What is an anaesthetic gas?
The term narcotic gases is used to describe so-called inhalation narcotics. Strictly speaking, these are not gases at all, but so-called volatile anaesthetics. These volatile anaesthetics are characterized by the fact that they vaporize at low temperatures.
This chemical property is exploited by developing special vaporizers in which the vaporization of the anesthetics can be controlled and regulated. This is used to induce or maintain anaesthesia. Only nitrous oxide and xenon are real gases that can be used for anaesthesia. However, due to its severe side effects, nitrous oxide is rarely used in clinical routine and xenon is currently only used experimentally.
What narcotic gases are available?
There is a whole range of anaesthetic gases. Each anaesthetic gas has its own advantages and disadvantages, and is adapted to the patient on the basis of these. The optimal anaesthetic gas has the properties of flooding the body quickly and consequently a fast onset of action, a low solubility in blood and a high solubility in fat.
At the same time, the anaesthetic gas should be quickly excreted as soon as the supply is stopped at the end of the anaesthesia, so that the patient can wake up again quickly. Among the common anaesthetic gases are Desflurane, sevoflurane and isoflurane. Laughing gas or xenon are also used in some clinics, but are rather the exception. Older anaesthetic gases like : halothane, enflurane and diethyl ether are no longer approved for clinical use.
How do anaesthetic gases work?
Anaesthetic gases act on many different target structures at the molecular level. Due to their high solubility in fat, the anaesthetic gases are distributed throughout the body and interact here particularly with components of the cell membrane. The exact processes at the cell membrane are not known, but it has been found that the higher the affinity of an anaesthetic gas to fat-like substances, the higher the relative effectiveness of the anaesthetic gas (see Meyer-Overton correlation).
In addition to these influences at the cell membrane, however, anaesthetic gases also have an influence on other metabolic pathways, which is why the effect is also referred to as the concept of multiple mechanisms and sites of action. This includes the modification of ion channels, which are responsible for the transmission of stimuli. Also discussed is an effect on different receptors, such as the GABA-A-receptors, 5-HT3-receptors, NMDA-receptors and mACh receptors. Here, each anaesthetic gas has a different influence on the different sites of action in a different way, which is why such a wide range of modes of action and strength of action is revealed.
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