**7. Clinical effects of high-volume oHDF**

**Figure 10.** Switch from manual to automatic mode. TMP, transmembrane pressure.

16 Advances in Hemodiafiltration

uous adaptation of UF flow takes place (**Figure 11**).

flow.

**Figure 10** shows the red line in manual mode favouring increasing convective volume and efficacy, whereas yellow line represents safety and favours TMP limitations, which means that TMP increases over time during the dialysis session as convective volume increases. However, in automatic mode on the right side of **Figure 10**, the optimisation of substitution volume has been achieved by setting the safety target range so that the machine itself sets the safe TMP target range and continuously regulates the optimal UF rate at an optimal time throughout the session in order to keep the TMP in optimal range to prevent haemoconcentration and membrane complications specified above (**Table 1**). However, the nurse can still switch to manual mode or even to conventional HD should extraordinary conditions prevent highvolume oHDF (such as special rheologic properties of a patient's blood) [32]. Owing to continuous analysis of haemorheological conditions throughout the dialysis session, contin‐

**Figure 11.** Continuous adaptation of ultrafiltration flow in AutoSub plus mode while keeping UF loss constant; red line within the dialyser illustrates dynamic analysis of pressure pulses along the blood flow pathway; UF, ultrafiltrate to be lost during the dialysis session; HDF, haemodiafiltration; FF, filtration fraction; QUF, ultrafiltrate flow; QB, blood The main clinical effects of high-volume oHDF include haemodynamic stability [34, 35], possibly improved quality of life [30], a delay in the development of dialysis-related amyloi‐ dosis [36], improvement in anaemia management [17], plasma lipid profiles [37] and inflam‐ mation [37].

Haemodynamic stability is maintained by salt loading via substitution fluid administration [38]. A higher predialysis plasma sodium concentration in patients with higher frequency of oHDF was reported, thus suggesting reduced sodium removal [39]. Haemodynamic stability is maintained by decreasing core body temperature as a result of the infusion of large amounts of fluid at a lower temperature, leading to vasoconstriction [34]. Imamović et al. demonstrated reduction in both erythropoietin (EPO) consumption and EPO resistance index in patients on HV oHDF compared to high-flux HD [17], which reveals the evidence of an increased haemodynamic stability due to improved anaemia management [40].
