SAH patient cerebral hypoxia and ischemia real-time evaluation method based on multi-modal monitoring

Abstract

The invention discloses a multi-modal monitoring-based SAH patient cerebral hypoxia and ischemia real-time evaluation method, and belongs to the technical field of medical and industrial integration. The method comprises the following steps: collecting end-expiratory carbon dioxide data and electroencephalogram data; preprocessing the electroencephalogram data; calculating the power of each frequency band; calculating a delta wave power proportion according to each frequency power; dPR differences of different brain regions of the brain before and after treatment and in the treatment period and the interval period are evaluated through statistical analysis. According to the method, the electroencephalogram is combined with the end-tidal carbon dioxide data, the change of low-frequency activity of the brain is quantified by calculating the ratio of the electroencephalogram delta wave power, and the cerebral cortex hypoxia and ischemia degree of the SAH patient during respiratory therapy is evaluated according to the change value.

Description

Technical Field

[0001] The present invention relates to the field of medical-engineering integration technology, and in particular to a real-time evaluation method for cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring. Background Art

[0002] Subarachnoid hemorrhage (SAH) is a serious hemorrhagic neurovascular disease. The mortality rate of SAH in the neurointensive care unit is as high as 50% to 60%. Due to the physiological and pathological mechanisms of mutual influence between the brain and the lungs, the patient's brain neurological function damage may further aggravate lung dysfunction. Mechanical ventilation (MV) is widely used in SAH patients as a clinical treatment method to help patients restore alveolar stability by maintaining positive end-expiratory pressure (PEEP). However, mechanical ventilation may cause increased intracranial pressure, decreased cerebral perfusion pressure, and cerebral hemodynamic instability in the brain. The brain of SAH patients already has original damage. During treatment, respiratory therapy should be avoided to cause irreversible damage to the patient's brain. Traditional methods mainly rely on the experience and subjective judgment of clinicians, and the monitoring of brain function in SAH patients lacks real-time and objectivity.

[0003] As a non-invasive, high-temporal-resolution monitoring technology, EEG can capture fast dynamic information of the brain and has been successfully applied to a variety of neurocognitive disorders, including cerebral infarction, epilepsy, schizophrenia, autism, Alzheimer's disease, etc. Compared with traditional doctors' subjective judgment, this method has the advantages of objectivity, accuracy, timeliness and visualization, providing a scientific basis for the treatment and prognosis evaluation of SAH patients.

[0004] Therefore, it is necessary to provide a real-time monitoring method based on EEG and ventilator multimodal data to objectively evaluate the degree of ischemia and hypoxia in the patient's cerebral cortex. Summary of the invention

[0005] The purpose of the present invention is to provide a real-time assessment method for cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring. By combining the non-invasive and high time resolution characteristics of the electroencephalogram (EEG) with the end-tidal carbon dioxide data of the ventilator, the EEG delta wave power ratio (Delta Power Ratio, DPR) is calculated to quantify the changes in low-frequency brain activity, and the degree of cerebral cortical hypoxia-ischemia in SAH patients during respiratory treatment is accurately assessed based on the change value.

[0006] To achieve the above object, the present invention provides a method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring, the steps comprising:

[0007] S1, real-time collection of end-tidal carbon dioxide data and EEG data before, during and after treatment;

[0008] S2, preprocessing EEG data;

[0009] S3, performing Fourier transform on the preprocessed EEG signal and calculating the power of each frequency band;

[0010] S4. Calculate the delta wave power ratio (DPR) based on the power of each frequency, and compare the changes in DPR before and after treatment, during and between respiratory treatments, to quantify the changes in the degree of hypoxia-ischemia in the cerebral cortex of SAH patients;

[0011] S5. Use statistical analysis to evaluate the differences in DPR in different brain regions before and after treatment and during and after treatment, and evaluate the degree of cerebral cortical hypoxia-ischemia in SAH patients during respiratory therapy based on the DPR difference value.

[0012] Preferably, in step S1, the treatment period includes a respiratory treatment period and an interval period. During the treatment period, the beginning and end of each respiratory treatment are marked with end-tidal carbon dioxide and EEG labels. When the respiratory treatment begins, the end-tidal carbon dioxide data drops significantly, corresponding to the beginning EEG data.

[0013] Preferably, the preprocessing in step S2 includes filtering, artifact removal and whole-brain average reference.

[0014] Preferably, step S3 specifically includes: performing Fourier transform on the preprocessed EEG signal, converting the time domain signal into the frequency domain, and calculating the average power of delta waves, theta waves, alpha waves, beta waves and gamma waves.

[0015] Preferably, in step S4, the formula for calculating the delta wave power ratio DPR according to the power of each frequency is:

[0016]

[0017] Where P represents the average power.

[0018] Preferably, step S5 specifically comprises: dividing the brain into left frontal lobe, right frontal lobe, central lobe, parietal lobe, occipital lobe, left temporal lobe and right temporal lobe according to the electrodes, performing a paired sample T test on the DPR of each brain region of the SAH patient before and after treatment, when the DPR value during respiratory treatment is higher than that during the interval, it indicates that the treatment will aggravate the hypoxia-ischemia state of the cerebral cortex, and the DPR value of the patient decreases after treatment, indicating that the degree of hypoxia-ischemia of the cerebral cortex has improved.

