Effect of total parenteral nutrition in the restitution of body nitrogen, potassium and weight

The effects of nutritional support on body weight, nitrogen and potassium were investigated and were compared with changes in serum albumin and delayed cutaneous hypersensitivity (DCH). Fifteen malnourished patients (maintained by total parenteral nutrition (TPN) were studied for periods of 5 to 33 months. The TPN consisted of infusions of amino acids with a dual substrate of glucose and lipids. Body nitrogen was measured by prompt gamma ray analysis and potassium was determined by measurement of the naturally occurring radio-active 40K in a whole body counter.Results of sequential measurements show on average a significant increase in body nitrogen of 30% (P<0.001) and a smaller but significant increase of 10% in body weight but a mean increase of 4.5% for potassium was not significant. While the nutritional support was very effective in improving body nitrogen, it was less effective in improving serum albumin or DCH.Thus, changes in body protein are not necessarily reflected by measurements of the body parameters of nutritional status. For a reliable estimate of body protein, the direct measurement of body nitrogen is required.