Table 1 Table describing the pertinent studies examining vitamin C dosing in RRT
Author [ref], year | Design and technique used | Sample size | Main findings | Effects on vitamin C levels | Conclusion |
|---|---|---|---|---|---|
Morena [19] 2002 | Observational CVVHDF vs. controls | 19 HDF patients 1846 healthy controls | Vit C levels significantly lower in HDF patients compared with controls Vit C levels reduced by almost 50% during a HDF session Increased oxidative stress | 66 (8–230) mg loss per session of HDF | 2/3 loss by diffusion and 1/3 loss by convection |
Ferhmann-Ekholm [20] 2008 | Observational Low-flux HD vs. on-line HF/HDF | Low-flux HD 15 patients On-line HF/HDF 14 patients | Vit C levels lowered by 51% and 53% in the HD and on-line groups, respectively | Concentrations below reference values in 12/14 patients not receiving vit C supplementation. | Vit C was reduced by both dialysis and filtration treatment |
Kamel [21] 2017 | Retrospective chart review CRRT | 75 patients | 80% of patients had below-normal levels of at least 1 macronutrient | Vit C deficiency was identified in 87% (13 of 15) | Vit C deficiency in critically ill patients requiring CRRT was higher than previously reported |
Story [22] 1999 | Prospective controlled study | 8 critically ill patients requiring CVVH 9 critically ill patients not requiring RRT 9 healthy controls | Compared with normal volunteers, critically ill patients on CVVH had significantly lower median blood vit C levels | No differences in serum vit C levels between critically ill patients on CVVH or not on CVVH | Clinical significance of reduced blood concentrations of vit C in critically ill patients and ultrafiltrate losses of vit C remains unclear |
Marik [24] 2018 | Observational | 12 septic shock patients on CRRT receiving 1.5 g vit C 4-times daily | No AKI (n = 5) vit C–trough 224 μmol/l peak 543 μmol/l AKI +TCRRT (n = 4) vit C–trough 263 μmol/l peak 461 μmol/l CRF + Intermittent HD (n = 3) vit C–trough 346 μmol/l peak 914 μmol/l | CVVH at 2 l/h with a sieving coefficient of 1, results in a loss of 1.68 g/vit C/day (200 * 2 * 24) = 9600 μmol/day | 6 g vit C daily seems to be adequate in septic shock patients undergoing CRRT |