Composition and use of anesthesia machine
Anesthesia refers to the temporary loss of consciousness in whole or in part of an organism for the purpose of surgical treatment. 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 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, integrated breathing circuit, and integrated gas monitoring system. High and low micro-flow anesthesia is the best combination of modern anesthesia machines.
The new generation of anesthesia workstations will expand into the entire medical system, and can systematically network with hospital equipment, communicate, define, adjust the anesthesia process and record and evaluate the effect of anesthesia to improve the quality of patient care. 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, overflow valve, filter, pressure gauge, gas pressure regulator, flow meter and N2O/O2 proportional interlock control device, nitrous oxide shut-off valve, etc. Anesthesia machines must be equipped with flow meters for various gas sources. Flowmeter units are available in L/min and mL/min (or less than 2L/min flowtubes) flowtubes for 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. The common N2O/O2 proportional interlock control device and nitrous oxide shut-off valve are mechanical devices, so be careful to prevent failure. In the daily use process, we must pay attention to the ratio of O2/N2O, check whether the flowmeter is leaking, and rely on the anesthesia machine or other monitoring system to monitor the O2/N2O concentration in the breathing circuit, which can accurately measure the current operation of the anesthesia machine. 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 the anesthetic drug into evaporative gas, and through a certain amount of carrier gas, a part of the gas carries the saturated anesthetic gas into an airflow with a certain concentration of anesthetic vapor directly into the anesthesia. loop.
3. Breathing circuit
The breathing circuit is a combined air circuit device connecting the anesthesia machine and the patient, delivering anesthesia mixed gas to the patient and returning the patient's exhaled gas, thereby realizing the normal exchange of oxygen and carbon dioxide gas. It is mainly composed of breathing pipeline, CO2 absorption tank, breathing valve, storage bag, mask, computer-controlled manual valve, exhaust valve, pressure limiting valve, development/semi-open valve, etc. The directional circulation of gas is formed by the valve and the pipeline, 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 facilitates the user to choose between manual control or machine control through an anesthesia ventilator. The semi-open valve, pressure limiting valve, etc. can make the breathing circuit flexibly control the pressure limit, which is conducive to spontaneous breathing.
4. Anesthesia ventilator
Anesthesia ventilator has become an essential part of anesthesia machine. Due to the rapid development of mechanical ventilation in inhalation anesthesia in recent years, it is fully functional and miniaturized. The drives of the anesthesia ventilator are pneumatic, pneumatic electric control and electric. The newer anesthesia machines are equipped with anesthesia ventilators, most of which are oxygen-driven electronically controlled. The latest anesthesia ventilators are built-in electric and electronically controlled ventilators. They can be supplemented by the atmosphere when the gas is cut off without a driver to ensure the safety of patients. . A typical anesthesia ventilator is a pneumatic and electronically controlled ventilator. The inside and outside of the folding bag in the transparent sealing cover are two sets of air circuit circuits, which drive the air to compress the folding bag and drive the anesthetic gas in the bag to enter the patient, forming a driving gas source. , Anesthesia airflow two-loop system.
4. Safety monitoring system
Modern anesthesia machines have safety monitoring systems. The system includes an alarm for insufficient oxygen supply, a cut-off device for insufficient oxygen supply/interruption of nitrous oxide, a volume and concentration monitoring part and a fault alarm. The monitoring part mainly includes inhaled oxygen concentration, expiratory tidal volume, airway pressure, minute ventilation, end-tidal CO2 concentration, and anesthetic gas concentration. Use microcomputer to process and display various data, and attach alarm device system, especially 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 .
5. Residual gas removal system
The residual gas removal system collects the excess residual gas in the anesthesia machine and the exhaust gas exhaled by the patient, and discharges it out of the operating room through the pipeline to avoid air pollution in the operating room. It mainly includes waste gas collection and discharge device, which is composed of regulating valve, discharge valve, vacuum generator, pipeline and connecting parts.
