By Haibo Zhang

The 17th International Symposium on Intensive Care and Emergency Medicine was held March 18-21, 1997 at the congress center in Brussels, Belgium. The four-day symposium's objective was to review current concepts and technologies, and to present recent advances in the management of critically ill patients. More than 170 faculty, led by the world's leading physicians and scientists in the critical care/emergency medicine fields, presented the latest advances in research and clinical practice in all areas of intensive care and emergency medicine.

Dr. Jean-Louis Vincent, chairman of the organizing committee of the symposium, and head of the Department of Intensive Care at the Erasme University Hospital of Brussels, opened the symposium by welcoming the approximately 3,200 participants including critical care, pulmonary, surgery, and internal medicine clinicians, scientists, nurses, and therapists from around the world. He then introduced to the audience the current status of intensive care medicine in Europe.

The opening session included a report of the roundtable conference on acute lung injury and five plenary lectures. D.N. Granger, Professor of Physiology at the Louisiana State University Medical Center, Shreveport, U.S.A., discussed endothelial cell- leukocyte interactions. Noting that leukocyte adhesion to vascular endothelium is a hallmark of the inflammatory process, Granger gave an overview concerning the expression of endothelial cell adhesion molecules on monolayers of cultured endothelial cells. He compared this information to in vivo estimates derived from the dual radio-labeled monoclonal antibodies technique. He concluded that the critical role of endothelial cell adhesion molecules in the recruitment of leukocytes to inflammatory sites has been more clearly defined in recent years.

It was also noted that considerable progress has been made in defining the chemical mediators that are responsible for the upregulation of the specific cell adhesion molecules. For example, leukocyte rolling is mediated by a distinct family of adhesion molecules residing on both endothelial cells and leukocytes, known as the selectin family of cell adhesion receptors. This family includes E- and P-selectin, which are expressed on the surface of stimulated endothelial cells, with the latter also found on the surface of activated platelets. In addition, the intracellular adhesion molecular 1 (ICAM-1) has been implicated as a key modulator of leukocyte recruitment in several inflammatory models. Vascular cell adhesion molecule (VCAM-1) is another member of the supergene immunoglobulin family that mediates the binding of leukocytes to vascular endothelium.

Granger concluded the talk by noting that development of new methods such as radio- labeled monoclonal antibodies have enabled investigators to assess the kinetics of endothelial cell molecule expression in vivo during an inflammatory response. He stated that :

These measurements should extend our understanding of the relationship between adhesion molecule expression and different aspects of leukocyte recruitment, including leukocyte rolling, adhesion, and emigration in post-capillary venules. This information should assist in the definition of molecular and cellular mechanisms that underlie the processes resulting in leukocyte recruitment in acutely and chronically inflamed tissues.

Discussing myocardium in sepsis in the session on organ function in sepsis, J.E. Parrillo, Professor of Medicine at the Rush-Presbyterian-St. Luke's Medical College, Chicago, U.S.A., pointed out that "myocardial depression, like vascular dysfunction, is typical of human septic shock. Human septic myocardial depression is characterized by biventricular dilatation, decreased ejection fraction, and decreased response to fluid resuscitation." "Multiple aspects of the systemic inflammatory response including circulating cytokines, chemokines, leukocyte-endothelial cell-myocyte interactions, tissue-damaging mediators from leukocytes and other cells, and mismatching of oxygen demand and supply in microvascular beds lead to myocardial depression during sepsis," said K.R. Walley, Associate Professor of Medicine at St. Paul's Hospital, Vancouver, Canada.

