Frontiers in anaesthesia: Allergy, immunology and anaesthetic action

missing) notified in his lecture that the days of whole blood transfusion are over and, if anything, administration of blood products may in the future be even more selective. According to him, the number of exposures that a potential recipient will have to various blood components will in the future decrease even further. Physicians have earlier been criticised for being too liberal with their transfusion practice but now there may be a risk of the transfusion pendulum swinging too far the other way so that patients who would benefit from a blood transfusion occasionally do not receive it. Effects of anaesthesia and surgery on the endothelial-polymorphonuclear neutrophil interactions, which is an area at the very frontiers of current research, was discussed by Prof. Hans G. Kress (University of Vienna, Austria). The few studies already published show that anaesthetics have direct and indirect effects on endothelial cells that are likely to alter their physiologic interaction with circulating neutrophils. That may have a role in inflammation and antimicrobial defence. However, no clinical evidence exists to show impaired immune defence or development of postoperative infections due to the effects on endothelial cell activity. Earlier studies have already shown that inhalational and intravenous anaesthetics inhibit other neutrophil functions, including oxidative and microbicidal activity, phagocytosis, migration and mediator release (3). Prof. Matti Salo (University of Turku, Finland) drew attention to the link between gastrointestinal and respiratory immunity. In mice, enteral nutrition has been shown to have beneficial effects on respiratory immunity and decrease the likelihood of postoperative respiratory infection (4). The gut has in general received increasing attention as an immunologic organ. It is together with the skin one of the largest immune organs and is part of the mucosal immune system. It has been known for some time that if nutritients are supplied only by the parenteral route then dysfunction and atrophy of the gut and gut-associated lymphoid tissue occur. Meta-analyses on immunonutrition have shown decreased risk of infectious complications (5) and in one study reduction of mortality in septic patients (6). However, the value of immunonutrition in critically ill patients is still disputed. A hypothesis was also presented that a disturbance in the balance between postoperative polyclonal B-cell Frontiers in anaesthesia symposium activation and depressed cell-mediated immunity may arouse an autoimmune response in patients prone to autoimmune diseases (7). Prof. Paul R. Knight, III (State University of New York at Buffalo, USA) has made extensive studies on host responses to viral respiratory tract infections during anaesthesia and surgery in humans, mice and ferrets. Based on these studies, he suggested that anaesthesia and surgical trauma in the presence of viral respiratory tract infection alters specific and non-specific immune responses and increases the risk of a subsequent bacterial pneumonia. Perioperative anaphylaxis Prof. Jonathan Moss (University of Chicago, USA) pointed out in the opening lecture that during their preoperative evaluation patients tell far more often about allergic drug reactions during their previous anaesthesia than what has in fact occurred. In spite of this exaggeration, such a history should be regarded as a warning sign and in the evaluation true anaphylactic/anaphylactoid reactions should be distinguished from other adverse events. Whether cells from an allergic patient are more prone to chemically mediated histamine release or not is still a contentious issue. On the other hand, patients with cardiovascular disease or haemodynamic instability may be especially vulnerable to drug-induced histamine release. Treatment of the reaction should be the topic of continuous education since in a simulation study only 40% of anaesthesiologists recognised and treated anaphylaxis appropriately (8). A study with similar results has been subsequently published (9). A plan for recognition and treatment of anaphylaxis should also be available, particularly when dealing with patients at risk. According to Prof. Marie-Claire Laxenaire (CHU Hôpital Central, Nancy, France) the occurrence of anaphylactic reactions to latex is decreasing in France, due to increased consciousness of the reaction, better detection of patients at risk, improved testing and prevention. The immediate reaction is due to specific IgEs against natural rubber latex proteins, of which there have already been characterised seven natural rubber latex allergens. The type I immediate hypersensitivity reaction takes place after contact with the skin or mucous membranes or tissue by natural rubber latex but also after inhaling airborne latex par1195 ticles carried by glove powder. Atopy is considered as an important sensitisation factor, particularly in health professionals and patients with multiple previous surgical procedures. Trials are now in process in France to use immune therapy in latex allergic pro-