Table 3.
Comparison of net fluid balance achieved across studies on net ultrafiltration rate
| Study | Metric | Low | Moderate | High |
|---|---|---|---|---|
| Murugan et al. (2018)53 CKRT subset only |
Thresholds for UF rate intensity | ≤20 ml/kg per day | 20–25 ml/kg per day | >25 ml/kg per day |
| Fluid balance before KRT | 2.3 L (15.6%) | 2.7 L (17.3%) | 2.3 L (21.0%) | |
| UF during KRT (CKRT+intermittent HD) | 19.5 L | 27.9 L | 26.6 L | |
| Cumulative fluid balance during KRT (excludes UF) | 13.5 L | 22.0 L | 19.0 L | |
| Cumulative fluid balance during KRT (includes UF) | −6 L (inferreda) | −5.9 L (inferreda) | −7.6 L (inferreda) | |
| Thresholds for UF rate intensity | <5 ml/kg per hour | 0.5–1.0 ml/kg per hour | >1 ml/kg per hour | |
| Fluid balance before KRT | Unknown | Unknown | Unknown | |
| Net UF during CKRT | 3.4 L | 11.6 L | 16.2 L | |
| Cumulative fluid balance during KRT (includes UF) | Unknown | Unknown | Unknown | |
| Tehranian et al. (2019)54 | Thresholds for UF rate intensity | <35 ml/kg per day | No moderate group | ≥35 ml/kg per day |
| Fluid balance before KRT | 4.2 L | — | 5.8 L | |
| UF during CKRT | Unknown | — | Unknown | |
| Cumulative fluid balance during KRT (includes UF) | Unknown | — | Unknown | |
| Murugan et al. (2019)55 | Thresholds for UF rate intensity | <1.01 ml/kg per hour | 1.01–1.75 ml/kg per hour | >1.75 ml/kg per hour |
| Fluid balance before CKRT | Unknown | Unknown | Unknown | |
| UF during CKRT | 1.7 L | 8.5 L | 16.5 L | |
| Cumulative fluid balance during CKRT (excludes UF) | 4.6 L | 8.5 L | 11.1 L | |
| Cumulative fluid balance during CKRT (includes UF) | +2.3 L | −0.4 L | −3.6 L | |
| Naorungroj et al. (2021)56 | Thresholds for UF rate intensity | <1.01 ml/kg per hour | 1.01–1.75 ml/kg per hour | >1.75 ml/kg per hour |
| Fluid balance before KRT | 0.22 L | 0.31 L | 0.68 L | |
| UF during CKRT | 1.0 L | 3.6 L | 5.3 L | |
| Cumulative fluid balance during KRT (includes UF) | +0.53 L | −0.66 L | −1.75 L |
This table provides a detailed comparison of the net fluid balance within each of the net ultrafiltration groups (low, moderate, and high) across the four studies detailed in Table 2. Net fluid balance before initiation of KRT and during KRT is listed for each category of ultrafiltration intensity, when available. CKRT, continuous KRT; UF, ultrafiltration; HD, hemodialysis.
An inferred value rather than a reported value based on the following two assumptions for comparison purposes only. If fluid balance during KRT is not reported, then the net fluid balance after KRT including UF, the difference between the cumulative fluid balance during KRT (excluding UF), and the UF during KRT was used to estimate the median cumulative fluid balance during KRT (including UF). Note that while the studies refer to a net UF to account for the administration of intravenous fluids needed to complete KRT (in the case of these studies, this consisted of replacement fluid during hemofiltration), to avoid confusion all fluid removal achieved using KRT is referred to simply as UF.