Carbon dioxide absorption free canister anesthesia apparatus

Abstract

This invention provides a carbon dioxide-free anesthesia machine, comprising a ventilator, an anesthetic vaporizer, a gas sieving tank, and a molecular sieve membrane. This invention utilizes a gas separation membrane for selective permeation of carbon dioxide, achieving precise molecular-scale sieving in the separation of carbon dioxide-containing gas mixtures. Simultaneously, a multi-channel ceramic hollow fiber membrane is used as the support for the gas separation membrane, increasing the membrane packing density and miniaturizing the carbon dioxide separation device. This invention solves the problem of existing anesthesia breathing devices lacking end-tidal carbon dioxide concentration (P0.05) concentration in practical applications. ET The failure to monitor CO2 and inhaled carbon dioxide concentration (FiCO2), or the failure to replace the carbon dioxide absorbent in a timely manner, can lead to carbon dioxide re-inhalation in patients, resulting in carbon dioxide accumulation.

Description

Technical Field

[0001] This invention relates to the field of anesthesia breathing devices, specifically to an anesthesia machine without a carbon dioxide absorption canister. Background Technology

[0002] Most modern anesthesia machines use closed or semi-closed breathing circuits during mechanical ventilation. In this type of circuit, carbon dioxide in the patient's exhaled air must be absorbed and removed by a carbon dioxide absorption device before being returned to the anesthesia machine's breathing circuit, thus preventing the patient from re-inhaling carbon dioxide and endangering their life.

[0003] Commonly used carbon dioxide absorbents in clinical practice include soda lime, calcium lime, and barium lime. Their mechanism of action involves a chemical reaction between the absorbent and carbon dioxide, thereby achieving absorption. The absorption efficiency of carbon dioxide absorbents is affected by factors such as gas humidity, temperature, fresh air flow rate, ventilation volume, and the type of breathing circuit in the anesthesia machine. Furthermore, there is currently no universally accepted standard for when to replace a depleted carbon dioxide absorbent. In the absence of end-tidal carbon dioxide concentration (P<0.05), the absorption efficiency is significantly reduced. ET Failure to promptly replace the carbon dioxide absorbent during CO2 monitoring and inhaled carbon dioxide concentration (FiCO2) monitoring can cause re-inhalation of carbon dioxide, leading to carbon dioxide accumulation and seriously affecting patient safety.

[0004] In addition, to ensure the safety of patients' breathing, anesthesiologists may choose aggressive measures to frequently change carbon dioxide absorbents, which may also bring a series of risks, including damage or loss of tank parts, increased workload for anesthesiologists, increased medical costs, increased occupational exposure to toxic substances caused by chemical dust, increased consumption of chemical medical resources, and environmental pollution.

[0005] This application is filed to address the aforementioned deficiencies. Summary of the Invention

[0006] This invention addresses the problem of carbon dioxide absorbents in existing anesthesia circuits by providing an anesthesia machine without a carbon dioxide absorbent tank.

[0007] To address the problems mentioned above in the background section, the present invention provides the following technical solution:

[0008] A carbon dioxide-free anesthesia machine includes a gas circulation circuit and a ventilator connected to the gas circulation circuit. The circuit is provided with an inspiratory one-way valve and an expiratory one-way valve. A patient-end connection port is provided between the downstream side of the inspiratory one-way valve and the upstream side of the expiratory one-way valve for connecting to the patient's airway. A carbon dioxide removal device is provided between the downstream side of the expiratory one-way valve and the upstream side of the inspiratory one-way valve for removing carbon dioxide exhaled by the patient from the breathing circuit.

[0009] The structure of the carbon dioxide removal device includes a gas screening tank and a gas separation membrane installed inside it. The gas separation membrane is a carbon dioxide permeable membrane, which is used to separate carbon dioxide in the breathing circuit of the anesthesia machine from the gas by passing through the membrane layer. The gas separation membrane is connected to the breathing circuit through the air inlet and delivers reusable gas with carbon dioxide removed by connecting the intercepted gas outlet.

