CN104888293B - Implantable axial-flow type blood pump temperature detection system and method based on fiber bragg gratings - Google Patents

Abstract

The invention provides an implantable axial flow blood pump temperature detection system and method based on fiber grating. The system includes: a blood pump, an optical fiber grating (8) pasted on the axial channel (7) of the blood pump, a motor controller (10) and a demodulator (14) respectively connected to the outlets of the optical fiber grating (8), And a computer (13) connected to the demodulator (14) through a data line. The steps of the method include: laying an optical fiber grating on a brushless motor stator, laying an implantable axial-flow artificial heart pump optical fiber grating, leading out an optical fiber to a human body and connecting it to a demodulator. The invention utilizes fiber grating to detect the temperature of the implantable axial flow blood pump. While realizing the temperature detection, the introduction of the sensor will not cause compatibility problems, so as to achieve intelligent detection and control, and reduce the power consumption and implantation of the blood pump. into the problem.

Description

Implantable axial flow blood pump temperature detection system and method based on fiber grating

technical field

The invention relates to temperature detection technology, in particular to an implantable axial flow blood pump temperature detection system and method based on fiber grating.

Background technique

In recent years, with the shortage of heart transplant donors and the rapid development of cardiac surgery, the assistance time of patients with heart failure has been gradually extended, and the patients have higher and higher requirements for quality of life. Therefore, various impeller pumps, especially implantable The axial flow blood pump is becoming more and more popular, but the blood pump will also have corresponding influence and changes on the blood pump and blood temperature during the working process.

In the working state of the blood pump, the biggest cause of temperature is the continuous work of the blood pump motor.

1. The heat emitted by the iron loss and copper loss caused by the permanent magnet brushless motor coil of the blood pump will be transferred to the blood in the flow channel of the blood pump through the intermediate medium on the inner wall of the blood pump, resulting in changes in the blood temperature;

2. When the impeller runs at high speed, the friction of the sliding bearing on the wheel shaft will also cause the temperature of the blood flowing through the blood pump to change;

3. The material and smoothness of the inner surface of the blood pump flow channel and the material and smoothness of the impeller and guide wheel of the blood pump, the temperature change caused by the friction under the blood convection form under the same viscosity.

Red blood cells are one of the most important cells for sustaining life. They have a variety of important physiological functions. In addition to carrying oxygen and transporting carbon dioxide, red blood cells can transport substances and transmit information. , Cellular immunity also depends on red blood cells. It can be seen that red blood cells play a very important role in maintaining homeostasis. As an important allosteric factor of hemoglobin and red blood cells, temperature can cause changes in the molecular structure, concentration, and function of hemoglobin, as well as the shape and structure of red blood cells. , Significant changes in functionality.

As mentioned above, blood pump blood temperature detection becomes more and more important. However, different types of existing temperature sensors have inconsistent characteristics. Thermocouple sensors have medium precision and slow response speed. RTD sensors have high precision but are expensive. Digital and analog output IC temperature sensors have slow response speed and are greatly affected by interference. At the same time, these sensors Both need to be powered on. Therefore, it is necessary to find an alternative sensor that can overcome the drawbacks of this temperature sensor.

Contents of the invention

The technical problem to be solved by the present invention is to provide an implantable axial-flow blood pump temperature detection system and method based on fiber gratings, so as to solve the above-mentioned defects in the prior art.

The present invention solves its technical problem and adopts the following technical solutions:

The fiber grating-based implantable axial flow blood pump temperature detection system provided by the present invention includes: a blood pump, a fiber grating pasted on the axial flow channel of the blood pump, a motor controller connected to the leading end of the fiber grating, A demodulator, and a computer connected to the demodulator through a data line; there are three fiber gratings, which are respectively pasted on the first fiber grating pasting point, the second fiber grating pasting point and the third optical fiber on the outer surface of the axial flow channel At the pasting points of the grating, they are respectively used to detect the front guide wheel, impeller and rear guide wheel of the blood pump.

The optical fiber grating and the electric cable of the blood pump are sealed with the same material and led out of the human body together.

