitted, and each part may be controlled by the cardiac output measuring device 1. In addition, for example, the pressure sensor 27 may be omitted, or another pressure sensor may be added between the blood pump 21 and the artificial lung 22. For example, the blood flow sensor 24 may be disposed in the blood supply line 26. In addition, the type of the heart-lung machine 2 that can be used in the present embodiment may not be particularly limited, and may be either a type that bears a part of cardiac output required for the human body or a type that bears all. Good. As the artificial heart-lung machine 2 as described above, a known artificial heart-lung machine can be used. For example, Terumo Corporation Capiox (registered trademark) can be used as the oxygenator 2.

(Respiration monitor)
Next, an example of the hardware configuration of the respiratory monitor 3 will be described. As illustrated in FIG. 1, the respiration monitor 3 includes a flow sensor 31 that measures the flow rate of respiration, and a carbon dioxide concentration meter 32 that measures the concentration of carbon dioxide contained in respiration (may be referred to as a capnometer). And. Thus, the respiratory monitor 3 calculates the amount of carbon dioxide contained in the patient's exhalation, that is, the amount of carbon dioxide emitted from the patient's lungs, by the product of the flow rate of exhalation and the concentration of carbon dioxide contained in the exhaled breath. Measure.

  The flow sensor 31 is not particularly limited as long as it is a sensor that can measure the flow rate of gas discharged or inflowed by respiration, and may be appropriately selected according to the embodiment. The type of the flow sensor 31 may be, for example, a differential pressure type, a hot wire type (hot wire type), a Karman vortex type, or the like.

  The carbon dioxide concentration meter 32 is not particularly limited as long as it is a sensor capable of measuring the concentration (ratio) of carbon dioxide contained in the gas, and may be appropriately selected according to the embodiment. The type of the carbon dioxide concentration meter 32 may be, for example, a mass spectrometry type, a non-dispersive infrared type, or the like.

  Note that the configuration of the respiratory monitor 3 is not limited to such an example, and may be appropriately selected according to the embodiment. In addition, the type of the respiratory monitor 3 that can be used in the present embodiment may be appropriately selected according to the embodiment as long as the amount of carbon dioxide contained in the patient's breath can be measured. For example, Cpex-1 manufactured by Interliha, Aero Monitor AE-310S manufactured by Nihon Kohden Co., Ltd., or the like can be used as the respiratory monitor 3.

(CO2 concentration meter)
Next, the carbon dioxide concentration meter 4 that measures the concentration of carbon dioxide contained in the exhaust gas discharged from the gas outflow port 224 of the artificial lung 22 will be described. Similarly to the carbon dioxide concentration meter 32, the carbon dioxide concentration meter 4 is not particularly limited as long as it is a sensor that can measure the concentration of carbon dioxide contained in the exhaust gas discharged from the gas outflow port 224. Depending on the embodiment, it may be appropriately selected. The type of the carbon dioxide concentration meter 4 may be, for example, a non-dispersive infrared type. For example, TG-920 (TG-900 series) manufactured by Nihon Kohden Co., Ltd. can be used as the carbon dioxide concentration meter 4.

  As described above, the flow rate of the supply gas supplied from the gas supply line 25 is set by the setting value of the console that controls the flow rate of the supply gas. The flow rate of the exhaust gas discharged from the gas outflow port 224 is substantially the same as the flow rate of the supply gas supplied from the gas supply line 25. Therefore, if the concentration of carbon dioxide in the exhaust gas discharged from the gas outflow port 224 is measured, the product of the set value of the flow rate of the supply gas and the measured concentration of carbon dioxide results in the amount of carbon dioxide contained in the exhaust gas, That is, the amount of carbon dioxide discharged from the artificial lung 22 can be specified.

  However, the method for measuring the amount of carbon dioxide discharged from the oxygenator 22 may not be limited to such an example, and may be appropriately selected according to the embodiment. For example, when the set value of the flow rate of the supply gas is not used, a respiration monitor similar to the respiration monitor 3 may be used instead of the carbon dioxide concentration meter 4. Thereby, the amount of carbon dioxide discharged from the oxygenator 22 can be measured by the same method as that of the respiratory monitor 3.

