Skip to content

Advertisement

  • Letter
  • Open Access

Dosing adjuvant vitamin C in critically ill patients undergoing continuous renal replacement therapy: We are not there yet!

  • 1Email author,
  • 1,
  • 1,
  • 1,
  • 1,
  • 1 and
  • 2
Critical Care201923:5

https://doi.org/10.1186/s13054-018-2297-1

  • Received: 29 November 2018
  • Accepted: 19 December 2018
  • Published:

The original article was published in Critical Care 2018 22:320

We read with great interest the recent letter to Critical Care by Marik and Hooper [1]. Vitamin C (vit C) is increasingly recognized as a crucial compound to alleviate morbidity in critically ill patients. Vit C concentrations, however, are usually far below normal and even close to “scurvy levels” in this population. Vit C also is substantially cleared by continuous renal replacement therapy (CRRT). Significant vit C deficiency was observed in 80% of patients subjected to various types of CRRT despite receiving a daily intravenous (IV) supplement of 500 to 1000 mg [2]. Therefore, high-dose (from 6 to 12 g) vit C substitution during CRRT seems justified [3].

Marik and Hooper argued against such dose increase in patients receiving CRRT. To support their statement, they provided serum vit C dosages in a small number of septic patients who received 6 g vit C IV while undergoing continuous veno-venous hemofiltration (CVVH). Vit C trough and peak levels were largely above normal and comparable to levels obtained in patients not receiving CVVH [1].

We want to warn against oversimplification. Marik and Hooper measured vit C within 30 min after the end of vit C infusion. It would have been more relevant to measure vit C after 24 to 48 h of CVVH treatment. Up to 50% of vit C is cleared in a time-dependent manner during a 4-h session of intermittent hemodialysis or hemodiafiltration [4, 5], which suggests that continuous techniques may exacerbate vit C losses. Vit C also is eliminated by both diffusion (dialysis) and convection (filtration). During hemodiafiltration, diffusion is responsible for two thirds of the vit C loss whereas convection accounts only for one third [5]. CVVH is a sheer convective technique in contrast with other often-used CRRT modes in the critically ill, such as continuous veno-venous hemodialysis (CVVHD) and continuous veno-venous hemodiafiltration (CVVHDF). Marik and Hooper thus report the most modest way of CRRT-induced vit C elimination. It is reasonable to think that more diffusion-based CRRT techniques may yield other results.

We agree with Marik and Hooper that 6 g/day vit C IV is sufficient for patients without acute kidney injury and not requiring CRRT. However, vit C measurements should be performed after prolonged CVVH sessions to ensure that a 6 g daily supplement can keep levels within normal range. More studies are needed in patients receiving CVVHD or CVVHDF to exclude overlooking too great a vit C loss.

Notes

Declarations

Acknowledgments

None.

Funding

None.

Availability of data and materials

Not applicable.

Authors’ contributions

PMH and HDS designed the paper. All authors participated in drafting and reviewing and read and approved the final version of the manuscript.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
ICU Department, Centre Hospitalier Universitaire Brugmann-Brugmann University Hospital, 4, Place Arthur Van Gehucthen, 1020 Brussels, Belgium
(2)
Ageing & Pathology Research Group, Vrije Universiteit Brussel, 101, Laarbeeklaan, 1070 Brussels, Belgium

References

  1. Marik PE, Hooper MH. Adjuvant Vitamin C in critically ill patients undergoing renal replacement therapy: What's the right dose? Crit Care. 2018;22:320. https://doi.org/10.1186/s13054-018-2190-y. No abstract available.View ArticlePubMedPubMed CentralGoogle Scholar
  2. Kamel AY, Dave NJ, Zhao VM, Griffith DP, Connor MJ Jr, Ziegler TR. Micronutrient Alterations During Continuous Renal Replacement Therapy in Critically Ill Adults: A Retrospective Study. Nutr Clin Pract. 2018;33:439–46. https://doi.org/10.1177/0884533617716618 Epub 2017 Dec 18.View ArticlePubMedGoogle Scholar
  3. Honore PM, De Bels D, Preseau T, Redant S, Attou R, Spapen HD. Adjuvant vitamin C in cardiac arrest patients undergoing renal replacement therapy: an appeal for a higher high-dose. Crit Care. 2018;22:207. https://doi.org/10.1186/s13054-018-2115-9. View ArticlePubMedPubMed CentralGoogle Scholar
  4. Fehrman-Ekholm I, Lotsander A, Logan K, Dunge D, Odar-Cederlöf I, Kallner A. Concentrations of vitamin C, vitamin B12 and folic acid in patients treated with hemodialysis and on-line hemodiafiltration or hemofiltration. Scand J Urol Nephrol. 2008;42:74–80. https://doi.org/10.1080/00365590701514266.View ArticlePubMedGoogle Scholar
  5. Morena M, Cristol JP, Bosc JY, Tetta C, Forret G, Leger CL, et al. Convective and diffusive losses of vitamin C during haemodiafiltration session: a contributive factor to oxidative stress in haemodialysis patients. Nephrol Dial Transplant. 2002;17:422–7.View ArticleGoogle Scholar

Copyright

© The Author(s). 2019

Advertisement