JP2007260312A - Catheter for measuring cardiac output - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catheter for measuring cardiac output dispensing with a signal line in the catheter, being safe for a subject and calculating the cardiac output by Stewart-Hamilton method. <P>SOLUTION: This catheter for measuring the cardiac output is provided with a first lumen for storing an IC tag having a temperature sensor and a storage part, and a second lumen being communicated with a liquid outlet for measuring the cardiac output by thermal dilution, in the catheter body; and the IC tag measures the temperature for every prescribed time in response to a reading signal from the outside and transmits the value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a cardiac output measuring catheter for calculating cardiac output by the Stewart Hamilton method, which is used in a cardiac output measuring device used when a cardiac function test is performed.

Thermodilution is used to measure cardiac output for cardiac function tests. In order to use this thermodilution method, a cardiac output measurement catheter is usually inserted and placed by the right heart catheter method. In the right heart catheterization, as shown in FIG. 3, a cardiac output measuring catheter 1 is connected from the jugular vein, femoral vein, elbow vein, etc., and the superior vena cava or inferior vena cava, right atrium, right ventricle After that, it is placed so that its tip is located in the pulmonary artery trunk. The cardiac output measuring catheter 1 is provided with a discharge port 5 so as to be located in the right atrium and a temperature sensor 104a such as a thermistor as a thermosensitive element so as to be located in the pulmonary artery trunk.

In this case, the discharge port 5 is provided on the proximal end side with respect to the temperature sensor 104a, and a liquid having a temperature higher or lower than the blood temperature is injected from the discharge port 5. At this time, the temperature of the indicator liquid (indicator) is diffused and diluted in the right atrium and right ventricle. The diluted temperature is detected by the thermistor temperature sensor 104a located in the pulmonary artery trunk, and the cardiac output is calculated by the Stewart Hamilton method from the time change of the dilution curve temperature.

In such a cardiac output measuring catheter 1, a signal line must be provided in the catheter in order to obtain an electrical signal from the temperature sensor (thermistor) 104a, and this signal line causes noise and the like. (For example, Patent Document 1: Japanese Patent Publication No. 6-46984).
Japanese Patent Publication No. 6-46984

An object of the present invention is to provide a cardiac output measuring catheter for calculating cardiac output by the Stewart Hamilton method which is safer for a subject and does not require a signal line in the catheter. Objective.

In order to achieve the above object, a cardiac output measuring catheter according to the present invention includes a first lumen that houses an IC tag having a temperature sensor and a storage unit in a catheter body, and a thermodiluted cardiac output. A cardiac output measuring catheter having a second lumen that communicates with a liquid ejection port for measurement, wherein the IC tag measures the temperature every predetermined time according to a read signal from the outside; This value is transmitted. The cardiac output measuring catheter of the present invention includes a first lumen that houses an IC tag having a temperature sensor and a storage unit in the catheter body, and discharge of a liquid for measuring thermodilution cardiac output. A cardiac output measuring catheter having a second lumen communicating with the outlet, wherein the IC tag measures the temperature every predetermined time according to a read signal from the outside, and transmits the value A high X-ray contrast metal body is disposed in the vicinity of the distal end side of the discharge port of the second lumen and in the vicinity of the temperature sensor and / or the vicinity thereof, and the position of the discharge port and the temperature sensitive element during measurement It is characterized by being configured to be able to grasp the position of. Further, the cardiac output measuring catheter of the present invention is provided with an IC tag including a temperature sensor and a storage unit without providing a lumen in the catheter body, and is provided at a liquid discharge port for thermodilution cardiac output measurement. A cardiac output measuring catheter having a communicating lumen, wherein the IC tag measures temperature at a predetermined time in accordance with a read signal from the outside and transmits the value. To do. In addition, the cardiac output measuring catheter of the present invention is provided with an IC tag having a temperature sensor and a storage unit without providing a lumen in the catheter body, and is capable of discharging liquid for thermodilution cardiac output measurement. A cardiac output measuring catheter having a lumen communicating with an outlet, wherein the IC tag includes means for measuring a temperature every predetermined time in accordance with a read signal from the outside and transmitting the value; A high X-ray contrast metal body is arranged in the vicinity of the front end side of the discharge port of the lumen and the temperature sensor and / or the vicinity thereof, and the position of the discharge port and the position of the temperature sensing element are grasped at the time of measurement. It is characterized by having comprised so that it may obtain.

According to the cardiac output measuring catheter of the present invention, there is no need for a signal line from the temperature sensor, and the cardiac output can be safely measured by the patient with a simple configuration. Further, since the temperature sensor can be provided in the catheter body without providing a lumen, a thinner catheter can be obtained in order to inflate an equivalent balloon with the lumen having the same thickness. In addition, the lumen has the same wall thickness, and a smaller diameter catheter can be obtained for injecting the same indicator. Further, in the case of the same outer diameter, the number of lumens is reduced, so that thinning in the inner tube manufacturing process can be avoided, and a stronger catheter can be obtained.

