The danger period for brain hemorrhage and coma caused by car accident is about 2-3 weeks, or 14-21 days, but it must be noted that as long as the patient is comatose and the vital signs are unstable, it is more important to judge according to the actual condition of the patient. Because of the brain hemorrhage caused by the car accident, once it reaches the level of coma, the overall physical condition of the patient is very poor. In the case of poor physical condition, if corresponding therapeutic measures are not given in time to control it, the bleeding may increase again and the degree of coma may worsen again, even affecting the vital signs, which is very unfavorable to the overall prognosis of the patient. Therefore, it is important to pass the 2 most dangerous periods, namely the period when brain hemorrhage occurs again and the peak period of brain swelling. After passing the above 2 periods, active wake-up treatment should be carried out, so that the patient can pass the complete dangerous period when he/she is relatively awake.