Fatal Right Heart Thrombus-in-Transit at the End of Hip Hemiarthroplasty Under Hypobaric Spinal Anaesthesia in a Frail Octogenarian With a Neglected Femoral Neck Fracture: A Case Report

Intraoperative massive pulmonary embolism is a rare but catastrophic complication of hip fracture surgery that is easily mistaken for the effects of neuraxial anaesthesia or for bone cement implantation syndrome. We report an 86-year-old man with dementia, severe frailty (Clinical Frailty Scale 7) and a body mass index of 19 kg/m2, admitted four days after a fall with a displaced (Garden IV) left femoral neck fracture. Preoperative transthoracic echocardiography was normal; no venous Doppler ultrasound was performed, and enoxaparin prophylaxis was started on admission. Cemented hemiarthroplasty was performed under unilateral hypobaric spinal anaesthesia (bupivacaine 5 mg, fentanyl 25 µg) with low-dose noradrenaline, and the 90-minute procedure was haemodynamically stable. During skin closure, the patient developed extreme bradycardia (35 beats/min) with loss of consciousness, followed by cardiac arrest. After return of spontaneous circulation, subxiphoid point-of-care echocardiography showed a large mobile right atrial thrombus prolapsing into a dilated right ventricle, with paradoxical septal motion. Thrombolysis was withheld because of the immediate postoperative context, and embolectomy was discussed with cardiovascular surgeons. A second arrest (pulseless ventricular tachycardia) was reversed by defibrillation, but a third arrest was refractory, and the patient died after 30 minutes of resuscitation. A normal preoperative echocardiogram does not exclude venous thrombosis after delayed presentation; under spinal anaesthesia, sudden bradycardia may be the first sign of massive embolism, and bedside echocardiography is decisive for the diagnosis.