Decision system for enteral nutrition therapy to prevent aspiration in patients on invasive mechanical ventilation

Abstract

The application belongs to a nasogastric feeding decision system, in particular to a decision system for preventing regurgitation and aspiration during enteral nutrition treatment of a patient with invasive mechanical ventilation, comprising a collection and execution module, a preprocessing module, a decision engine and a microcirculation determination module, characterized in that the collection and execution module acquires a gastric pressure time sequence and establishes a non-disturbance baseline at the end of expiration, the preprocessing module calculates a first-order derivative of the gastric pressure in a sliding time window by least square slope, the decision engine performs segmented injection when the injection condition is met, and the microcirculation determination module performs zero-net-volume microcirculation in a silent window to acquire an instantaneous stretch response for risk and source tendency determination without changing the net load.

Description

Technical Field

[0001] This invention pertains to nasogastric feeding decision systems, specifically a decision system for preventing reflux and aspiration in enteral nutrition therapy for patients undergoing invasive mechanical ventilation. Background Technology

[0002] Patients on invasive mechanical ventilation often require early enteral nutrition via nasogastric tube feeding; sedation and bed rest increase the risk of gastroesophageal reflux and aspiration. Therefore, evidence-based consensus advocates elevating the head of the bed by 30 to 45 degrees to reduce aspiration and ventilator-associated pneumonia; at the same time, the interpretation of gastric retention is becoming more conservative: feeding should not be stopped if there are no signs of intolerance, even if the amount of food remaining is less than 500 ml (6 hours), to avoid unnecessary interruption and insufficient energy supply.

[0003] The existing technology CN116869832A proposes a nasogastric feeding nutrition delivery system, which consists of a nasogastric tube, an external device that can be injected and aspirated, a detection module, and a control module. It first generates an initial plan based on the body's metabolic information, and then dynamically adjusts the single dose, speed, and frequency based on the difference between the gastric retention information obtained by aspiration and the "gastric pressure relative to the initial pressure" to reduce the risk of reflux and aspiration.

[0004] However, its core trigger still relies on amplitude exceeding the threshold, and it can only start slowing down, reducing the amount, or pausing when the gastric pressure rises significantly relative to the baseline or the retention exceeds the threshold; moreover, the injection itself will increase the gastric pressure, which couples the monitoring and operation, resulting in problems of delayed warning and easy misjudgment.

[0005] Furthermore, the protocol can only determine whether reflux will occur, but cannot determine whether the reflux is gastric or caused by the downward displacement of upper respiratory tract secretions. Clinically, different treatment methods are usually used for these two types of reflux. For example, gastric reflux is usually treated conservatively by changing the body position, and proton pump inhibitors are given in severe cases. For reflux caused by the downward displacement of upper respiratory tract secretions, drooling is usually controlled by suctioning, direct administration of anticholinergic drugs or botulinum toxin injection into the salivary glands.

[0006] In other words, the above-mentioned scheme has a delay in the judgment result and cannot distinguish whether the reflux is gastric or caused by the downward movement of upper respiratory tract secretions. The existing judgment methods are basically based on the content of pepsin and salivary amylase in the airway after reflux, which is even more lagging. Therefore, a decision system that can predict reflux and reflux type is needed. Summary of the Invention

[0007] The purpose of this invention is to provide a decision-making system for preventing reflux and aspiration in enteral nutrition therapy for patients undergoing invasive mechanical ventilation, in order to solve the above-mentioned technical problems.

[0008] A decision-making system for preventing reflux and aspiration in enteral nutrition therapy for patients undergoing invasive mechanical ventilation includes a data acquisition and execution module, a preprocessing module, a decision engine, and a microcirculation determination module. Its key feature is that the data acquisition and execution module acquires gastric pressure time-series data. Establish an undisturbed baseline at the end of expiration.

[0009]

[0010] The preprocessing module calculates the first derivative of gastric pressure using the least squares slope within a sliding time window.

[0011]

[0012] The decision engine is used for blood sugar, gastric retention, and When the injection conditions are met, the target traffic is used. To target volume Perform segmented injection, and satisfy either the pressure limit or trend limit condition at any given time.

[0013]

[0014] The injection is stopped and the process enters a silent window, where the next stage of treatment or injection strategy is determined by the outcome of the silent window.

