Acute Myocardial Infarction Induced by Neostigmine after a Laryngoscopic Microsurgery: A Case Report

Perioperative myocardial ischemia is always the anesthesiologist's major concern. We report herein a case who suffered from acute myocardial infarction after undergoing laryngoscopic microsurgery. A 65-year-old female was scheduled as an outpatient surgery and the anesthesiologist's first visit was at the nurse station of the operation room on the operation day. All other systemic diseases were denied by the patient except hypertension. The operation only took 5 minutes, and we kept the patient anesthetized for 30 minutes to allow recovery from muscle relaxant. Neostigmine (0.5 mg) and atropine (0.2 mg) were given intravenously because patient was awaked and weak. Unfortunately, large amount of pink frothy sputum appeared in the endotracheal tube 5 minutes later. We explained the patient's condition to her daughter. Through our conversation, we noted that this patient had coronary artery disease and increased frequency of chest pain was noted in recent one week. Coronary angiography was performed 3 hours later and 50-60% stenosis of left anterior descending artery was revealed. The time of occurring of myocardial infarction was compatible with the time of intravenous administering of neostigmine. Neostigmine had been reported to cause coronary vasospasm. This patient would have unstable angina before operation. Unstable angina is a major risk of perioperative cardiovascular complications. This procedure should have to be postponed if we had been awared of this patient's recent condition earlier. Thus, we suggest that using neostigmine in such patients should be more cautious.