Apparatus and method for evaluating cerebral autoregulation ability

Abstract

An apparatus and method for evaluating cerebral autoregulation ability are disclosed. The apparatus for evaluating cerebral autoregulation ability according to one embodiment includes a data acquisition unit that acquires blood pressure data and oxygen saturation data of a patient during surgery, a correlation coefficient calculation unit that calculates a correlation coefficient between the acquired blood pressure data and the acquired oxygen saturation data, a filtering unit that filters the calculated correlation coefficient using a moving average filter having a predetermined time window, and a cerebral autoregulation ability evaluation unit that evaluates the cerebral autoregulation ability of the patient during the surgery based on the filtered correlation coefficient.

Description

Technical Field

[0001] The present invention relates to a technique for evaluating cerebral autoregulation in real time during surgery.

Background Art

[0002] Cerebral autoregulation is a physiological mechanism that maintains a constant cerebral blood flow even when the cerebral perfusion pressure changes. As long as cerebral autoregulation is maintained normally, the brain can protect itself from excessive high blood flow and low blood flow regardless of the cerebral perfusion pressure. However, when cerebral autoregulation is impaired, it may lead to negative consequences in various neurological conditions such as traumatic brain injury, intracranial hemorrhage, and cerebral infarction.

[0003] One of the cerebrovascular diseases related to cerebral autoregulation is moyamoya disease. Moyamoya disease refers to a disease in which stenosis or occlusion occurs at the terminal part of the internal carotid artery in the skull, that is, at the beginning of the anterior cerebral artery and the middle cerebral artery, and abnormal blood vessels called moyamoya vessels are observed in the vicinity. The onset of cerebral infarction in patients with moyamoya disease is the main form of neurological damage closely related to the damaged cerebral autoregulation.

[0004] Therefore, in order to predict and prevent postoperative complications in patients with moyamoya disease, it is necessary to develop a technique for evaluating cerebral autoregulation in real time during surgery.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an apparatus and a method for evaluating cerebral autoregulation in real time during surgery.

Means for Solving the Problems

[0006] An apparatus for evaluating cerebral autoregulation ability according to one aspect may include a data acquisition unit that acquires blood pressure data and oxygen saturation data of a patient during surgery, a correlation coefficient calculation unit that calculates a correlation coefficient between the acquired blood pressure data and the acquired oxygen saturation data, a filtering unit that filters the calculated correlation coefficient using a moving average filter having a predetermined time window, and a cerebral autoregulation ability evaluation unit that evaluates the cerebral autoregulation ability of the patient during surgery based on the filtered correlation coefficient.

[0007] The predetermined time window may be 25 minutes or more and 30 minutes or less.

[0008] The correlation coefficient calculation unit can calculate the correlation coefficient between the blood pressure data and the oxygen saturation data at the first time at the second time interval.

[0009] The first time may be 5 minutes, and the second time may be 10 seconds.

[0010] If the absolute value of the filtered correlation coefficient is in a first interval less than a predetermined threshold value, the cerebral autoregulation ability evaluation unit evaluates the cerebral autoregulation ability of the patient during surgery as normal, and if the absolute value of the filtered correlation coefficient is in a second interval greater than or equal to the predetermined threshold value, the cerebral autoregulation ability evaluation unit can evaluate the cerebral autoregulation ability of the patient during surgery as abnormal.

[0011] The apparatus for evaluating cerebral autoregulation ability may further include an alarm unit that outputs an alarm based on the evaluation result of the cerebral autoregulation ability.

[0012] A method for evaluating cerebral autoregulation ability according to another aspect may include the steps of acquiring blood pressure data and oxygen saturation data of a patient during surgery, calculating a correlation coefficient between the acquired blood pressure data and the acquired oxygen saturation data, filtering the calculated correlation coefficient using a moving average filter having a predetermined time window, and evaluating the cerebral autoregulation ability of the patient during surgery based on the filtered correlation coefficient.

[0013] The predetermined time window may be 25 minutes or more and 30 minutes or less.

[0014] The step of calculating the correlation coefficient can calculate the correlation coefficient between the blood pressure data and the oxygen saturation data at the first time at a second time interval.

[0015] The first time may be 5 minutes, and the second time may be 10 seconds.

[0016] The step of evaluating the cerebral autoregulation ability may evaluate the cerebral autoregulation ability of the patient during the operation as normal if the absolute value of the filtered correlation coefficient is in a first interval less than a predetermined threshold, and evaluate the cerebral autoregulation ability of the patient during the operation as abnormal if the absolute value of the filtered correlation coefficient is in a second interval greater than or equal to the predetermined threshold.

