Anaphylaxis during general anaesthesia - Prevention and management

Any drug administered in the peri-operative period has the potential to pro duce life-threatening immune-mediated anaphylaxis, The incidence of anaphyl axis has been estimated at between 1 in 10 000 and 1 in 20 000 anaesthesias in Australia and 1 in 13 000 anaesthesias in France. In the most recent Fr ench epidemiological survey, the compounds most frequently involved in anap hylaxis were muscle relaxants (60%), followed by latex (16%). Activation of humoral and cellular pathways resulting from immunoglobulin E -mediated adverse reactions usually produces characteristic respiratory, ca rdiovascular and skin responses, but effects can be seen in virtually any s ystem. These responses may occur as isolated clinical events. As a result, an anaphylactic reaction restricted to a single clinical symptom (e.g.. bro nchospasm, tachycardia) can easily be misdiagnosed. Intra- and postoperativ e investigations must be performed to confirm the nature of the adverse rea ction, the role of the suspected drugs, and to define precise recommendatio ns for future anaesthesias. The patient must be fully informed, and given a detailed written account of the anaphylactic episode, the results of the a llergological assessment performed and the resulting recommendations. Furth ermore, the patient should be strongly advise to wear a warning bracelet or carry a warning card. Since no specific treatment has been proven to reliably prevent the onset o f anaphylactic reactions, allergological assessment must be performed in al l high risk patients. The only possible strategy is to avoid the drug teste d positively during the allergy work-up. Nevertheless, in cases where muscl e relaxants are incriminated, patients allergic to one muscle relaxant can be administered another agent, the choice of which is based on skin test re sults. However, it should be borne in mind that rare cases of adverse react ions in spite of such screening procedures have been reported. On the contr ary, there is no indication for allergological assessment in atopic patient s who do not have additional anaesthetic agent risk factors or those allerg ic only to non-anaesthetic substances. The treatment of anaphylaxis is aimed at interrupting contact with the resp onsible antigen, modulating the effects of released mediators, and inhibiti ng mediator production and release. Treatment must be initiated as quickly as possible, and relies on generally accepted principles.