[Anaphylactic Shock Induced by Indocyanine Green During Right Lung Segmentectomy]

A 79-year-old man underwent thoracoscopic right S6 segmentectomy for suspected lung adenocarcinoma. Indocyanine green (ICG) was intravenously administered twice to identify the intersegmental plane. Approximately 10 minutes after the second injection, profound hypotension refractory to vasopressors developed. Cutaneous flushing was subsequently observed, and intraoperative anaphylactic shock was diagnosed. Hemodynamic stability was achieved after intramuscular adrenaline administration along with antihistamines and corticosteroids. The surgery was completed without further complications, and the postoperative course was uneventful. Although ICG is generally considered safe, it can rarely cause life-threatening anaphylaxis. Under general anesthesia, early symptoms may be masked, delaying diagnosis. With the increasing use of ICG fluorescence in thoracic surgery, perioperative preparedness, prompt recognition of circulatory changes, and immediate availability of adrenaline are essential for patient safety.