Background: Although cases of anaphylaxis caused by sugammadex have been reported, its incidence remains uncertain. Conversely, no studies have evaluated the incidence of anaphylaxis to neostigmine. Methods: This was a retrospective multicentre observational study of patients who underwent surgery under general anaesthesia between 2012 and 2016 to compare the incidence of anaphylaxis with sugammadex with that of neostigmine at four tertiary hospitals in Japan. To ensure the quality of diagnosis, only cases with a clinical history suggestive of anaphylaxis, along with positive results from in vitro or in vivo testing, were assessed. Results: From a total of 49 532 patients who received general anaesthesia included in this study, 18 cases of anaphylaxis were reported, of which six were attributable to sugammadex and none to neostigmine. There were no fatalities attributable to anaphylaxis. The incidence of anaphylaxis caused by all drugs or by sugammadex was calculated as 0.036% (95% confidence interval [CI]: 0.022e0.057%) and 0.02% (of the number of sugammadex cases) (95% CI: 0.007e0.044%), respectively. Conclusions: The results suggest that neostigmine might be safer than sugammadex when assessing only the incidence of anaphylaxis. We believe that there is room for reconsideration of the choice of reversal agent for neuromuscular blocking agents by all anaesthetists. Clinical trial registration: UMIN000022365; UMIN000033561.

BackgroundSugammadex has a unique mechanism of action and is widely used because of its safety and efficacy. A few recent reports have described allergic reactions to clinical doses of sugammadex. We hereby describe another series of cases of possible anaphylaxis to sugammadex.Case presentationWe present three suspected cases of sugammadex-induced anaphylactic shock, including a 13-year-old boy who underwent laparoscopic appendectomy, a 75-year-old woman who underwent left knee arthroplasty, and a 34-year-old man who underwent left pansinectomy for sinobronchitis. All three patients received general anesthesia with rocuronium and their tracheas were intubated. Shortly after injection of sugammadex for reversal of rocuronium, all of them experienced a decrease in blood pressure along with mucocutaneous erythema. In the most severe case, reintubation after extubation was required due to difficulty in manual ventilation. All patients recovered with anti-allergic therapy. On later investigation, all three patients had a positive skin reaction to sugammadex.ConclusionOur results suggest that physicians using sugammadex should be aware of the possibility of sugammadex-induced anaphylaxis.

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Background: Staining of exteriorized basophil granule matrix by fluorescent avidin might be a reliable technique to monitor basophil degranulation. This study compares the avidin-based technique with the upregulation of CD203c and appearance of CD63 in response to various stimuli. Methods: Fourteen individuals responsive to anti-IgE, nine healthy controls, and five birch pollen-allergic patients, and five nonresponders were studied. Activation experiments included anti-IgE, fMLP, interleukin-(IL)-3, and birch pollen allergen. Basophil activation/degranulation was analyzed by flow cytometry and microscopy using anti-CD63, anti-CD203c, and avidin. Results: Stimulation with anti-IgE, fMLP, and relevant allergen results in upregulation of CD203c, CD63 appearance, and an increase in avidin binding. In response to anti-IgE and allergen, upregulation of CD203c peaks within 10 min, CD63 and avidin binding reach a plateau after 10-20 min. CD63 staining leads to a bimodal distribution, avidin staining causes a unimodal shift with a less clear discrimination between degranulating and nondegranulating cells. In response to fMLP, upregulation of CD203c and CD63 and avidin binding are maximal after 2.5 min. Following incubation with anti-IgE and fMLP, percentages of CD203c+ cells are higher than those of CD63+ and avidin+ cells, pointing to a dissociation between activation and degranulation. Percentages of CD63+ cells are systemically higher than those of avidin+ cells. Incubated with IL-3 only upregulates CD203c, while no CD63 or avidin binding is observed. Conclusions: Staining of exteriorized proteoglycans by avidin is a reliable technique to quantify basophil degranulation but offers no added value when compared to traditional assays that use CD63 as a readout.