"It depends what functions you want them to be able to perform and how long you want them to survive," she said. "If you literally want them to have only conscious thought, you could maybe take away a lot for a short period."
It gets worse:
"You can take out the pancreas by administering insulin/glucose and providing pancreatic enzyme replacement therapy. You could take out multiple smaller blood vessels and the target tissue probably wouldn't become necrotic for a while."
Well, alright. What else?
"All reproductive organs can go, as can eyes, tongue, nasal cavity, ears. You can provide total parenteral nutrition to render the digestive tract below the laryngopharynx pretty much useless. You would also then need to take out salivary glands, and the patient could keep their mouth hydrated with water—which they would be have to spit out due to absence of swallowing."