الفهرس | Only 14 pages are availabe for public view |
Abstract Anaphylaxis is a potentially lethal reaction resulting from the sudden, clinically significant release of mast celland/ or basophil-derived mediators into the circulation. Both IgE-and non IgE-mediated mechanisms have been implicated, and some agents may cause reactions by more than one mechanism. The most common identifiable causes of intraoperative anaphylaxis are neuromuscular blocking agents (NMBAs), antibiotics, latex, hypnotic induction agents (primarily barbiturates), opioids, and colloids. However, there is a much longer list of agents that are implicated less regularly Risk factors include asthma, female sex (for certain medications), other allergic conditions such as eczema or hay fever, multiple past surgeries or procedures (especially for latex), and mast cell disorders including mast cell activation syndrome, monoclonal mast cell activation syndrome, and systemic mastocytosis. Intraoperative anaphylaxis presents with cutaneous, respiratory, and cardiovascular signs and symptoms, as well as variable involvement of other organ systems. One-half of cases are initially detected as sudden cardiovascular collapse. Bronchospasm may present as an increase in the ventilatory pressure required to inflate the lungs or as a decrease in arterial oxygen saturation. Intraoperative anaphylaxis tends to be severe and has a higher mortality rate than anaphylaxis occurring in other settings. This is at least partly attributable to factors that impair early recognition of anaphylaxis, such as the inability of the patient to report initial symptoms and coverage of the skin with surgical drapes. The intravenous administration of drugs and concomitant stresses of surgery or illness may also contribute.The diagnosis of intraoperative anaphylaxis is clinical. An elevated serum total tryptase, plasma histamine level, or elevated histamine or prostaglandin metabolites in the urine, obtained at appropriate time intervals during and after the reaction, are highly suggestive of anaphylaxis, although normal levels do not exclude the diagnosis. Documentation of anaphylaxis during anesthesia, referral to an allergist for identification of the causative drug, and appropriate labeling of the patient are essential to prevent future episodes of anaphylaxis. Patient must be fully informed about anaphylaxis, its cause, signs and symptoms and causative agent. And he must be instructed to give thorough history whenever he reports to any hospital for treatment be it minor or major. He can be instructed to wear bracelet or carry card with him detailing which drugs he is allergic to. What is needed is improved accuracy in assessment of the rate of occurrence of anaphylaxis, and rapid, specific, sensitive in vitro test or panel of tests to confirm the clinical diagnosis of acute anaphylaxis. |