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Associate Professor of Anethesiology, Pharmacology, Obstetrics & Gynecology, University of Pennsylvania, Philadelphia, PA
S. Lampotang, D. Lizdas, E. B. Liem, J. S. Gravenstein.
Gainesville, FL: University of Florida Department of Anesthesiology, 2002. 50 pp, $free
The anesthesia resident is expected to master many concepts and to develop different techniques during the residency. One area encompassing both is the anesthesia machine. An anesthesia resident should know the mechanics of the machine as well as its proper check-out. Currently, the anesthesia machine is taught by lecture/discussion format, accompanied by trial and error in the operating room. The University of Florida in conjunction with the Anesthesia Patient Safety Foundation has corrected this deficiency with the publication of the Anesthesia Patient Safety Foundation Anesthesia Machine Workbook. This workbook is to be used in conjunction with the Virtual Anesthesia Machine (VAM) simulations at http://www.anest.ufl.edu/vam. The VAM is an interactive real-time simulation of gas flows in an anesthesia machine. This workbook is actually the first chapter of an electronic textbook that is being developed and is also available free of charge at the VAM Web site. Adobe Acrobat ReaderTM 5.0 or higher is required to view or print the workbook.
The first chapter of this eventual text begins with the purpose of the anesthesia machine. The requirements of the anesthesia machine are outlined, and the reader begins by building a machine based on these requirements. The objective for this first chapter is to cover the normal operation of the anesthesia machine, such as those in the Modulus and Narkomed product lines. The chapter is divided into six sections: high pressure system, low pressure system, breathing circuit, manual ventilation, mechanical ventilation, and scavenging system. Each section is organized in a similar fashion and begins with a list of learning objectives. The objectives are presented as questions. The reader should attempt to answer the question before reading the section to gauge the knowledge of the material. Following the objectives, a series of clinical scenarios are presented covering the objectives. The fact that the material is organized around a clinical situation reinforces and solidifies the material. Educators could use the scenarios and questions in their teaching. The authors then take the reader through the scenario on the VAM. The authors have made the use of the VAM easy by supplying a grid map, so one can locate and perform the manipulations quickly. The reader is able to visualize and actually model the scenario. The section ends with posttest questions. This part is the only weak point of the manual. The reader answers the question, but is unable to verify the response. It would have been helpful to provide the answers to confirm whether the reader has truly mastered the material.
The high-pressure system and low-pressure system deserve to be highlighted. The clinical scenarios are extremely relevant and easily modeled on the VAM. Many of these scenarios have occurred to me during my time in practice. The only section I found confusing was the scavenging system, which is also one of the shortest sections. To answer the postsection questions, I needed to review this section three times. I would suggest expanding this section to improve its clarity.
As Program Director, I endorse this manual with the accompanying simulation. In fact, our program plans to incorporate it in the education of our residents. The manual fills a void that has existed in the field of anesthesia. While I am not an expert in the anesthesia machine, I feel that I am better equipped to troubleshoot the anesthesia machine after completing the exercises. I also wish to emphasize the Patient Safety Disclaimer that appears on page 14: "While it is generally agreed that it is good for anesthesia providers to understand machine function, it should be equally clear that if an anesthesia provider suspects a malfunction in the anesthesia machine, a safe response is to immediately switch to a self-inflating resuscitation bag and call for help. There is always the danger that the anesthesia provider shifts attention from the patient to debugging the anesthesia machine." I recommend this manual to all anesthesia providers.
Russell Norton, MD, University of Rochester, Strong Memorial Hospital, Rochester, NY
S. Malviya, N. N Naughton, K. K. Tremper, eds.
Totowa, NJ: Humana Press, 2003. ISBN 0-89603-863-7. 310 pp, $125.00.
One might well ask why is another book on sedation (e.g., "conscious sedation, sedation and analgesia) needed when Barnes & Noble has 18 medical text publications on sedation?
The authors sought to produce a work that would be of interest to a wide range of readers, covering topics from the neurobiology and physiology of sedation through the clinical issues and on to quality improvement and process issues. The first chapter, "Opioids, Sedation and Sleep: Different States, Similar Traits and the Search for Common Mechanisms," sounds like a rational place to begin. The authors propose the ambitious hypothesis that a sort of "unified theory" of sedation exists. That is, that the brain mechanisms which generate the states of natural sleep are the same mechanisms which generate the "traits" that define the levels of sedation. A more clear definition of "trait" would have been helpful. It becomes apparent that sleep is very different from pharmacological sedation. This sets the stage for some doubt as to their original hypothesis. The emphasis on opioid pharmacology seems somewhat astray as sedative-hypnotics and anxiolytics, not opioids, are largely viewed as more integral to producing sedation. The chapter ultimately highlights how little we still know about "states" of sedation.
