Low Flow Anaesthesia

Abstract

Low Flow Anaesthesia, Jan A. Baum. Oxford: Butterworth-Heinemann, 1996, ISBN 0-7506-2127-3, 208 pp, $75.00. This book provides a comprehensive survey of the published literature on low-flow anesthesia and describes the low-flow devices currently available. The reader quickly learns that Europe is technologically ahead of the USA in reducing flows to a closed circuit, since most of the commercial delivery systems described (e.g., PhysioFlex[R] by Physio Medical Systems BV, Haarlem, The Netherlands) are not yet available for sale in the USA. The author amply justifies the need for anesthesia machines to provide low-flow and closed-circuit anesthesia on clinical and economic grounds. The book extensively reviews 40 yr of publications, many of which are not often cited in today's literature. In several areas, it is difficult to determine which stated principles are meant to apply today and which should be discarded for real data. For example, the early 1980s requirement and reliance on 30% inspired oxygen to protect against hypoxia during both high- and low-flow anesthesia seems unjustified when oximetry is used. Also, dismissing manual liquid circuit injection without discussion, data, or evidence appears unjust. Mathematics is nicely avoided throughout most of the book. In the section on pharmacokinetics where some mathematics is presented, however, the distinction between exponential (e-t/t) and power function (t-1/2) relationships is not disclosed. The strengths and weaknesses of products available in the USA are not clearly stated. For example, the ability of the RAMAN Spectrometer (Ohmeda Inc., Madison, WI) to measure nitrogen is not adequately presented. Also, the marked differences in low-flow capability in Narkomed and Ohmeda machines is not sufficiently explored. Despite these few criticisms, Baum's Low Flow Anaesthesia is a good addition to the English-language literature on this technique that should be mastered by all practitioners. This book should be made available to all anesthesia trainees and should be read by anesthesiologists interested in this important anesthesia technique. James H. Philip, ME(E), MD Harvard Medical School; Department of Anesthesia; Brigham and Women's Hospital; Boston, MA 92115