For those on IV tpn--- are patients still hungry or does appetite get relieved?

Partially relieved. Appetite is a complex sensation that comes from the brain. Your brain may sense hunger if you have an empty stomach or from low blood glucose levels. Appetite may be "turned off" if you have eaten or if your blood glucose levels are high. Appetite is also decreased in times of stress such as illness or injury. Therefore, TPN may decrease appetite as the brain will sense higher glucose levels.