Anesthesia machine without carbon dioxide absorption tank

Abstract

The invention provides an anaesthesia machine without a carbon dioxide absorption tank. The anaesthesia machine comprises a breathing machine, an anesthetic volatilization tank, a gas screening tank body and a molecular sieve membrane. According to the invention, the gas separation membrane is utilized to selectively permeate carbon dioxide, and molecular-scale precise screening is realized in separation of mixed gas containing carbon dioxide; meanwhile, the multi-channel ceramic hollow fiber membrane is used as a support body of the gas separation membrane, so that the filling density of the membrane is improved, and the miniaturization of the carbon dioxide separation device is realized. The problems that in the practical application process of an existing anesthesia breathing device, due to the fact that end-expiratory carbon dioxide concentration (PETCO2) monitoring and inhaled air carbon dioxide concentration (FiCO2) monitoring are lacked or a carbon dioxide absorbent is not replaced in time, carbon dioxide re-inhalation of a patient is caused, and carbon dioxide accumulation of the patient is caused are solved.

Description

Technical Field

[0001] The invention relates to the technical field of anesthesia breathing devices, and in particular to an anesthesia machine without a carbon dioxide absorption tank. Background Art

[0002] Most modern anesthesia machines use closed or semi-closed breathing circuits during mechanical ventilation. In this circuit, the carbon dioxide in the patient's exhaled gas must be absorbed and removed by a carbon dioxide absorption device and then returned to the anesthesia machine's breathing circuit, thereby preventing the patient from repeatedly inhaling carbon dioxide and threatening his life.

[0003] Commonly used carbon dioxide absorbents in clinical practice mainly include soda lime, calcium lime, and barium lime. Their working principle is to utilize the chemical reaction between carbon dioxide absorbent and carbon dioxide to achieve carbon dioxide absorption. The gas humidity, temperature, fresh gas flow, ventilation volume, and breathing circuit type of the anesthesia machine in the circuit affect the absorption efficiency of the carbon dioxide absorbent. At present, there is no recognized standard for the timing of replacing the carbon dioxide absorbent when the carbon dioxide absorbent is exhausted. In the absence of end-tidal carbon dioxide concentration (P ET CO 2 ) monitors and inspiratory carbon dioxide concentration (FiCO 2 ) During monitoring, failure to replace the carbon dioxide absorbent in time may cause the patient to re-inhale carbon dioxide, resulting in carbon dioxide accumulation in the patient, seriously affecting the patient's safety.

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

[0005] In view of the above-mentioned defects, this application is proposed. Summary of the invention

[0006] The invention aims at the problem of carbon dioxide absorber in the existing anesthesia circuit and provides an anesthesia machine without carbon dioxide absorption tank.

[0007] In order to solve the problems in the above background technology, the present invention provides the following technical solutions:

[0008] An anesthesia machine without a carbon dioxide absorption tank comprises a gas circulation loop and a ventilator connected to the gas circulation loop. An inhalation check valve and an exhalation check valve are arranged in the loop. A patient end connection port is arranged between the downstream side of the inhalation check valve and the upstream side of the exhalation check valve for connecting to the patient's respiratory tract. A carbon dioxide removal device is arranged between the downstream side of the exhalation check valve and the upstream side of the inhalation check valve for removing carbon dioxide exhaled by the patient in the breathing circuit.

[0009] The structure of the carbon dioxide removal device includes a gas screening tank and a gas separation membrane installed inside the tank. The gas separation membrane refers to a carbon dioxide permeable membrane, which is used to separate the carbon dioxide in the breathing circuit of the anesthesia machine from the gas through the membrane layer. The gas separation membrane is connected to the breathing circuit through the air inlet and is connected to the retained gas outlet to transport reusable gas from which carbon dioxide has been removed.

[0010] The structure of the carbon dioxide removal device also includes: an alternative gas separation membrane and a pressure check valve; the alternative gas separation membrane is connected to the air inlet through the pressure check valve, and its retained gas outlet is also connected to the breathing circuit, and 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 and pressure cause the check valve to open, and the alternative gas separation membrane separates the carbon dioxide from the remaining gas.

[0011] The material of the gas separation membrane is one of a molecular sieve membrane and a polymer membrane.

[0012] The material of the molecular sieve membrane is high silicon or full silicon molecular sieve.

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

[0014] The supporting material of the molecular sieve membrane is alumina.

[0015] The structure of the carbon dioxide removal device also includes: a volatilizer of anesthetic gas, which is connected to the ventilator and is used to release anesthetic gas into the pipeline.

