KR101047547B1 - Method for Increasing Compatibility of Oxygen Saturation Measuring Sensor Using Light Output Characteristics - Google Patents
Method for Increasing Compatibility of Oxygen Saturation Measuring Sensor Using Light Output Characteristics Download PDFInfo
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- KR101047547B1 KR101047547B1 KR20080107074A KR20080107074A KR101047547B1 KR 101047547 B1 KR101047547 B1 KR 101047547B1 KR 20080107074 A KR20080107074 A KR 20080107074A KR 20080107074 A KR20080107074 A KR 20080107074A KR 101047547 B1 KR101047547 B1 KR 101047547B1
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Abstract
Description
The present invention relates to an oxygen saturation measuring device, and in particular, by detecting the frequency characteristics of the mounted oxygen saturation measuring sensor and correcting the oxygen saturation measuring algorithm according to the detection result to increase the compatibility of the oxygen saturation measuring sensors purchased from different companies. The present invention relates to a method for increasing the oxygen saturation measurement sensor compatibility.
Oxygen saturation measuring device is a device for measuring the saturation of oxygen hemoglobin contained in the artery by using the difference in the light absorption coefficient of oxygen hemoglobin and hemoglobin for two different wavelengths. In general, the oxygen saturation measuring device is composed of an oxygen saturation measuring sensor for detecting the oxygen saturation in the blood and an oxygen saturation measuring module for calculating the oxygen saturation. In particular, the oxygen saturation measuring sensor includes a light emitting element and a light receiving element, and the oxygen saturation measuring module includes an LED driver and a processor.
On the other hand, the oxygen saturation measuring sensor can not be used semi-permanently because it is a consumable, it must be replaced after a certain time. However, the replaceable coral saturation measurement sensor has a problem of having different light output characteristics depending on the manufacturer, resulting in an incorrect oxygen saturation measurement result. In addition, although the light output characteristics including frequency and light quantity are specified in the instructions for each company product, the light output characteristics of the actual product are different from the instructions, which makes it difficult to modify the oxygen saturation measurement algorithm.
The technical problem to be solved by the present invention is to provide a method for increasing the oxygen saturation measurement sensor compatibility that can increase the reliability of the measurement results even when the oxygen saturation measuring sensor having different optical output characteristics connected to the oxygen saturation measuring module. have.
Oxygen saturation measurement sensor compatibility increasing method according to an embodiment of the present invention for solving the technical problem,
Determining whether the measurement sensor is coupled to the measurement module, increasing the driving current applied to the light emitting device stepwise, storing the optical data input to the light receiving device stepwise, and measuring the data based on the stored optical data Analyzing the characteristics of the sensor, and modifying an oxygen saturation measurement algorithm based on the analysis result.
Preferably, the step of increasing the driving current comprises: stepwise increasing the first drive current applied to the first light emitting device, and stepwise increasing the second drive current applied to the second light emitting device. Characterized in that it comprises a step.
Preferably, the step of increasing the drive current is characterized in that the step is performed until the first drive current and the second drive current reaches a set value.
Preferably, the step of storing the optical data step by step, the step of storing the first optical data input from the first light emitting element, and the step of storing the second optical data input from the second light emitting element And storing the same.
Preferably, analyzing the characteristics of the light emitting device is characterized in that the step of analyzing the rate of change of the first optical data and the rate of change of the second optical data.
Preferably, analyzing the characteristics of the light emitting device is characterized in that the step of analyzing the difference between the rate of change of the first optical data and the rate of change of the second optical data.
Preferably, the analyzing of the characteristic of the light emitting device is characterized in that the first optical data for a specific first driving current and the second optical data for a specific second driving current.
Preferably, the analyzing of the characteristics of the light emitting device is characterized in that the step of analyzing the difference between the first optical data for a specific first driving current and the second optical data for a specific second driving current.
Oxygen saturation measuring apparatus according to an embodiment of the present invention for solving the technical problem,
An oxygen saturation measuring sensor including a light emitting element and a light receiving element, and an oxygen saturation measuring module including a microprocessor, wherein the microprocessor determines whether the measuring sensor and the measuring module are coupled, and the light emitting element Increasing the applied current applied to the step by step, storing the optical data input to the light-receiving device step by step, analyzing the characteristics of the light emitting device based on the stored optical data, measure the oxygen saturation based on the analysis result It is characterized by modifying the algorithm.