[0019] Therefore, the present invention adopts the above-mentioned method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring, which has the following beneficial effects:

[0020] (1) Using EEG monitoring is non-invasive to patients and can capture rapid dynamic changes in the brain;

[0021] (2) By combining electroencephalogram (EEG) with end-tidal carbon dioxide data, the change in the low-frequency brain activity is quantified by calculating the proportion of the power of the EEG delta wave (DPR), objectively reflecting the brain function state of the patient, helping clinicians optimize the treatment plan and improve the prognosis of the patient, and providing a scientific basis for treatment decision-making.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0023] Figure 1 is the flowchart of the method according to the embodiment of the present invention;

[0024] Figure 2 is the schematic diagram of the preprocessed EEG signal according to the embodiment of the present invention;

[0025] Figure 3 is the brain topographic map during the RM period according to the embodiment of the present invention;

[0026] Figure 4 is the brain topographic map during the interphase according to the embodiment of the present invention;

[0027] Figure 5 is the schematic diagram of the statistical analysis of DPR between the RM period and the interphase according to the embodiment of the present invention;

[0028] Figure 6 is the schematic diagram of the statistical difference of DPR before and after treatment according to the embodiment of the present invention. Detailed Embodiments

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment

[0031] Referring to Figure 1 , the present invention provides a real-time assessment method for brain hypoxia-ischemia in SAH patients based on multimodal monitoring. The steps include:

[0032] S1. Connect the patient to a ventilator and an EEG device, wear an EEG cap and apply conductive paste to reduce the impedance to a reasonable range.

[0033] S2. Real-time collection of end-tidal CO2 data and EEG data before, during and after treatment, and visualization of CO2 data using ICM+ software. Collect resting EEG data and end-tidal CO2 data before and 5 minutes after treatment. Collect EEG data and end-tidal CO2 data of SAH patients during the entire treatment process. When respiratory treatment begins, the end-tidal CO2 data will drop significantly, corresponding to the label of the beginning of EEG.

[0034] The treatment period includes the respiratory treatment period and the interval period. The waiting time for respiratory treatment between adjacent respiratory treatment periods is called the interval period. A total of 8 SAH patients were collected during the entire respiratory treatment process. Each patient underwent 6 respiratory treatments, and each treatment was called lung recruitment (RM). The beginning and end of each RM were labeled with EEG and end-tidal carbon dioxide, which facilitated the subsequent analysis of the difference between the respiratory treatment period and the interval period.

[0035] S3. Preprocess the EEG data, including filtering, artifact removal, and whole-brain average reference. The processed EEG data is as follows: Figure 2 shown.

[0036] The international 10-20 system was used to record 19 monopolar channel EEG signals. The preprocessing process included:

[0037] Bandpass filtering (0.1–40 Hz) removed low- and high-frequency noise;

[0038] Notch filtering (49–51Hz) removes power frequency interference;

[0039] Downsample to 250Hz;

[0040] The MATLAB EEGLAB toolkit was used to remove artifacts and re-reference the whole-brain average signal to obtain EEG data with good signals.

[0041] S3. Perform Fourier transform on the preprocessed EEG signal, convert the time domain signal into the frequency domain, and calculate the average power of delta wave, theta wave, alpha wave, beta wave and gamma wave every 5 seconds. Use MATLAB software to draw brain topography to show the spatial distribution characteristics of power in different frequency bands. The brain topography of a patient during and between RM is shown in the figure below: Figure 3 and Figure 4 shown.

[0042] The contents of each band are shown as follows:

[0043] Delta waves (1–4 Hz): Lowest frequency, highest amplitude, reflecting deep sleep or brain damage.

[0044] Theta waves (4–8 Hz): associated with light sleep and relaxation states.

[0045] Alpha waves (8–13Hz): awake and relaxed state, mainly observing the occipital lobe area.

[0046] Beta waves (13–30 Hz): active thinking and attention state.

[0047] Gamma waves (30–60Hz): related to higher cognitive functions.

[0048] S4. Calculate the delta power ratio (DPR), visualize the DPR value, and compare the changes in DPR before and after treatment, during and between respiratory treatments to quantify the changes in the degree of hypoxia-ischemia in the cerebral cortex of SAH patients.

[0049] The formula for calculating the delta wave power ratio DPR based on the power of each frequency is:

[0050]

[0051] Where P represents the average power.

[0052] S5. Use statistical analysis to evaluate the differences in DPR in different brain regions before and after treatment and during and after treatment, and evaluate the degree of cerebral cortical hypoxia-ischemia in SAH patients during respiratory therapy based on the DPR difference value.

