Brainstem hemorrhage does not have a specific volume that can be fatal; the brainstem is the central hub for respiration and circulation in the human body, including the medulla, midbrain, and pons. For the pons and midbrain, a hemorrhage of five milliliters can be fatal. For the medulla, which is very narrow and densely packed with neural tissue, even one milliliter of bleeding can suddenly cause the patient's respiration and circulation to stop. Therefore, even one milliliter of brainstem hemorrhage is an immeasurable loss, and brainstem hemorrhages should be classified as critically severe. Immediate hospitalization and treatment are crucial to achieve a relatively better prognosis.