The device is lightweight and applicable, can directly utilize air and oxygen as carrier gases, and is capable of assisted and controlled respiration to meet various surgical requirements.
Its working principle is: after the patient has completed the induction of anesthesia, the air anesthesia machine is connected to a closed mask or tracheal tube. During inhalation, the anesthetic gas mixture enters the patient's body through the open inspiratory valve; during exhalation, the expiratory valve opens while the inspiratory valve closes to expel the exhaled gas. When assisted or controlled breathing is used, a folding bellows is utilized. It is pressed down during inhalation and pulled up during exhalation to ensure that the patient has sufficient ventilation. At the same time, the ether switch is adjusted to maintain a stable level of anesthesia as needed.
The shortcoming of this device is that the concentration of ether is low, which can only be used as the maintenance of anesthesia, and the consumption of ether is large, which is easy to cause environmental pollution. Since Lanning first applied ether anesthesia in 1846, inhalation anesthesia has been perfected. The development of modern pharmacology, scientific and technological progress, especially the application of electronic computer technology, more modern inhalation anesthesia level greatly improved. Inhalation anesthesia is easy to control, safe and effective. It is the first choice for surgery in current hospitals.
The so-called anesthesia refers to the organism all or part of the temporary loss of consciousness, in order to carry out surgical treatment method. There are various methods of anesthesia, such as needle anesthesia, injection anesthesia and inhalation anesthesia. At present, the method of general anesthesia used in hospitals is still mainly inhalation anesthesia. Anesthesia machine is the use of inhalation anesthesia method of general anesthesia instrument.
Modern anesthesia machine is moving towards the development of intelligent, integrated system, the combination of components coordinated, flexible, reliable, compact, reasonable structure, the use of a clear and friendly interface, easy and fast operation. Electronically controlled gas delivery system, built-in electronically controlled anesthesia ventilator, integrated breathing circuit, integrated gas monitoring system, high and low micro-flow anesthesia is the best combination of modern anesthesia machine. The new generation of anesthesia workstations will be extended to integrate into the whole medical system, which can be systematically networked, communicated, defined, and adjusted to the anesthesia process and records with the hospital equipment, to evaluate the anesthesia effect, to improve the quality of patient care, and to create a good working atmosphere for clinicians. Modern anesthesia machine can be divided into: gas supply and delivery system, anesthesia gas evaporation tank, breathing circuit, anesthesia ventilator, safety monitoring system and residual gas removal system according to the structural principle. Gas supply system includes: compressed gas cylinder (or central gas source), check valves, relief valves, filters, pressure gauges, gas pressure regulators, flow meters and N2O - O2 proportional interlocking control device, laugh - oxygen shut-off valve.
The anesthesia machine must be equipped with flowmeters for all gas sources, with flowmeters in L/min and mL/min (or less than 2L/min flow tubes) for both readings to facilitate low-flow anesthesia delivery. A N2O-O2 proportional interlock control device must also be provided to ensure that the output oxygen concentration level of the anesthetic gas does not fall below 25 % and that the nitrous oxide supply is automatically cut off when the oxygen supply is insufficient or interrupted. Common N2O - O2 ratio interlock control device, laugh - oxygen shut-off valve for mechanical devices, careful to prevent failure, in the daily use of the process, must pay attention to the O2, N2O ratio, check whether the flow meter leakage, relying on the anesthesia machine or other monitoring systems to monitor the respiratory circuit of the O2, N2O concentration, the more accurate measurement of the current anesthesia machine operation. Many modern anesthesia machines have 55L/min oxygen bypass, which can quickly and directly enter the respiratory circuit through the emergency interface, which greatly facilitates the clinical anesthesiologist's oxygen supply operation. The volatile canister (also known as: anesthesia evaporator, evaporation canister) is an important part of the anesthesia machine, and its quality not only marks the manufacturing level of the anesthesia machine, but also relates to the effect of inhalation anesthesia and the success or failure of the patient's safety is directly related to the patient.
The basic principle of evaporation canister is to use the temperature of the surrounding environment and the change of heat source, the anesthetic drugs into evaporating gas, through a certain amount of carrier gas, which part of the gas carries away the saturated anesthetic gases, and becomes a certain concentration of anesthetic vapors of the gas flow, directly into the anesthetic circuit. Anesthesia ventilator has become a necessary part of anesthesia machine. Because of the inhalation anesthesia to achieve mechanical ventilation, in recent years the rapid development, and fully functional, miniaturized.
Anesthesia ventilator drive pneumatic, pneumatic electric control and electric. Pneumatic type of respirator is an older product, purely compressed oxygen as a power source, oxygen consumption, is out of the respirator; the newer anesthesia machine supporting anesthesia ventilator is mostly oxygen-driven, electrically controlled; newer anesthesia ventilator is a built-in electric electric control ventilator without driver, can be in the case of gas cuts, supplemented by the atmosphere to carry on the ventilation, to ensure the safety of the patient; more typical anesthesia ventilator for pneumatic Typical anesthesia ventilators are pneumatic electrically controlled ventilators, with two sets of airway circuits inside and outside the folded capsule inside the transparent sealing cover, in which the driving air compresses the folded capsule and drives the anesthesia gas inside the capsule into the patient, forming a two-loop system of the driving air source and anesthesia gas flow. Air anesthesia machine belongs to semi-open anesthesia device. It is mainly composed of medicine tank, ether adjustment switch, folding air box and inhalation and exhalation one-way valve and bellows. As shown in Figure 2-1-1. The device is lightweight and applicable, can directly utilize air and oxygen as carrier gas, and can perform assisted and controlled breathing to meet various surgical requirements.