Unexplained seizure after trauma

Patient: 30 year old man presented to ER by his brother after he has been involved in a street fight. The brother stated that the victim has been stabbed several times in the chest by a sharp metal and he bled a lot. In ER, the victim was drowsy, covered in blood with labored breathing. He was immediately put under critical care, and the surgical team arrived. He was transfused with 5 units of PRBC, and bilateral chest tubes were inserted because the CXR showed bilateral huge hemothorax. The patient was stabilized on mechanical ventilation and was taken to ICU. That night, and about 15 hours after the event, he suddenly started seizing. The ICU tean rushed to him and was given one dose of diazepam. The lab results then showed:Hgb: 9.1wbc: 22×10 3Plt: 210×10 3Normal differentialpH: 7.36pCO2: 45HCO3: 23O2sat. : 99%BUN: 15Cr: 0.8Na: 121K: 4.1Cl: 91Normal bleeding profileWhat is the explaination for this case

Symptoms: Haemothorax, seizure