Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 12 1 2026 01 01 97 101 Mehrdad Mesbah Kiaei Department of Anesthesiology and Pain Medicine, Hasheminejad Kidney Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Siavash Sangi Department of Anesthesiology and Operating Room, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Seyed Mohammad Reza Amouzegar Zavareh Arthrosclerosis Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Maryam Aligholizadeh Department of Anesthesiology and Operating room, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Mahmoud Reza Mohaghegh Dolatabadi Department of Anesthesia, Hospital Management Research Center, Health Management Research Institute, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Mohsen Abbasi Department of Anaesthesia and Critical Care, Hasheminejad Hospital, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Melika Aligholizadeh Department of Laboratory Sciences, Langroud School of Allied Medical Sciences, Guilan University of Medical Sciences, Langroud, Iran. Fatemehsadat Mostafavi Mobasher Anesthesiologist and Critical Care Specialist, Moheb Kowsar Hospital, Iran University of Medical Sciences,Tehran, Iran. 2025 01 23 2025 02 11 Fat embolism syndrome (FES) is a rare but life-threatening condition often associated with long bone fractures, particularly femoral fractures. It typically manifests within 24–72 hours post-injury, presenting with a combination of neurological, pulmonary, dermatological, and hematological symptoms. This case report describes a 48-year-old male who sustained a femoral fracture in a work-related accident and subsequently developed FES during perioperative management. Despite aggressive interventions, including mechanical ventilation, hemodynamic support, and lipid emulsion therapy, the patient’s condition deteriorated, leading to cardiac arrest and death. The case highlights the diagnostic and therapeutic challenges of FES, emphasizing the need for early recognition, multidisciplinary management, and advanced diagnostic tools. The possibility of inadvertent intrathecal administration of an incorrect drug or local anesthetic systemic toxicity (LAST) further complicates the diagnosis, underscoring the importance of meticulous documentation and verification of administered medications. This report aims to contribute to the growing body of evidence necessary to address these significant research gaps and advance patient care in high-risk perioperative scenarios. https://aacc.tums.ac.ir/index.php/aacc/article/view/1184