[0017] The method for evaluating the cerebral autoregulation ability may further include a step of outputting an alarm based on the evaluation result of the cerebral autoregulation ability.

Advantages of the Invention

[0018] The cerebral autoregulation ability of a patient during surgery can be evaluated in real time during surgery. Thereby, side effects that may occur after surgery can be predicted in advance, and by assisting the judgment of medical staff to take appropriate measures during surgery, side effects that may occur after surgery can be prevented.

Brief Description of the Drawings

[0019]

Figure 1

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Best Mode for Carrying Out the Invention

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. When assigning reference numerals to the components of each drawing, it should be noted that for the same components, as much as possible, the same reference numerals are used even if they are shown on other drawings. Further, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0021] On the other hand, in each process, each process may be performed in an order different from the specified order unless the context clearly specifies a particular order. That is, each process may be performed in the same order as the specified order, may be performed substantially simultaneously, or may be performed in the reverse order.

[0022] The terms described below are terms defined in consideration of the functions in the present invention and may vary depending on the intention or convention of the user or operator. Therefore, the definition should be made based on the content throughout this specification.

[0023] Terms such as "first", "second", etc. are used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. Singular expressions include plural expressions unless the context clearly indicates a different meaning. Terms such as "comprising" or "having" indicate the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof in advance.

[0024] In addition, the classification of components in this specification is only a classification according to the main functions each component undertakes. That is, two or more components may be grouped into one component, or one component may be divided into two or more according to more refined functions. And each of the components may additionally perform part or all of the functions undertaken by other components in addition to the main function it undertakes, and part of the main function each component undertakes may be exclusively performed by other components. Each component may be implemented in hardware or software, or may be implemented in a combination of hardware and software.

[0025] FIG. 1 is a block diagram showing an apparatus for evaluating cerebral autoregulation ability according to an exemplary embodiment.

[0026] An apparatus 100 for evaluating cerebral autoregulation ability according to an exemplary embodiment is an apparatus that can evaluate a patient's cerebral autoregulation ability in real time during surgery based on the patient's blood pressure data and oxygen saturation data during surgery, and can be mounted on an electronic device or realized as a separate device. Here, the electronic device can include a cart-type device and a portable device, and the portable device can include, but is not limited to, a personal computer, a notebook computer, a tablet, etc.

[0027] Referring to FIG. 1, an apparatus 100 for evaluating cerebral autoregulation ability according to an exemplary embodiment may include a data acquisition unit 110, a correlation coefficient calculation unit 120, a filtering unit 130, and a cerebral autoregulation ability evaluation unit 140.

[0028] The data acquisition unit 110 can acquire blood pressure data and oxygen saturation data of a patient during surgery. Here, the blood pressure data and oxygen saturation data may be time-series data.

[0029] For example, the data acquisition unit 110 includes a blood pressure measurement device and an oxygen saturation measurement device, and by using the blood pressure measurement device and the oxygen saturation measurement device to measure the blood pressure and oxygen saturation of a patient during surgery, the blood pressure data and oxygen saturation data of the patient during surgery can be acquired. Here, the blood pressure measurement device may be a device that measures blood pressure using an invasive method, and the oxygen saturation measurement device may be a device that measures oxygen saturation using near-infrared spectroscopy, but these are only one embodiment and are not limited thereto.

[0030] As another example, the data acquisition unit 110 can acquire the blood pressure data and oxygen saturation data of a patient during surgery by receiving the blood pressure data and oxygen saturation data of the patient during surgery from an external device that measures and / or stores blood pressure and / or oxygen saturation. At this time, the data acquisition unit 110 can use wired or wireless communication technologies. Here, the wireless communication technologies can include Bluetooth (registered trademark) communication, BLE (Bluetooth Low Energy) communication, Near Field Communication (NFC), WLAN communication, Zigbee (registered trademark) communication, Infrared Data Association (IrDA) communication, Wi-Fi Direct (WFD) communication, ultra-wideband (UWB) communication, Ant+ communication, Wi-Fi communication, Radio Frequency Identification (RFID) communication, 3G communication, 4G communication, and 5G communication, etc., but are not limited thereto.

[0031] The correlation coefficient calculation unit 120 can calculate the correlation coefficient between the acquired blood pressure data and oxygen saturation data. At this time, the correlation coefficient may be a Pearson correlation coefficient, but is not limited thereto. The Pearson correlation coefficient is a numerical value that quantifies the linear correlation between two variables and takes a value between +1 and -1. Here, +1 can mean a perfect positive linear correlation, 0 can mean no linear correlation, and -1 can mean a perfect negative linear correlation.