Oxygen saturation measurement sensor compatibility increase method according to the present invention, there is an effect that can be used to ensure the reliability of oxygen saturation measurement results while using the oxygen saturation measurement sensor manufactured by different manufacturers having different light output characteristics.
In order to fully understand the present invention, the operational advantages of the present invention, and the objects attained by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the drawings.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related well-known configuration or function may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.
1 is a block diagram showing a typical oxygen saturation measuring device.
Referring to FIG. 1, a general oxygen saturation measuring apparatus 100 includes an oxygen saturation measuring sensor 110 and an oxygen saturation measuring module 120. Hereinafter, these components will be described in detail.
The oxygen saturation measurement sensor 110 includes a first LED 112, a second LED 114, and a photodiode 116. The first LED 112 may be a light emitting device that outputs a red signal, and the second LED 114 may be a light emitting device that outputs a near infrared signal. Here, the red signal may be a signal having a wavelength of 640 to 690 nm, and the near infrared signal may be a signal having a wavelength of 860 to 900 nm. The photodiode 116 may be a light receiving device that receives an optical signal output from the first LED 112 and the second LED 11 and passing through the skin.
The oxygen saturation measurement module 120 includes an LED driver 122, a C-V converter 124, a microprocessor 126, a RAM 128, and a ROM 129. The LED driver 122 applies a driving current to the first LED 112 and the second LED 114, the CV converter 124 converts the current output from the photodiode 116 into a voltage, and the microprocessor ( 126 calculates the oxygen saturation degree according to the oxygen saturation calculation algorithm, RAM 128 stores the calculated oxygen saturation degree, and ROM 129 stores the oxygen saturation calculation algorithm.
On the other hand, unlike the oxygen saturation measurement module 120, since the oxygen saturation measurement sensor 110 is a part in direct contact with the skin of the patient, it is preferable to replace it after a certain time. However, since the light output characteristics of the oxygen saturation measurement sensor 110 are specialized in the oxygen saturation measurement module 120 manufactured by the same company, compatibility problems occur. That is, when the oxygen saturation measurement sensor 110 and the oxygen saturation measurement module 120 output from different companies are used at the same time, an error may occur in the oxygen saturation measurement result.
2 is a diagram comparing the characteristics of the red signal and the characteristics of the near infrared signal.
Referring to FIG. 2, the components of the red signal and the near infrared signal that pass through the skin are shown. Both the red and near-infrared signals that pass through the skin consist of DC and AC components. In particular, the DC component of the near infrared signal is larger than the DC component of the red signal, and the AC component of the near infrared signal is larger than the AC component of the red signal. Oxygen saturation is based on the difference in the reaction of oxygen hemoglobin and hemoglobin for red and near-infrared signals.
Where R is the ratio of the red signal to the near infrared signal, S R is the red signal, S IR is the near infrared signal, AC R is the AC component of the red signal, DC R is the DC component of the red signal, and AC IR is the AC of the near infrared signal. Component, DC IR is the DC component of the near infrared signal)
3 is a view showing the change in oxygen saturation according to the ratio of the signal.
Referring to FIG. 3, a change in oxygen saturation is shown according to a ratio of a red signal and a near infrared signal. That is, the oxygen saturation decreases as the size of the red signal is larger than the near infrared signal, and the oxygen saturation increases as the size of the red signal is smaller than the near infrared signal. On the other hand, oxygen saturation is a criterion for determining heart function and lung function, the normal person is close to 100 oxygen saturation. On the other hand, the relationship between the ratio of the red signal and the near infrared signal and the oxygen saturation is as follows.
Where SpO 2 is the oxygen saturation, A is the y-intercept, B is the slope, and R is the ratio of the signal.
4 is a graph showing the change of the light absorption coefficient according to the wavelength.
