John Oyston

Department of Anaesthesia; Orillia Soldiers' Memorial Hospital; Orillia, Ontario, Canada L3V 1Y2; E-mail: oyston@oyston.comJames C. Eisenach, M.D., EditorURL: http://www3.ncbi.nlm.nih.gov/Omim/Sponsor: Johns Hopkins University, Baltimore, MarylandAuthor: Dr. Victor A. McKusick and colleaguesWeb Version: National Center for Biotechnology InformationReaders of this column may be interested in Online Mendelian Inheritance in Man (OMIM) for two reasons: Firstly, some patients have genetic conditions that must be considered when planning anesthesia. Secondly, it is an excellent demonstration of the use of the Internet to make a vast amount of medical information widely available in a format that is more convenient to use and more up-to-date than would be possible in any other way.OMIM is a database with 9,145 entries, each reviewing a specific genetic disease, which is continually being updated at the rate of 60 new entries and 500 revisions per month by Dr. Victor A. McKusick and his colleagues at Johns Hopkins University and elsewhere. It has been made freely available on the Web by the National Center for Biotechnology Information. The site begins with a warning: "OMIM is intended for use primarily by physicians and other professionals concerned with genetic disorders, by genetics researchers, and by advanced students in science and medicine. Non-medical users are strongly urged to seek the assistance of an expert in the interpretation of OMIM text and images."The site consists of plain text with small link buttons. Animations, Java, frames, plug-ins, and multimedia are not used. Unfortunately, a link to the Cedars-Sinai Medical Center Genetics Image Archive was not available at the time of this review.For anesthesiologists, the most important feature is the search engine. Type in almost any variation of any name for an inherited disease, and, if spelling is correct, a link will be provided to the appropriate entry for that disease. Because many genetic syndromes have various names, this is more convenient than most textbook indices. A facility that offers alternative spelling when a search produces no results would be a useful addition.Each disease entry is presented as a Web page. A Table ofcontents provides shortcuts to sections that typically include "Clinical Features," "Diagnosis," "Clinical Management," and "References," and several sections that would only interest a geneticist, such as "Population Genetics." A clinical synopsis is sometimes available as a separate Web page.Each entry is referenced heavily, with links from the text to the relevant PubMed abstract. The full text can be ordered online through "Loansome Doc." There are extensive links to MEDLINE and to other genetics resources. Each page has a link to a form that can be used to add comments or new information.I compared OMIM to two standard anesthetic textbooks, Anesthesia and Co-Existing Disease, 3rd edition, 1993, by Stoelting and Dierdorf, and Anesthesia and Uncommon Diseases, 4th edition, 1998, by Benumof. I searched each resource for information about five genetic conditions of interest to anesthetists, which I saw recently in the preadmission clinic.The anesthetic textbooks both had extensive and detailed accounts of this condition, indexed under both words. OMIM has 11 pages about "hyperthermia of anesthesia." This contains a good history of the disease from the first case report in 1962 to recent developments, but no practical information for anesthesiologists. There was no link to clinical resources such as the Malignant Hyperthermia Association of the United States Emergency Hotline.The anesthetic texts mentioned pseudocholinesterase only in the context of liver disease. OMIM had no relevant information. Perhaps an inherited enzyme deficiency is not really a disease, but it was surprising that none of the resources mentioned this condition.Both anesthetic textbooks had more than a page of information, although Anesthesia and Uncommon Diseases indexed acute intermittent porphyria under "H" for "hepatic porphyrias." Both textbooks listed safe and unsafe anesthetic drugs. OMIM has 23 pages of text with 82 references. Although the section about clinical features mentions that attacks can be precipitated by barbiturates or sulfonamides, there was not enough information to plan a safe anesthetic.Both anesthetic texts had brief entries that mentioned difficult tracheal intubation and the risk of malignant hyperthermia. OMIM produced five pages of information, including 26 references (compared with five between the two textbooks), but none of the references were to anesthesia journals, and there was no mention of difficult tracheal intubation or malignant hyperthermia.Anesthesia and Co-Existing Disease had 134 words, half of which was about anesthetic implications, indexed under both names, whereas Anesthesia and Uncommon Diseases provided 118 words, indexed only under "Osler-Weber-Rendu." Each had one reference. OMIM had 16 pages and 82 references. An extensive history section included fascinating nuggets, including the correct pronunciation ("OHz-ler, ren-DYU, and VAY-ber"), with a note that Weber "pronounced his name in the Germanic manner even though he was born in England."OMIM is an invaluable resource for physicians dealing with patients with genetic diseases. It uses the Web to make medical information accessible in a way that should inspire other specialties to develop similar resources. Although it does not contain enough anesthesia-related information to act as a sole source of information about genetic conditions for anesthesiologists, it would be of great benefit to any anesthesiologist writing a consult note, preparing rounds, or publishing a case report about a patient with an inheritable condition.John Oyston, M.B., B.S., F.F.A.R.C.S.Department of Anaesthesia; Orillia Soldiers' Memorial Hospital; Orillia, Ontario, Canada L3V 1Y2; E-mail: oyston@oyston.com