[0010] The structure of the carbon dioxide removal device further includes: a backup gas separation membrane and a pressure check valve; the backup gas separation membrane is connected to the air inlet through the pressure check valve, and its intercepted gas outlet is also connected to the breathing circuit. Its permeation side is connected to the interface of the anesthetic waste gas removal system. When the patient's breathing volume is greater than the set threshold, the increased flow rate and pressure cause the check valve to open, and the backup gas separation membrane separates the remaining gas into carbon dioxide.

[0011] The gas separation membrane is made of either a molecular sieve membrane or a polymer membrane.

[0012] The molecular sieve membrane is made of high-silicon or all-silicon molecular sieve.

[0013] The molecular sieve membrane support is a hollow fiber structure with four channels, and the diameter of the hollow fiber structure is 1mm-5mm.

[0014] The support material for the molecular sieve membrane is alumina.

[0015] The carbon dioxide removal device further includes: an anesthetic gas vaporizer connected to the ventilator for releasing anesthetic gas into the tubing.

[0016] The anesthetic gas is selected from propofol, thiopental sodium, halothane, chloroform, lorazepam, phenobarbital, caffeine, etc.

[0017] Beneficial effects

[0018] Gas separation membranes possess a regular microporous structure, enabling precise sieving at the molecular scale. They exhibit excellent carbon dioxide permeability and separation selectivity, particularly in studies of separating mixed gases containing carbon dioxide. The gas separation membrane is made of molecular sieve membrane, with four-channel hollow fiber alumina as the support, which facilitates increased membrane packing density and miniaturization of carbon dioxide separation devices.

[0019] Molecular sieve membranes have a high-silica (or all-silica) structure, strong hydrophobicity, good chemical stability and biocompatibility, which can extend the service life of membrane modules and thus significantly reduce application costs. They can also withstand high temperature, alcohol or ultraviolet disinfection and sterilization treatment, and have the advantage of recyclability. Attached Figure Description

[0020] Figure 1 : A schematic diagram of the front section structure of the present invention.

[0021] 1. Air inlet; 2. Gas screening tank; 3. Gas separation membrane; 4. Retained gas outlet; 5. Interface for anesthetic waste gas removal system. Figure 2 Flowchart of the carbon dioxide removal device in an anesthesia machine.

[0022] 6. Air source; 7. Inspiratory check valve; 8. Inspiratory end; 9. Patient end; 10. Expiratory end; 11. Expiratory check valve; 12. Respiratory mode control switch; 13. APL valve; 14. Reservoir bag; 15. Ventilator; 16. Carbon dioxide removal device.

[0023] Figure 3 Experimental results of treating carbon dioxide using molecular sieve membranes under saturated water vapor conditions.

[0024] Figure 4 : Another structural diagram of a carbon dioxide removal device.

[0025] 1. Air inlet; 2. Gas screening tank; 3. Gas separation membrane; 4. Retained gas outlet; 5. Interface for anesthetic waste gas removal system; 17. Alternative gas separation membrane; 18. Pressure check valve. Detailed Implementation

[0026] To address the drawbacks of traditional anesthesia machines that use soda lime or barium lime as carbon dioxide absorbents, such as strong corrosiveness, easy dust pollution in the operating room, increased workload for anesthesia staff, and increased burden of medical waste disposal, this invention employs a gas separation membrane. For example... Figure 1 As shown, the carbon dioxide removal device consists of an air inlet, a gas sieving tank, a gas separation membrane, a trapped gas outlet, and an interface for the anesthetic waste gas removal system. The patient's exhaled gas enters the gas sieving tank equipped with the gas separation membrane through the air inlet. Due to differences in the dynamic diameter, properties, and concentration of gases in the anesthetic circuit, such as oxygen, carbon dioxide, nitrogen, and anesthetic gases (e.g., sevoflurane), the gases are separated. Carbon dioxide passes through the gas separation membrane and is discharged from the circulation system, while the remaining gases are trapped in the anesthetic circuit and reused by the body.

[0027] More specifically, the carbon dioxide-free anesthesia machine in this embodiment includes a gas circulation circuit and a ventilator 15 connected to the gas circulation circuit. The circuit is provided with an inspiratory one-way valve 7 and an expiratory one-way valve 11. A patient-end connection port 9 is provided between the downstream side of the inspiratory one-way valve 7 and the upstream side of the expiratory one-way valve 11 for connecting to the patient's airway. A carbon dioxide removal device 16 is provided between the downstream side of the expiratory one-way valve 11 and the upstream side of the inspiratory one-way valve 7 for removing carbon dioxide exhaled by the patient from the breathing circuit.

