Hemodiafiltración en línea pre-dilucional, frente a post-dilucional: estudio comparativo de eficacia dialítica y tolerancia hemodinámica

on-line haemodiafiltration is a dialysis technique which combines the advantages of high-flow haemodialysis (diffusive transport) and haemofiltration (convective transport). this technique allows different alternatives depending on how the reinfusion liquid is added: pre-dilution (before the dialyser) and post-dilution (after the dialyser), each of them having advantages and disadvantages. the object of this study was to compare different dialytic and haemodynamic parameters in the pre- and post-dilution haemodiafiltration modes. a transversal prospective study was conducted of a population in dialysis already being treated with on-line haemodiafiltration, using each of the modes (pre- and post-dilution) with them for 4 weeks. the following values were recorded: systolic and diastolic arterial pressure and cardiac frequency pre- and post-session, blood flow, venous pressure, volume of blood dialysed and replacement volume. dialysis dosage was measured by means of ionic dialysance. 26 patients were studied: 30% women and 70% men, with an average age of 61±13 years. the average time under renal replacement treatment was 117±124.45 months, and the average time in haemodialysis was 50±54.38 months. the haemodynamic parameters showed no significant differences between the two modes studied (pre- and post-dilution). a statistically significant higher value for kt was obtained for the post-dilution haemodiafiltration technique, requiring half the replacement volume of the pre-dilution mode. conclusions: the on-line haemodiafiltration technique is tolerated well in both infusion modes. with the same blood flow, venous pressure and volume of blood dialysed, a higher dialysis dosage was achieved using the post-dilution mode. post-dilution haemodiafiltration appears to be a better alternative than the pre-dilution mode in terms of the parameters studied as long as the issue of vascular access is not taken into account. better kt results were achieved with this technique, requi