Efficacy and complications of regional citrate anticoagulation during continuous renal replacement therapy in critically ill patients with COVID-19

J Crit Care. 2022 Feb:67:126-131. doi: 10.1016/j.jcrc.2021.10.010. Epub 2021 Nov 9.


Background: We compared filter survival and citrate-induced complications during continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA) in COVID-19 and Non-COVID-19 patients.

Methods: In this retrospective study we included all consecutive adult patients (n = 97) treated with RCA-CRRT. Efficacy and complications of RCA-CRRT were compared between COVID-19 and Non-COVID-19 patients.

Results: Mean filter run-time was significantly higher in COVID-19 patients compared to Non-COVID-19 patients (68.4 (95%CI 67.0-69.9) vs. 65.2 (95%CI 63.2-67.2) hours, respectively; log-rank 0.014). COVID-19 patients showed significantly higher activated partial thromboplastin time (aPTT) throughout the CRRT due to intensified systemic anticoagulation compared to Non-COVID-19 patients (54 (IQR 45-61) vs. 47 (IQR 41-58) seconds, respectively; p < 0.001). A significantly higher incidence of metabolic alkalosis, hypercalcemia and hypernatremia, consistent with reduced filter patency and citrate overload, was observed in COVID-19 patients compared to Non-COVID-19 patients (19.1% vs. 12.7%, respectively; p = 0.04). These metabolic disarrangements were resistant to per-protocol adjustments and disappeared after replacement of the CRRT-filter.

Conclusions: RCA-CRRT in COVID-19 patients with intensified systemic anticoagulation provides an adequate filter lifespan. However, close monitoring of the acid-base balance appears warranted, as these patients tend to develop reduced filter patency leading to a higher incidence of citrate overload and metabolic disturbances.

Trial registration (local authority): EA1/285/20 (Ethikkommission der Charité - Universitätsmedizin Berlin); date of registration 08.10.2020.

Keywords: COVID-19; Clogging; Clotting; Continuous renal replacement therapy; Filter patency; Regional citrate anticoagulation.

MeSH terms

  • Anticoagulants / adverse effects
  • COVID-19*
  • Citrates
  • Citric Acid / adverse effects
  • Continuous Renal Replacement Therapy*
  • Critical Illness
  • Humans
  • Retrospective Studies
  • SARS-CoV-2


  • Anticoagulants
  • Citrates
  • Citric Acid