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Metabolic Effects of Anesthesia. By Ngai S. H. Papper E. M. Published by Charles C. Thomas. Pp. viii + 89. Price $5.75.
BRITISH JOURNAL OF ANAESTHESIA
594 may be inferred not only about body levels of the agent, but also about certain features of the distribution of the drug. (5) Tensions (strictly, fugacities) are a measure of thermodynamic activity and may be more directly related to theories of anaesthesia. A possible objection to considering the blood level as a tension is that blood tensions, unlike concentrations, cannot be measured directly. However, those who do measure arterial concentrations will generally be
familiar with the further small step necessary to express their result as a tension. J. F. NUNN R. A. BUTLER
London REFERENCE
Meyer, K. H., and Hemmi, H. (1935). Beitrage zur Theorie der Narkose III. Biochem. Z., Ill, 39.
Metabolic Effects of Anesthesia. By S. H. Ngai and E. M. Papper. Published by Charles C. lhomas. Pp. viii + 89. Price $5.75. A great deal of information is summarized and analyzed in this small book, with its 367 references and fewer than 50 pages of text. There are two sections, the first according to the title (but including endocrine actions), the second part dealing with many important facets of carbon dioxide accumulation; since respiratory acidosis probably never occurs without a metabolic component, this seems a reasonable inclusion. The effects of general anaesthetics on metabolic and endocrine systems can be regarded in several ways. Thus, the agents may have direct, even specific actions; this is suggested most obviously in the case of diethyl ether, so many of whose effects, like those of carbon dioxide are attributable to sympathoadrenal discharge. But if the autonomic nervous system is also aroused by cyclopropane, why are the metabolic actions of this anaesthetic so much less pronounced? In any case, can an anaesthetic be a stimulant? Clearly, metabolic changes do not stand alone, but when ether is excluded from consideration the effects of other anaesthetics seem unremarkable. When metabolic and hormonal changes do occur with these agents, is this simply an accompaniment to coincident respiratory and circulatory alterations, which are in turn merely reflections of the distinctive action of individual anaesthetics on central nervous circuits? These and other questions will not be answered in this book, nor indeed in any other. Even after 115 clinical years of diethyl ether there is remarkably little detailed knowledge of its mode of action— perhaps this is a case of experimental neglect accounted for by clinical safety. The challenge to the research worker will remain, however, to keep diethyl ether on the bench, and in full view, for some time to come. This is not all, for there are fascinating similarities between ether and carbon dioxide. Ether is still a widely used laboratory anaesthetic, its metabolic actions being particularly pronounced in the dog. If this monograph finds its way on to the right bookshelf, therefore, its value could be the greater to the research worker sometimes inclined
to play down the detrimental effects on his experimental findings of the anaesthetic used. In no sphere is this more relevant than in neurophysiology, where the hours taken in initial preparation, together with respiratory factors, some blood loss, and perhaps ether anaesthesia, may all combine to lead to rampant metabolic changes. Is it too stringent to suggest that no studies involving anaesthetics can be considered definitive without excluding by measurement the existence of acidosis (or alkalosis, which is not discussed in the present publication)? Here, perhaps, is the main message. The standard of presentation in this monograph is high, and points of criticism are largely matters of opinion. The style of writing is terse, but this, and the omission of a few articles, is probably a result of the scientific approach and an efficient compression of subject matter. In the introduction there is one sentence whose meaning is obscure; there are small misprints on pages 42 and 49. Strangely enough, there is no mention of pH, nor of one common cause of metabolic acidosis during surgery—untreated haemorrhage. Methods of measurement are not discussed, which matters only occasionally—for instance when results given were obtained with the ethylene diamine method (which includes catechol in its plasma noradrenaline value). More important, perhaps, and raising wider issues, it could be argued (as so often nowadays) that much of the material summarized in this book has already been presented elsewhere in recent anaesthetic journals, and that (with one exception) there are no references later than 1960. This monograph is, in fact, scarcely larger than an article in "Physiological" or "Pharmacological Reviews". A defence of publication in book form might be, sadly, that all anaesthetic journals do not find their way into every basic science laboratory. In many ways, certainly, monographs are an ideal way to summarize and disseminate information, provided they are presented critically (as in the present case), and that they are up-to-date and inexpensive. This book can be recommended to both scientist and clinician (if such division of cultures can be tolerated). It is a useful summary and may be read (but not digested) in one short evening. R. A. Millar
Printed in Great Britain by John Sherrau & Son, Park Road, Aitrincham
Downloaded from http://bja.oxfordjournals.org/ at University of California, Santa Barbara on July 19, 2015
BOOK REVIEW
594 may be inferred not only about body levels of the agent, but also about certain features of the distribution of the drug. (5) Tensions (strictly, fugacities) are a measure of thermodynamic activity and may be more directly related to theories of anaesthesia. A possible objection to considering the blood level as a tension is that blood tensions, unlike concentrations, cannot be measured directly. However, those who do measure arterial concentrations will generally be
familiar with the further small step necessary to express their result as a tension. J. F. NUNN R. A. BUTLER
London REFERENCE
Meyer, K. H., and Hemmi, H. (1935). Beitrage zur Theorie der Narkose III. Biochem. Z., Ill, 39.
