Dr Deco
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Dear Readers:
Oxygen Toxicity and Solubility
It has been mentioned here that anesthetic gases can be ranked in their potency by the rule of Overton and Meyer. At the beginning of the last century, they noted that the gaseous (inhalation) anesthetics (not barbiturates or other injectable drugs) could be ranked in terms of their relative solubility in water and olive oil. This was believed to reflect the fact that some component of lipid-rich nerve tissue was dissolving the anesthetic. What change it then actually effected was the subject of considerable controversy. Most ideas focus on cell membranes, and the ability of these anesthetic molecules to modify the membrane and alter its ability to transport sodium and potassium ions (those ions responsible for the nerve impulse).
Inertness
One major aspect of inhalation anesthetics is that they are physiologically inert. That is, some chemical reaction is not necessary for them to produce their anesthetic effect. Some are detoxified in the liver and will be exhaled in a chemically altered form. This does not affect their anesthetic potential but is certainly not salutary for the liver. Some inhalation anesthetics such as xenon are excreted quantitatively, that is, you get back everything in an unchanged form.
Oxygen
When we get into those substances that are chemically active in the body, then the situation begins to change. Actually virtually any organic liquid can be inhaled to produce some sort of narcotic effect. Glue sniffing and gasoline sniffing are example of unhealthy behaviors (to say the least) of this. For something to be of clinical utility, certain expectations must be met. Chloroform is a good anesthetic but it will stop the heart before it arrests breathing. It is easy to ventilate a patient with a hose and breathing bag but not easy to start a heart. Carbon tetrachloride is a good anesthetic but it is also a poison. Another bad agent.
Oxygen is certain not chemically inert in the body. Thus the Overton-Meyer rule of solubilities might not be expected to apply.
Dr Deco :doctor:
Oxygen Toxicity and Solubility
It has been mentioned here that anesthetic gases can be ranked in their potency by the rule of Overton and Meyer. At the beginning of the last century, they noted that the gaseous (inhalation) anesthetics (not barbiturates or other injectable drugs) could be ranked in terms of their relative solubility in water and olive oil. This was believed to reflect the fact that some component of lipid-rich nerve tissue was dissolving the anesthetic. What change it then actually effected was the subject of considerable controversy. Most ideas focus on cell membranes, and the ability of these anesthetic molecules to modify the membrane and alter its ability to transport sodium and potassium ions (those ions responsible for the nerve impulse).
Inertness
One major aspect of inhalation anesthetics is that they are physiologically inert. That is, some chemical reaction is not necessary for them to produce their anesthetic effect. Some are detoxified in the liver and will be exhaled in a chemically altered form. This does not affect their anesthetic potential but is certainly not salutary for the liver. Some inhalation anesthetics such as xenon are excreted quantitatively, that is, you get back everything in an unchanged form.
Oxygen
When we get into those substances that are chemically active in the body, then the situation begins to change. Actually virtually any organic liquid can be inhaled to produce some sort of narcotic effect. Glue sniffing and gasoline sniffing are example of unhealthy behaviors (to say the least) of this. For something to be of clinical utility, certain expectations must be met. Chloroform is a good anesthetic but it will stop the heart before it arrests breathing. It is easy to ventilate a patient with a hose and breathing bag but not easy to start a heart. Carbon tetrachloride is a good anesthetic but it is also a poison. Another bad agent.
Oxygen is certain not chemically inert in the body. Thus the Overton-Meyer rule of solubilities might not be expected to apply.
Dr Deco :doctor:
