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Background: The diagnosis of acute life-threatening allergic reactions during anesthesia relies on clinical signs, histamine and/or tryptase measurements, and allergic testing. In patients who die after the reaction, skin tests cannot be performed, and the effect of resuscitation manoeuvres on mediator concentrations is unknown. The authors compared plasma histamine and tryptase concentrations in patients with severe allergic reactions during anesthesia with those measured in patients with shock due to other causes., Methods: Patients with life-threatening allergic reactions were retrieved from a previous database (Group ALLERGY). All had positive allergy tests to administered agents. Patients with severe septic/cardiogenic shock or cardiac arrest (Group CONTROL) had histamine and tryptase measurements during resuscitation manoeuvres. Receiver operating characteristics curves were built to calculate the optimal mediator thresholds differentiating allergic reactions from others., Results: One hundred patients were included, 75 in Group ALLERGY (cardiovascular collapse, 67; cardiac arrest, 8) and 25 in Group CONTROL (shock, 11; cardiac arrest, 14). Mean histamine and tryptase concentrations remained unchanged throughout resuscitation in Group CONTROL and were significantly higher in Group ALLERGY. The optimal thresholds indicating an allergic mechanism were determined as 6.35 nmol/l for histamine (sensitivity: 90.7% [95% CI, 81.7 to 96.1]; specificity: 91.7% [73.0 to 98.9]) and 7.35 μg/l for tryptase (sensitivity: 92% [83.4 to 97.0]; specificity: 92% [73.9 to 99.0])., Conclusions: Resuscitation manoeuvres by themselves did not modify mediator concentrations. Virtually all life-threatening reactions during anesthesia associated with mediator concentrations exceeding the thresholds were allergic events. These findings have potential forensic interest when a patient dies during anesthesia.

Purpose of Review: Immediate hypersensitivity reactions are an important cause for mortality and morbidity in anesthesia. The present review considers reports covering epidemiology, diagnosis, and treatment of these reactions., Recent Findings: Immediate hypersensitivity reactions are largely under-reported, adult women being at significantly higher risk than men. The role of sex hormones associated with increased risk in adult women has been demonstrated. Neuromuscular blocking agents (NMBAs) remain the most frequently incriminated drugs. Reactions involving antibiotics, dyes, or nonsteroidal anti-inflammatory agents are reported with increasing frequency, in parallel with changing trends in clinical practice. A recent hypothesis concerning a link between pholcodine exposure and allergic reactions to NMBAs is under investigation. Detailed guidelines concerning skin testing have been provided. The use of several inotropes or vasopressor such as vasopressin is proposed in case of reactions refractory to epinephrine and volume expansion. The use of cyclodextrin to mitigate severe allergic reactions to rocuronium, by specific drug encapsulation, has been proposed., Summary: Hypersensitivity reactions remain a major cause of concern in the perioperative setting. Although largely under-reported, their incidence is higher than previously reported. NMBAs remain the most frequently incriminated drug, followed by latex and antibiotics. The number of reactions involving new allergens like vital dyes or nonsteroidal anti-inflammatory drugs is rapidly increasing. The mechanism of sensitization to NMBAs could be influenced by as yet unidentified environmental factors. The possible role of pholcodine is under investigation. Several guidelines concerning the diagnosis and management of immediate hypersensitivity reactions in anesthesia are now available.

Background: The types of agents implicated to trigger intraoperative anaphylactic reactions vary among reports, and there are no recent series from the United States. In this retrospective study, we examined perioperative anaphylactic reactions that occurred at a major tertiary referral academic center., Methods: To characterize perioperative allergens associated with anaphylactic reactions, we reviewed the Mayo Clinic Division of Allergic Diseases skin test database between 1992 to 2010. The records of all patients who were tested for perioperative and anesthetic medications were reviewed. Charts that included a detailed history obtained by an allergist, skin test results, and tryptase measurements when available were reviewed and categorized., Results: Thirty-eight patients were found to have an anaphylactic reaction during anesthesia, of which 18 were immunoglobulin (Ig)E-mediated anaphylactic reactions (likely causative agent identified by skin test), 6 were non-IgE-mediated anaphylactic reactions (elevated tryptase levels and negative skin test), and 14 were probable non-IgE-mediated anaphylactic reactions (tryptase levels normal or not obtained and negative skin test). Of the IgE-mediated anaphylactic reactions, antibiotics were the most prevalent likely causative agent (50%) whereas neuromuscular blocking drugs were implicated as a likely causative agent in 11% of reactions., Conclusion: Antibiotics were the most common likely causative agent associated with IgE-mediated anaphylactic reactions; however, for 52.6% of reactions, a causative agent could not be determined, suggesting a non-IgE-mediated anaphylactic reaction. The undiagnosed allergic reactions place patients at risk of a subsequent reexposure to the same allergen, or lead to unnecessary avoidance of needed medications.

Background: Anaphylactic and anaphylactoid reactions occurring during anesthesia remain a major cause of concern for anesthesiologists. The authors report the results of a 2-yr survey of such reactions observed during anesthesia in France., Methods: Between January 1, 1999, and December 31, 2000, 789 patients who experienced immune-mediated (anaphylaxis) or nonimmune-mediated (anaphylactoid) reactions were referred to one of the 40 participating centers. Anaphylaxis was diagnosed on the basis of clinical history, skin tests, and/or specific immunoglobulin E assay., Results: Anaphylactic and anaphylactoid reactions were diagnosed in 518 cases (66%) and 271 cases (34%), respectively. The most common causes of anaphylaxis were neuromuscular blocking agents (NMBAs) (n = 306, 58.2%), latex (n = 88, 16.7%), and antibiotics (n = 79, 15.1%). Rocuronium (n = 132, 43.1%) and succinylcholine (n = 69, 22.6%) were the most frequently incriminated NMBAs. Cross-reactivity between NMBAs was observed in 75.1% of cases of anaphylaxis to an NMBA. No difference was observed between anaphylactoid and anaphylactic reactions when the incidences of atopy, asthma, or drug intolerance were compared. However, atopy, asthma, and food allergy were significantly more frequent in the case of latex allergy when compared with NMBA allergy. Clinical manifestations were more severe in anaphylaxis. The positive predictive value of tryptase for the diagnosis of anaphylaxis was 92.6%; the negative predictive value was 54.3%. The diagnostic value of specific NMBA immunoglobulin E assays was confirmed., Conclusions: These results further corroborate the need for systematic screening in the case of anaphylactoid reaction during anesthesia and for the constitution of allergoanesthesia centers to provide expert advice to anesthesiologists and allergists.