[0032] For example, the correlation coefficient calculation unit 120 can calculate the correlation coefficient between the blood pressure data and oxygen saturation data at the first time at a second time interval. At this time, the first time may be 5 minutes, and the second time may be 10 seconds, but these are only one embodiment and are not limited thereto.

[0033] The correlation coefficient between the blood pressure data and oxygen saturation data can be referred to as the cerebral oxygenation measurement index (COx).

[0034] The filtering unit 130 can filter the correlation coefficient calculated by the correlation relationship calculation unit 120 using a moving average filter having a predetermined time window. At this time, the predetermined time window may be a value experimentally derived so that the cerebral autoregulation ability of the patient during surgery can be evaluated in real time during surgery. For example, the predetermined time window may be 25 minutes or more, preferably 25 minutes or more and 30 minutes or less.

[0035] The cerebral autoregulation ability evaluation unit 140 can evaluate the cerebral autoregulation ability of the patient during surgery based on the correlation coefficient filtered by the moving average filter having a predetermined time window.

[0036] For example, the cerebral autoregulation ability evaluation unit 140 can evaluate that the cerebral autoregulation ability of the patient during surgery operates better as the absolute value of the correlation coefficient filtered by the moving average filter is smaller.

[0037] As another example, the cerebral autoregulation ability evaluation unit 140 divides the absolute value of the filtered correlation coefficient into a first interval less than a predetermined threshold and a second interval greater than or equal to the predetermined threshold. If the absolute value of the filtered correlation coefficient is in the first interval, the cerebral autoregulation ability of the patient during the operation is evaluated as normal. If the absolute value of the filtered correlation coefficient is in the second interval, the cerebral autoregulation ability of the patient during the operation can be evaluated as abnormal (damaged).

[0038] According to an exemplary embodiment, the cerebral autoregulation ability evaluation device 100 may further include a preprocessing unit 150 and / or an alarm unit 160.

[0039] The preprocessing unit 150 can preprocess the acquired blood pressure data and oxygen saturation data. For example, the preprocessing unit 150 can remove noise from the acquired blood pressure data and oxygen saturation data. At this time, the preprocessing unit 150 can utilize various publicly available noise removal techniques.

[0040] The alarm unit 160 can output an alarm based on the evaluation result of the cerebral autoregulation ability of the patient during the operation. For example, when the evaluation result of the cerebral autoregulation ability is determined to be abnormal and the abnormal state persists for a predetermined time, the alarm unit 160 can generate and output an alarm. As another example, when the evaluation result of the cerebral autoregulation ability and the cumulative duration of the abnormal state are equal to or greater than a predetermined time, the alarm unit 160 can generate and output an alarm.

[0041] FIG. 2 is a block diagram for exemplarily explaining a computing environment including a computing device suitable for use in an exemplary embodiment. In the illustrated embodiment, each component can have different functions and capabilities other than those described below and can include additional components other than those described below.

[0042] The illustrated computing environment 200 can include a computing device 210. In one embodiment, the computing device 210 may be an evaluation device 100 for cerebral autoregulation ability.

[0043] The computing device 210 can include at least one processor 211, a computer-readable storage medium 212, and a communication bus 213. The processor 211 can operate the computing device 210 according to the foregoing exemplary embodiments. For example, the processor 211 can execute one or more programs stored in the computer-readable storage medium 212. The one or more programs can include one or more computer-executable instructions. When the computer-executable instructions are executed by the processor 211, the computing device 210 can be configured to perform operations according to the exemplary embodiments.

[0044] The computer-readable storage medium 212 can be configured to store computer-executable instructions or program codes, program data, and / or other appropriate forms of information. The program 214 stored in the computer-readable storage medium 212 can include a set of instructions executable by the processor 211. In one embodiment, the computer-readable storage medium 212 may be a memory (such as a volatile memory like a random access memory, a non-volatile memory, or a suitable combination thereof), one or more magnetic disk storage devices, an optical disk storage device, a flash memory device, other forms of storage media that can be accessed by the other computing device 210 to store desired information, or a suitable combination thereof.

[0045] The communication bus 213 can interconnect various other components of the computing device 210.

[0046] Computing device 210 can also include one or more input / output interfaces 215 that provide an interface for one or more input / output devices 220, and one or more network communication interfaces 216. The input / output interface 215 and the network communication interface 216 can be connected to the communication bus 213. The input / output device 220 can be connected to other components of the computing device 210 via the input / output interface 215. Exemplary input / output devices 220 can include input devices such as a pointing device (such as a mouse or trackpad), a keyboard, a touch input device (such as a touchpad or touch screen), a voice or sound input device, various types of sensor devices and / or imaging devices, and / or output devices such as a display device, a printer, a speaker and / or a network card. Exemplary input / output devices 220 may be included within the computing device 210 as a component that constitutes the computing device 210, or may be connected to the computing device 210 as a separate device distinct from the computing device 210.