The fiber grating-based implantable axial-flow blood pump temperature detection method provided by the present invention is realized by using the above-mentioned fiber-optic grating-based implantable axial-flow blood pump temperature detection system. The steps include:

Step 1: Lay Fiber Bragg Grating on Brushless Motor Stator

The stator coil of the brushless motor is wound on the cylindrical stator, and then the fiber grating is routed and drawn out along the slot on the stator;

Step 2: Laying of Fiber Bragg Gratings for Implantable Axial Artificial Heart Pump

Embedding Bragg gratings in an optical fiber, making full use of the compactness and precision of optical fiber gratings, connecting multiple gratings in series on one optical fiber to form an optical fiber grating sensing array, which are respectively arranged in the corresponding axial directions of the front guide wheel, impeller and rear guide wheel The outer surface of the flow channel is distributed in a straight line to avoid bending of the optical fiber and damage to the optical fiber;

Step 3: Fiber leads out to the human body to access the demodulator

The optical fiber laid on the outer surface of the blood pump axial flow channel and the cable of the permanent magnet brushless motor are led out of the human body together. The leading end of the cable is connected to the power supply and the motor controller, and the leading end of the optical fiber is connected to the demodulator. The demodulator converts the obtained optical signal corresponding to the wavelength and temperature into a corresponding electrical signal, and uses a computer to display the temperature change inside the blood pump in real time.

In the above step 1, a hole is drilled at a distance of 1 mm from the outer surface of the axial flow channel of the blood pump where the stator is close to, for the extraction of the optical fiber.

The diameter of the through hole is 1 mm.

Compared with the prior art, the present invention has the following main advantages:

The fiber grating sensor is adopted, the sensor head has simple structure, small size, combined with optical fiber, low loss, good spectral characteristics, high reliability, and has the characteristics of anti-corrosion and anti-electromagnetic interference. In addition, a fiber grating sensor can be written into multiple gratings to form a sensing array. Using the characteristics of fiber grating "one line, multiple points, distributed measurement", it can detect the temperature inside the implantable axial flow artificial heart pump in real time.

Using silica fiber at normal temperature, the temperature sensitivity of the fiber Bragg grating is 7.2×10 ^-6 /°C. For 1.3nm series gratings, the grating wavelength drift caused by unit temperature change is 1300×7.2×10 ^-6 = 0.0094nm/°C, ie 0.0094nm/°C. The sensitivity is high, and the detection error of temperature is small.

The present invention uses optical fiber gratings to detect the temperature of an implantable axial-flow artificial heart pump. While realizing temperature detection, it does not cause compatibility problems due to the introduction of sensors, so as to achieve intelligent detection and control, and the optical fiber and the brushless motor optical cable are unified. The encapsulation is led out of the human body with the cable packaging wire made of material compatible with the human body.

Description of drawings

Fig. 1 is a schematic structural diagram of an implantable axial flow blood pump temperature detection system based on a fiber grating.

Fig. 2 is a schematic diagram of fiber grating pasting distribution and optical fiber leading out of human body together with brushless motor wires.

In the figure: 1. blood pump inlet; 2. front guide wheel; 3. impeller; 4. permanent magnet brushless motor; 5. rear guide wheel; 6. blood pump outlet; 7. axial flow channel; 8. fiber grating; 9. First fiber grating sticking point; 10 motor controller; 11. Second fiber grating sticking point; 12. Third fiber grating sticking point; 13. Computer; 14. Demodulator; 15. Brushless motor cable.

specific implementation plan

The present invention provides an implantable axial flow blood pump temperature detection system and method based on fiber grating. Temperature detection and detection of blood pump working conditions are fed back to the user interface. Compared with the existing blood pump detection, fiber gratings are pasted on the outer surface of the blood pump flow channel, and fiber gratings are laid on the front guide wheel, rear guide wheel and impeller of the blood pump. The temperature sensor, through the demodulator, finally converts the data and displays it on the user interface. By consulting the data, it is found that blood pump detection at the present stage is a new research direction and a new application direction of fiber gratings.

