Magnesium Balance of Citrate-based Continuous Venovenous Hemofiltration, Effect of Citrate Dose.

Summary

Rationale: A higher citrate dose during continuous venovenous hemofiltration provides better anticoagulation but possibly a higher risk of citrate accumulation in case of metabolic limitations. A higher citrate dose also increases magnesium loss in ultrafiltrate, while a negative magnesium balance is unwanted. Objective: Aim of this study is to determine the magnesium balance of citrate-based continuous veno-venous hemofiltration (CVVH) and to determine whether and to which extent the magnesium balance depends on citrate dose. Study design and methods: A prospective randomized study conducted in critically ill patients with acute kidney injury (AKI), treated with CVVH, with either low dose citrate (2.5 mmol/L blood flow in the filter) or high dose citrate (4.5 mmol/L blood flow in the filter) as anti-coagulant, targeting a postfilter ionized Calcium (iCa) of resp. 1.3-1.6 mg/dL (0.325-0.4 mmol/L) and 0.8-1.1 mg/dL (0.2-0.275 mmol/L). Post-filter blood as well as effluent aliquots and bloodconcentrations in the patient are tested for the following variables: (0 , 2 , 4, 6, 12 and 24 hrs): Total Magnesium (tMg) and total Calcium (tCa), ionized Ca (iCa)(bloodgas analyzer). In addition, hematocrit, albumin, total protein, ureum and creatinine and parathormone (PTH) are determined in arterial blood at 0 and 24 hrs or at the time of protocol exit and citrate concentrations in postfilter and arterial blood at 1 and 24 hrs or at protocol exit. Sample sites: arterial line, postfilter port (after postdilution and calcium compensation), effluent sample. All flow rates to be noted. Study population: Twenty patients admitted to intensive care, requiring continuous renal replacement therapy (CRRT) for AKI. Intervention: Anti-coagulation with either low dose citraat (2.5 mmol/L blood flow) or high dose citraat (4.5 mmol/L blood flow) targeting postfilter iCa of resp. 1.3-1.6 and 0.8-1.1 mg/dL. Both regimens are within standard protocolled CVVH treatment in the intensive care department.

Timeline

Start

2014-07

Primary completion

2017-06

Completion

2017-06

Publications

• Boer W, Fivez T, Vander Laenen M, Bruckers L, Gron HJ, Schetz M, Oudemans-van Straaten H. Citrate dose for continuous hemofiltration: effect on calcium and magnesium balance, parathormone and vitamin D status, a randomized controlled trial. BMC Nephrol. 2021 Dec 11;22(1):409. doi: 10.1186/s12882-021-02598-2.
• Tsujimoto H, Tsujimoto Y, Nakata Y, Fujii T, Takahashi S, Akazawa M, Kataoka Y. Pharmacological interventions for preventing clotting of extracorporeal circuits during continuous renal replacement therapy. Cochrane Database Syst Rev. 2020 Dec 14;12(12):CD012467. doi: 10.1002/14651858.CD012467.pub3.

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