Introduction

Today, anaesthetists normally use mixtures of nitrous oxide and oxygen as a background anaesthetic and carrier to introduce a potent volatile liquid

Figure 1 Molecular structures for the volatile liquid anaesthetics (A) halothane, (B) enflurane and (C) isoflurane.

Figure 1 Molecular structures for the volatile liquid anaesthetics (A) halothane, (B) enflurane and (C) isoflurane.

anaesthetic such as halothane (2-bromo-2-chloro-1,1, 1-trifluoroethane), isoflurane (1-chloro-2,2,2trifluoro-ethyl difluoromethyl ether) or enflurane (2-chloro-1,1,2-trifluoroethyl difluoromethyl ether: Figure 1) to produce a state of anaesthesia and analgesia and to sedate a patient. Monitoring the patient's inhaled and exhaled breath during surgery is very important as a measure of the anaesthetic uptake and the depth of the anaesthesia. In operating theatres, therefore, physical methods of analysis (e.g. dedicated infrared analysers) are employed on account of their speed of response and continuous display facilities, though most can reliably handle only one component at a time. However, there is still the need to analyse such mixtures for all the major components, either in the course of research programmes involving different agents and different combinations such as inhaled or exhaled mixture analysis, blood and body fluid analysis, anaesthetic pollution studies, thermal decomposition studies or as a back-up to confirm the performance of the dedicated analysers. The major gases present in such mixtures, in addition to air, are carbon dioxide, nitrous oxide and halothane, isoflurane or enflurane (or cyclopropane, which is still in use in some places). If all the components (gases and vapours) need to be detected, gas chromatography is extremely powerful in the separation and quantification of the components, in comparison with the other techniques available.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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