High efficiency haemofiltration (ultrafiltration of more than 250ml/min for two hours) in eight uraemic patients.

In eight uraemic patients a haemofiltration of very high efficiency was carried out from a double extracorporeal circuit set up via an arteriovenous fistula. The weight of the patients was kept constant throughout the session. The average ultrafiltration flow rate was 274ml/min; the total ultrafiltration volume was 32.9L/min. The clinical tolerance was very good. The loss of efficiency associated with the magnitude of the ultrafiltration volume and with the diffusion delay of the removed molecules was evaluated at 9 per cent for urea and 17 per cent for creatinine. In spite of a considerable phosphorus depletion no severe hypophosphoraemia was observed; the stable value of the phosphoraemia between the 90th and the 120th minute of the session suggests the existence of a physico-chemical balance around the value of 0.74mmol/L.