[Determination of the best amino acid input after orthotopic liver transplantation]. / Determinazione dell'apporto aminoacidico ottimale dopo trapianto ortotopico di fegato.

Ten-three patients were investigated during the early postoperative phase after orthotopic liver transplantation to assess the adequacy of the amino acid (AA) supply during both parenteral (days 1-5) and enteral (days 6-9) nutrition. Plasma AA profile was determined preoperatively, on day 4 and 5 during TPN and on day 8 and 9 during EN, urea production rate was measured every day. Calories input was 28 kcal.kg-.day as glucose, nitrogen intake was 0.25 g.kg- day, supplying individual AA on the basis of previous studies. Urea nitrogen production during TPN (9-11 gN/m2.day) outlines the ability of the transplanted liver to manage the overall nitrogen load. Individual AA plasma profile was considered the expression of an adequate input when comprised between 1 and 1.5 times the normal value, in this respect we obtained adequate levels of all essential AAs. Particularly phenylalanine, methionine and branched chain AA, critical during liver failure, were kept in this range by supplying 68, 48 and 500 mg.kg-1.day. According to AA profile the supply of cystine and tyrosine (conditionally essential AAs), and of histidine, taurine, proline and serine could be safely increased. Not given dispensable AAs (glutamine, asparagine, citrulline and alfa amino butyric) showed a plasma level below the norm and should be added to the diet.

[Changes in the plasma amino acid profile in critically ill patients during total parenteral therapy]. / Variazioni del profilo aminoacidico plasmatico in pazienti critici durante terapia parenterale totale.

The aim of this study was to evaluate the kinetics of arterial plasma amino acid profile during the first 48 h of clinical TPN in order to assess the time necessary to reach the steady-state condition during infusion. Each patient was treated with one of three different amino acid solutions yielding, in the same nitrogen intake, different intakes of individual amino acids. We found four different kinetics for the administered amino acids: an increase of plasma levels immediately after the start of the TPN with no variations during the steady period; the same trend with the steady-state obtained after 6-24 h of TPN infusion; no influence at all; a decrease of fasting plasma levels with the steady-state attained variably during the study period. Each given amino acid showed a different trend partly depending on the supply, suggesting that the steady-state was reached sooner for most amino acids, when the supply was larger. With lower intakes, plasma levels were unaffected or decreased. We conclude that in critically ill patients at least 24 h are needed to obtain stable arterial plasma amino acid concentration during TPN with adequate intakes of amino acid. Knowledge offers the possibility for a quick and accurate assessment of the adequacy of a given preparation (tailored for critically ill patients), it reduces the time span of the study and, as a consequence, the influence of varied metabolic conditions.