Chapter 2, "Practice Guidelines for Pediatric Sedation," is a discussion of the various guidelines and Joint Commission on the Accreditation of Health Care Organizations (JACHO) policy standards addressing sedation. The chapter succinctly reviews many of the published subspecialty guidelines, demonstrating that significant differences exist and quite likely create confusion in numerous clinical settings. For example, there is wide variation among the guidelines about aspiration risk and required fasting intervals, monitoring equipment, and personnel requirements. Whether one set of guidelines should work for all settings is unclear.
The third chapter, "Practice Guidelines for Adult Sedation and Analgesia," is a good overview and contains much of the information that one can use when starting or reviewing a sedation practice. Some sections are outdated, and the updated version of the ASA’s guidelines on sedation was not available to the authors. The authors do refer to the ASA’s House of Delegates work defining the continuum of sedation, which has been adapted by JCAHO. Most of the information that is missing or not reflective of the current state of the art is not critical. For example, patients who are administered a drug to help them sleep do not require care as defined in sedation guidelines. This point, which is similar to the point the authors do make concerning the administration of analgesics, is not made and can be a source of confusion in institutions. In the section on personnel requirements, it remains unclear in the book, as it is in most sources of information, that when a diagnostic test (not a procedure) is being performed (no proceduralist present) whether or not there is really a need for two skilled clinicians to be present. Such a requirement would not reflect clinical practice in most settings. The authors provide a very interesting summary of the morbidity and mortality associated with sedation. We would have chosen to highlight this information even more, in the introduction for example, to emphasize the significance of the problem. The "Future Directions" section is most interesting for its paragraph on the need for sedation. It appears that a significant number of patients specifically wish not to receive sedation—a fact we must continually teach to anesthesiology residents as well.
Pediatric patients have the same ventilation and hemodynamic complications with sedation as adults. This theme is clear in the chapter on "Procedure and Site-Specific Considerations for Pediatric Sedation." Thus the time spent explaining the need for sedation protocols designed around promoting patient safety is justified. More details and recommendations for pharmacological approaches other than the "old standby" chloral hydrate would be welcome. The discussions concerning sedation in dentistry and emergency department settings are especially important.
Chapter 5, "Adult Sedation by Site and Procedure," surveys various sedation techniques for procedures by body site. The discussion about nonanesthesiologists using sedative hypnotics (like propofol and methohexital by gastroenterologists and cardiologists for example) to induce deep sedation or even general anesthesia is very relevant and interesting. There is recent evidence that propofol is being used successfully for colonoscopy (Rev Gastroenterol Disord 2003;Spring 3(2):70-80; Gastrointest Endosc 2002;Aug 56(2):324). There is appropriate emphasis on the benefits of combining local anesthesia with mild intravenous sedation analgesia. However, this may not work for procedures involving catheters passing through solid organs or for testing defibrillation thresholds of AICDs in the electrophysiology lab. Major complications of sedation remain measurable. If the quoted mortality rate of 0.5–3.0 per 10,000 is accurate, it is astounding that a stronger outcry has not been made.
The chapter on "Pharmacology of Sedative Agents" (Chapter 6) seems more like a textbook chapter than a review of practical information for sedation and analgesia. Many readers might be looking for more clinically relevant information on the most commonly used drugs (i.e., the benzodiazepines) than the chapter provides. In addition, the information on the effects of propofol on cerebral blood flow may not interest most readers. In contrast, there is no mention of combining propofol and ketamine, a popular technique in office-based surgery, to obtain a sedative with analgesia.
Pharmacokinetics and pharmacodynamics of opioids make up the bulk of the chapter on "Opioids in the Management of Acute Pediatric Pain." Appropriate emphasis is made concerning the fact that pain is inadequately treated in pediatric patients. The concept of context sensitive half time, perhaps one the most important advances in clinical pharmacology in the past decade, should have been contrasted in some detail to traditional half-life, pharmacokinetic information. A wealth of information is provided on the opioids, and most readers will benefit from the review. The focus on morphine to the exclusion of more information on the short-acting opioids is a weakness. There is an informative section on novel delivery methods that are important considerations, such as in outpatient procedures where the act of placing an IV in a child may cause more pain and suffering than the actual procedure.
The chapter on "Patient Monitoring during Sedation" (chapter 8) is a detailed and succinct review of the rationale and methods for the relevant monitoring systems (oxygenation, ventilation, and circulation) used during sedation and analgesia. Anyone interested in learning how a monitoring technique works will find it particularly useful. There is a good discussion about some of the hazards regarding monitoring equipment in the MRI suite. The section concerning sedation side effects relating to the need for monitoring standards illuminates the importance of monitoring for patient safety. It also demonstrates the problems regarding the range of sedation scales used clinically.
The chapter "Assessment of Sedation Depth" is an excellent summary of the topic. The difficulties created by the predicament that there is no uniform definition or understanding of what "sedation" really is again sets the stage. The authors present a concise review of sedation scoring systems, replete with their significant limitations. Physiologic variables (e.g. blood pressure, heart rate), which are frequently used as surrogate measures of anesthetic depth by anesthesiologists, are briefly mentioned. Most of these measures, including lower esophageal sphincter tone, are of questionable utility. A discussion of neurophysiologic monitoring focuses primarily on the electroencephalogram (EEG), evoked potentials, and the bispectral index (BIS). Although it is stated that the "BIS represents the most accurate neurophysiologic monitor currently available for monitoring," discussion of why the BIS has not been highly accepted even by the anesthesia community was avoided. The chapter appropriately ends as it began, with more questions than answers and the conclusion that the ideal sedation monitor is not just around the corner.
