There is no specific amount of time to show how long a person can stay on a ventilator, as it depends on the individual's condition. A patient may only come off the ventilator when he or she starts improving.
When a patient's condition starts getting better, the weaning process begins, as stated by UPMC. This is the process of getting a person off the ventilator. There is also a trial called the weaning trial. If the trial is successful, one may be removed from the ventilator. A person who is using the ventilator for a long time may obtain nutrition via special tubes to the stomach or veins. Ventilators are medical systems that are used for patients with severe breathing difficulties.