[0015] Furthermore, the microcirculation determination module performs zero net volume microcirculation within a silent window, injecting a volume of... Later Equal amount extracted from the inside make

[0016]

[0017] The zero net volume microcirculation is used to obtain instantaneous stretch response without changing the net load for risk and source tendency determination.

[0018] Furthermore, the observation window based on zero net microcirculation Calculate the sensitivity index :

[0019]

[0020]

[0021] in For silent windows The 95th percentile, The baseline fall-off time, This represents the allowable peak pressure rise margin for the current segment. As an indicator of reproducibility, the weight ratio ;when and Tightening strategies that trigger sensitive gastric side scenarios.

[0022] Furthermore, the derivative adaptive threshold and the duration caliber are defined as follows:

[0023]

[0024] Only when Duration The time is recorded as a trend exceeding the limit, and Preferred .

[0025] Furthermore, the injection window and the silent window are arranged alternately in a time sequence: Total planned volume Cut into injection window Set the duration of the silent window between adjacent injection windows. Preferred The mechanical pump operates at a constant flow rate within the injection window. Advance to Alternatively, it may switch to a silent window in advance when the limit-crossing condition described in claim 1 is met.

[0026] Furthermore, within the silent window, hierarchical and coordinated control is performed based on three core signals: peak proximity.

[0027]

[0028] percentage of upward trends

[0029]

[0030] Recovery time If the high-risk rule is met, no further injection will be performed and the silence period will be extended or the process will be terminated; if the medium-risk rule is met, the target volume and target flow will be reduced in subsequent iterations. And prolong the silence When the risk is low, proceed as originally planned or make a slight adjustment not exceeding [amount not specified]. .

[0031] Furthermore, it introduces a stress budget and quota allocation mechanism: total stress budget

[0032]

[0033] Single-stage pressure quota

[0034]

[0035] Individual conversion factor obtained from a previous period of observation

[0036]

[0037] Convert quotas to suggested volume

[0038]

[0039] And according to risk classification Adjust downwards or upwards.

[0040] Furthermore, a peak prediction check is performed before initiating the next injection segment.

[0041]

[0042] when At that time, rollback Alternatively, the target traffic can be reduced and the silent window extended until... It can only be started after that; among them Preferred warning zone below the safety threshold .

[0043] Furthermore, to avoid frequent start-stop cycles, restart lag and debouncing rules are set: restart threshold.

[0044]

[0045] Only when the end of the silent window is consecutive Simultaneously satisfy and Only if the next injection window is started will the silence period be extended or the current process be terminated.

[0046] Furthermore, before formal implementation, feedforward learning and threshold formation are performed: small-dose, multi-stage reinjection is used, with each injection approximately... And in Completed within the timeframe, settings are configured after each bet. Silent window; select the high percentile of the upward trend indicator from data that has never caused adverse reactions. and superimposed The safety margin is used to determine the trend stopping threshold, and the restart threshold is taken as the stopping threshold. Individual conversion factors are obtained from the backinjection data. and the upper limit within the segment This is for use in subsequent three-gate control and quota conversion.

[0047] The beneficial effects achieved by the present invention using the above structure are as follows:

[0048] This invention focuses on segmented injection, silent judgment, pressure budgeting, and trend advance, enabling individualized closed-loop control of the nasogastric feeding process without altering existing safety threshold management.

[0049] Within a silent window, instantaneous stretching probes with zero net volume are achieved through equal injection and aspiration, without altering the net gastric load or excessively raising the pressure baseline. This decouples the injection self-perturbation from the actual precursors of reflux, allowing for early detection of gastric stretching hypersensitivity and reducing the risk of misjudgment and unnecessary feeding interruptions.

[0050] By identifying pressure peaks and upward trends within a silent window and verifying them with a restart threshold, backflow risks can be detected in advance, reducing overstepping of limits and misjudgments, and avoiding blindly stopping feeding. Attached Figure Description

[0051] Figure 1 This is a system architecture diagram of the decision system for preventing backflow and accidental aspiration according to the present invention;

[0052] Figure 2 This is a decision flowchart of the decision system for preventing backflow and accidental aspiration according to the present invention;

[0053] Figure 3 This is a flowchart of the threshold generation process for the decision-making system of the present invention. Detailed Implementation

[0054] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0055] The decision-making system for preventing reflux and aspiration in enteral nutrition therapy for patients undergoing invasive mechanical ventilation proposed in this invention is as follows: Figures 1-3 As shown, it includes a data acquisition and execution module, a preprocessing module, a decision engine, and a micro-loop determination module;

