How long a senior citizen can live on a ventilator depends mainly on the reason for being on a ventilator and whether there is a combination of other underlying diseases. Reversible diseases such as pneumonia do not affect life expectancy once the primary disease disappears. Some reversible diseases, such as pneumonia leading to acute respiratory failure, as long as the primary disease, pneumonia, is under control, the elderly can continue to survive without affecting life expectancy. But if it is some irreversible diseases, such as chronic obstructive pulmonary disease, progressive progress, the ventilator to some extent can only delay or extend the life of the patient, can not solve the problem from the root. This situation will seriously affect the patient’s life expectancy. At the same time, the ventilator itself can cause ventilator-associated pneumonia or ventilator-associated pneumothorax, leading to worsening of hypoxia, which can also easily lead to the death of the patient. Meanwhile, if there is a combination of other serious underlying diseases, such as uncontrolled diabetes mellitus, hypertension, coronary artery disease or even myocardial infarction, it will also affect the survival time of the elderly after being put on a ventilator. It is recommended that the elderly inform their doctors of any discomfort that occurs during the use of a ventilator, so as to avoid aggravation of the condition due to delays, which may affect their life expectancy.