Anesthesia refers to the temporary loss of consciousness, either in whole or in part, in an organism so that surgical treatment can be performed. There are various methods of anesthesia, such as acupuncture anesthesia, injection anesthesia and inhalation anesthesia. At present, the method of general anesthesia used in hospitals is still mainly inhalation anesthesia.
An anesthesia ventilator machine is an instrument that uses inhalation anesthesia for general anesthesia. Modern anesthesia machines are developing towards an intelligent and integrated system. The components are coordinated, flexible, reliable, compact, and reasonably used. The interface is clear and friendly, and the operation is convenient and fast.
Electronically controlled gas delivery system built-in electronically controlled anesthesia ventilator has an integrated breathing circuit, an integrated gas monitoring system, general anesthesia trolley and anesthesia methods of high and low microflow, which are the best combination of modern anesthesia machines.
The new generation of anesthesia workstations will be expanded into the entire medical system, which can network with hospital equipment, communicate, define, adjust the anesthesia process, record and evaluate the effect of anesthesia, improve the quality of patient care, and create a good working atmosphere for clinicians.
The modern anesthesia machine 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 cylinder or central gas source, one-way valve, relief valve, filter, pressure gauge, gas pressure regulator, flow meter and N2O/O2 proportional interlock control device, shut-off valve, etc.
Anesthesia machines must be equipped with flow meters for various gas sources. The flowmeter units for anesthesia machines are L/min and mL/min (or less than 2L/min flow tubes), both of which read flow tubes to facilitate low-flow anesthesia.
At the same time, it must be equipped with a N2O/O2 proportional interlock control device 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 nitrous oxide supply is automatically cut off.
Many modern anesthesia machines have a 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 affects the effect and success of inhalation anesthesia, and directly affects the safety of the patient.
The basic principle of the vaporizer is to use the changes in the temperature and heat source of the surrounding environment to turn anesthetics into vaporized gas, and a certain amount of carrier gas will carry a part of the gas to carry the saturated anesthetic gas. After it becomes an airflow with a certain concentration of anesthesia vapor, it directly enters the anesthesia circuit.
3. Breathing circuit
The breathing circuit is a combined air circuit device that connects the anesthesia machine to the patient. It delivers anesthesia mixed gas for the patient, and returns the patient's exhaled gas, so as to realize the normal exchange of oxygen and carbon dioxide gas.
It is mainly composed of breathing pipe, CO2 absorption tank, breathing valve, storage bag, mask, computer-controlled manual valve, exhaust valve, pressure limiting valve, open/semi-open valve, etc.
4. Anesthesia ventilator
Anesthesia ventilator has become an essential part of anesthesia machine. Mechanical ventilation has been achieved due to inhalation anesthesia, and it has developed rapidly in recent years. The anesthesia ventilator is fully functional and miniaturized, and its drives are pneumatic and electric.
Most of the anesthesia ventilators matched with the newer portable anesthesia machines are oxygen-driven and electronically controlled. The recent anesthesia ventilator belongs to the built-in electric and electronically controlled ventilator. It can be supplemented by the atmosphere for ventilation without a driver, which can ensure the safety of the patient.
5. Safety monitoring system
Modern general anesthesia machine has safety modular patient monitor systems, which include insufficient oxygen supply alarms, insufficient oxygen supply/interruption nitrous oxide cut-off devices, volume and concentration monitoring parts and fault alarms.
The monitoring part of the anesthesia machine mainly includes inhaled oxygen concentration, exhaled tidal volume, airway pressure, minute ventilation, end-tidal CO2 concentration, and anesthetic gas concentration.
It can process and display various data with a microcomputer, and is equipped with an alarm device system. In particular, the monitoring functions of breathing, circulation, nerve and muscle can be realized, which greatly improves the quality of clinical anesthesia and the safety of patients, and improves the success rate of surgery.
6. Residual gas removal system
The residual gas removal system is used to collect the excess residual gas in the anesthesia machine and the exhaust gas exhaled by the patient, and discharge it out of the operating room through the pipeline to avoid air pollution in the operating room.
It is mainly composed of waste gas collection and discharge device, which is composed of regulating valve, discharge valve, vacuum generator, pipeline and connecting parts.