The 11th chapter, "Recovery and Transport of Sedated Patients," deals with an important but often neglected area of patient care. It is pointed out that patients may be at even greater risk for problems after a procedure requiring sedation because of reduced stimulation, monitoring, and/or supervision. It is duly noted that production pressure exacerbates the risks in this setting, as it does virtually everywhere in health care. Also, without reference, comments such as "...virtually all anti-emetics have sedative effects that may prolong the patient’s recovery" are probably not only misleading but also incorrect.
The 12th and final chapter was one of the best in the book and clearly authored by an individual well versed in the area of "quality." The chapter flows seamlessly, an almost impossible feat, considering the material to be dealt with. Although the introductory sections are interesting, the real value in the chapter is how it lays out how to perform, both in principle and in practice, all aspects of quality improvement that will allow both the highest levels of safety and improvement as well as adherence to national standards and JCAHO requirements.
Overall the book is a significant contribution to a complex and challenging area in health care. The outstanding chapters alone make the text worthwhile. With over 200,000,000 sedations performed each year in the United States, any incidence of associated morbidity or mortality can lead to a significant number of individuals experiencing harm. Inevitably, some chapters in any book on sedation will not meet the needs or interests of any one of several specialties. Although this reflects the diverse nature of the practice of sedation, as well as the state of art and knowledge, it should not dissuade those who are qualified from attempting to provide such useful sources of information.
Professor and Holder of the Margaret Milam McDermott Distinguished Chair in Anesthesiology, UT Southwestern Medical Center, Dallas, TX
I. P. Osborn, ed.
Philadelphia, PA: Lippincott Williams & Wilkins, 2003. ISSN 0020-5907. 111 pp, $246.00 (annual subscription for 4 issues or $90.00 per single issue).
Anesthesia Outside the Operating Room is a very timely addition to the anesthesia literature. As mentioned in the first chapter, the anesthesia monitoring standards should be the same whether intravenous (IV) sedation or general anesthesia is provided in a conventional hospital-based operating room (OR), an ambulatory (or office-based) facility, or a diagnostic suite. Nevertheless, it is important to discuss this issue in light of the recent reports of serious morbidity (and even mortality) related to substandard monitoring and accreditation practices in ambulatory (and office-based) facilities (1,2)
The type of postanesthesia recovery facility utilized for procedures outside the OR will clearly differ depending on the patient-care setting. When anesthesia is provided outside the OR, most patients are expected to recover quickly, thereby obviating the need for a conventional postanesthesia care unit (PACU) facility. Most of these "remote" anesthetizing sites will have a modified PACU that is more analogous to a phase II recovery unit. Although pediatric sedation is obviously very important, as pointed out in this monograph, it is surprising that may children hospitals in this country still do not have a designated sedation service for their pediatric patients. The special anesthetic and monitoring considerations for magnetic resonance imaging (MRI) were clearly delineated in this book. However, the chapter on office-based anesthesia is very disappointing because it focuses on only one anesthetic technique (involving the author’s personal experience in plastic surgery), while ignoring many of the peer-reviewed articles on this topic.
Increasingly, anesthesiologists are becoming involved in providing IV sedation for diagnostic procedures in the gastroenterology, neuroradiology, and cardiac catheterization suites, and these topics were thoroughly discussed. Although anesthetic techniques for procedures like ultrarapid opioid detoxification and in vitro fertilization were also extensively reviewed in this monograph, anesthesia for electroconvulsive therapy (ECT) procedures was virtually ignored. Interestingly, ECT is one of the most common anesthetic procedures performed in the United States.
In summary, in spite of some significant deficiencies and relatively high cost ($90 for a 100-page book), this monograph contains useful information for anesthesia providers.
References
The Journal solicits reviews of new books and multimedia from its readers. If you wish to submit a review, before proceeding please send a letter of intent, identifying the book or multimedia in question, to Norig Ellison, MD, Department of Anesthesia, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104-4283. The Journal reserves the right of final decision on publication.
Integrity in Scientific Research: Creating an Environment That Promotes Responsible Conduct, Committee on Assessing Integrity in Research Environment, Institute of Medicine, National Research Council of the National Academics, The National Academy Press, Washington, D.C., 2002.
ISBN 0-309-08523-3. 202 pp, $34.95.
Davis PD, Kenny GC: Basic Physics and Measurement in Anaesthesia, Butterworth-Heinemann, London, 2003.
ISBN 0-7506-4828-7. 314 pages, $59.95.
O’Connor T, Abram S: Atlas of Pain Injections Techniques, Churchill Livingstone, New York, 2003.
ISBN 0-443-06380-X. 141 pages, $75.00.
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