[0056] The data acquisition and execution module detects blood glucose, gastric residue, gastric pressure, and gastric pressure derivative as prerequisites for nasogastric feeding;

[0057] Specifically, after obtaining the gastric pressure, the preprocessing module calculates the first derivative of the gastric pressure using a sliding time window least squares slope:

[0058]

[0059] in: For the first one inside the window Each sampling time; To correspond to the measured pressure; This represents the number of samples within the window. The average value within the window; This represents the average pressure inside the window. This is the estimated value of the pressure derivative obtained from this window.

[0060] When blood glucose, gastric retention, gastric pressure, and gastric pressure derivative all meet the conditions for nasogastric feeding, the decision engine initiates the feeding process. The nasogastric tube is connected to a disposable pressure transducer via a three-way connector to collect the gastric pressure time series Pt. Sampling at 50 Hz is preferred, and values ​​are taken at the end of expiration to reduce respiratory phase interference. Pumping and aspiration are stopped within a silent window, and only data is collected, defining a undisturbed baseline.

[0061]

[0062] Where T0 is the duration of the silent window in seconds, the zero point is placed at the level of the mid-axillary line and the body position is kept consistent; the above practice of aligning the end-expiratory pressure with the zero point is consistent with the consensus on intra-abdominal pressure monitoring.

[0063] The gastric pressure derivative is calculated using the existing formula without modification. Within a silent window, a noise threshold for the derivative is statistically analyzed to form an adaptive threshold. The percentile of the absolute value of the derivative is defined as...

[0064]

[0065] The safety factor s is set to be between 1.5 and 2.0, and the derivative rise threshold is...

[0066]

[0067] When satisfied

[0068]

[0069] This is recorded as a derivative elevation event; Tmin is preferably one second; this elevation indicates an increased trend of gastric distension and is associated with transient lower esophageal sphincter relaxation, which is a leading signal of reflux.

[0070] Windowed injection is performed using a mechanical pump, alternating between injection and quiescent windows. The total planned volume is Vtot ml, divided into K injection windows. Let the target volume and target flow rate of the k-th segment be denoted as follows: milliliters and Milliliters per hour, with a preferred silent window Ts of four to eight seconds between adjacent segments; intra-segment control is achieved using a mechanical pump. Inject at a constant rate until reached Alternatively, the system may terminate early and enter a silent window if any safety condition is met. Safety conditions include two categories: pressure exceeding limits and trend exceeding limits.

[0071]

[0072] Within the silent window, only data is collected, and the current baseline and derived values ​​are updated for one to three seconds at the end. Three criteria are defined for classification, including peak proximity. for

[0073]

[0074] in The warning zone is 2 to 5 mmHg below the safety threshold; the percentage of those showing an upward trend. The derivative within the silent window exceeds the micro threshold. Time percentage

[0075]

[0076] Recovery time The time constant from the end of the segment to the return to steady state is obtained using an existing algorithm; based on this, risks are divided into three categories: high, medium, and low, and actions are given. High risk satisfies... ;or And lasting for one to two seconds; or the silence lasting for two consecutive seconds without simultaneously satisfying the conditions of trend stability and... High-risk: No further injections will be made this time, and the silence period will be extended. If necessary, the current process will be terminated. Medium-risk: Meeting one of the following three criteria: a high percentage of upward trends, a significant increase relative to the baseline, or a long recovery time. Subsequently, the target volume and target flow will be reduced by 10% to 30%, and the silence period will be extended by one to three seconds. Low-risk: Meeting the criteria of rapid stabilization and... If the area is far from the warning zone and the trend is stable or slightly decreasing most of the time, proceed as planned or slightly increase the volume and flow rate by no more than 5% to 10%. In case of a conflict, prioritize the high-risk case; if two consecutive cases are classified as medium or high risk, terminate the current process and prompt for manual review. To ensure overall controllability, set a pressure budget and quota, defining the remaining pressure space between the safety threshold and the current baseline as...

[0077]

[0078] By coefficient Consumption budget to obtain single-stage pressure quota The pressure-volume conversion factor G observed in the above section is used as an individualized gain.

