Abstract:

BACKGROUND: When regional citrate anticoagulation (RCA) is used in continuous renal replacement therapy (CRRT), one of the key aspects to achieve safe and effective extracorporeal circulation is the management of calcium ions. For calcium-free RCA-CRRT, there are generally two ways to do this: the deep vein and the venous line. The anticoagulant effects of different calcium supplementation pathways have not yet been explored.

OBJECTIVE: In this trial, we would test our hypothesis that compared with the subclavian vein, when calcium was infused through the venous line of blood filter catheter, the arterial iCa²⁺ was lower.

METHODS: This was a prospective, single-center, randomized crossover trial. From December 2018 to December 2019, 48 patients with RCA-CRRT at the Department of Intensive Care Unit of the First Hospital of Lanzhou University were selected. According to the different calcium sites, the patients were randomly divided into two groups. The calcium supplementation order of group A (n=24) was the venous line of the blood filter catheter-subclavian vein. Group B (n=24) was supplemented with subclavian vein-the venous line. Blood gas analysis results were compared using blood gas analyzers before and after replacement of the calcium supplementation route in all cases. The primary measurement outcome was the differences between arterial iCa²⁺ and post-filtration iCa²⁺ with different calcium supplementation pathways, and the simultaneous recording of pH, K⁺, and total hemoglobin. The secondary measurement outcomes were the incidences of catheter dysfunction and hypocalcemia during the intervention. The trial was approved by the Ethics Committee of the First Hospital of Lanzhou University (approval No. LDYYLL2018-165) in December 2018. The study was registered on the China Clinical Trial Registration Center (ChiCTR1800020046) in December 2018. Sample and data collection time is from December 2018 to November 2019, data analysis time and test completion time is December 2019.

DISCUSSION: This is the first trial on the anticoagulant effects of calcium-free RCA-CRRT through different calcium supplement routes. We will confirm that the arterial iCa²⁺ level is slightly lower when calcium is infused in the venous line of blood filter catheter than in the subclavian vein, and the incidence rates of catheter dysfunction and hypocalcemia will help us to determine which site is safer.

Key words: continuous renal replacement therapy, citrate anticoagulation, calcium ion, safety, hypocalcemia, catheter dysfunction, tissue engineering