[Function configuration]
Next, an example of a functional configuration of the cardiac output measuring device 1 will be described with reference to FIG. FIG. 3 schematically illustrates an example of a functional configuration of the cardiac output measuring device 1 according to the present embodiment. In the present embodiment, the control unit 11 of the cardiac output measuring device 1 expands the program 8 stored in the storage unit 12 in the RAM. And the control part 11 interprets and executes the program 8 expand | deployed by RAM by CPU, and controls each component. Accordingly, the cardiac output measuring device 1 functions as a computer including the information acquisition unit 111, the cardiac output calculation unit 112, and the display control unit 113.

  The information acquisition unit 111 measures the value of the carbon dioxide emission of the patient's lung measured from the breath of the patient wearing the oxygenator 2 and the gas measured from the gas discharged from the gas outflow port 224 of the artificial lung 22. The value of the carbon dioxide emission amount of the artificial lung 22 and the value of the stroke amount of the blood pump 21 are acquired. The stroke volume calculation unit 112 adds the obtained value of carbon dioxide emission of the artificial lung 22, the value of carbon dioxide emission of the patient's lung, and the stroke volume of the blood pump 21 to the relational expression shown in the above formula 1. The value of the cardiac output of the patient is calculated by substituting the value of. The display control unit 113 causes the display device 15 to display the calculated value of the cardiac output of the patient together with the value of the output of the blood pump 21.

  In the present embodiment, an example in which these functions are realized by a general-purpose CPU has been described. However, some or all of these functions may be realized by one or more dedicated processors. In addition, regarding the functional configuration of the cardiac output measuring device 1, functions may be omitted, replaced, and added as appropriate according to the embodiment. Each function will be described in detail in an operation example described later.

§3 Example of operation Next, an example of the operation of the cardiac output measuring device 1 will be described with reference to FIG. FIG. 4 illustrates a processing procedure related to cardiac output measurement of the cardiac output measuring device 1. The processing procedure relating to cardiac output measurement described below corresponds to the “cardiac output measuring method” of the present invention. However, the processing procedure related to cardiac output measurement described below is merely an example, and each processing may be changed as much as possible. Further, in the processing procedure described below, steps can be omitted, replaced, and added as appropriate according to the embodiment.

<Step S101>
First, in step S <b> 101, the control unit 11 functions as the information acquisition unit 111, the value of carbon dioxide emission in the patient's lungs measured from the exhalation of the patient wearing the cardiopulmonary apparatus 2, The value of the carbon dioxide discharge amount of the artificial lung 22 and the value of the stroke amount of the blood pump 21 measured from the gas discharged from the outflow port 224 are acquired. If each value is acquired, the control part 11 will advance a process to following step S102.

  In the present embodiment, the value of carbon dioxide emission from the lungs of the patient can be acquired from the respiratory monitor 3. Therefore, for example, the control unit 11 accesses the respiration monitor 3, acquires the value of the expiration flow from the flow sensor 31, and acquires the value of the carbon dioxide concentration contained in the expiration from the carbon dioxide concentration meter 32. Then, the control unit 11 integrates the product of the acquired exhalation flow rate value and the carbon dioxide concentration value over time, so that the value of the amount of carbon dioxide contained in the exhalation of the patient, that is, the carbon dioxide in the lungs of the patient. The value of carbon emissions can be obtained.

  Similarly, the value of the carbon dioxide emission amount of the artificial lung 22 can be specified from the carbon dioxide concentration of the exhaust gas discharged from the gas outflow port 224 measured by the carbon dioxide concentration meter 4. That is, for example, the control unit 11 accesses the carbon dioxide concentration meter 4 and acquires the value of the carbon dioxide concentration contained in the exhaust gas discharged from the gas outflow port 224 from the carbon dioxide concentration meter 4. Further, the control unit 11 acquires the value of the flow rate of the gas supplied through the gas supply line 25. The value of the flow rate of the gas supplied through the gas supply line 25 may be acquired from the console of the heart-lung machine 2 or may be given in advance as a set value. The control unit 11 integrates the product of the obtained carbon dioxide concentration value of the exhaust gas and the value of the gas flow rate over time, so that the value of the amount of carbon dioxide contained in the exhaust gas, that is, the carbon dioxide of the artificial lung 22 is integrated. The value of carbon emissions can be obtained.