Circulation in Sepsis was one of the most interesting sessions during the meeting. Although the feature of global hemodynamics is known, much information on microcirculation is needed. Dr. Granger described the microcirculatory alterations in sepsis, showing that activated leukocytes represent the major source of oxidant generated in the hepatic and mesenteric microcirculation in sepsis. Dr. Walley demonstrated the mismatch of oxygen supply and demand in peripheral tissues, Dr. Thijs (Amsterdam, the Netherlands) showed vascular permeability changes, Dr. Evans (London, UK) reported an abnormal microvascular control of oxygenation, and finally Dr. Zhang (Université Libre de Bruxelles, Brussels, Belgium) introduced several possible approaches to improve tissue oxygen extraction capabilities in experimental sepsis by improving microcirculation and anti-inflammatory and antioxidant effects.

"Nitric oxide inhibition: friend or foe?" remains an unresolved issue. Dr. Payen (Paris, France) said that as nitric oxide is essential to maintaining tissue perfusion, a combination of nitric oxide donors and inhibitors may be good in treating sepsis. Professor Traber (Galveston, USA) emphasized that the timing of giving nitric oxide inhibitors is important. Premature inhibition produces constriction greater than needed; an inhibitor should not be given prior to endogenous stimulation of the inducible form of nitric oxide synthetase.

A large number of young clinicians, scientists, medical students, nurses, and therapists enjoyed the excellent educational programs including tutorials, meet-the-experts presentations, when-how-and-how-much meetings, pro-con debates, roundtables, and workshops.

One hundred thirty-four original basic and cli nical research abstracts from all intensive care and emergency medicine fields were accepted for poster presentation. After four days of discussion, four posters were selected and awarded as the best original scientific research presentations by the Scientific Committee of the International Symposium. They were :"Cardiopulmonary dysfunction during porcine endotoxin shock is effectively counteracted by the endothelin receptor antagonist bosentan" by Dr. M. Wanecek et al. (Sweden), "Bosentan restores gut oxygen delivery and reverses intestinal mucosal acidosis in porcine endotoxin shock" by Dr. A. Oldner et al. (Sweden); "Troponin T as myocardial ischemia marker to guide therapy with positive inotropes in septic shock patients" by O.V. Hein et al. (Germany), and "Influence of dopexamine on leukocyte adherence and vascular permeability during endotoxemia in rat mesenteric venules" by W. Schmidt et al.

A roundtable conference was held March 15-17, 1997 at Royal Windsor Hotel in Brussels, Belgium. This was a meeting of experts, held without audience, prior to the annual International Symposium. Thirty participants from around the world focused their discussion on the topic "Acute Lung Injury" in order to integrate basic and clinical science, to update the acquired knowledge, to underline the persistent problems and therapy, and to identify the essential topics for future research of acute lung injury. Discussion topics included epidemiology of acute lung injury, basic mechanics, pathophysiology and the pulmonary circulation, bronchoalveolar lavage fluid and surfactant, the alveolar epithelial barrier, mechanical ventilation, extra pulmonary supportive measures, pharmacological manipulation of ventilation/perfusion in acute lung injury and acute respiratory distress syndrome, liquid ventilation, and clinical trials in the next fifteen years.

Among the highlights of the roundtable conference was the summary on pulmonary circulation in acute lung injury presented by Dr. Timothy W. Evans, Professor of Critical Care Medicine, Imperial College School of Medicine, National Heart and Lung Institute & Royal Brompton Hospital, London, UK, the cochairman of the roundtable. His research team found that damage to the pulmonary vascular endothelium is a fundamental step in the initiation and mediation of the inflammatory process that produces tissue injury. Clearly the endothelium and its release of nitric oxide, endothelin, and eicosanoids represents a dynamic fulcrum during sepsis, and the balance of these factors determines both the local pulmonary vascular tone and the extent of the inflammatory reaction. However, it is increasingly evident that other cell types, including vascular smooth muscle, can release these substances after exposure to endotoxin or cytokines. Thus, during inflammatory events the vascular smooth muscle may serve to compensate due to a failing and damaged endothelium. Research is currently concerned with identifying therapeutic ways of altering the balance of these vasoactive and inflammatory mediators in a favorable way, to dampen the inflammatory response and restore the usual beneficial effects of hypoxic pulmonary vasoconstriction, which is disrupted in lung injury.

