The composition and use of anesthesia machines

Anesthesia is a method of temporarily rendering all or part of an organism unconscious to facilitate surgical treatment. There are many methods of anesthesia, such as acupuncture anesthesia, injection anesthesia and inhalation anesthesia. At present, the main method of general anesthesia used in hospitals is inhalation anesthesia.

An anesthesia machine is an instrument that uses inhalation anesthesia to perform general anesthesia. Modern anesthesia machines are developing towards intelligent and integrated systems. The combination of various components is coordinated, flexible, reliable, compact and rationally used. The interface is clear and friendly, and the operation is convenient and fast. Electronically controlled gas delivery system with built-in electronically controlled anesthesia ventilator, integrated breathing circuit, and integrated gas monitoring system. High and low micro-flow anesthesia methods are the best combination of modern anesthesia machines.

The new generation of anesthesia workstations will be expanded and integrated into the entire medical system, and can be connected to hospital equipment for system networking, communication, definition, adjustment of anesthesia processes, and recording and evaluation of anesthesia effects to improve the quality of patient care. Create a good working atmosphere for clinicians.

According to the structural principles, modern anesthesia machines can be divided into: gas supply and delivery system, anesthetic gas vaporizer, breathing circuit, anesthesia ventilator, safety monitoring system and residual gas removal system.

1. Gas supply and delivery system
The gas supply system includes compressed gas cylinders or central gas sources, one-way valves, relief valves, filters, pressure gauges, gas pressure regulators, flow meters, N2O/O2 proportional interlock control devices, laughing oxygen cut-off valves, etc. Anesthesia machines must be equipped with flow meters for various gas sources. Flowmeter units are available in L/min and mL/min (or flow tubes below 2L/min). Two reading flow tubes are available to facilitate low-flow anesthesia administration. At the same time, an N2O/O2 proportional interlock control device must be equipped to ensure that the oxygen concentration level of the output anesthetic gas is not less than 25%; when the oxygen supply is insufficient or interrupted, the laughing gas supply is automatically cut off. Common N2O/O2 proportional interlock control devices and laughing oxygen cut-off valves are mechanical devices, so be careful to prevent failure. During daily use, you must pay attention to the O2/N2O ratio, check whether the flow meter is leaking, and rely on the anesthesia machine or other monitoring system to monitor the O2/N2O concentration in the breathing circuit to accurately measure the current operation of the anesthesia machine. Many modern anesthesia machines have 55L/min oxygen bypass, which can quickly and directly enter the breathing circuit through the emergency interface, which greatly facilitates the oxygen supply operation of clinical anesthesiologists.

2. Anesthetic gas vaporizer
The vaporizer is an important part of the anesthesia machine. Its quality not only marks the manufacturing level of the anesthesia machine, but also is related to the effect and success of inhalation anesthesia, and is directly related to the safety of the patient. The basic principle of the vaporizer is to use changes in the surrounding environment's temperature and heat source to turn anesthetic drugs into vaporized gases. Through a certain amount of carrier gas, part of the gas carries away the saturated anesthetic gas and becomes a flow of anesthetic vapor with a certain concentration that directly enters the anesthesia. loop.

3. Breathing circuit
The breathing circuit is a combined gas circuit device connected between the anesthesia machine and the patient. It delivers anesthesia mixed gas to the patient and returns the patient's exhaled gas, thereby achieving normal exchange of oxygen and carbon dioxide. It is mainly composed of breathing tube, CO2 absorption tank, breathing valve, air storage bag, mask, machine-controlled manual valve, exhaust valve, pressure limiting valve, open/semi-open valve, etc. A directional circulation of gas is formed by the valve and the pipe, and the soda lime in the CO2 absorption tank is used to absorb CO2 and water to supply fresh gas to the patient. The machine-controlled manual valve allows users to choose between manual control or machine control through the anesthesia ventilator. Semi-open valves, pressure-limiting valves, etc. can allow the breathing circuit to flexibly control the pressure limit, which is beneficial to spontaneous breathing.

4. Anesthesia ventilator
Anesthesia ventilators have become an essential part of anesthesia machines. Due to the rapid development of mechanical ventilation during inhalation anesthesia in recent years, it has become fully functional and miniaturized. Anesthesia ventilator drives include pneumatic, pneumatic electronic control and electric. Newer anesthesia machines are equipped with anesthesia ventilators, most of which are oxygen-driven and electronically controlled. The recent anesthesia ventilators are built-in electric electronically controlled ventilators that do not require a driver and can be replenished by the atmosphere for ventilation when the air is cut off, ensuring the safety of the patient. . The more typical anesthesia ventilator is a pneumatic electronically controlled ventilator. There are two sets of air circuits inside and outside the foldable bag in the transparent sealing cover. The driving air compresses the folding bag and drives the anesthesia gas in the bag into the patient, forming a driving air source. , Anesthesia airflow two-loop system.

4. Safety monitoring system
Modern anesthesia machines have safety monitoring systems. The system includes an oxygen supply shortage alarm, a oxygen supply shortage/interruption laughing gas cut-off device, a volume and concentration monitoring part and a fault alarm. The monitoring part mainly includes inspired oxygen concentration, exhaled tidal volume, airway pressure, minute ventilation, end-tidal CO2 concentration, and anesthetic gas concentration. A microcomputer is used to process and display various data, and is equipped with an alarm device system, especially respiratory, circulation, nerve, and muscle monitoring functions, which greatly improves the quality of clinical anesthesia and patient safety, and improves the success rate of surgery. .

5. Residual gas removal system
The residual air removal system collects excess residual air in the anesthesia machine and the exhaust gas exhaled by the patient, and discharges it out of the operating room through pipelines to avoid air pollution in the operating room. It mainly includes waste gas collection and discharge devices, which are composed of regulating valves, discharge valves, vacuum generators, pipes and connectors, etc.

The above is the composition and usage principle of an anesthesia machine. YSENMED is a medical equipment supplier from China. YSENMED has 20 years of experience in the medical equipment industry.
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