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

[0017] Beneficial Effects

[0018] The gas separation membrane has a regular microporous structure and can achieve precise screening at the molecular scale, especially in the separation of mixed gases containing carbon dioxide, showing excellent carbon dioxide gas permeability and separation selectivity. The gas separation membrane is made of molecular sieve membrane, with four-channel hollow fiber alumina as the support of the molecular sieve membrane, which is conducive to improving the packing density of the membrane and facilitating the miniaturization of the carbon dioxide separation device.

[0019] The molecular sieve membrane has a high silicon (or all-silicon) structure with strong hydrophobicity, good chemical stability and biocompatibility. It can extend the service life of the membrane component and thus significantly reduce the application cost. It can also withstand high temperature, alcohol or ultraviolet disinfection and sterilization treatment and has the advantage of being recyclable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : A schematic diagram of the cross-sectional structure of the present invention.

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

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

[0023] Figure 3 : Experimental results of molecular sieve membrane treatment of carbon dioxide under saturated water vapor conditions.

[0024] Figure 4 : Structural diagram of another carbon dioxide removal device.

[0025] 1. Air inlet; 2. Gas screening tank; 3. Gas separation membrane; 4. Retained gas outlet; 5. Anesthetic waste gas removal system interface; 17. Alternative gas separation membrane; 18. Pressure check valve. DETAILED DESCRIPTION

[0026] In view of the defects of the conventional anesthesia machine using soda lime and barium lime as carbon dioxide absorbent, which are highly corrosive, easily cause dust pollution in the operating room, increase the workload of anesthesia medical staff, and increase the burden of medical waste disposal, the present invention adopts a gas separation membrane. Figure 1As shown, the carbon dioxide removal device is composed of an air inlet, a gas screening tank, a gas separation membrane, a trapped gas outlet, and an interface for anesthesia waste gas removal system. The patient's exhaled gas enters the gas screening tank equipped with a gas separation membrane through the air inlet. Due to the differences in the dynamic diameter, properties, and concentration of oxygen, carbon dioxide, nitrogen, anesthetic gas (sevoflurane, etc.) and other gases in the anesthesia circuit, 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 anesthesia circuit and reused by the human body.

[0027] More specifically, the anesthesia machine without a carbon dioxide absorption tank in this embodiment includes a gas circulation loop and a ventilator 15 connected to the gas circulation loop. An inhalation check valve 7 and an exhalation check valve 11 are provided in the loop. A patient-end connection port 9 is provided between the downstream side of the inhalation check valve 7 and the upstream side of the exhalation check valve 11 for connecting to the patient's respiratory tract. A carbon dioxide removal device 16 is provided between the downstream side of the exhalation check valve 11 and the upstream side of the inhalation check valve 7 for clearing the carbon dioxide exhaled by the patient in the breathing circuit.

[0028] The structure of the carbon dioxide removal device 16 includes a gas screening tank body 2 and a gas separation membrane 3 installed therein. The gas separation membrane 3 is used to separate the carbon dioxide in the breathing circuit of the anesthesia machine from the gas through the membrane layer. The gas separation membrane 3 is connected to the breathing circuit through the air inlet 1 and is connected to the retained gas outlet 4 to transport reusable gas from which carbon dioxide has been removed.

[0029] The structure of the carbon dioxide removal device 16 also 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 trapped gas outlet 4 is also connected to the breathing circuit, and its permeability test is connected to the anesthesia waste gas removal system interface 5. 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 alternative gas separation membrane 17 separates the carbon dioxide from the remaining gas.

[0030] The structure of the carbon dioxide removal device 16 also includes: a volatilizer of anesthetic gas, connected to the ventilator, for releasing anesthetic gas into the pipeline.

[0031] Specific operation process:

[0032] (1) The exhaled air of a patient who is artificially ventilated using an anesthesia machine 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 the gas separation membrane and are discharged from the permeation side. At the same time, most of the intercepted 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.

[0033] (2) The gas passes through the hollow fiber molecular sieve membrane group, and the air source gas flow is adjusted by the inhalation check valve, and is delivered to the patient end at an appropriate oxygen permeation rate, and the patient's exhaled gas is selectively separated.

[0034] like Figure 2 As shown in the whole gas exchange flow chart, carbon dioxide and oxygen enter the loop through the mass flow controller, and the concentration of carbon dioxide and oxygen before gas separation is first detected by an analytical device. After gas exchange through the membrane assembly, the concentration of carbon dioxide and oxygen on the interception side and the exhaust side are detected again.

[0035] The specific experimental process is: using high-silicon CHA molecular sieve membrane as the gas separation membrane, adjusting the inlet to 95% oxygen and 5% carbon dioxide under normal temperature and pressure (298K, 101kPa) humid conditions to simulate the patient's exhaled gas, and calculating the concentrations of oxygen and carbon dioxide on the inlet side, interception side, exhaust side and separation performance before and after gas separation.