[0047] FIG. 3 is a flowchart showing a method for evaluating cerebral autoregulation ability according to an exemplary embodiment. The method for evaluating cerebral autoregulation ability in FIG. 3 can be executed by the evaluation device 100 for cerebral autoregulation ability in FIG. 1.

[0048] Referring to FIG. 3, the evaluation device for cerebral autoregulation ability can obtain blood pressure data and oxygen saturation data of a patient during surgery (310).

[0049] For example, the evaluation device for cerebral autoregulation ability includes a blood pressure measurement device and an oxygen saturation measurement device, and by using the blood pressure measurement device and the oxygen saturation measurement device to measure the blood pressure and oxygen saturation of a patient during surgery, the blood pressure data and oxygen saturation data of the patient during surgery can be obtained.

[0050] As another example, the cerebral autoregulation ability evaluation device can obtain the blood pressure data and oxygen saturation data of a patient during surgery by receiving the blood pressure data and oxygen saturation data of the patient during surgery from an external device that measures and / or stores blood pressure and / or oxygen saturation.

[0051] The cerebral autoregulation ability evaluation device can calculate the correlation coefficient between the acquired blood pressure data and oxygen saturation data (320). At this time, the correlation coefficient may be a Pearson correlation coefficient, but is not limited thereto.

[0052] For example, the cerebral autoregulation ability evaluation device can calculate the correlation coefficient between the blood pressure data and oxygen saturation data at the first time at a second time interval. At this time, the first time may be 5 minutes and the second time may be 10 seconds, but these are only one embodiment and are not limited thereto.

[0053] The cerebral autoregulation ability evaluation device can filter the correlation coefficient using a moving average filter having a predetermined time window (330). At this time, the predetermined time window can be experimentally derived so as to be able to evaluate the cerebral autoregulation ability of the patient during surgery in real time during surgery, and may be 25 minutes to 30 minutes.

[0054] The cerebral autoregulation ability evaluation device can evaluate the cerebral autoregulation ability of the patient during surgery based on the correlation coefficient filtered by the moving average filter having a predetermined time window (340).

[0055] For example, the cerebral autoregulation ability evaluation device can evaluate that the better the cerebral autoregulation ability of the patient during surgery operates, the smaller the absolute value of the correlation coefficient filtered by the moving average filter.

[0056] As another example, the cerebral autoregulation ability evaluation device divides the absolute value of the filtered correlation coefficient into a first interval less than a predetermined threshold and a second interval greater than or equal to the predetermined threshold. If the absolute value of the filtered correlation coefficient is in the first interval, the cerebral autoregulation ability of the patient during surgery is evaluated as normal. If the absolute value of the filtered correlation coefficient is in the second interval, the cerebral autoregulation ability of the patient during surgery can be evaluated as abnormal.

[0057] According to an exemplary embodiment, the cerebral autoregulation ability evaluation device can preprocess the acquired blood pressure data and oxygen saturation data (315). For example, the cerebral autoregulation ability evaluation device can use various noise removal techniques to remove noise from the blood pressure data and oxygen saturation data acquired in step 310.

[0058] According to an exemplary embodiment, the cerebral autoregulation ability evaluation device can output an alarm based on the evaluation result of the cerebral autoregulation ability of the patient during surgery (345). For example, when the evaluation result of the cerebral autoregulation ability is determined to be abnormal and the abnormal state persists for a predetermined time, the cerebral autoregulation ability evaluation device can generate and output an alarm. As another example, when the evaluation result of the cerebral autoregulation ability and the cumulative duration of the abnormal state are longer than a predetermined time, the cerebral autoregulation ability evaluation device can generate and output an alarm.

[0059] [Experimental Example] To evaluate the cerebral autoregulation ability, surgical signals of patients with moyamoya disease, a typical cerebrovascular disease, were collected. The patients were divided into two groups according to the occurrence of postoperative cerebral infarction, and an experiment was conducted to evaluate how the cerebral autoregulation ability differed between the two groups. Ten out of 68 surgical records were classified as the cerebral infarction occurrence group.

[0060] The average correlation coefficient between blood pressure and oxygen saturation collected during the entire operation time was at the 0.78 level in terms of the AUROC (area under the receiver operating characteristic curve) value, and the two groups were significantly classified. However, when the correlation coefficient was evaluated in real time, no significant difference was found between the two groups. Therefore, an attempt was made to find a difference between the groups by applying a moving average filter with different time windows.

