Extracellular volume, nutritional status, and refeeding changes.

ECW, and particularly its interstitial component, expands easily with malnutrition, sepsis, and trauma and after aggressive intravenous fluid therapy. In this scenario, hypoalbuminemia is usually the result of both an increased capillary escape rate due to leaky endothelium and increased distribution volume; this can be worsened by artificial intravenous nutrition with sodium, water, and glucose. Monitoring ECW is essential during TPN. Short-term changes in weight and serum albumin concentration are helpful to control ECW volume and prevent ECW expansion. Tetrapolar bioimpedance analysis is a promising technique for accurate bedside measurement of changes in body fluid compartments.