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CN-120910381-B - Method for constructing inert gas tension calculation model in human tissue

CN120910381BCN 120910381 BCN120910381 BCN 120910381BCN-120910381-B

Abstract

The invention discloses a method for constructing an inert gas tension calculation model in human tissues, which comprises the steps of establishing a pressure change rate function of a certain tissue of a human body, carrying out form transformation to obtain a corresponding first-order non-homogeneous linear differential equation, establishing a standard form and a complete solution form of the first-order non-homogeneous linear differential equation, carrying out corresponding assignment and substitution of the first-order non-homogeneous linear differential equation and the complete solution form of the first-order non-homogeneous linear differential equation to obtain a general human tissue pressure function, respectively constructing a human tissue pressure function G 1 (x) in a respiratory gas index pressurizing scene, a human tissue pressure function G 2 (x) in a linear depressurizing scene and a human tissue pressure function G 3 (x) in a linear pressurizing scene by using the general human tissue pressure function, and respectively constructing index pressurizing, linear depressurizing and linear pressurizing scene inert gas tension calculation models G 1 (x)、G 2 (x) and G 3 (x) by using G 1 (x)、g 2 (x) and G 3 (x) and inert gas percentage content d.

Inventors

  • Di shuai
  • GU JINGHUA
  • LIU CHUMENG

Assignees

  • 中国人民解放军海军特色医学中心

Dates

Publication Date
20260508
Application Date
20250721

Claims (6)

  1. 1. The method for constructing the inert gas tension calculation model in the human tissue is characterized by comprising the following steps of: S1, establishing a pressure change rate function of a certain tissue of a human body based on the theory that the diffusion speed of gas is in direct proportion to the pressure difference, wherein the pressure change rate function is expressed as a formula (1): (1) in the formula, The unit is m, which is the pressure of breathing gas, namely ambient gas; Is the pressure of a certain tissue in the body, and the unit is m; The unit is m/s, k is defined as saturation coefficient, dimensionless, and k is greater than 0 when Greater than In the time-course of which the first and second contact surfaces, Greater than 0, when Less than In the time-course of which the first and second contact surfaces, Less than 0, calculated k=ln2/t, t is half-saturation time of a certain tissue in the body, and the unit is s; S2, performing form transformation on a pressure change rate function of a certain tissue of a human body to obtain a corresponding first-order non-homogeneous linear differential equation; s3, constructing a standard form and a full solution form of a first-order non-homogeneous linear differential equation; S4, carrying out corresponding assignment on the first-order non-homogeneous linear differential equation and the general solution form thereof, and substituting the first-order non-homogeneous linear differential equation and the general solution form thereof to obtain a general human body tissue pressure function; S5, respectively constructing a pressure function of a certain tissue of the human body under the respiratory gas index pressurizing scene by utilizing the pressure function of the certain tissue of the human body Human body tissue pressure function under breathing gas linear decompression scene Pressure function of certain tissue of human body in breathing gas linear pressurization scene ; S6, utilizing a pressure function of a certain tissue of the human body And constructing a calculation model of the inert gas tension of a certain tissue of a human body under the breathing gas index pressurization scene by the percentage content of the inert gas ; By using pressure function of certain tissue of human body And constructing a calculation model of the inert gas tension of a certain tissue of a human body under a respiratory gas linear decompression scene by the percentage content of the inert gas ; By using pressure function of certain tissue of human body And constructing a calculation model of the inert gas tension of a certain tissue of a human body under the linear pressurization scene of the breathing gas by the percentage content of the inert gas 。
  2. 2. The method for constructing a model for calculating the tension of inert gas in human tissue according to claim 1, wherein the method is characterized in that S2, the pressure change rate function of a certain tissue of the human body is transformed in form to obtain a corresponding first-order non-homogeneous linear differential equation expressed as formula (2): (2) S3, a standard form for constructing a first-order non-homogeneous linear differential equation is marked as a formula (3) and a general solution form thereof is marked as a formula (4): (3) (4) s4, carrying out corresponding assignment on the formula (4) and the formula (2), and then , Substituting formula (4) to obtain a general human body tissue pressure function as formula (5): (5) Wherein C is any constant and is determined by initial conditions; S5, taking an exponential pressurization function, doubling the pressure every n seconds, and setting Where P 0 is the initial pressure of the breathing gas, the pressure will Substituting into (5) to obtain (6) The value of g (0) is generally known, and x=0 s is substituted into formula (6) (7) Substituting C into (6) to construct a pressure function of a certain tissue of a human body in a breathing gas index pressurization scene : (8) If the pressure of human tissue is sufficiently balanced with the ambient pressure at the beginning of pressurization If the test person repeatedly dives, increases, decreases, etc. at the beginning of pressurization, the value of g (0) should sufficiently consider the actual situation; S6, constructing a calculation model of inert gas tension of a certain tissue of a human body under a respiratory gas index pressurization scene , Is the percentage content of inert gas.
  3. 3. The method for constructing a model for calculating the tension of inert gas in human tissue according to claim 2, wherein in S5, the mathematical model for linearly decompressing the breathing gas is as follows Where P 1 is the initial pressure of the breathing gas, the pressure will Substituting into (5) to obtain (11) The value of g (0) is generally known, and x=0 s is substituted into formula (11) (12) At this time, g (0) is a tissue pressure value before decompression, and formula (12) is substituted into formula (11) to construct a function of the pressure of a certain tissue of a human body in a respiratory gas linear decompression scene : (13) S6, constructing a calculation model of inert gas tension of a certain tissue of a human body under a respiratory gas linear decompression scene 。
  4. 4. A method of constructing a model of inert gas tension calculation in human tissue according to claim 3, wherein the breathing gas linear decompression scenario comprises: The diver rises from a large depth to a shallow depth at a constant speed; And in the use scene B, the diver is positioned in the pressurizing cabin, and the pressure of the control cabin is reduced at a constant speed.
  5. 5. The method for constructing a model for calculating the tension of inert gas in human tissue according to claim 2, wherein in S5, the mathematical model for linearly pressurizing the breathing gas is as follows Where P 0 is the initial pressure of the breathing gas, the pressure will Substituting into (5) to obtain (14) The value of g (0) is generally known, and x=0 s is substituted into formula (14) (15) Substituting formula (15) into formula (14) (16) If the pressure of human tissue is sufficiently balanced with the ambient pressure at the beginning of pressurization If the test person repeatedly dives, increases, decreases, etc. at the beginning of pressurization, the value of g (0) should sufficiently consider the actual situation; s6, constructing a calculation model of inert gas tension of a certain tissue of a human body under a breathing gas linear pressurization scene 。
  6. 6. The method for constructing a model for calculating the tension of inert gas in human tissue according to claim 5, wherein the breathing gas linear pressurization scene comprises: The method comprises the following steps of using a scene A, wherein a diver dives to a certain large depth from a shallow depth at a constant speed; The use scene B is that the diver is in the pressurizing cabin, and the pressure of the control cabin is increased at a constant speed.

