Yes, one can survive quite a while on IVs, but there would need to be special fluids that provide additional nutritional support (calories), not just fluid replacement. Nasogastric tubes (through the nose and into the stomach) can be inserted to put special nutritional solutions directly in the stomach, or a surgical portal can be put int he stomach to do the same.
For this is only for a short time, IV fluids will suffice. Of course, a confused person would have to tolerate any of these tubes and not pull them out.
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