Dr. Arthur S. Slutsky, professor at the University of Toronto stated that the stress response is protective in sepsis and acute lung injury. He pointed out that there are a number of potential clinical uses related to the stress response and the heat shock proteins in disease processes other than sepsis and acute respiratory distress syndrome. It is possible that patients at risk for developing sepsis and acute respiratory distress syndrome could benefit from the use of some strategy to trigger the stress response. Why? "Stress response could protect against mechanically induced lung injury, and attenuate the release of tumor necrosis factor."

Haibo Zhang, M.D., Ph.D., is a coordinator of the research program at the Department of Intensive Care, Erasme University Hospital, Brussels, Belgium.

Endlinks

All accepted abstracts were published both in the electronic version and printed version of Critical Care, the official journal of the Critical Care Forum. The journal is published by BioMedNet. The original abstracts appeared in the journal is the electronic version, available to all members of the Critical Care Forum on the World Wide Web.

The American Thoracic Society is a professional organization dedicated to all aspects of lung disease and critical care medicine, with special attention given to research, professional education, and clinical practice. The American Journal of Respiratory and Critical Care Medicine and the American Journal of Respiratory Cell and Molecular Biology are official journals of the society.

The 7th World Congress of Intensive and Critical Care Medicine will be hosted by the Canadian Critical Care Society this year. The congress theme is "Critical Care, Critical Times, Critical Decisions."

The Shock Society was founded 20 years ago for the purpose of fostering a greater understanding of basic and clinical sciences as they relate to circulatory shock. The Shock Society has served to establish the state-of- the-art knowledge about mediators, mechanisms, and clinical applications of shock research. Although septic shock, by virtue of its prominence as one of the 10 leading causes of death, is emphasized in the annual meetings, the Shock Society also includes research in the field of hemorrhagic shock, burn injury, trauma, and CNS injury. Shock is the official journal of the Shock Society.

The American College of Chest Physicians (ACCP) is the leading resource for the improvement in cardiopulmonary health and critical care worldwide. Its mission is to promote the prevention and treatment of diseases of the chest through leadership, education, research, and communication. It operates a Virtual World Congress, for which a 30-day free trial is offered.

Also of interest to researchers and clinicians in the field:

Proceedings of the 17th International Symposium on Intensive Care and Emergency Medicine, entitled Year Book of Intensive Care and Emergency Medicine 1997 were published by Springer-Verlag, and part of the yearbook was, as usual, distributed to the Symposium attendees. The yearbook compiles the most recent widespread developments of experimental and clinical research and practice in one comprehensive reference book. It is addressed to everyone involved in internal medicine, anesthesia, surgery, pediatrics, intensive care, and emergency medicine.

The book Acute Lung Injury from the roundtable conference will be published in the series Update in Intensive Care and Emergency Medicine (Springer-Verlag). This book reviews the most recent developments in the pathophysiology and therapy of acute lung injury. Of particular interest are the descriptions of new modalities of ventilatory assistance, as well as new knowledge regarding pharmacological manipulation of ventilation/perfusion in acute lung injury and acute respiratory distress syndrome. Finally, the reader will find a state-of-art reviews of the latest research and practical applications in this most critical area of intensive care medicine.

Previous Meeting Briefs:

Tackling the Mysteries of Breast Cancer

by Mary S. Wolff (Issue 6 · posted April 18, 1997)

Ifgene and "The Future of DNA"

by David J. Heaf and Pat Cheney (Issue 5 · posted April 4, 1997)

Cross-Talk Among AIDS Researchers

by Karen P. Beckerman, M.D. (Issue 4 · posted March 21, 1997)

New Tiny Tools Shown: IBC Conference on

Molecular Nanotechnology

by Jim Lewis (Issue 2 · posted February 20, 1997)

The Phylogeny of Life and the

Accomplishments of Phylogenetic Biology

by Laura Landweber (Issue 1 · posted February 1, 1997)