Have minimal training in clinical nutrition and pn .buy often are responsible for its management and prescription guidelines for the use of pn have been developed by several nutrition societies such as the german society of nutritional medicine (dgem) as well as the European society of clinical nutrition and metabolism (espen) a reduced dietary intake together with an increased energy requirement is the main cause of hospital undernutrition treating malnutrition should firsh of all be based on the evaluation of individual causes of malnutrition and should precede nutritional intervention strategies.