Review Question - QID 108712

A 50-year-old male presents to the emergency room after getting hit by a car while biking. He complains of severe pain in both thighs. His thighs appear swollen, bruised, and angulated. Radiographic imaging demonstrates bilateral femoral shaft fractures. He subsequently undergoes surgical fixation of his fractures. Initially he has an uneventful post-operative course; however, on post-op day 4 he becomes confused and develops chest pain, tachypnea, and dyspnea. A new petechial rash is seen over his chest and neck. Electrocardiogram reveals normal sinus rhythm. Which of the following is the most likely cause of this patient’s respiratory symptoms?