The present invention will be further described below in conjunction with the embodiments and accompanying drawings, but the present invention is not limited.

Embodiment 1. Implantable axial flow blood pump temperature detection system based on fiber grating

The fiber grating-based implantable axial flow blood pump temperature detection system provided in this embodiment, as shown in Figure 1 and Figure 2, includes: a blood pump, a fiber grating 8 pasted on the axial flow channel 7 of the blood pump, and The output ends of the fiber grating 8 are respectively connected to a motor controller 10 , a demodulator 14 , and a computer 13 connected to the demodulator 14 through data lines.

The blood pump is an axial-flow artificial heart pump. The domestic research is mainly in the past 20 years, and it has a large gap with foreign countries. It is an existing technology. The casing of the flow channel 7, the front guide wheel 2, the impeller 3, and the rear guide wheel 5 arranged in the axial flow channel 7 from left to right, and the permanent magnet brushless motor 4 installed in the inner cavity.

There are multiple fiber gratings 8, which are sealed with the same material as the blood pump motor cable and lead out of the human body together. This embodiment provides three fiber gratings pasted on the outer surface of the axial flow channel 7, which are fiber gratings located at the first fiber grating pasting point 9, the second fiber grating pasting point 11 and the third fiber grating pasting point 12, They are respectively used to detect the front guide wheel 2, the impeller 3 and the rear guide wheel 5 of the blood pump, and are not limited to this sticking.

The motor controller 10 adopts an ordinary brushless motor controller, which is composed of an electronic commutator, a single-chip microcomputer main control circuit, a speed limiting circuit, a Hall signal detection circuit, an undervoltage detection circuit and a protection circuit, and is supplied by an external power supply without The brush motor controller performs smooth speed-limited control on the operation of the brushless motor.

The demodulator 14 adopts SM130 demodulator. SM130 is a high-power, high-speed, multi-sensor measurement system, which is mainly improved for mechanical sensing applications. Using MicronOptics patented technology to calibrate the wavelength scanning laser, SM130 has high power and fast scanning (up to 2KHz), it is a complete system with scanning light source, and can measure the light reflected by each fiber through 4 detectors at the same time Signal.

The computer 13 processes the corresponding relationship between wavelength and temperature obtained by the demodulator 14 with a temperature compensation algorithm, and then displays the temperature change inside the blood pump in real time.

The working process of the fiber grating-based implantable axial flow blood pump temperature detection system provided by the present invention is as follows: the working analysis of the invention is carried out by using the sensing principle of the fiber grating. When the human body is exercising or feeling unwell, the fiber grating detection system is used to detect the temperature of the blood pump with 2 front guide wheels, 3 impellers, and 5 rear guide wheels to estimate the blood temperature and the working condition of the blood pump. In fiber grating sensing, since the sensing quantity is coded to the wavelength, LED light sources with wide bandwidth, strong output power and stability are used to meet the needs of multi-point and multi-parameter measurement in distributed sensing systems, without power supply , after passing through the coupler, the broadband light incident on the fiber Bragg grating, using the effective refractive index of the fiber grating and the sensitivity of the grating period to the external parameters, converts the change of the blood pump temperature into the movement of its Bragg wavelength, so that after 14 demodulation The instrument measures the temperature of the blood pump by detecting the movement of the central wavelength reflected by the grating, and at the same time optimizes the data through the 13 data acquisition system to feed back to the display interface.

Embodiment 2. Implantable axial flow blood pump temperature detection method based on fiber grating

The method is realized by using the fiber grating-based implantable axial-flow artificial heart pump temperature detection system provided in Embodiment 1, and the steps include:

Step 1: Slot the brushless motor stator to facilitate the laying of fiber gratings

The stator coil of the brushless motor is wound on the cylindrical stator, and the wiring of a fiber grating needs to pass through the stator, and the stator needs to be slotted to lead out the optical fiber. Drill a hole 1 mm away from the outer surface of the flow path of the heart pump where the stator is close to, and the diameter of the hole is 1 mm.

