Patients with cerebral infarction who are in a coma are most at risk on the 3rd day after the coma. This is because the 3rd day after coma is the time when neurological deficit symptoms and cerebral edema reach their peak. Patients often experience complete limb paralysis, double vision, violent vomiting, pupil changes, respiratory rhythm changes, seizures and other symptoms at this time, which can cause a decrease in oxygen saturation and respiratory distress in severe cases, easily leading to respiratory failure and brain herniation formation. After 3 days, most of the patients’ symptoms have stabilized, the cerebral infarction liquefied and softened, the lateral circulation has been basically established, the patients’ neurological functions have gradually recovered, and the patients have basically passed the dangerous period. However, a small number of patients with severe disease will continue to be in coma, with progressive worsening of symptoms, and eventually die easily from pneumonia and brain herniation.