Referring to FIG. 4, the change in the light absorption coefficient of oxygen hemoglobin and hemoglobin with respect to wavelength is shown. That is, it can be seen that the light absorption coefficient of oxygen hemoglobin is larger than the light absorption coefficient of hemoglobin for a signal having a small wavelength, and the light absorption coefficient of oxygen hemoglobin is smaller than the light absorption coefficient of a hemoglobin for a signal having a large wavelength. In particular, it can be seen that the difference in the light absorption coefficients of oxygen hemoglobin and hemoglobin varies considerably even if the wavelength is slightly changed for the red signal having 640 to 690 nm.
5 is a table showing the wavelength of the oxygen saturation measurement sensor according to the manufacturer.
Referring to FIG. 5, the red signal wavelength and the near infrared signal wavelength of oxygen saturation measuring sensors produced by different manufacturers are shown. That is, the wavelengths of the near infrared signal and the red signal are different according to each manufacturer. However, as described above, since a difference in the light absorption coefficients of the oxygen hemoglobin and the hemoglobin occurs according to the wavelength of the signal, different manufacturers may show different calculation results for the same person. In particular, the difference in the wavelength of the red signal may show a greater difference in results.
6 is a detailed flowchart illustrating a method of increasing an oxygen saturation measurement sensor compatibility according to the present invention.
It is determined whether the oxygen saturation measuring sensor is mounted on the oxygen saturation measuring module (S605). That is, it is determined whether the previous oxygen saturation measuring sensor is removed and the new oxygen saturation measuring sensor is installed. When the new oxygen saturation measuring sensor is mounted, the current I 1 applied to the first light emitting device and the current I 2 applied to the second light emitting device are initialized (S610). The current initialization can be performed by a microprocessor in the oxygen saturation measurement module. The first light emitting device may be a red LED device, the second light emitting device may be a near infrared LED device, and the light receiving device may be a photodiode device.
The current I 1 applied to the first light emitting device is increased by a unit size (S615). The first light emitting device performs the light output of the red signal (S620). Photodetection of the red signal is performed through the light receiving element (625). The first photodetection data detected by the light receiving element is stored in the memory (S630). The current I 2 applied to the second light emitting device is increased by a unit size (S635). The second light emitting device performs optical output of the near infrared signal (S640). The light receiving device performs photodetection of the near infrared signal (S645). The second photodetection data detected by the light receiving element is stored in the memory (S650). Here, the unit size may be a unit of ㎂.
It is determined whether the current I 1 applied to the first light emitting device and the current I 2 applied to the second light emitting device have respectively reached the set values (S655). If the first current I 1 and the second current I 2 do not reach the set value, the first current I 1 is further increased by a unit size, and the steps 620 to 630 are repeated, and the second Steps 640 to 650 are repeated by further increasing the current I 2 by unit size. That is, the first current I 1 and the second current I 2 are continuously increased until the valid data necessary for analyzing the characteristics of the oxygen saturation measuring sensor are obtained.
If the first current I 1 and the second current I 2 reach the set values, respectively, the first photodetection data and the second photodetection data are analyzed (S660 and S665). That is, the change rate of the first photodetection data value according to the increase of the first current I 1 is analyzed (first analysis), and the change rate of the second photodetection data value according to the increase of the second current I 2 is determined. Analyze (second analysis). In addition, the difference between the rate of change of the first photodetection data value with the increase of the first current I 1 and the rate of change of the second photodetection data value with the increase of the second current I 2 is analyzed (third analysis). ). Further, the value of the first photodetection data for the first current I 1 having a specific magnitude is analyzed (fourth analysis), and the second photodetection data for the second current I 2 having the same magnitude is analyzed. The value is analyzed (fifth analysis). In addition, the difference between the value of the second photodetection data for the second current I 2 having the same magnitude as the value of the first photodetection data for the first current I 1 having a specific magnitude is analyzed. 6 analysis).
