Suspected Neostigmine-Associated Bronchospasm Complicated by Pulmonary Edema During General Anesthesia: A Case Report

Neostigmine inhibits cholinesterase activity and increases acetylcholine at the neuromuscular junction. Neostigmine is thus administered as an antagonist for non-depolarizing muscle relaxants during general anesthesia. However, neostigmine-induced pulmonary edema is extremely rare, making its diagnosis and appropriate treatment in the perioperative period challenging for anesthesiologists. A middle-aged obese woman underwent surgery for ptosis under general anesthesia because she was allergic to local anesthetics. At the end of surgery, she developed severe hypoxia (peripheral oxygen saturation (SpO2) 47%) after administration of neostigmine, and before tracheal extubation. Salbutamol sulfate, a beta2 adrenergic receptor stimulant, was administered through her tracheal tube, which was suspected of bronchospasm, and anesthesia was reintroduced. Chest X-ray showed severe lung infiltration bilaterally, suggestive of negative pressure pulmonary edema. Following improvement of oxygenation by positive pressure ventilation with a high positive end-expiratory pressure (PEEP), her trachea was extubated under deep anesthesia, and manual ventilation was performed until recovery of spontaneous respiration. This report details the management of pulmonary edema that developed acutely after administration of neostigmine during general anesthesia and discusses the cause of hypoxia in our case.