Membrane Distillation of Human Plasma Ultrafiltrate and its Theoretical Applications to Haemodialysis Techniques

Abstract

Membrane Distillation (MD) is a technique that allows the extraction of water from aqueous solutions. The basic principle is that vapour, but not liquid water, can pass through hydrophobic micro-porous membranes, along a temperature gradient, with consequent separation of water from solutes. In this study we evaluated the possibility to utilise MD to extract water from Plasma Ultrafiltrate (PU) of patients with Chronic Renal Failure (CRF). The experiments were carried out in vitro by a hydro-phobic polypropylene hollow-fibre distillation module; PU was obtained by a CRF patient utilising a high permeability polisulphone membrane. The results show that water can be extracted by MD from PU of CRF subjects at a constant rate and that none of the substances analysed in PU was able to pass through the polypropilene membrane. In the future MD could integrate extra-corporeal blood purification techniques allowing the re-utilisation of plasmatic water thus ameliorating the treatment of uraemia.