Step 2: Laying of Fiber Bragg Gratings for Implantable Axial Artificial Heart Pump

The laying feature of the implantable axial-flow artificial heart pump fiber grating lies in the distribution measurement of one line and multiple points, that is, the laying condition of the fiber grating on the outer surface of the heart pump.

The implantable axial-flow artificial heart pump fiber grating is laid by embedding the Bragg grating into an optical fiber, making full use of the compactness and precision of the fiber grating, and multiple gratings can be connected in series on one optical fiber, as shown in Figure 2 As shown, the fiber grating sensing array made in series in one optical fiber is respectively arranged on the outer surface of the blood pump flow channel corresponding to the front guide wheel 2, the impeller 3 and the rear guide wheel 8, and is distributed in a straight line to avoid bending of the optical fiber. damage to the optical fiber.

Step 3: Fiber leads out to the human body to access the demodulator

Lead the optical fiber out of the human body together with the permanent magnet brushless motor 4 cable in the blood pump body, without additional treatment and increase the trauma area, the cable is connected to the power supply and the motor controller, and then the optical fiber is connected to the demodulator 14, through the demodulation The instrument 14 converts the obtained optical signal corresponding to the wavelength and temperature into a corresponding electrical signal, and uses the computer 13 to display the temperature change inside the blood pump in real time.

Claims (5)

1. An implantable axial flow blood pump temperature detection system based on a fiber grating, characterized in that it includes: a blood pump, a fiber grating (8) pasted on the blood pump axial flow channel (7), and a fiber grating (8) The motor controller (10), the demodulator (14) connected to the lead end, and the computer (13) connected to the demodulator (14) through the data line; the optical fiber grating (8) has 3, respectively pasted At the first fiber grating sticking point (9), the second fiber grating sticking point (11) and the third fiber grating sticking point (12) on the outer surface of the axial flow channel (7), they are respectively used for the blood pump The front guide wheel (2), the impeller (3) and the rear guide wheel (5) are tested. 2. The implantable axial-flow blood pump temperature detection system according to claim 1, characterized in that the optical fiber grating (8) is sealed with the same material as the cable of the motor of the blood pump and led out of the human body together. 3. The temperature detection method of an implantable axial flow blood pump based on fiber grating, which is characterized in that it is realized by utilizing the temperature detection system of an implantable axial flow blood pump according to claim 1 or 2, and its steps include: Step 1: Lay Fiber Bragg Grating on Brushless Motor Stator The stator coil of the brushless motor is wound on the cylindrical stator, and then the fiber grating is routed and drawn out along the slot on the stator; Step 2: Laying of Fiber Bragg Gratings for Implantable Axial Artificial Heart Pump Embedding Bragg gratings in an optical fiber, making full use of the compactness and precision of optical fiber gratings, connecting multiple gratings in series on one optical fiber to form an optical fiber grating sensing array, which are respectively arranged in the front guide wheel (2), impeller (3) and rear guide wheel The outer surface of the axial channel (7) corresponding to the wheel (8) is distributed in a straight line to avoid bending and damage to the optical fiber; Step 3: Fiber leads out to the human body to access the demodulator Lead the optical fiber laid on the outer surface of the blood pump axial channel (7) and the cable of the permanent magnet brushless motor (4) out of the human body, wherein the leading end of the cable is connected to the power supply and the motor controller, and the leading end of the optical fiber is connected to Enter the demodulator (14), through the demodulator (14), the optical signal of the corresponding relationship between the wavelength and temperature obtained is converted into a corresponding electrical signal, and the computer (13) is used to display the temperature change inside the blood pump in real time. 4. The temperature detection method of an implantable axial flow blood pump based on fiber gratings according to claim 3, characterized in that in step 1, the distance between the stator and the outer surface of the axial flow channel (7) of the blood pump is 1 mm Drill through holes for the fiber optic lead out. 5. The temperature detection method of an implantable axial flow blood pump based on fiber gratings according to claim 4, characterized in that the diameter of the through hole is 1mm.