[0053] Specifically, the brain is divided into left frontal lobe (FP1, F3, F7), right frontal lobe (FP2, F4, F8), central lobe (C3, CZ, C4), parietal lobe (P3, PZ, P4), occipital lobe (O1, O2), left temporal lobe (T3, T5), right temporal lobe (T4, T6) according to the electrodes. Each area of ​​the brain reflects different functions. The main functions of the frontal lobe are advanced cognitive functions and motor speech functions, and it participates in the regulation of emotions and plays an important role in short-term memory and information integration. The central lobe of the brain is related to autonomic nervous system regulation and emotional processing, and is the somatomotor cortex area. The parietal lobe area is mainly used to reflect spatial perception functions, and cooperates with the frontal lobe to plan and coordinate complex movements. The occipital lobe is the visual cortex, which is the visual perception and processing center of the human body. The temporal lobe is the hearing and speech center. The hippocampus is located deep in the temporal lobe and is related to the formation of learning and memory. A paired sample T test was performed on the DPR of various brain regions in SAH patients before and after treatment. When the DPR value during respiratory therapy was higher than that during the interval, it indicated that the treatment would aggravate the hypoxia-ischemia state of the cerebral cortex. After treatment, the DPR value of the patient decreased, indicating that the degree of hypoxia-ischemia of the cerebral cortex had improved.

[0054] As shown in Tables 1 and 2, the DPR values ​​of each brain region during and between RM and before and after respiratory treatment for a certain patient were obtained. The statistical analysis results were as follows: Figure 5 and Figure 6 By comparing the changes in DPR before and after treatment and during respiratory therapy and intervals, the effect of respiratory therapy on the degree of hypoxia-ischemia in the cerebral cortex of SAH patients can be accurately monitored, providing a scientific basis for the treatment and prognosis evaluation of SAH patients.

[0055] Table 1 DPR values ​​of various brain regions during and between RM

[0056]

[0057]

[0058] Table 2 DPR values ​​of various brain regions before and after respiratory therapy

[0059] DPR Before treatment sum After treatment sum Left frontal lobe 0.548333 0.339523 0.426887 0.555313 Right frontal lobe 0.558262 0.285278 0.288467 0.558294 Central District 0.441163 0.280944 0.398995 0.331615 Top area 0.494134 0.223344 0.487752 0.364326 Occipital area 0.519179 0.350521 0.405742 0.458513 Left temporal lobe 0.525439 0.278496 0.38495 0.472195 Right temporal lobe 0.512438 0.34959 0.360204 0.489566

[0060] Therefore, the present invention adopts the above-mentioned real-time assessment method of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring, uses electroencephalogram combined with end-tidal carbon dioxide data, calculates the EEG delta wave power ratio DPR, quantifies the changes in low-frequency brain activity, objectively reflects the patient's brain function state, and provides a scientific basis for treatment decisions.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring, characterized in that the steps include: S1, real-time collection of end-tidal carbon dioxide data and EEG data before, during and after treatment; S2, preprocessing EEG data; S3, performing Fourier transform on the preprocessed EEG signal and calculating the power of each frequency band; S4. Calculate the delta wave power ratio (DPR) based on the power of each frequency, and compare the changes in DPR before and after treatment, during and between respiratory treatments, to quantify the changes in the degree of hypoxia-ischemia in the cerebral cortex of SAH patients; S5. Use statistical analysis to evaluate the differences in DPR in different brain regions before and after treatment and during and after treatment, and evaluate the degree of cerebral cortical hypoxia-ischemia in SAH patients during respiratory therapy based on the DPR difference value.

2. The method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring according to claim 1, characterized in that: In step S1, the treatment period includes the respiratory treatment period and the interval period. During the treatment period, the beginning and end of each respiratory treatment are marked with end-tidal carbon dioxide and EEG labels. When the respiratory treatment begins, the end-tidal carbon dioxide data drops significantly, corresponding to the beginning EEG data.

3. The method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring according to claim 1, characterized in that: The preprocessing in step S2 includes filtering, artifact removal and whole-brain average reference.

4. The method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring according to claim 1, characterized in that: Step S3 specifically includes: performing Fourier transform on the preprocessed EEG signal, converting the time domain signal into the frequency domain, and calculating the average power of delta wave, theta wave, alpha wave, beta wave and gamma wave.

5. The method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring according to claim 4, characterized in that: In step S4, the formula for calculating the delta wave power ratio DPR according to the power of each frequency is: Where P represents the average power.

6. The method for real-time assessment of cerebral hypoxia-ischemia in SAH patients based on multimodal monitoring according to claim 1, characterized in that: Step S5 is specifically as follows: the brain is divided into left frontal lobe, right frontal lobe, central lobe, parietal lobe, occipital lobe, left temporal lobe and right temporal lobe according to the electrodes, and a paired sample T test is performed on the DPR of each brain region of the SAH patient before and after treatment. When the DPR value during respiratory treatment is higher than that during the interval, it indicates that the treatment will aggravate the hypoxia-ischemia state of the cerebral cortex. After the treatment, the DPR value of the patient decreases, indicating that the degree of hypoxia-ischemia of the cerebral cortex has improved.

Images