Abstract

FERNANDEZ MARTINEZ, Ana Vanessa et al. The difference between programmed time and effective time in online haemodiafiltration: Does every minute count in dialytic efficiency?. Enferm Nefrol [online]. 2012, vol.15, n.4, pp.277-281. ISSN 2255-3517.  https://dx.doi.org/10.4321/S2254-28842012000400006.

Aim: To determine the difference between programmed time and effective dialysis time, and once it has been found, to increase the duration of the session so that the effective time is actually as desired for each patient, and never less than 240 minutes per session. Finally, we determined whether there are differences in dialytic efficiency, by measuring Kt and total reinfusion volume. Patients and methods: We designed a prospective study on the prevalent population in online haemodiafiltration. We recruited 152 patients undergoing online haemodiafiltration. For 6 consecutive sessions (912 sessions), the dialysis was carried out with a programmed time ≥ 240 minutes. In a second period of 6 consecutive sessions (912 sessions), the dialysis session was extended to an effective time equal to the previously programmed time. The principal variable in the study was time, with blood flow, Kt and total reinfusion volume as secondary variables. In the second period, any intradialytic complications in the added time were noted. Results: A total of 152 patients were analysed, 66% of whom were man, 65.7 ± 14.9 (26-88) years old, with 56.5 ± 59.5 months on dialysis, in a total of 1824 online haemodiafiltration sessions. No significant differences in Qb were observed (428.74±39.73 v. 429.86±38.54 ml/min). The average duration of the session increased significantly (p<0.001) by 7 minutes (from 233.58±3.29 to 240.67±2.71 minutes). Kt increased significantly (p<0.001) by 3.2% (from 60.06±5.86 to 61.99±5.80 litres), with a reduction in the % of sessions in which the desired Kt per body surface area is not reached (from 5.7% to 3.1%). The total reinfusion volume increased significantly (p<0.001) by 1.5% (from 24.10±2.72 to 24.46±2.77 litres), with a similar % of sessions in which the target of 20 litres was not reached (4.6% compared to 4.3%). No intradialytic complications or coagulation episodes were observed in the increased time period. Discussion and conclusions Both Kt and total reinfusion volume are the main acknowledged indicators for measuring the adequacy of dialysis in online haemodiafiltration. Kt has been referred to by some authors as a more demanding dialysis does indicator than Kt/V. The effective time of the session is a key factor for achieving optimal Kt tailored to body surface area and total reinfusion volume targets in post-dilutional online haemodiafiltration patients, with important implications for mortality. In post-dilutional online haemodiafiltration, every minute is important. Increasing the programmed time (by approximately 7 minutes per session) should be considered so that the effective time is equal to or greater than 720 minutes/week, managing to optimize both the dialysis dose and the reinfusion volume.

Keywords : Effective time; Programmed time; Dialytic efficiency.

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