**8. Efficiency of treatment**

Effects of the achieved cardiovascular stability were accompanied by an improved efficiency of treatment. A lower urea rebound was observed during the HBS sessions, resulting in a higher equilibrated Kt/V (eKt/V) as shown by several groups (Ronco et al., 2000, McIntyre et al., 2003, Dasselaar et al., 2007, Neshrallah et al., 2008, Winkler et al. 2008).

In hypotension-prone patients, total urea removed was significantly higher during HBS compared to HD sessions (Ronco et al., 2000). This was also demonstrated for nonhypotension-prone patients. The eKt/V ratio increased from 1.01 ± 0.03 to 1.13 ± 0.03 with HBS (*P*<0.01) (McIntyre et al., 2003) In this group of patients, the mass of urea removed increased from 24.9 to 32.7 (*P*<0.01).

### **9. Interdialytic events**

The effect of HBS on interdialytic symptoms, such as muscle cramps, headache, dizziness, thirst, dyspnoe, angina, vomiting, itching, the need to lie down, anorexia and asthenia, was analysed by Santoro (Santoro et al., 2002) They looked at the number of symptoms between 2 consecutive sessions within the first 6 hours from the end of dialysis (early symptoms) and later until the beginning of the next dialysis session (late symptoms) and observed a 10% overall reduction (*P*<0.001) in symptoms after treatment with HBS.
