Blood gas solubility

Xenon 131 kDa boiling point —108 °C blood gas solubility coefficient 14 oibgas solubility coefficient 1.9 MAC 71 odourless. 

Ethanol, having high blood gas solubility is excreted very slowly by the lungs and nitrogen oxide, which are not very soluble in blood, will be excreted rapidly. 

It is a isomer of enflurane and its chemical and physical properties are similar to enflurane, but it is approximately Vi times more potent, more volatile. It has a lower blood gas solubility coefficient than enflurane. It produces rapid induction and recovery. 

Sevoflurane is a fluorinated methyl isopropyl ether (Figure 3.2). It was first released for clinical use in Japan in 1990 and it is now available in many other countries worldwide. Being relatively insoluble (blood/gas solubility coefficient, 0.68) it has the potential to provide rapid anaesthetic induction and recovery. Unlike isoflurane it is non-irritant to the airway and can be given in high concentrations for anaesthetic induction. Its MAC ranges from 3.3 in infants to 2.5 in older children and 1.8 in adults. 

Desflurane is a fluorinated methyl ethyl ether identical to isoflurane except for the substitution of a chlorine by a fluorine atom (Figure 3.2). It is the least soluble of all the volatile anaesthetics with a similar blood/gas solubility to nitrous oxide (0.42). It is non-flammable under all clinical conditions. The vapour pressure of desflurane approaches 1 atm at 23°C making controlled administration impossible with a conventional vaporiser. A desflurane vaporiser is an electronically controlled pressurised device that delivers an accurately metered dose of vaporised desflurane into a stream of fresh gases passing through it. The MAC of desflurane (6.5% in adults) is the highest of any modern fluorinated agent but in common with these the value decreases in the elderly and in other circumstances (see below). 

Nitrous oxide is rapidly absorbed from the alveoli. Due to its low blood/gas solubility equilibrium is rapidly established between the alveoli and the blood, and across the blood-brain barrier (Figure 3.1). The vast majority of... 

A highly flammable compound, ethylene forms dangerously explosive mixtures with air. It is phytotoxic (toxic to plants). Ethylene, itself, is not very toxic to animals, but it is a simple asphyxiant (see Section 13.3 and Table 13.1). At high concentrations, it acts as an anesthetic to induce unconsciousness. The only significant pathway of human exposure to ethylene is through inhalation. This exposure is limited by the low blood-gas solubility ratio of ethylene, which applies at levels below saturation of blood with the gas. This ratio for ethylene is only 0.14, compared, for example, with the very high value of 15 for chloroform.4... 

Desflurane is identical in structure to isoflurane, except that it is halogenated completely with fluorine instead of fluorine and chlorine. Desflurane is a volatile anesthetic that combines low blood gas solubility with moderate potency and high volatility. Its pharmacology has been reviewed (1,2). 

Sevoflurane [(CF3)2CHOCH2F] was first used in Japan and introduced into American clinical practice in 1995. Sevoflurane is defluorinated to approximately the same extent as enflurane. In fact, initial studies reported that plasma levels of fluoride associated with sevoflurane anesthesia are comparable to those seen after enflurane administration [54, 55]. More recent studies, however, report that plasma fluoride concentrations often rise above 50 mM [56, 57]. Due to sevoflurane s low blood/gas solubility, only limited quantities build up during anesthesia and, as a result, fluoride levels fall very quickly after termination of anesthesia. In vivo, defluorination in rats is increased by pretreatment with phenobarbital [58]. 

Studies in humans and animals have shown that Stoddard Solvent is readily absorbed through the lungs. In general, the aromatic components are likely to be more completely absorbed due to their higher blood/gas solubility. It is expected that volatile components or metabolites of Stoddard Solvent that have low blood solubility would be most easily excreted in exhaled breath. Aromatic components would be expected to be excreted primarily in urine as metabolites. 

Inhaled anesthetics with low blood gas solubility characteristically have a fast onset of action and a short duration of recovery. The new agent described here resembles nitrous oxide but is much more potent, as indicated by its low MAC value. Not all halogenated anesthetics undergo hepatic metabolism. The answer is (D). 

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