[0028] The structure of the carbon dioxide removal device 16 includes a gas sieving tank 2 and a gas separation membrane 3 installed inside it. The gas separation membrane 3 is used to separate carbon dioxide in the breathing circuit of the anesthesia machine from the gas by passing through the membrane layer. The gas separation membrane 3 is connected to the breathing circuit through the air inlet 1 and delivers reusable gas with carbon dioxide removed by connecting the interception gas outlet 4.

[0029] The structure of the carbon dioxide removal device 16 further includes: a backup gas separation membrane 17 and a pressure check valve 18; the backup gas separation membrane 17 is connected to the air inlet 1 through the pressure check valve 18, and its intercepted gas outlet 4 is also connected to the breathing circuit. Its permeameter is connected to the interface 5 of the anesthetic waste gas removal system. When the patient's breathing volume is greater than the set threshold, the increased flow and pressure cause the check valve 18 to open, and the backup gas separation membrane 17 separates the remaining gas into carbon dioxide.

[0030] The carbon dioxide removal device 16 further includes: an anesthetic gas vaporizer connected to the ventilator for releasing anesthetic gas into the tubing.

[0031] Specific operation process:

[0032] (1) When a patient is ventilated by an anesthesia machine, the exhaled air enters the gas separation membrane assembly through the air inlet. Driven by the gas osmotic pressure, most of the carbon dioxide, a small amount of oxygen and nitrogen selectively permeate through the gas separation membrane and are discharged from the osmotic side. At the same time, most of the oxygen, nitrogen, anesthetic gas and a small amount of carbon dioxide that are retained are recovered from the retention side and mixed with fresh gas to continue to participate in human gas exchange and anesthesia.

[0033] (2) The gas passes through the hollow fiber molecular sieve membrane group, and the air source gas flow rate is adjusted by the inhalation one-way valve to deliver it to the patient end at a suitable oxygen permeation rate, and selectively separate the patient's exhaled gas.

[0034] like Figure 2 As shown in the complete gas exchange process diagram, carbon dioxide and oxygen enter the loop through the mass flow controller. The concentration of carbon dioxide and oxygen before gas separation is detected by the analysis equipment. After gas exchange through the membrane module, the concentration of carbon dioxide and oxygen on the interception side and the exhaust side is detected again.

[0035] The specific experimental procedure is as follows: a high-silica CHA molecular sieve membrane is used as the gas separation membrane. The inlet is controlled to contain 95% oxygen and 5% carbon dioxide under normal temperature and pressure (298K, 101kPa) humid conditions to simulate the patient's exhaled gas. The concentrations of oxygen and carbon dioxide on the inlet side, the interception side, and the exhaust side, as well as the separation performance, are calculated before and after gas separation.

[0036] Figure 3 This presents the experimental results of treating carbon dioxide using a molecular sieve membrane under saturated water vapor conditions. The inlet gas composition was 5% carbon dioxide and 95% air. At an inlet gas flow rate of 50 mL / min, the carbon dioxide concentration after membrane separation decreased to 0.2%. In the figures: Left: Horizontal axis: Total gas flow rate; Vertical axis: Carbon dioxide concentration on the retentative side; Red line: Carbon dioxide concentration; Blue line: Corrected carbon dioxide concentration. Right: Horizontal axis: Total gas flow rate; Left vertical axis: Gas permeability; Right vertical axis: Carbon dioxide concentration on the permeate side; Blue line: Permeate gas flow rate; Red line: Carbon dioxide concentration on the permeate side.

[0037] Figure 3 It is evident that as the inlet gas flow rate increases, the carbon dioxide content on the retrieval side also increases accordingly, while the carbon dioxide content on the permeate side decreases. This is mainly due to the limited processing load of the membrane. In another embodiment, the tank also includes an alternative gas separation membrane. This alternative gas separation membrane is connected to the gas inlet via a pressure check valve, and its retrieval side is also connected to the breathing circuit. Its permeate side is connected to the exhaust gas outlet. When the patient's respiratory volume exceeds a set threshold, the increased flow rate and pressure cause the check valve to open, allowing the alternative gas separation membrane to separate carbon dioxide from the remaining gas, thus avoiding the problem of reduced separation efficiency caused by increased gas flow load.

[0038] like Figure 3 As shown, gas separation membranes exhibit high selectivity for separating carbon dioxide and oxygen, high mechanical strength, stable properties, and good biocompatibility, making them promising materials to replace traditional carbon dioxide absorbents such as soda lime and barium lime.

[0039] This type of carbon dioxide removal device can be used as a fixed accessory for anesthesia machines for extended periods of time.

[0040] The embodiments of the present invention are given for illustrative and descriptive purposes only and are not exhaustive or intended to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A carbon dioxide-absent absorption canister anesthesia machine characterized by, The system includes a gas circulation circuit and a ventilator (15) connected to the gas circulation circuit. The gas circulation circuit is provided with an inspiratory one-way valve (7) and an expiratory one-way valve (11). A patient end connection port (9) is provided between the downstream side of the inspiratory one-way valve (7) and the upstream side of the expiratory one-way valve (11) for connecting to the patient's airway. A carbon dioxide removal device (16) is provided between the downstream side of the expiratory one-way valve (11) and the upstream side of the inspiratory one-way valve (7) for removing carbon dioxide exhaled by the patient from the breathing circuit. The carbon dioxide removal device (16) includes a gas sieving tank (2), a gas separation membrane (3) installed inside the gas sieving tank (2), an air inlet (1), a tamper gas outlet (4), and an anesthetic waste gas removal system interface (5). The gas separation membrane (3) is a carbon dioxide permeable membrane. The air inlet (1) is connected to the breathing circuit. The tamper gas outlet (4) is connected to the breathing circuit. The anesthetic waste gas removal system interface (5) is connected to the permeation side of the gas separation membrane (3). The carbon dioxide removal device (16) further includes an alternative gas separation membrane (17) and a pressure check valve (18). The alternative gas separation membrane (17) is connected to the air inlet (1) through the pressure check valve (18), and its intercepted gas outlet (4) is connected to the breathing circuit. Its permeation side is connected to the interface (5) of the anesthetic waste gas removal system. When the patient's breathing volume is greater than the set threshold, the increased flow rate and pressure cause the pressure check valve (18) to open, and the alternative gas separation membrane (17) separates the remaining gas into carbon dioxide to avoid the reduction in separation effect caused by the increase in gas flow load. The gas separation membrane (3) is a molecular sieve membrane; The molecular sieve membrane is made of high-silica CHA molecular sieve membrane and is hydrophobic, which can sieve carbon dioxide in exhaled air under saturated water vapor conditions. The molecular sieve membrane is supported by a hollow fiber structure with four channels, and the diameter of the hollow fiber structure is 1mm-5mm.

2. The anesthesia machine without a carbon dioxide absorption canister according to claim 1, characterized in that, The support is made of aluminum oxide.

3. The anesthesia machine without a carbon dioxide absorption canister according to claim 1, characterized in that, The structure of the carbon dioxide removal device (16) also includes an anesthetic gas vaporizer, which is connected to the ventilator (15) for releasing anesthetic gas into the tubing.

4. The anesthesia machine without a carbon dioxide absorption canister according to claim 1, characterized in that, The gas separation membrane (3) is configured such that after the patient's exhaled gas enters the gas sieving tank (2) through the air inlet (1), most of the carbon dioxide, a small amount of oxygen and nitrogen are discharged from the osmotic side under the push of gas osmotic pressure, while most of the oxygen, nitrogen, anesthetic gas and a small amount of carbon dioxide are recovered from the interception side and mixed with fresh gas to continue to participate in human gas exchange and anesthesia.

5. The anesthesia machine without a carbon dioxide absorption canister according to claim 1, characterized in that, It also includes an air source (6), which is located between the inhalation check valve (7) and the carbon dioxide removal device (16). The inhalation check valve (7) regulates the gas flow of the air source (6) to deliver it to the patient end connection port (9) at a suitable oxygen permeation rate, and works with the gas separation membrane (3) to selectively separate the patient's exhaled gas.

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