Metabolic Effects of Anesthesia. By S. H. Ngai and E. M. Papper. Published by Charles C. lhomas. Pp. viii + 89. Price $5.75. A great deal of information is summarized and analyzed in this small book, with its 367 references and fewer than 50 pages of text. There are two sections, the first according to the title (but including endocrine actions), the second part dealing with many important facets of carbon dioxide accumulation; since respiratory acidosis probably never occurs without a metabolic component, this seems a reasonable inclusion. The effects of general anaesthetics on metabolic and endocrine systems can be regarded in several ways. Thus, the agents may have direct, even specific actions; this is suggested most obviously in the case of diethyl ether, so many of whose effects, like those of carbon dioxide are attributable to sympathoadrenal discharge. But if the autonomic nervous system is also aroused by cyclopropane, why are the metabolic actions of this anaesthetic so much less pronounced? In any case, can an anaesthetic be a stimulant? Clearly, metabolic changes do not stand alone, but when ether is excluded from consideration the effects of other anaesthetics seem unremarkable. When metabolic and hormonal changes do occur with these agents, is this simply an accompaniment to coincident respiratory and circulatory alterations, which are in turn merely reflections of the distinctive action of individual anaesthetics on central nervous circuits? These and other questions will not be answered in this book, nor indeed in any other. Even after 115 clinical years of diethyl ether there is remarkably little detailed knowledge of its mode of action— perhaps this is a case of experimental neglect accounted for by clinical safety. The challenge to the research worker will remain, however, to keep diethyl ether on the bench, and in full view, for some time to come. This is not all, for there are fascinating similarities between ether and carbon dioxide. Ether is still a widely used laboratory anaesthetic, its metabolic actions being particularly pronounced in the dog. If this monograph finds its way on to the right bookshelf, therefore, its value could be the greater to the research worker sometimes inclined
to play down the detrimental effects on his experimental findings of the anaesthetic used. In no sphere is this more relevant than in neurophysiology, where the hours taken in initial preparation, together with respiratory factors, some blood loss, and perhaps ether anaesthesia, may all combine to lead to rampant metabolic changes. Is it too stringent to suggest that no studies involving anaesthetics can be considered definitive without excluding by measurement the existence of acidosis (or alkalosis, which is not discussed in the present publication)? Here, perhaps, is the main message. The standard of presentation in this monograph is high, and points of criticism are largely matters of opinion. The style of writing is terse, but this, and the omission of a few articles, is probably a result of the scientific approach and an efficient compression of subject matter. In the introduction there is one sentence whose meaning is obscure; there are small misprints on pages 42 and 49. Strangely enough, there is no mention of pH, nor of one common cause of metabolic acidosis during surgery—untreated haemorrhage. Methods of measurement are not discussed, which matters only occasionally—for instance when results given were obtained with the ethylene diamine method (which includes catechol in its plasma noradrenaline value). More important, perhaps, and raising wider issues, it could be argued (as so often nowadays) that much of the material summarized in this book has already been presented elsewhere in recent anaesthetic journals, and that (with one exception) there are no references later than 1960. This monograph is, in fact, scarcely larger than an article in "Physiological" or "Pharmacological Reviews". A defence of publication in book form might be, sadly, that all anaesthetic journals do not find their way into every basic science laboratory. In many ways, certainly, monographs are an ideal way to summarize and disseminate information, provided they are presented critically (as in the present case), and that they are up-to-date and inexpensive. This book can be recommended to both scientist and clinician (if such division of cultures can be tolerated). It is a useful summary and may be read (but not digested) in one short evening. R. A. Millar
Printed in Great Britain by John Sherrau & Son, Park Road, Aitrincham
Downloaded from http://bja.oxfordjournals.org/ at University of California, Santa Barbara on July 19, 2015
BOOK REVIEW