A comparison of the effectiveness of two online haemodiafiltration modalities: mixed versus post-dilution.
BACKGROUND
Haemodiafiltration (HDF) with high reinfusion volumes is the most effective technique for clearing uraemic toxins. There are various modalities depending on the location where the replacement volume is administered in the extracorporeal circuit: pre-dilution, mixed or mid-dilution and post-dilution, in which the infusion is carried out pre-dilution, pre- and post-dilution simultaneously and post-dilution, respectively.


OBJECTIVE
Compare the clearance of small, medium-sized and protein-bound molecules and the convective volume administered in online HDF (OL-HDF) in post-dilution and mixed (pre-post-dilution) infusion.


METHODS
A prospective, randomised, crossover study comparing post-dilution and mixed OL-HDF. Patients (n=8) were randomly assigned to receive 6 sessions in each technique. We conducted 89 sessions, of which 68 were at a scheduled time (ST) and 21 at an effective time (ET). We determined the reduction rate (RR) percentages for various substances and the infusion volumes. The RR study was performed using ET.


RESULTS
The KT value obtained was greater with post-dilution OL-HDF [68 (8.1) compared to 64.9 (8.8) litres] (P=.009) when patients were dialysed at ST. This difference disappeared when dialysis was performed at ET. The difference between ST and ET was greater in mixed HDF than in post-dilution HDF [10.3 (7.4) compared to 6.5 (3.1) minutes, P=.02]. We found no differences in the RR of the substances analysed.


CONCLUSIONS
Mixed OL-HDF is not inferior to post-dilution OL-HDF either in the clearance of small and medium-sized molecules or in the clearance of protein-bound molecules at the same ET.
Patricia
P
de Sequera
Marta
M
Albalate
Rafael
R
Pérez-García
Elena
E
Corchete
Marta
M
Puerta
Mayra
M
Ortega
Roberto
R
Alcázar
Tamar
T
Talaván
María J
MJ
Ruiz-Álvarez
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000418:Albumins / Q000032:analysis; D001794:Blood Pressure; D001798:Blood Proteins / Q000032:analysis; D018481:Convection; D018592:Cross-Over Studies; D015314:Dialysis Solutions / Q000737:chemistry; D005260:Female; D006400:Hematocrit; D017583:Hemodiafiltration / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009391:Nephelometry and Turbidimetry; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy; D012177:Retinol-Binding Proteins / Q000032:analysis; D014511:Uremia / Q000097:blood / Q000209:etiology / Q000628:therapy*; D001613:beta 2-Microglobulin / Q000032:analysis
D000418:Albumins; D001798:Blood Proteins; D015314:Dialysis Solutions; D012177:Retinol-Binding Proteins; D001613:beta 2-Microglobulin