Sudden Cardiac Arrest in Proximal Femur Fracture: The Role of Admission Blood Parameters.

Proximal femur fractures in the elderly are associated with high mortality rates due to reduced physiological reserve and a high risk of thromboembolic events, where admission laboratory parameters can serve as early indicators of clinical vulnerability. This case highlights a catastrophic clinical deterioration in a 92-year-old man who was admitted following a fall resulting in a displaced right intertrochanteric fracture. On admission, the patient was hemodynamically stable, but laboratory findings revealed an elevated neutrophil-to-lymphocyte ratio (NLR) of 10.1 and significant hyponatremia (126 mmol/L), reflecting high physiological stress and reduced compensatory reserve. Approximately 10 hours after admission, during preoperative preparation, he developed sudden dyspnea, hypotension, and pulseless electrical activity (PEA). Despite 30 minutes of advanced cardiac life support, the patient died. Arterial blood gas analysis during resuscitation showed profound hypoxemia (PaO₂ 42 mmHg) and severe metabolic acidosis (pH 6.98). Early mortality in geriatric hip fractures can occur even before surgical intervention, and abnormal admission parameters like elevated NLR and electrolyte imbalances should alert clinicians to a reduced compensatory reserve. In cases of sudden PEA arrest in the emergency department (ED), both massive pulmonary embolism and early-onset fat embolism syndrome should be considered in the differential diagnosis as plausible but unconfirmed causes.