Hereinafter, the cardiac output measuring catheter of the present invention will be described based on examples. FIG. 1 is a block diagram of an IC tag mounted in a cardiac output measuring catheter of the present invention.

<Configuration of IC tag>
In FIG. 1, reference numeral 101 denotes a RAM which is a computer-readable storage medium that stores a program that receives a signal from an IC tag reading unit (not shown) and operates the logic unit 110 in a predetermined flow. An EEPROM 102 stores an offset value, a temperature correction value, and the like corresponding to each temperature sensor 104. In addition, measured body temperature information, information on the subject P, and the like can be stored. The logic unit 110 may be a CPU that can control a more complicated processing flow.

As the temperature sensor 104, analog output is performed almost linearly with respect to temperature change, miniaturization and integration with an IC tag is possible, and the temperature resolution is 0.1 to 0.05 ° C between 32 to 42 ° C. A semiconductor type temperature sensor such as a C-MOS temperature sensor is preferably used, but a thermistor type or a thermopile (thermocouple) type is also possible. Reference numeral 103 denotes a transmission / reception circuit for acquiring temperature information of an IC tag (RFID) 100 having a temperature measurement unit provided in a cardiac output catheter described below, 103a is an antenna, and 104 is a power supply unit. The power supply unit 106 supplies power to each part of the IC tag 100 having the temperature measuring unit when the temperature information is read via the antenna unit 103a having a coil. Reference numeral 107 denotes an A / D converter, which performs A / D conversion on a temperature signal generated by the temperature sensor 106 and an oscillation circuit (not shown).

The IC tag 100 may be of any frequency as long as it can communicate (transmit / receive) with an electromagnetic wave having a frequency that can pass through a living body, but is preferably capable of transmitting with an electromagnetic wave of 13.56 MHz. Thus, temperature information can be obtained at a distance of 3 cm to 1 m, particularly 3 cm to 10 cm. It is possible to prevent the acquisition of wrong subject information, or to provide a security function by enabling encryption processing of a signal output from the antenna 103a.

<Configuration of catheter for measuring cardiac output>
Example 1
2A and 2B are an overall view and a cross-sectional view of one embodiment of a cardiac output measuring catheter according to the present invention. FIG. 2A is an overall external view, and FIG. 2B is an IC including a temperature sensor 104a. FIG. 5C is a longitudinal sectional view when the tag 100 is mounted on the cardiac output measuring catheter 1, and FIG. 5C is a sectional view taken along the line XX ′ in the circumferential direction of the catheter main body of the cardiac output measuring catheter. FIG. 3 is a diagram showing a cardiac output measuring catheter placed in the heart of a subject.

The cardiac output measuring catheter 1 has a plurality of (for example, four) lumens in the catheter body 2. More specifically, the distal end of the catheter body 2 has a pressure port 6 and a balloon 8 made of a flexible elastic body attached so as to cover the entire catheter tube several millimeters behind the distal end. Further, in order to diffuse and deflate the balloon 8, the catheter body 2 has a balloon side hole 7 provided on the side surface of the inner tube of the balloon and a second temperature sensor 104b provided at a position of 10 to 20 mm from the tip. Further, a predetermined distance, for example, a first temperature sensor 104a disposed at the base end of 10 to 15 mm, and a predetermined distance away from the first temperature sensor 104a and the second temperature sensor 104b (for example, 8.5). And a discharge port 5 provided at a predetermined distance from the tip, for example, 12 to 40 cm.

Since this is used for arteries, a first temperature sensor 104a and a second temperature sensor 104b are provided on the distal end side of the catheter, which is downstream of the discharge port 5 in the blood flow direction. However, in the case of using in veins, the first temperature sensor 104a and the second temperature sensor 104b are disposed on the proximal end side of the catheter, which is downstream of the discharge port 5 in the blood flow direction. Become. The pressure port 6, the balloon side hole 7, the first temperature sensor 104a, the second temperature sensor 104b, and the discharge port 5 communicate with four independent lumens, respectively. That is, the pressure port 6 is a lumen 26 for measuring pressure such as pulmonary artery pressure, the balloon side hole 7 is a balloon lumen 27, the first temperature sensor 104a, the second temperature sensor 104b is a temperature sensor lumen 24, and a discharge port. 5 communicates with an indicator liquid injection lumen 25 for injection. However, since the first temperature sensor 104a and the second temperature sensor 104b do not require a signal line, they are embedded in the tube (molded), the temperature sensor lumen 24 is not provided, and other lumens such as the balloon lumen 27 are provided. It may be provided inside.

In addition, the pressure measuring lumen 26, the indicator solution injection lumen 25, and the balloon lumen 27, which are circumferentially arranged at the rear end portion of the catheter body 2, are respectively connected to connectors 96, 95, and 97 via tubes. It is connected. The first temperature sensor 104a as a temperature sensitive element is for measuring the thermodilution cardiac output. A high X-ray contrast metal tip 3 is disposed on the distal end side of the discharge port 5 of the lumen 25 for injecting the indicator liquid. As a material of the metal chip 3, gold, silver, platinum, palladium, tungsten, or the like is preferable from the viewpoint of contrast and safety. The dimensions may be about 1.0 to 5.0 mm in the longitudinal direction of the catheter and about 0.2 to 1.2 mm ^{2 in the} catheter radial direction area.