Based on the analysis result, the stored oxygen saturation calculation method is modified (S670). That is, the oxygen saturation measurement algorithm (Equations 1 and 2) is modified to be suitable for the oxygen saturation measurement sensor having a new light output characteristic. Modification of the oxygen saturation measurement algorithm may be comprehensively made based on the first to sixth analysis results. On the other hand, as described above, since the change in the wavelength of the red signal has the greatest influence on the oxygen saturation degree, the oxygen saturation measurement algorithm may be modified based on the first analysis and the fourth analysis. The microprocessor stores the modified oxygen saturation calculation method in a memory, and then calculates the oxygen saturation degree with reference to the modified oxygen saturation calculation method.
The best embodiment has been disclosed in the drawings and specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims.
Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.
1 is a block diagram showing a typical oxygen saturation measuring device.
2 is a diagram comparing the characteristics of the red signal and the characteristics of the near infrared signal.
3 is a view showing the change in oxygen saturation according to the ratio of the signal.
4 is a graph showing the change of the light absorption coefficient according to the wavelength.
5 is a table showing the wavelength of the oxygen saturation measurement sensor according to the manufacturer.
6 is a detailed flowchart illustrating a method of increasing an oxygen saturation measurement sensor compatibility according to the present invention.
Claims (9)
- Determining whether the measurement sensor and the measurement module are coupled;Incrementally increasing a driving current applied to the light emitting device;Step-wise storing optical data input to the light receiving element;Analyzing characteristics of the measurement sensor based on the stored optical data; AndModifying an oxygen saturation measurement algorithm based on the analysis result;Incrementally increasing the drive current,Incrementally increasing the first driving current applied to the first light emitting element until reaching a set value; AndIncrementally increasing a second driving current applied to the second light emitting element until reaching a set value,In step of storing the optical data,Step-wise storing first optical data input from the first light emitting element; AndStoring the second optical data inputted from the second light emitting element stepwise;Analyzing the characteristic of the measurement sensor,Analyzing the difference between the rate of change of the first optical data according to the increase of the first driving current and the rate of change of the second optical data according to the increase of the second driving current. Way.
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- Determining whether the measurement sensor and the measurement module are coupled;Incrementally increasing a driving current applied to the light emitting device;Step-wise storing optical data input to the light receiving element;Analyzing characteristics of the measurement sensor based on the stored optical data; AndModifying an oxygen saturation measurement algorithm based on the analysis result;Incrementally increasing the drive current,Incrementally increasing the first driving current applied to the first light emitting element until reaching a set value; AndIncrementally increasing a second driving current applied to the second light emitting element until reaching a set value,In step of storing the optical data,Step-wise storing first optical data input from the first light emitting element; AndStoring the second optical data inputted from the second light emitting element stepwise;Analyzing the characteristic of the measurement sensor,Analyzing the difference between the value of the first optical data for the specific first drive current and the value of the second optical data for the particular second drive current.
- An oxygen saturation measurement sensor including a light emitting element and a light receiving element; AndAn oxygen saturation measurement module including a microprocessor,The microprocessor,It is determined whether the measurement sensor and the measurement module are coupled, and gradually increasing the applied current applied to the light emitting device, and gradually storing the optical data input to the light receiving device, based on the stored optical data Analyze the characteristics of the light emitting device, modify the oxygen saturation measurement algorithm based on the analysis results,Stepwise increasing the applied current applied to the light emitting device,Gradually increasing the first driving current applied to the first light emitting device until reaching a set value, and gradually increasing the second driving current applied to the second light emitting device until reaching a set value,Step by step to store the optical data input to the light receiving element,Gradually storing first optical data input from the first light emitting device, and gradually storing second optical data input from the second light emitting device,Analyzing the characteristics of the light emitting device,And analyzing the difference between the rate of change of the first optical data according to the increase of the first driving current and the rate of change of the second optical data according to the increase of the second driving current.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10305026A (en) * | 1997-03-31 | 1998-11-17 | Ohmeda Inc | Oxygen concentration measuring sensor |
| KR20030054607A (en) * | 2001-12-26 | 2003-07-02 | 주식회사 멕 | Method for controlling quality of light for optical sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10305026A (en) * | 1997-03-31 | 1998-11-17 | Ohmeda Inc | Oxygen concentration measuring sensor |
| KR20030054607A (en) * | 2001-12-26 | 2003-07-02 | 주식회사 멕 | Method for controlling quality of light for optical sensor |
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