Background: Indocyanine green (ICG) is an emerging intraoperative fluorescence agent increasingly used for anatomical mapping and tissue visualization. Its administration through nebulisation or inhalation for tracheobronchial and lung segmentation mapping is expanding. However, life-threatening cardiovascular complications associated with ICG remain extremely rare.

Case Description: A 64-year-old female with carcinoma of the esophagus, scheduled for total esophagectomy, developed sudden malignant ventricular tachycardia (VT) within 30 seconds of initiating intraoperative ICG nebulisation. The arrhythmia was accompanied by cardiovascular collapse. Surgery was immediately halted, and the patient was repositioned from prone to supine. Cardiopulmonary resuscitation (CPR), electrical defibrillation, and appropriate resuscitative measures successfully restored normal sinus rhythm and hemodynamic stability. Considering the severity of the event, the surgical procedure was abandoned. Following stabilization, the patient was successfully extubated in the operating room and transferred to the Surgical Intensive Care Unit (SICU) for further monitoring and management.

Conclusion: This case highlights a severe, hyper-acute cardiovascular event temporally associated with nebulised ICG and emphasizes the need for vigilant monitoring and immediate resuscitative preparedness during its administration.

KEYWORDS: Indocyanine Green, Nebulisation, Ventricular Tachycardia, Esophagectomy, Intraoperative Arrhythmia, Fluorescence-guided Surgery.