To determine the minimum alveolar concentration (MAC) and hemodynamic responses to halothane, isoflurane, and sevoflurane in newborn swine, 36 fasting swine 4-10 days of age were anesthetized with one of the three volatile anesthetics in 100% oxygen. MAC was determined for each swine. Carotid artery and internal jugular catheters were inserted and each swine was allowed to recover for 48 h. After recovery, heart rate (HR), systemic systolic arterial pressure (SAP), and cardiac index (CI) were measured awake and then at 0.5, 1.0, and 1.5 MAC of the designated anesthetic in random sequence. The (mean +/- SD) MAC for halothane was 0.90 +/- 0.12%; the MAC for isoflurane was 1.48 +/- 0.21%; and the MAC for sevoflurane was 2.12 +/- 0.39%. Awake (mean +/- SD) measurements of HR, SAP, and CI did not differ significantly among the three groups. Compared to the awake HR, the mean HR decreased 35% at 1.5 MAC halothane (P less than 0.001), 19% at 1.5 MAC isoflurane (P less than 0.005), and 31% at 1.5 MAC sevoflurane (P less than 0.005). Compared to awake SAP, mean SAP measurements decreased 46% at 1.5 MAC halothane (P less than 0.001), 43% at 1.5 MAC isoflurane (P less than 0.001), and 36% at 1.5 MAC sevoflurane (P less than 0.005). Mean SAP at 1.0 and 1.5 MAC halothane and isoflurane were significantly less than those measured at equipotent concentrations of sevoflurane (P less than 0.005). Compared to awake CI, mean CI measurements decreased 53% at 1.5 MAC halothane (P less than 0.001) and 43% at 1.5 MAC isoflurane (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Department of Anesthesia The Scarborough Hospital, Toronto, Ontario, Canada oyston@oyston.com Temporarily jpoyston@hotmail.comNew York School of Regional Anesthesia URL: http://www.nysora.com Authors: Admir Hadzic and Jerry Vloka John Oyston, M.B., B.S., F.R.C.P.(C.) Department of Anesthesia The Scarborough Hospital, Toronto, Ontario, Canada oyston@oyston.com Temporarily jpoyston@hotmail.comDrs. Hadzic and Vloka have produced one of the best regional anesthesia Web sites, without sponsorship from any equipment or pharmaceutical company. They have assembled an impressive team of assistants to produce a site that has quality content and an elegant, professional appearance.The site was established in 1996 and has had three different addresses and several major revisions, the last of which (December 2000) occurred during the drafting of this review. It describes their practice of regional anesthesia at St. Luke’s–Roosevelt Hospital Center in New York City. It has all the usual features, such as links to other sites, details of meetings, information about anesthesia training at St. Luke’s, backgrounds of the authors, and a bulletin board. One nice touch is a collection of tributes from some of the surgeons at St. Luke’s–Roosevelt, who obviously appreciate the advantages of regional anesthesia.The main feature of the site is detailed information about how to perform a variety of peripheral nerve blocks. The descriptions are based on the authors’ practice and research. In many cases, useful, practical tips are offered. Some blocks are not referenced; others have many references. There are sections about setting up equipment, with details of their cart and block trays, which are well-illustrated. There is also a guide to choosing local anesthetics.The nerve blocks described include infraclavicular and interscalene blocks, thoracic paravertebral blocks, combined epidural–spinal blocks, and a wide variety of lower extremity blocks. The descriptions are clear and concise and are accompanied by excellent detailed photographs, including, in many cases, dissections of cadavers to display the relevant anatomy.The authors have prepared a number of short video clips, which are used to display information that could not be represented in any other way, such as a needle being inserted or a muscle twitching. The clips are not narrated but are documented clearly in the adjacent text. They are available in Real Video and QuickTime formats, in versions for different connection speeds. The authors are commended for attempting to use streaming video as a teaching aid, for producing excellent quality video images, and for resisting the temptation to use “talking heads.” However, I felt the clips could have been a little longer.The descriptions of the blocks are all written by the authors, except for two guest contributions.The authors have considerable practical experience related to regional anesthesia at a major academic center and have published many articles in established journals. The site expresses the authors’ experience and, like a conventional textbook, it is not peer reviewed. One assumes that no one would go to the effort of publishing a textbook unless he or she had useful and accurate information to propagate. There are a few typographical errors that have escaped spell checking but that might have been caught by an editor. Although the site offers excellent educational material, there is no method of testing one’s knowledge or of gaining continuing medical education credits.Navigation can be confusing. For example, a list of meetings is given in the What’s New section, although information about past meetings is included. Information about a specific nerve block could be available under Concepts, Techniques, or Guest Contributors. There is a site map, which reduces the confusion somewhat, and an efficient search engine.This is an excellent Web site, with a wealth of practical and research information about regional anesthesia.It shows how useful the Web can be as a teaching medium. It is especially good regarding peripheral blocks of the lower extremities, a rather neglected aspect of regional anesthesia.