1例74岁男性患者因心脏瓣膜病于全麻体外循环下行主动脉瓣置换+冠状动脉旁路移植术。术中在体外循环结束后给予硫酸鱼精蛋白注射液50 mg（5 ml）缓慢静脉注射以中和肝素钠。注射约3 min时（鱼精蛋白入量约15 mg），患者血压突然下降，心率加快，呼吸急促，注射部位周围皮肤泛红，出现淡红色斑丘疹。考虑鱼精蛋白过敏，立即停止滴注，并静脉注射苯海拉明、地塞米松和肾上腺素等抗过敏药物。约30 min后，患者血压回升，心率下降，皮疹逐渐消退。因鱼精蛋白用量不足，患者术后胸腔渗血、渗液较多，导致其血压下降，凝血酶原时间延长。将硫酸鱼精蛋白注射液50 mg（5 ml）用0.9%氯化钠注射液100 ml稀释后以60滴/min速度缓慢静脉滴注，患者未再出现过敏现象，胸腔引流液逐渐减少，血压恢复正常。“,”A 74-year-old male patient underwent aortic valve replacement and coronary artery bypass grafting under general anesthesia and cardiopulmonary bypass for valvular heart disease. After cardiopulmonary bypass, protamine sulfate injection 50 mg (5 ml) was slowly intravenously injected to neutralize heparin sodium. At about 3 minutes of the injection (injection dose was about 15 mg), the patient suddenly developed decreased blood pressure, increased heart rate, and shortness of breath. Redness appeared on the skin around the injection site and there were light red rashes. In consideration of protamine allergy, the infusion was stopped immediately and anti-allergic drugs such as diphenhydramine, dexamethasone, and adrenaline were injected intravenously. After about 30 minutes, his blood pressure increased, heart rate decreased, and the rashes gradually subsided. Due to insufficient dose of protamine, the patient had more oozing and exudation in the thoracic cavity, resulting in a decrease in blood pressure and prolonged prothrombin time. Then protamine sulfate injection 50 mg (5 ml) diluted in 0.9% sodium chloride injection 100 ml was given by intravenous injection at a rate of 60 drops/min. The patient did not have any allergy again, the pleural drainage fluid was gradually reduced, and his blood pressure returned to normal.