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CN-121971758-A - Exogenous CO needed for calculating and controlling alveolar ventilation2Method and system for supplementing flow

CN121971758ACN 121971758 ACN121971758 ACN 121971758ACN-121971758-A

Abstract

The invention provides a method and a system for calculating and controlling exogenous CO 2 supplementing flow required by alveolar ventilation. Belongs to the technical field of medical instruments and clinical respiratory physiology. The method comprises obtaining a target total minute ventilation And target alveolar carbon dioxide partial pressure Or target end tidal carbon dioxide partial pressure Physiological dead space ventilation of patient Is an estimate of the patient's rate of carbon dioxide production Based on the target total minute ventilation And said physiological dead space ventilation Calculating a target alveolar ventilation Calculating a required exogenous carbon dioxide replenishment flow rate according to a mass balance equation based on the target alveolar ventilation, the target alveolar carbon dioxide partial pressure or target end tidal carbon dioxide partial pressure, and the carbon dioxide production rate Due to the adoption of a predictive algorithm based on a core physiological equation, the method comprises And The key individualization parameters are calculated by the invention Far more accurate than methods based on body weight or fixed concentrations.

Inventors

  • DONG HUI
  • GUAN JINGTAO
  • LIN SHENGXIANG

Assignees

  • 广州蓝仕威克医疗科技有限公司

Dates

Publication Date
20260505
Application Date
20260120

Claims (10)

  1. 1. A method of calculating exogenous CO 2 replenishment flow required to control alveolar ventilation, the method comprising: S1, obtaining target total minute ventilation And target alveolar carbon dioxide partial pressure Or target end tidal carbon dioxide partial pressure Physiological dead space ventilation of patient Is an estimate of the patient's rate of carbon dioxide production Is a function of the estimated value of (2); S2, ventilation is performed based on the target total minute And said physiological dead space ventilation Calculating a target alveolar ventilation The calculation formula is as follows: S3, calculating the required exogenous carbon dioxide supplementing flow according to a mass balance equation based on the target alveolar ventilation, the target alveolar carbon dioxide partial pressure or target end tidal carbon dioxide partial pressure and the carbon dioxide production rate The calculation formula is as follows: Wherein the method comprises the steps of From the following components Or (b) Conversion is carried out to obtain; representing alveolar CO 2 fraction.
  2. 2. The method of calculating the exogenous CO 2 replenishment flow required to control alveolar ventilation according to claim 1, wherein obtaining an estimate of the physiological dead space ventilation comprises at least one of: Estimating based on a Radford formula; calculating based on a Bohr equation and combining carbon dioxide diagram monitoring values; Which is estimated as a predetermined proportion of the tidal volume.
  3. 3. The method of calculating the exogenous CO 2 replenishment flow required to control alveolar ventilation according to claim 1, wherein obtaining an estimate of the carbon dioxide production rate comprises at least one of: real-time measurement is performed by a gas analyzer in the breathing circuit; the estimation is performed by a pre-stored formula based on demographic parameters of the patient.
  4. 4. The method for calculating the exogenous CO 2 supplement flow required by controlling alveolar ventilation according to claim 1, wherein the method further comprises the step of S4 of outputting the calculated value of the exogenous carbon dioxide supplement flow, sending a control signal of the exogenous carbon dioxide supplement flow to a proportional valve or a mass flow controller, and automatically controlling the flow of the exogenous carbon dioxide gas source to supplement carbon dioxide to a respiratory circuit.
  5. 5. The method of calculating the exogenous CO 2 replenishment flow required to control alveolar ventilation according to claim 4, wherein S4 comprises: Receiving the obtained The original value is converted into a clinical common unit in BTPS state by combining the body temperature of the patient and the vapor saturation pressure of the breathing circuit according to a gas state equation; according to clinical equipment conditions and operation selection, the method is executed in two modes Additionally, the two modes comprise a manual mode and an automatic mode; After the regulation and control are started, the system verifies the conveying effectiveness.
  6. 6. The method for calculating the additional flow of exogenous CO 2 required to control alveolar ventilation according to claim 1, further comprising S5 monitoring the patient' S actual end tidal carbon dioxide partial pressure And comparing the actual end tidal carbon dioxide partial pressure with the target end tidal carbon dioxide partial pressure, and adjusting the calculated exogenous carbon dioxide supplementing flow based on the comparison result.
  7. 7. The method of calculating the exogenous CO 2 replenishment flow required to control alveolar ventilation according to claim 6, wherein S5 comprises: S51, collecting a patient through a main flow/side flow CO 2 analyzer of a breathing circuit Preprocessing the original data to generate preprocessed data ; S52, pretreating With S1 acquisition In contrast, the absolute deviation is calculated: : If it is Judging whether the mmHg is less than or equal to 2mmHg The system maintains the current parameters to continue monitoring without adjustment; If it is 2MmHg, triggering a deviation adjustment procedure; s53, for super threshold Invoking PID controller computation Adjustment amount: Proportional term P according to The magnitude output is instant adjustment; integral term I, accumulated deviation integral, compensation Static bias caused by slow variation; The differential term D is used for outputting an advance adjustment quantity according to the deviation change rate and inhibiting deviation rebound; Synthesizing the adjustment quantity by superposing P, I, D items, limiting the maximum amplitude of single adjustment to obtain new A value; S54, will be new The value falls to the ground through the execution logic of S4, and is re-acquired after being delayed for 10 seconds : If after adjustment Judging to be effective and recovering the conventional monitoring period, wherein the mmHg is less than or equal to 2; If the threshold value is still exceeded, repeating the step S53 to optimize the PID parameters until the deviation is qualified; and dynamically adjusting the monitoring period.
  8. 8. A system for calculating exogenous CO 2 replenishment flow required to control alveolar ventilation, comprising: One or more processors; A memory for storing one or more programs, Wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the method of any of claims 1 to 7.
  9. 9. The system for calculating the exogenous CO 2 replenishment flow required to control alveolar ventilation according to claim 8, further comprising: the parameter input interface is used for receiving the target total minute ventilation and the target end-tidal carbon dioxide partial pressure set by a user; A physiological parameter acquisition interface for receiving an estimate of the physiological dead space ventilation and an estimate of the carbon dioxide production rate from a measurement device or database; and the output interface is used for outputting the calculated exogenous carbon dioxide supplementing flow.
  10. 10. The system for calculating the supplemental flow of exogenous CO 2 required to control alveolar ventilation of claim 8, further comprising an exogenous carbon dioxide delivery device including a gas source and a flow control valve; The flow control valve is in communication connection with the output interface and is used for sending a control signal to the flow control valve so as to automatically adjust the exogenous carbon dioxide flow delivered to the breathing circuit to the calculated exogenous carbon dioxide supplementing flow.

