Elderly people in deep coma will show a series of unstable vital signs before they die. This manifestation is more intuitive if they can be well monitored in the hospital: first, heart rate. In the terminal phase, the heart rate will gradually slow down, normally between 60-100 beats. When the patient is failing the heart rate may gradually drop below 40 beats to a gradual arrest. Second, blood pressure. Terminal blood pressure will gradually decline, from the normal 140/90mmHg has fallen to below 90/60mmHg, shock patients will have cold limbs, some have sweating. Third, breathing. Respiratory rhythm will be significantly disorganized, can be short, shallow and fast respiration, can also be sigh-like or tidal breathing, there are more kinds. The patient’s oxygen saturation will often be accompanied by a decline, often as low as below 80%, and gradually reduced to below 30% in the terminal stage. Fourth, pupil to light reflex. When the patient’s pupil is irradiated with a flashlight, it will be found that the pupil is dilated, the light reflex is completely lost, and sometimes there is obvious corneal clouding.