Informed consent was obtained from the patient for publication of this case report and any accompanying images. A 74-year-old woman (body weight, 48 kg; height, 148 cm) without a history of drug allergy was scheduled to undergo open-heart surgery. She was taking oral medication for high blood pressure and atrial fibrillation. After hospitalization due to heart failure, severe mitral regurgitation and tricuspid regurgitation were found by echocardiography, and mitral valve replacement, tricuspid annuloplasty, and the maze procedure for atrial fibrillation were scheduled. Laboratory data were unremarkable except NT-proBNP 1920 pg/ml.
General anesthesia was induced with 4 mg of midazolam, 200 μg of fentanyl and 50 mg of rocuronium.
Tracheal intubation was performed uneventfully. Immediately after inserting a probe for recording a transesophageal echocardiogram, increase in airway pressure up to 40 cmH2O, reduction in blood pressure, and skin flushing and edema on her neck and arms were confirmed. Hate rate was 120 bpm or more and systolic arterial blood pressure fell to less than 60 mmHg and a low level persisted despite repeated administration of phenylephrine. An electrocardiogram showed no significant ST-T change in atrial fibrillation. With a possible diagnosis of anaphylaxis, we started chest compression and administered 1 mg adrenaline and 1000 mg methylprednisolone approximately 2 min after the onset of symptoms. In consideration of a possible latex allergy, the probe for a transesophageal echocardiogram was removed together with the probe cover, and the urinary catheter was also removed and replaced with a latex-free one. Following the insertion of a catheter into the right internal jugular vein, we started a continuous infusion of noradrenaline at 0.1 μg/kg/min. Although blood pressure and heart rate gradually stabilized approximately 30 min after starting treatment, the planned surgery was suspended. She remained orotracheally intubated and was transferred to the intensive care unit.
No further anaphylactic reaction or other complications occurred, and she was extubated the next day. Two days later, the results of drug-induced lymphocyte stimulation tests (DLSTs) for rocuronium and midazolam were negative.
Five weeks after anesthesia, skin prick test was conducted for rocuronium and vecuronium, following a method reported previously [1]. In brief, undiluted rocuronium and vecuronium (10 and 4 mg/ml, respectively), histamine (positive control) and normal saline (negative control) were prepared. One drop of the allergen was placed on the forearm flexion side, and the skin was punctured through the allergen with a 26 G needle. After 15 min, the diameter of the wheal (mean value of the longest diameter and the diameter perpendicular to the midpoint) was measured, and more than half of the positive control and 3 mm or more of the negative control were judged as positive [4]. The diameters of the wheals were 9 mm for histamine, 8 mm for rocuronium, and 0 mm for vecuronium and normal saline, and the results were therefore positive for rocuronium and negative for vecuronium (Fig. 1).
Surgery was performed seven weeks after anaphylaxis. General anesthesia was induced with midazolam, fentanyl, and vecuronium and was maintained with sevoflurane, vecuronium, and intermittent fentanyl. Surgery was completed uneventfully.