[0036] Figure 3 The experimental results of molecular sieve membrane treatment of carbon dioxide under saturated water vapor conditions. The inlet gas composition is 5% carbon dioxide and 95% air. When the inlet gas volume is 50mL / min, the carbon dioxide concentration after membrane separation is reduced to 0.2%. In the figure: Left figure: horizontal axis: total gas volume; vertical axis: carbon dioxide concentration on the interception side; red line: carbon dioxide concentration; blue line: corrected carbon dioxide concentration. Right figure: horizontal axis: total gas volume; left vertical axis: gas permeability; right vertical axis: carbon dioxide concentration on the permeate side; blue line: permeate gas volume; red line: carbon dioxide concentration on the permeate side.

[0037] Figure 3 It can be seen that as the intake air flow increases, the carbon dioxide content on the interception side will also increase accordingly, and the carbon dioxide content on the permeation side will decrease, which is mainly due to the limited processing load of the membrane. In another embodiment, the tank body also includes an alternative gas separation membrane, which is connected to the gas inlet through a pressure check valve, and its interception side is also connected to the breathing circuit, and its permeation side is connected to the exhaust gas outlet. When the patient's breathing volume is greater than the set threshold, the increased flow and pressure cause the check valve to open, and the alternative gas separation membrane separates the carbon dioxide from the remaining gas, avoiding the problem of reduced separation effect caused by increased gas flow load.

[0038] like Figure 3 As shown, the separation of carbon dioxide and oxygen based on gas separation membrane has high selectivity, high mechanical strength, stable properties, and good biocompatibility, and is expected to become a material to replace traditional carbon dioxide absorbers such as soda lime and barium lime.

[0039] This type of carbon dioxide removal device can be used for a long time as a fixed accessory of the anesthesia machine.

[0040] The embodiments of the present invention are provided for the purpose of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. An anesthesia machine without a carbon dioxide absorption tank, characterized in that: The invention comprises a gas circulation circuit and a breathing machine (15) connected to the gas circulation circuit. An inhalation check valve (7) and an exhalation check valve (11) are arranged in the circuit. A patient end connection port (9) is arranged between the downstream side of the inhalation check valve (7) and the upstream side of the exhalation check valve (11) for connecting to the patient's respiratory tract. A carbon dioxide removal device (16) is arranged between the downstream side of the exhalation check valve (11) and the upstream side of the inhalation check valve (7) for removing carbon dioxide exhaled by the patient in the breathing circuit.

2. The anesthesia machine without carbon dioxide absorption tank according to claim 1, characterized in that: The structure of the carbon dioxide removal device (16) includes a gas screening tank (2) and a gas separation membrane (3) installed inside the tank. The gas separation membrane (3) refers to a carbon dioxide permeable membrane, which is used to separate the carbon dioxide in the breathing circuit of the anesthesia machine from the gas through the membrane layer. The gas separation membrane (3) is connected to the breathing circuit through the air inlet (1) and is connected to the retained gas outlet (4) to transport reusable gas from which carbon dioxide has been removed.

3. The anesthesia machine without carbon dioxide absorption tank according to claim 1, characterized in that: The structure of the carbon dioxide removal device (16) also includes: an alternative gas separation membrane (17) and a pressure check valve (18); the gas separation membrane (17) is connected to the air inlet (1) through the pressure check valve (18), and its trapped gas outlet (4) is also connected to the breathing circuit, and its permeation side is connected to the anesthetic waste gas removal system interface (5). When the patient's breathing volume is greater than a set threshold, the increased flow and pressure cause the check valve (18) to open, and the alternative gas separation membrane (17) separates the carbon dioxide from the remaining gas.

4. The anesthesia machine without carbon dioxide absorption tank according to claim 2, characterized in that: The material of the gas separation membrane (3) is one of a molecular sieve membrane and a polymer membrane.

5. The anesthesia machine without carbon dioxide absorption tank according to claim 4, characterized in that: The material of the molecular sieve membrane is high silicon or all silicon molecular sieve.

6. The anesthesia machine without carbon dioxide absorption tank according to claim 5, characterized in that: The support of the molecular sieve membrane has a four-channel hollow fiber structure, and the diameter of the hollow fiber structure is 1mm-5mm.

7. The anesthesia machine without carbon dioxide absorption tank according to claim 5, characterized in that: The supporting material of the molecular sieve membrane is alumina.

8. The anesthesia machine without carbon dioxide absorption tank according to claim 1, characterized in that: The structure of the carbon dioxide removal device (16) also includes: a volatilizer of anesthetic gas, connected to the ventilator, for releasing anesthetic gas into the pipeline.

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