Nutritional effect of continuous hemodiafiltration

Continuous arterial-venous and reno-venous hemodiafiltration are reliable methods of renal replacement therapy and are particularly suited to critically ill patients in acute renal failure. Fluid and uremic toxin removal from continuous hemodiafiltration is sufficient to allow unrestricted nutrition support. However, the hemodiafilter cannot discriminate between uremic toxins and nutrients. Therefore, the potential exists for significant nutrient loss during continuous hemodiafiltration. Amino acid loss during continuous hemodiafiltration is approximately 10-15 g/day, although in individual cases ≥30 g/day can be lost. Neither lipids nor intact proteins are lost to any appreciable degree during continuous hemodiafiltration. Small amounts of glucose are lost if dextrose-free dialysate is used for dialysis. If dextrose-containing dialysate is used, significant amounts of glucose can be absorbed (35-45% of the infused glucose). Fluid replacement with dextrose- containing electrolyte solutions can also lead to significant infusion of glucose. Vitamin and mineral losses during continuous hemodiafiltration are not known; neither are the vitamin requirements for patients receiving continuous hemodiafiltration. Effects of continuous hemodiafiltration on vitamin and mineral loss and status remain an important research question.