A 32-year-old man wass involved in a high speed motorcycle accident. He sustained multiple injuries, including a pelvic fracture and an open left femur fracture. He was taken urgently to the operating room for irrigation and debridement of his wounds. They were unable to stabilize his fractures at the time of admission because he is medically unstable. On the second day in the hospital, he was doing well, however later that evening, he becomes confused, tachypneic, dyspneic, and develops petechiae. An electrocardiogram is normal. Chest X-ray were normal. Which of the following is the most likely diagnosis?

Fat embolism is usually seen 24-72 hours after trauma. Classic signs include tachypnea, confusion, and petechiae. Additional signs include tachycardia, hypoxemia, and pulmonary edema. Its incidence may be decreased by early skeletal stabilization of long bone fractures. Treatment includes pulmonary suppo. Pneumonia would most likely show up on the chest x-ray film, which was normal in this situation. Pneumothorax would cause pulmonary symptoms, but a significant pneumothorax will show up on chest x-ray films. Also if the patient had a pneumothorax from the initial accident, he most likely would have been symptomatic from it at initial presentation. A pulmonary contusion is possible, and should always be considered in patients with high-energy trauma, however the patient's symptoms of tachypnea, confusion, and petechiae are classic for fat embolism.