So here you go... People get intubated for a few reasons. Airway protection from a burn or seizure, head injuries and may vomit....

People get put on a ventilator because of inadequate breathing. Let's say ad asthma attack and eventually you fatigue and can't breath very well. When you don't breath very well it changes your blood pH and messes up body functions. A ventilator is used to make your breathes bigger or faster. They can manipulate it to restore you blood pH and oxygenation. Since the tube is open I to your lungs you can get a pneumonia. The hospital does certain things like not opening the circuit, keeping your head up, oral care, etc.

To be ventilated is very u comfortable so you get a pain drip and a sedation drip.. in certain circumstances they will need to take Co tool of your breathing completely and they will use a paralytic like vecuronium if you were a head injury they can Co trol your breathing to fi e tune the CO2 in your blood to help with control of brain swelling

Just a quick primer