The sequelae of subarachnoid hemorrhage after a car accident are due to subarachnoid hemorrhage, which can stimulate the contraction of cerebral blood arteries and cause cerebral vasospasm, cerebral ischemia, and cerebral neurological deficits, which can also cause headache, dizziness, hemiparesis, aphasia, or numbness of one limb and epilepsy. In subarachnoid hemorrhage, some blood clots can block the arachnoid granules, the cerebral aqueduct in the interventricular foramen and the cerebrospinal fluid circulation pathway, which can cause obstructive hydrocephalus, and the patient can be in a long-term coma. Therefore, for subarachnoid hemorrhage after a car accident, calcium antagonists, such as nimodipine, are usually used to prevent cerebral vasospasm. Severe hydrocephalus requires immediate ventricular borehole drainage or lumbar pool drainage, or lumbar puncture, etc.