Description

Method for constructing inert gas tension calculation model in human tissue Technical Field The invention relates to the technical field of model construction, in particular to a method for constructing an inert gas tension calculation model in human tissues. Background Diving (a process that a person is immersed below the water surface, reaches a certain depth, stays for a certain period of time and ascends to water out is called diving), is taken as a means for fight between the human and the nature, and has started in the original age of the human. With the demands of production fight, level fight, scientific experiments and the continuous improvement of the industrial technical level, diving technology is increasingly widely applied and correspondingly developed, and is now a special technology. Diving has become an indispensable technology in economic construction, national defense construction, scientific research and military operations, and carries a lot of important tasks in military and civil aspects. Such as rescue and diving, salvage of sunken vessels (sinkers), offshore rescue, underwater exploration, underwater construction (laying pipelines, cables, constructing harbour terminals, special engineering and facilities under water), cleaning of waterways, underwater investigation and blasting, underwater supply, bridge construction, aquaculture, reservoir maintenance, underwater resource exploration and development (petroleum, natural gas, mineral reservoirs), marine science investigation and research, etc., require a large number of diving operations. The atmospheric pressure of a human body is 1ata under normal pressure, the atmospheric pressure of 1ata and the hydrostatic pressure of 1ata are borne by the human body when the water is 10m under water (here, sea water and fresh water correspond to 10.3 m), the total environmental pressure is 2ata, the atmospheric pressure of 1ata and the hydrostatic pressure of 2ata are borne by the human body when the water is 20m under water, the total environmental pressure is 3ata, and the like. It follows that during a diving operation, a person is in a high pressure environment because he is subjected to both atmospheric pressure and hydrostatic pressure at a corresponding depth, and must breathe compressed gas to balance the internal and external pressures. In the case of breathing air, the main components are oxygen, carbon dioxide and nitrogen. When compressed air is breathed under high pressure, the oxygen and carbon dioxide content will not generally vary much due to the specific regulation function of the body (except for "oxygen poisoning" in case of excessively high oxygen partial pressure or "carbon dioxide poisoning" in case of specific accidents). Nitrogen is the most abundant component in air, and is the most commonly encountered inert gas (low in chemical activity, not involved in metabolism of the body, not utilized by the body, and exists in a purely physically dissolved state in the body), and this property of gas is called "inert gas" in diving medicine, such as nitrogen, helium, neon, argon, krypton, xenon, and the like. However, the human body cannot utilize nitrogen, nor is there a mechanism for adjusting the nitrogen content, and the amount of nitrogen dissolved in the body increases as the partial pressure of nitrogen of the inhaled air increases, and decreases as the partial pressure of nitrogen decreases. This feature creates a special problem for diving medicine. When the body is in a high-pressure environment, the inert gas is continuously dissolved in various tissues in the body. Over time, the total amount of inert gas dissolved in the tissue gradually increases until it is in equilibrium, i.e., the amount of gas entering and exiting the tissue is equal. In this way, a certain inert gas reaches a state at a certain pressure where it is no longer possible to increase the amount of dissolution into the tissue, called "saturation" of the gas in the tissue at this pressure. When the pressure is reduced from high to low, the amount of inert gas that has dissolved into the tissue at high pressure exceeds the maximum amount of dissolved gas that should be dissolved in the tissue at lower pressures, but the excess portion of the gas remains dissolved in the tissue, a condition known as "supersaturation". When the tension of the inert gas dissolved in the tissue is higher than the external air pressure, the inert gas is released from the tissue, so that the tension of the inert gas in the tissue is gradually balanced with the external air pressure, and the process is called 'desaturation'. Saturation and desaturation of inert gases within tissues is accomplished through the respiratory and blood circulatory systems. When compressed air is breathed, the partial pressure of nitrogen in the alveoli increases accordingly. As blood flows through the alveoli, nitrogen dissolves into the blood by the pressure differential between it and the nit