<Calculation of cardiac output measurement>
The cardiac output measuring catheter according to the present embodiment is intermittent by bringing an IC tag reading unit (not shown) close to or in contact with the skin surface of the subject in order to acquire temperature information of the IC tag (RFID) 100. A read signal (preferably an electromagnetic wave of 13.56 MHz) is generated at intervals (preferably at intervals of several seconds), and the acquired temperature information is read. Based on the temperature information, the cardiac output is conventionally calculated by the Stewart Hamilton method. Is calculated. In addition, it becomes possible to obtain | require the cardiac output of a subject more correctly by arrange | positioning the temperature sensor 104 in the catheter main body 2 spaced apart by predetermined spacing 3 or more (plural).

(Example 2)
4A and 4B are an overall view and a sectional view of a cardiac output measuring catheter according to another embodiment of the present invention. FIG. 4A is an overall external view, and FIG. 4B is an IC including a temperature sensor 104a. FIG. 4C is a longitudinal sectional view when the tag 100 is mounted on the cardiac output measuring catheter 1, and FIG. 5C is a YY ′ sectional view in the circumferential direction of the catheter main body of the cardiac output measuring catheter. The description of the same configuration as in the first embodiment is omitted. The difference from the first embodiment is that the temperature sensor lumen is not provided and the temperature sensor 104a is embedded (molded) in the catheter body 2, and the indicator injection lumen 25, the pressure measurement lumen 26, and the balloon lumen 27 are three. The point is that the lumens are arranged in a circumferential shape. In this case, since the number of lumens is reduced in the case of the same outer diameter, it is possible to avoid thinning of the inner tube manufacturing process and to obtain a stronger catheter.

  As mentioned above, although demonstrated based on the Example, each lumen | rumen may be arrange | positioned concentrically and the arrangement | positioning by the combination of a circumference / concentric form may be sufficient, and it is not restricted to an Example.

It is a block diagram of the IC tag mounted in the catheter for cardiac output measurement of this invention. It is the whole figure and sectional drawing of the catheter for cardiac output measurement of the Example of this invention. It is a figure which shows the catheter for cardiac output measurement indwelled in the heart. It is the whole figure and sectional drawing of the catheter for cardiac output measurement of the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cardiac output measurement catheter, 2 ... Catheter main body, 24 ... Temperature sensor lumen, 25 ... Indicator solution injection lumen, 26 ... Pressure measurement lumen, 27 ... Balloon lumen, 3 ... Metal tip, 35 ... Adhesive, 104a, 104b ... Temperature sensor, 5 ... Discharge port, 6 ... Pressure port, 7 ... Side hole, 8 ...・ Balloon, 39 ... Marker

Claims (4)

A cardiac output having a first lumen for storing an IC tag having a temperature sensor and a storage unit, and a second lumen communicating with a liquid discharge port for thermodilution cardiac output measurement in the catheter body. A quantity measuring catheter,
The IC tag is a cardiac output measuring catheter characterized in that a temperature is measured every predetermined time according to a reading signal from the outside and the value is transmitted. A cardiac output having a first lumen for storing an IC tag having a temperature sensor and a storage unit, and a second lumen communicating with a liquid discharge port for thermodilution cardiac output measurement in the catheter body. A quantity measuring catheter,
The IC tag includes means for measuring the temperature every predetermined time according to an external read signal and transmitting the value.
A high X-ray contrast metal body is disposed in the vicinity of the distal end side of the discharge port of the second lumen and the temperature sensor and / or the vicinity thereof, and the position of the discharge port and the feeling during measurement are measured. A catheter for measuring cardiac output, characterized in that the position of the temperature element can be grasped. A catheter for measuring cardiac output without providing a lumen in the catheter body, having an IC tag equipped with a temperature sensor and a storage unit and having a lumen communicating with a liquid discharge port for thermodilution cardiac output measurement. And
The IC tag is a cardiac output measuring catheter characterized in that a temperature is measured every predetermined time according to a reading signal from the outside and the value is transmitted. A catheter for measuring cardiac output without providing a lumen in the catheter body, having an IC tag having a temperature sensor and a storage unit, and having a lumen communicating with a liquid discharge port for thermodilution cardiac output measurement There,
The IC tag includes means for measuring the temperature every predetermined time according to an external read signal and transmitting the value.
A high X-ray contrast metal body is arranged in the vicinity of the distal end side of the discharge port of the lumen and the temperature sensor and / or the vicinity thereof, and the position of the discharge port and the temperature sensitive element of the temperature sensing element are measured during measurement. A catheter for measuring cardiac output, characterized in that the position can be grasped.

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