  The value of the stroke volume of the blood pump 21 is a known value because it is defined by the operation setting of the blood pump 21. Therefore, the value of the stroke volume of the blood pump 21 may be acquired from the console of the heart-lung machine 2 or may be given in advance as a set value. Further, the control unit 11 may access the heart-lung machine 2 and acquire the measurement result of the blood flow sensor 24 as the value of the stroke volume of the blood pump 21.

  As described above, the control unit 11 can acquire the value of the carbon dioxide discharge amount of the patient's lung, the value of the carbon dioxide discharge amount of the artificial lung 22, and the value of the stroke amount of the blood pump 21. The unit of each value may be appropriately selected according to the embodiment. For example, the unit of carbon dioxide emission may be [ml / min (milliliter / min)], and the unit of stroke volume may be [l / min (liter / min) (may be expressed as LPM). It may be.

<Step S102>
In the next step S102, the control unit 11 functions as the stroke volume calculating unit 112, and the relational expression shown in the above equation 1 is added to the value of the carbon dioxide emission amount of the artificial lung 22 acquired in step S101, the patient's lungs. The value of the cardiac output of the patient is calculated by substituting the value of the amount of carbon dioxide emission and the value of the stroke volume of the blood pump 21. When calculating the cardiac output of the patient, the control unit 11 advances the processing to the next step S103.

For example, the value of carbon dioxide output (VCO ₂ ahl) of the artificial lung 22 acquired in step S101 is 50 [ml / min], and the value of carbon dioxide output (VCO ₂ pt) of the patient's lung is 150. It is assumed that [ml / min] and the value of the stroke volume (COahl) of the blood pump 21 is 1 [l / min]. In this case, the control unit 11 substitutes each value into the relational expression 1 and solves for the cardiac output (Copt) of the patient, so that the value of the cardiac output of the patient is 3 [l / min].

<Step S103>
In the next step S103, the control unit 11 functions as the display control unit 113, and calculates the value of the cardiac output of the patient calculated in step S102 together with the value of the blood pump 21 obtained in step S101. It is displayed on the display device 15.

  For example, as illustrated in FIG. 5, each value may be displayed. FIG. 5 shows an example of the screen display of the display device 15. In the example of FIG. 5, the display device 15 is a general-purpose display, and includes a region 151 that displays the value of the stroke volume of the blood pump 21 and a region 152 that displays the value of the cardiac output of the patient. Each region (151 and 152) is arranged adjacent in the vertical direction so that both values can be confirmed at a glance. The control unit 11 displays the value of the stroke volume of the blood pump 21 acquired in step S101 in the area 151, and displays the value of the cardiac output of the patient calculated in step S102 in the area 152. 15 is controlled.

  Note that the screen display of the display device 15 is not limited to such an example, and may be appropriately selected according to the embodiment. For example, when the display device 15 is configured by a numerical display, the display device 15 may have two numerical display portions. In this case, it is preferable that the two numeric display portions are arranged adjacent to each other so that both values can be confirmed at a glance. The control unit 11 controls the display device 15 so that the value of the stroke volume of the blood pump 21 is displayed on one numeric display portion, and the value of the stroke volume of the patient's heart is displayed on the other numeric display portion. .

  When the display of each value is completed, the control unit 11 ends the processing according to this operation example. After completing the process according to this operation example, the control unit 11 may repeat the process from step S101. The control unit 11 may stand by until an operation using the input device 14 is performed. And the control part 11 may start a process from step S101 according to the operation which instruct | indicates the measurement of the amount of strokes of a patient's heart being performed via the input device 14. FIG.

[Action / Effect]
As described above, the cardiac output measuring device 1 according to the present embodiment can calculate the cardiac output of a patient based on easily obtainable information by the processes in steps S101 to S102. . Therefore, according to the cardiac output measuring device 1 according to the present embodiment, the cardiac output of the patient can be easily measured during the cardiopulmonary surgery. Thus, by using the measured value of the cardiac output of the patient as an index, it is possible to determine the timing of withdrawal of the oxygenator 2 or to determine the output of the blood pump 21 without depending on experience. It will be possible to adjust properly. Also, when the timing of withdrawal of the heart-lung machine 2 is set, if the measured cardiac output of the patient is small, it is decided to cancel the heart-lung machine 2 and maintain the heart-lung machine 2 can do.