[0079]

[0080] Convert quotas to suggested volume

[0081]

[0082] in The upper limit of the volume within the segment; medium risk is... Adjustments should be made downwards by 10% to 30% based on existing levels, and upwards by no more than 10% for low-risk cases; peak prediction verification should be conducted before initiating the next phase.

[0083]

[0084] like If necessary, the rollback suggestion volume or target flow rate should be reduced, and the silence period extended until the margin requirement is met before activation; activation can only proceed if the margin requirement is met simultaneously for one to three consecutive seconds at the end of the silence window. and Injection can only be restarted under two conditions, among which... The restart threshold is set to 60% to 80% of the stop threshold; the entire process is performed in a semi-recumbent position at 30 to 45 degrees to reduce the risk of reflux and aspiration and to ensure the stability of the criteria.

[0085] Through the aforementioned closed-loop strategy, without altering clinical safety threshold management, this invention employs a control process of segmented injection, silent determination, dose allocation, peak value verification, feedforward learning, and adaptive updates, transforming trend lead time and pressure budget into executable control parameters. This process ensures safety boundaries while reducing unnecessary feeding interruptions and misjudgments, and lowering the risks of reflux and aspiration.

[0086] To distinguish between reflux caused by gastric or oropharyngeal origin, this invention also sets a derivative elevation threshold. When the reflux is detected to be greater than the derivative elevation threshold, the microcirculation test is performed to predict whether the reflux is more likely to be gastric or more likely to be caused by downward displacement of oropharyngeal secretions.

[0087] Specifically, collecting intragastric pressure signals A undisturbed baseline was established. Pressure was continuously recorded via a three-way connector to the nasogastric tube using a pressure transducer. The sampling frequency is preferably 50 Hz; all values ​​are taken at the end of expiration to reduce respiratory phase interference; a 2 to 5 second silent window is inserted every 2 to 5 minutes to stop injection and aspiration to form a undisturbed segment;

[0088] Baseline gastric pressure is defined as

[0089]

[0090] in The duration of the silent window is specified; the zero point is kept consistent with the body position to ensure comparability across windows.

[0091] The gastric pressure derivative is calculated to form a noise threshold. The derivative is defined and implemented using the existing system without modification; the upper bound of the noise is obtained by calculating the percentile of the absolute value of the derivative within a silent window. ;

[0092]

[0093] The silent window fallback time constant is recorded synchronously as a subsequent normalization benchmark.

[0094]

[0095] All the above values ​​are derived from the silent window's undisturbed data to avoid injecting data that could contaminate the criteria.

[0096] Determine derivative elevation and generate forward risk markers. Set the safety multiple s between 1.5 and 2.0, and the derivative elevation threshold is [value missing].

[0097]

[0098] When satisfied

[0099]

[0100] This is then denoted as a derivative lift event; The optimal value is one second; the increase in derivative indicates an enhanced trend of gastric distension, which is related to the reflux pathway triggered by transient lower esophageal sphincter relaxation and is a leading signal before the event occurs.

[0101] Within the silent window, the microcirculation determination module performs unloaded injection and retraction microcirculation to trigger instantaneous stretching without changing the net volume.

[0102] Adult single injection volume Take 1-2 ml, then draw back an equal amount within one second. The rate is 0.5 to 1.0 ml per second; for pediatrics, the rate should not exceed 0.5 ml per kilogram based on body weight; and it should meet the following requirements.

[0103]

[0104] A 2-3 second observation window is provided after microcirculation to extract the transient response; this stretch probe is used to amplify the response of highly sensitive individuals on the gastric side to small perturbations, which helps to distinguish the source predisposition before the event.

[0105] A sensitivity index is constructed to quantify the immediate response strength after stretching. Three incremental indicators and one reproducibility indicator are defined within the observation window after microcirculation.

[0106]

[0107]

[0108]

[0109]

[0110] The sensitivity index was obtained by normalizing and linearly synthesizing in a dimensionless manner. ;

[0111]

[0112] Where W is the observation window. The percentile of the derivative noise. The baseline fall-off time, The allowable peak pressure rise margin for the current segment comes from the pressure budget, with a recommended weighting ratio of 2:1:1:1; the larger the index, the more sensitive it is to zero net load stress.

[0113] Based on a combined prospective judgment using derivative rise and sensitivity index, when a derivative rise event is confirmed, or when a derivative rise and fall slow down and occur within the same observation window, it is judged that a reversal is imminent. The source tends to be stratified using a threshold.

