Renal and Electrolyte Effects of Total Parenteral Nutrition

Abstract
Effects of short‐term (4–14 days) total parenteral nutrition on renal handling of water and electrolytes were studied retrospectively in 24 patients and prospectively in eight patients. There was 33% incidence of hyponatremia and significant reductions in serum creatinine (from 1.03 ± 0.06 to 0.88 ± 0.06 mg/dl, p < 0.001), phosphorus (from 3.2 ± 0.14 to 2.5 ± 0.17 mg/dl, p < 0.005) and uric acid (from 6.09 ± 0.38 to 3.66 ± 0.24 mg/dl, p < 0.001) were observed. Hypouricemia correlated with increased fractional excretion of urate (r = —0.81,p < 0.05). Hypophosphatemia was associated with increased tubular reabsorption of phosphate. Clearance studies in eight patients showed high urine flow rate (1.7 ± 0.2 ml/min), osmolar clearance (3.2 ± 0.7 ml/min), urinary nonelectrolyte, nonurea solute excretion (0.23 ± 0.14 mmol/min), and negative free water clearance (TcH2O = 1.5 ± 0.6 ml/min). These data suggest presence of compartmental shifts, expanded extracellular fluid volume, and possible direct effects on renal tubular transport functions during total parenteral nutrition. (Journal of Parenteral and Enteral Nutrition 8:546–551, 1984)