Body Composition & Nutritional Assessment in Dialysis

As a result of the continual growth in numbers of ESRD patients, the need for assessment of the nutritional status and body composition in this group has become of paramount importance. It has been found that ESRD patients on maintenance dialysis often have an electrolyte and fluid imbalance. These patients have shown evidence of Malnutrition.

These alternations may suggest in patients on maintenance dialysis, the necessity to investigate for the presence of co morbid conditions to assess the food intake or to change dialysis strategy and dose. The increase in body water appears to primarily accumulate in the extracellular space, particularly within the intersitium of superficial tissues. Partial to total failure of Kidney function also impairs excretion of Metabolic toxins (e.g. urea, creatinine and other middle molecules) and causes an inability to regulate normal electrolyte balance.

Haemodialysis is used to reduce uremic toxins, adjust electrolytes in the blood and remove excess body water. Clinical studies suggests that when fluid is withdrawn from the intravascular compartment, plasma volume falls refilling the vascular system depending on fluid shift from the interstitium.

Thus at the end of dialysis, a new equilibrium is established in which plasma volume is partially restored and fluid is lost from peripheral tissue interstitium. The peritoneal abdominal cavity is used as the diffusion membrane.