The Trigeminocardiac Reflex: An Unusual Suspect of Sudden Intraoperative Hemodynamic Alteration, Encountered during Endovascular Embolization with DMSO/Onyx

Abstract Continuous intraoperative hemodynamic monitoring is essential during endovascular procedures. Ethylene vinyl alcohol (EVOH) embolization, using Onyx liquid embolizing agent with dimethyl sulfoxide, can trigger an unusual brainstem reflex termed the “trigeminocardiac reflex (TCR),” characterized by sudden bradycardia and hypotension. We report a case of intracranial mycotic pseudoaneurysm in a postoperative case of coronavirus disease 2019-associated rhinocerebral mucormycosis patient, treated with parent artery occlusion using Onyx and coils. Intraoperatively, TCR was promptly recognized and managed, ensuring hemodynamic recovery and favorable outcome. This case highlights the importance of early TCR detection and management during EVOH embolization for optimal patient care.