Description

Method and system for calculating exogenous CO 2 supplementary flow required by controlling alveolar ventilation Technical Field The invention provides a method and a system for calculating and controlling exogenous CO 2 supplementing flow required by alveolar ventilation, and belongs to the technical field of medical equipment and clinical respiratory physiology. Background In clinical scenes such as general anesthesia reviving and gas poisoning emergency treatment, alveolar ventilation is increased) To accelerate the washout of volatile anesthetics or other gases. However, simple hyperventilation can lead to partial pressure of arterial blood carbon dioxide) Reduce, cause hypocapnia, cause cerebral vasoconstriction, oxygen dissociation curve left shift (Bohr effect), and breathing pause after hyperventilation. Isocarbonic acid high aeration (IHV) is a technique for solving the problem, and the core is that the minute ventilation is increased) At the same time, exogenous CO 2 is supplemented into the inhaled gas to maintain physiological normalAnd thus avoid hypocarbonic acid blood symptoms while accelerating gas washout. Disclosure of Invention The invention provides a method and a system for calculating and controlling the exogenous CO 2 supplementing flow required by alveolar ventilation, which are used for solving the problems in the prior art that the real-time physiological state (such as) And anatomical features (e.g) The passive rebreathing device has poor control. Although the closed loop feedback system is subject to individual adjustment, the initial setting still depends on estimation, most methods (such as CLEARMATETM) require additional special hardware, cannot be seamlessly integrated with the existing anesthesia machine or breathing machine, increase the operation complexity and cost, and prevent clinical popularization, and non-computerized methods (such as manual addition and fixed concentration) have the problems of causing unexpected hypercapnia or hypocapnia due to the fact that the requirements and the supply of CO 2 cannot be accurately matched: the invention provides a method for calculating exogenous CO 2 supplementing flow required by controlling alveolar ventilation, which comprises the following steps: S1, obtaining target total minute ventilation And target alveolar carbon dioxide partial pressureOr target end tidal carbon dioxide partial pressurePhysiological dead space ventilation of patientIs an estimate of the patient's rate of carbon dioxide productionIs a function of the estimated value of (2); S2, ventilation is performed based on the target total minute And said physiological dead space ventilationCalculating a target alveolar ventilationThe calculation formula is as follows: S3, calculating the required exogenous carbon dioxide supplementing flow according to a mass balance equation based on the target alveolar ventilation, the target alveolar carbon dioxide partial pressure or target end tidal carbon dioxide partial pressure and the carbon dioxide production rate The calculation formula is as follows: Wherein the method comprises the steps of From the following componentsOr (b)Conversion is carried out to obtain; representing alveolar CO 2 fraction. The method for calculating the exogenous CO 2 supplementing flow required by controlling alveolar ventilation, provided by the invention, comprises the following steps of: Estimating based on a Radford formula; calculating based on a Bohr equation and combining carbon dioxide diagram monitoring values; Which is estimated as a predetermined proportion of the tidal volume. The method for calculating the exogenous CO 2 supplementing flow required by controlling alveolar ventilation, provided by the invention, comprises the following steps of: real-time measurement is performed by a gas analyzer in the breathing circuit; the estimation is performed by a pre-stored formula based on demographic parameters of the patient. S4, outputting the calculated value of the exogenous carbon dioxide supplementing flow, sending a control signal of the exogenous carbon dioxide supplementing flow to a proportional valve or a mass flow controller, and automatically controlling the flow of the exogenous carbon dioxide gas source supplementing carbon dioxide to a respiratory circuit. The method for calculating the exogenous CO 2 supplementing flow required by controlling alveolar ventilation provided by the invention comprises the following steps of: Receiving the obtained The original value is converted into a clinical common unit in BTPS state by combining the body temperature of the patient and the vapor saturation pressure of the breathing circuit according to a gas state equation; according to clinical equipment conditions and operation selection, the method is executed in two modes Additionally, the two modes comprise a manual mode and an automatic mode; After the regulation and control are started, the system verifies the conveying effecti