The Pharmacology of Inhaled Anesthetics
E. I. Eger, J. B. Eisenkraft, R. B. Weiskopf (eds)
Sponsored by the Dannemiller Memorial Educational Foundation and privately published under an educational grant from Baxter Healthcare, 2002, 327 pp; indexed, illustrated
Availability: By Internet:[email protected]
By post: Messrs Baxter Healthcare (local regional office)
The package includes two digital versatile disks (DVDs), which cover the material in the book in the form of a 10 h seminar conducted by Professor Eger together with Post Test Questions. There is also a ‘Clinical Express Lane’, which allows rapid access to some of the material. Limited quantities of the book and DVDs will be available exclusively through Baxter Healthcare in Europe with preference given to teaching institutions that plan to use them as part of their formal educational programme.
At the outset, it should be noted that Baxter Healthcare are the manufacturers of desflurane, Suprane®. Professor Eger states in the faculty disclosure in the foreword that he has worked in a variety of capacities for the company. This is no way detracts from the relevance of the material presented and the prominence given to the various anaesthetics mentioned in the text.
Of considerable relevance and interest to UK anaesthetists (and I suspect anaesthesiologists in the USA as well) is the intended audience as stated in the foreword. ‘This material is intended for anaesthesiologists and certified registered nurse anaesthetists (CRNAs)’. Indeed, the seminar is presented to a group of both residents and student RNAs (SRNAs) at Wake Forest University Baptist Medical Center, Winston-Salem, North Carolina, USA. The first DVD is introduced by the respective heads of both the resident and CRNA programmes. The American Association of Nurse Anesthetists also approves the teaching material for continuing education.
The book is beautifully produced. The authors state in the preface that ‘individual texts have described the pharmacology and clinical application of individual inhaled anaesthetics … the present text enlarges that view (and) provides a broader inclusive focus'. Each chapter includes learning objectives and an abstract as well as a comprehensive and generally up-to-date reference section. The chapters cover all the necessary material including History, Physical Properties, MAC (minimum alveolar concentration), Mechanisms, Pharmacokinetics, Effects on Major Systems, Vaporization and Delivery, Clinical Applications and a Recipe for delivery of the (nearly) ideal anaesthetic. It concludes with a comprehensive question section on each chapter. Adequate emphasis is given also to the use of reduced gas flows, economy of agents and drug acquisition costs and the effect of anaesthetic department budgets with use of the different agents. The DVDs cover in seminar form much of the material in the book.
The book is clearly presented and pretty comprehensive. Not surprisingly the chapter on MAC is masterly and beyond reproach. However, I would have liked to see more on the relationship of infusions of remifentanil and reduction in MAC of the modern inhalation agents. I also felt that there was too much emphasis placed on nitrous oxide as a supplement, a role that can now be taken by remifentanil, thus removing any possibility of hypoxic mixtures and facilitating the use of closed circuit anaesthesia. The chapter on mechanisms was rather sketchy but covered most of the ground. Another omission was the use of awareness monitoring during inhalation (vs. i.v. anaesthesia). Bispectral analysis gets a couple of sentences and the authors dismissed the use of auditory evoked potentials in one sentence as ‘demanding appreciable preparation and is not widely used’. The latest reference is 1997 and none of the more recent work using the Alaris auditory evoked potential monitor is mentioned.
However, it is the inclusion of the seminars on DVDs, all conducted by Professor Eger to an audience of about 25 residents and SRNAs, that makes this publication a real winner. The seminars last altogether about 10 h and are presented in the same order as in the book, although not quite as comprehensively. They are masterly and are a lesson to all of us who teach medical students or residents. The seminars were held over a period of 2 days and the filming captures beautifully the atmosphere of the sessions. I was as impressed by the attentiveness, knowledge and participation of the audience as I was by the enthusiasm and expertise of the presenter. In fact, it was not long before I became part of that audience, interjecting and answering questions alongside the participants. Incidentally, the knowledge of the residents and SRNAs seemed equal. In fact, apart from those who participated in the operating session or in whom the identity badge was visible, it was impossible to tell between the two groups. However, I understand that joint sessions are unusual and are by no means the norm. Why not, one wonders?
The fact that I sat through the whole 10 h programme in about three sessions underlines the excellence of the material. Where appropriate, we were able to witness actual patients being anaesthetized in the operating rooms at the medical centre. It was particularly interesting to see the effects of a rapid increase in desflurane concentration on heart rate and blood pressure both before and after fentanyl. We also witnessed smooth induction with desflurane in front of a doubting audience. Given the rivalry between desflurane and sevoflurane and the respective Baxter and Abbott protagonists and antagonists, the presentation of good and bad points of both anaesthetics were very well balanced considering the grant had been obtained from Baxter. However, European audiences may be unaware that the packaging of sevoflurane in the USA includes the following statement ‘To minimize exposure to Compound A, sevoflurane exposure should not exceed 2 MAC hours at flow rates of 1 to <2 L min−1. Fresh gas flows of the <1 L min−1 are not recommended’. No such statement is included in the European packaging. The role and potential toxicity of Compound A is thus given quite a degree of prominence in both text and the seminars.
In conclusion, this is quite frankly one of the most important teaching resources to become available to anaesthetists in recent years. The fact that it is obtainable free of charge is all the more remarkable. There is absolutely no doubt that this material should form the core knowledge of anaesthetic practice with inhalation agents and ideally should be seen and digested by all anaesthesia practitioners prior to giving their first solo inhalation anaesthetic.
D. W. Green