[0114]

[0115] Then it is judged to be of gastric origin; if the following conditions are met...

[0116] Or it may not respond significantly to microcirculation;

[0117] If the result is positive, it indicates a tendency for downward displacement of oropharyngeal secretions; for the uncertain interval of 1.0 to 1.5, the microcirculation can be repeated once in the next silent window for verification.

[0118] The microcirculation determination module is connected to the alarm record interface, and outputs the tendency of gastric or oropharyngeal secretions to the alarm record, so that medical staff can provide care for the cause of reflux.

[0119] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A decision-making system for preventing reflux and aspiration in enteral nutrition therapy for patients undergoing invasive mechanical ventilation, characterized in that, It includes a data acquisition and execution module, a preprocessing module, a decision engine, and a microcirculation determination module. Its key feature is that the data acquisition and execution module acquires the gastric pressure time series. Establish an undisturbed baseline at the end of expiration. The preprocessing module calculates the first derivative of gastric pressure using the least squares slope within a sliding time window. The decision engine is used for blood sugar, gastric retention, and When the injection conditions are met, the target traffic is used. To target volume Perform segmented injection, and satisfy either the pressure limit or trend limit condition at any given time. That is, stop the injection and enter the silent window, and the next stage of treatment or injection strategy is determined by the judgment result of the silent window; The microcirculation determination module performs zero-net-volume microcirculation within a silent window, injecting a volume of [unclear] into the stomach. Later Equal amount extracted from the inside make The zero net volume microcirculation is used to obtain instantaneous stretch response without changing the net load for risk and source tendency determination.

2. The decision-making system according to claim 1, characterized in that, Among them, the observation window based on zero net volume microcirculation Calculate the sensitivity index : in For silent windows The 95th percentile, The baseline fall-off time, This represents the allowable peak pressure rise margin for the current segment. As an indicator of reproducibility, the weight ratio ;when and Tightening strategies that trigger sensitive gastric side scenarios.

3. The decision-making system according to claim 1, characterized in that, Where the derivative adaptive threshold and the duration caliber are defined as follows: Only when Duration The time is recorded as a trend exceeding the limit, and Preferred .

4. The decision-making system according to claim 1, characterized in that, The injection window and the silent window are arranged alternately in time sequence: Total planned volume Cut into injection window Set the duration of the silent window between adjacent injection windows. Preferred The mechanical pump operates at a constant flow rate within the injection window. Advance to Alternatively, it may switch to a silent window in advance when the limit-crossing condition described in claim 1 is met.

5. The decision-making system according to claim 1, characterized in that, Within the silent window, hierarchical and coordinated control is based on three core signals: peak proximity. percentage of upward trends Recovery time If the high-risk rule is met, no further injection will be performed and the silence period will be extended or the process will be terminated; if the medium-risk rule is met, the target volume and target flow will be reduced in subsequent iterations. And prolong the silence When the risk is low, proceed as originally planned or make a slight adjustment not exceeding [amount not specified]. .

6. The decision-making system according to claim 1, characterized in that, This includes the introduction of a stress budget and quota allocation mechanism: total stress budget Single-stage pressure quota Individual conversion factor obtained from a previous period of observation Convert quotas to suggested volume And according to risk classification Adjust downwards or upwards.

7. The decision-making system according to claim 1, characterized in that, This includes performing peak prediction verification before initiating the next injection segment. when At that time, rollback Alternatively, the target traffic can be reduced and the silent window extended until... It can only be started after that; among them Preferred warning zone below the safety threshold .

8. The decision-making system according to claim 1, characterized in that, To avoid frequent start-stop operations, restart lag and debouncing rules are set: Restart threshold Only when the end of the silent window is consecutive Simultaneously satisfy and Only if the next injection window is started will the silence period be extended or the current process be terminated.

9. The decision-making system according to claim 1, characterized in that, Before formal implementation, feedforward learning and threshold formation are performed: small-dose, multi-stage reinjections are used, approximately [number missing] times per injection. And in Completed within the timeframe, settings are configured after each bet. Silent window; select the high percentile of the upward trend indicator from data that has never caused adverse reactions. and superimposed The safety margin is used to determine the trend stopping threshold, and the restart threshold is taken as the stopping threshold. Individual conversion factors are obtained from the backinjection data. and the upper limit within the segment This is used for subsequent three-gate control and quota conversion.

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