TPN stands for Total Parenteral Nutrition, while PPN stands for Peripheral Parenteral Nutrition. These two are given to the patient by IV. They are given to those who do not have other sources of nutrition. Though they both serve the same purpose, they are also different in many aspects. A patient is given Total Parenteral Nutrition when he or she refuses to receive other forms of nutrition. The patient relies totally on this total nutrition.
The peripheral parenteral nutrition is a kind of partial nutrition given to a patient, whereby he or she can still take nutrition from other sources. The total parenteral nutrition is given in higher concentration, and it is administered through the larger veins, usually in the neck or chest. The peripheral parenteral nutrition is given in a lesser concentration, and it is usually administered through in the smaller veins. The TPN contains minerals, glucose, and even electrolytes, which make it more caustic than PPN.