[0061] As a result of evaluating how well the cerebral infarction occurrence group could be discriminated at what level while changing the time window of the moving average filter, the results shown in Fig. 4 were obtained.

[0062] Referring to Fig. 4, it can be seen that when the time window size of the moving average filter is 25 minutes, the AUROC for predicting cerebral infarction is about 0.75, and when the time window size is 30 minutes, the AUROC for predicting cerebral infarction is about 0.74. Also, when the time window size is between 30 minutes and 300 minutes, the AUROC for predicting cerebral infarction shows values between about 0.72 and about 0.82, and when the time window size is 300 minutes or more, it is maintained at about 0.77.

[0063] That is, it was confirmed that when the time window size of the moving average filter is 25 minutes or more, the cerebral infarction occurrence group after surgery can be discriminated at a relatively high level. Thereby, it was confirmed that when the time window size is set to 25 minutes or more, preferably 25 minutes or more and 30 minutes or less, the cerebral autoregulation ability during the operation can be evaluated in real time at a relatively high level.

[0064] As described above, the present invention has been described mainly with respect to its preferred embodiments. Those having ordinary knowledge in the technical field to which the present invention pertains will be able to understand that the present invention can be embodied in a modified form without departing from the essential characteristics of the present invention. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but must be analyzed to include various embodiments within the scope equivalent to the content described in the claims.

Claims

1. A data acquisition unit that acquires blood pressure data and oxygen saturation data of a patient during surgery; A correlation coefficient calculation unit that calculates a correlation coefficient between the acquired blood pressure data and the acquired oxygen saturation data; A filtering unit that filters the calculated correlation coefficient using a moving average filter having a predetermined time window; A cerebral autoregulation ability evaluation unit that evaluates the cerebral autoregulation ability of the patient during surgery based on the filtered correlation coefficient, An apparatus for evaluating cerebral autoregulation ability.

2. The predetermined time window is 25 minutes or more and 30 minutes or less, The apparatus for evaluating cerebral autoregulation ability according to Claim 1.

3. The correlation coefficient calculation unit calculates a correlation coefficient between blood pressure data and oxygen saturation data at a first time at a second time interval. The apparatus for evaluating cerebral autoregulation ability according to Claim 1.

4. The first time is 5 minutes and the second time is 10 seconds, The apparatus for evaluating cerebral autoregulation ability according to Claim 3.

5. The cerebral autoregulation ability evaluation unit evaluates that the cerebral autoregulation ability of the patient during surgery is normal if it is in a first interval where the absolute value of the filtered correlation coefficient is less than a predetermined threshold, and evaluates that the cerebral autoregulation ability of the patient during surgery is abnormal if it is in a second interval where the absolute value of the filtered correlation coefficient is greater than or equal to the predetermined threshold. The apparatus for evaluating cerebral autoregulation ability according to Claim 1.

6. Further includes an alarm unit that outputs an alarm based on the evaluation result of the cerebral autoregulation ability, The apparatus for evaluating cerebral autoregulation ability according to Claim 1.

7. A step of acquiring blood pressure data and oxygen saturation data of a patient during surgery; A step of calculating a correlation coefficient between the acquired blood pressure data and the acquired oxygen saturation data; A step of filtering the calculated correlation coefficient using a moving average filter having a predetermined time window; A step of evaluating the cerebral autoregulation ability of the patient during surgery based on the filtered correlation coefficient, A method for evaluating cerebral autoregulation ability.

8. The predetermined time window is 25 minutes or more and 30 minutes or less, The method for evaluating cerebral autoregulation ability according to Claim 7.

9. The step of calculating the correlation coefficient calculates a correlation coefficient between blood pressure data and oxygen saturation data at a first time at a second time interval. The method for evaluating cerebral autoregulation ability according to Claim 7.

10. The first time period is 5 minutes, and the second time period is 10 seconds. The method for evaluating cerebral autoregulation ability according to claim 9.

11. The step of evaluating the cerebral autoregulation ability is If the absolute value of the filtered correlation coefficient is in a first interval less than a predetermined threshold, the cerebral autoregulation ability of the patient during the operation is evaluated as normal. If the absolute value of the filtered correlation coefficient is in a second interval greater than or equal to the predetermined threshold, the cerebral autoregulation ability of the patient during the operation is evaluated as abnormal. The method for evaluating cerebral autoregulation ability according to claim 7.

12. Further including the step of outputting an alarm based on the evaluation result of the cerebral autoregulation ability. The method for evaluating cerebral autoregulation ability according to claim 7.

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