Letter: Intravenous feeding

Alterations in the enzyme profile in intensive care patients undergoing total parenteral nutrition

Total parenteral nutrition (TPN) has been demonstrated to be an effective therapeutic means in improving the clinical course of the critically ill patients. Various metabolic complications are described; the cause of some of these remain unclear. The changes in some plasma enzyme indices (GOT, GPT, GIDH, LDH, HBDH, CPK, ChE, AP, gamma-GT) in two groups of critically ill patients undergoing TPN (group with more marked enzyme alterations and group with less marked alteration) were examined. Two types of alterations were found: (1) early increase of some enzymes (GOT, GPT, GIDH); (2) constant increase of plasma enzyme level during TPN (AP, gamma GT). These two evolutionary patterns were more evident in the complicated group and the enzyme changes were statistically significant for GOT and GPT (P = 0.05) and not significant for initial values of G1DH, ap and gamma-GT. Both groups presented constant elevated plasma values of LDH, HBDH, CPK and depressed constant ChE value during treatment; the difference was not significant in both groups for the same enzymes. The data were interpreted from a functional point of view; that is they were related to both the metabolic post-aggressive state and TPN. A relationship between the rate of protein catabolism and the inductive increase of some enzymes (GOT, GPT, G1DH) was found. Whereas a final induction in the energy metabolism is suggested for other enzymes (LDH, HBDH), the alteration of CPK, AP, gamma-GT and ChE was interpreted as dependent on: (1) direct muscular trauma (CPK); (2) functional increase in relation to the duration of TPN (AP and gamma-GT); (3) possible depressed malnutritive synthesis (ChE). The improvement of the enzymatic patterns with the early use of TPN and with the improvement of clinical and nutritional conditions was emphasized.

Metabolic changes during prolonged total parenteral nutrition in intensive care

Intensive care patients receiving prolonged total parenteral nutrition (TPN) developed alterations of liver function tests, seen in the activity of certain serum enzymes. Hepatomegaly and jaundice sometimes appeared. The changes in chemical pathology were in serum transaminases activity (GOT, GPT, GDH); alkaline phosphatase and gamma-glutamyltranspeptidase as indices of cholestasis; lactate dehydrogenase, hydroxybutyrate dehydrogenase and creatine phosphokinase, as enzymes related to energy metabolism; pseudocholinesterase, as a protein metabolism-related enzyme. The possible causes of these alterations in critically ill patients undergoing TPN are considered and a functional final metabolic interpretation is proposed.