La pratique de la nutrition artificielle est modifiee en cas d'insuffisance renale aigue (IRA). En effet, cette dysfonction viscerale a deux consequences : 1) un certain nombre de modifications metaboliques sont rattachees soit a l'IRA elle-meme, soit a sa cause, au sein de ce qui constitue un etat d'agression ; 2) la mise en oeuvre des techniques d'epuration extrarenale (EER) interagit avec la situation nutritionnelle, avant tout en rendant possible un apport nutritif normal et adapte a la situation metabolique du patient. De facon relativement marginale, l'EER entraine la perte de certains nutriments hydrosolubles : glucose, acides amines, petits peptides, vitamines et oligoelements ; les molecules lipidiques (triglycerides, vitamines) ne sont pas eliminees. Aucune carence nutritionnelle veritable n'est reliee directement a la pratique de l'EER, si l'on excepte les hypokaliemies et les hypophosphoremies nettement favorisees par la dialyse. Chez le patient severement agresse, les recommandations d'apports nutritionnels ne doivent pas etre modifiees en cas d'IRA : apport energetique representant 120 a 130 % de la depense energetique theorique, ou 100 % de la depense mesuree ; apports azotes de l'ordre de 1,25 a 1,5 g de proteines par kg et par jour ; calories glucidiques 60 %, lipidiques 40 % de la ration calorique non proteique. Les besoins en micronutriments ne sont que peu modifies et les apports doivent etre conformes aux apports recommandes, ajustes en cas de carence probable ou confirmee preexistante (vitamines B1 et B9, zinc, selenium). La voie d'administration de la nutrition artificielle doit etre enterale en priorite et parenterale uniquement en cas de stricte necessite.
Artificial nutrition management can be affected by the occurrence of acute renal failure (ARF). Indeed this organ dysfunction, which is frequent in ICU, has two main consequences: 1) metabolic disorders related either to the causal disease or to the metabolic consequences of renal failure, 2) the method used (hemofiltration and/or hemodialysis) may interfere with metabolic and nutritional consequences of this organ failure. Among various metabolic consequences, renal replacement therapy permits these ARF-patients to be provided with adequate nutritional intakes. Although replacement therapy is responsible for losses of nutrients such as glucose, aminoacids, peptides, vitamins and trace elements (lipophilic substances, which are not water-soluble, are not dialyzed), this is probably only of a minor importance. Indeed, there is almost no actual nutritional deficiency directly related to the renal replacement therapy except for hypokaliemia and hypophosphatemia, which are much more frequent during hemodialysis. The occurrence of ARF does not affect the nutritional needs as compared to similar patients without ARF. Hence recommended energy intake is 120-130 % of resting energy expenditure, or should match the actual energy expenditure whenever assessed, protein intakes should be 1.25-1.5 g/kg body weight, and the glucose/lipid ratio is close to 60 %/40 %. The needs for micronutrients and vitamins are not really modified by ARF and intakes should follow the recommended values. In the case of probable or documented deficiency (vitamins B1 and B9, selenium, zinc) intakes must be adapted. Finally the prefered route for nutritional supply must be enteral (gastric or jejunal) as generally recommended in the ICU, parenteral nutrition being reserved for real necessity.