  Further, the cardiac output measuring device 1 according to the present embodiment displays the value of the cardiac output of the patient calculated in step S102 together with the value of the cardiac output of the blood pump 21 in step S103. To display. Therefore, since a user such as a doctor can check the stroke volume of the patient's heart together with the stroke volume of the blood pump 21, the pulsation state of the patient's heart can be easily compared with the operation of the heart-lung machine 2. Can grasp. In addition, the total amount of blood circulating around the patient's whole body can be grasped by the heart-lung machine 2 and the patient's own heart by the sum of both stroke volumes.

§4 Modifications Embodiments of the present invention have been described in detail above, but the above description is merely an illustration of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention.

  For example, in step S103, the control unit 11 omits the display of the value of the stroke volume of the blood pump 21 acquired in step S101, and displays only the value of the cardiac output of the patient calculated in step S102. May be displayed.

1 ... cardiac output measuring device,
11 ... Control unit, 12 ... Storage unit, 13 ... External interface,
14 ... input device, 15 ... display device, 16 ... drive,
111 ... Information acquisition unit, 112 ... Stroke amount calculation unit, 113 ... Display control unit,
2 ... Cardiopulmonary apparatus,
21 ... Blood pump,
22 ... Artificial lung, 221 ... Blood inflow port, 222 ... Blood outflow port,
223 ... Gas inflow port, 224 ... Gas outflow port,
23 ... Blood removal line, 24 ... Blood flow sensor,
25 ... Gas supply line, 26 ... Blood supply line, 27 ... Pressure sensor,
3 ... Respiration monitor,
31 ... Flow sensor, 32 ... Carbon dioxide concentration meter,
4 ... Carbon dioxide concentration meter,
8 ... Program, 9 ... Storage medium

Claims (4)

The value of the carbon dioxide emission of the patient's lung measured from the exhalation of the patient wearing the heart-lung machine including the oxygenator and blood pump, and the oxygenator measured from the gas discharged from the gas outlet of the oxygenator An information acquisition unit for acquiring the value of the carbon dioxide emission amount and the value of the stroke amount of the blood pump;
The ratio of the carbon dioxide exhausted from the artificial lung and the carbon dioxide exhausted from the patient's lung is equal to the ratio of the blood pump output and the patient's heart output. By substituting the acquired value of carbon dioxide output of the artificial lung, the value of carbon dioxide output of the patient's lungs, and the value of the stroke volume of the blood pump into the relational expression, A stroke volume calculation unit for calculating a value of the stroke volume;
Comprising
Cardiac output measuring device. In addition to the value of the stroke volume of the blood pump, a display control unit for causing the display device to display the calculated value of the cardiac output of the patient.
The cardiac output measuring device according to claim 1. Computer
The value of the carbon dioxide emission of the patient's lung measured from the exhalation of the patient wearing the heart-lung machine including the oxygenator and blood pump, and the oxygenator measured from the gas discharged from the gas outlet of the oxygenator Obtaining a value of carbon dioxide emissions and a value of stroke volume of the blood pump;
The ratio of the carbon dioxide exhausted from the artificial lung and the carbon dioxide exhausted from the patient's lung is equal to the ratio of the blood pump output and the patient's heart output. By substituting the acquired value of carbon dioxide output of the artificial lung, the value of carbon dioxide output of the patient's lungs, and the value of the stroke volume of the blood pump into the relational expression, Calculating a value for the stroke volume;
Perform cardiac output measurement method. On the computer,
The value of the carbon dioxide emission of the patient's lung measured from the exhalation of the patient wearing the heart-lung machine including the oxygenator and blood pump, and the oxygenator measured from the gas discharged from the gas outlet of the oxygenator Obtaining a value of carbon dioxide emissions and a value of stroke volume of the blood pump;
The ratio of the carbon dioxide exhausted from the artificial lung and the carbon dioxide exhausted from the patient's lung is equal to the ratio of the blood pump output and the patient's heart output. By substituting the acquired value of carbon dioxide output of the artificial lung, the value of carbon dioxide output of the patient's lungs, and the value of the stroke volume of the blood pump into the relational expression, Calculating a value for the stroke volume;
Cardiac output measurement program for running.

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