Metabolic disturbances potentially attributable to clogging during continuous renal replacement therapy

Mattia M Müller; Larina Caspar; Onur Sazpinar; Daniel A Hofmaenner; Rolf Erlebach; Rea Andermatt; Christoph C Ganter; Reto A Schuepbach; Pedro D Wendel-Garcia; Sascha David

doi:10.1186/s40635-023-00581-9

Metabolic disturbances potentially attributable to clogging during continuous renal replacement therapy

Intensive Care Med Exp. 2023 Dec 21;11(1):99. doi: 10.1186/s40635-023-00581-9.

Authors

Affiliations

¹ Institute of Intensive Care Medicine, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland.
² Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada.
³ Institute of Intensive Care Medicine, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland. sascha.david@usz.ch.
⁴ Department of Nephrology, Hannover Medical School, Hanover, Germany. sascha.david@usz.ch.

Abstract

Background: Clogging is characterized by a progressive impairment of transmembrane patency in renal replacement devices and occurs due to obstruction of pores by unknown molecules. If citrate-based anti-coagulation is used, clogging can manifest as a metabolic alkalosis accompanied by hypernatremia and hypercalcemia, primarily a consequence of Na₃Citrate infusion. An increased incidence of clogging has been observed during the COVID-19 pandemic. However, precise factors contributing to the formation remain uncertain. This investigation aimed to analyze its incidence and assessed time-varying trajectories of associated factors in critically ill patients on continuous renal replacement therapy (CRRT).

Methods: In this retrospective, single-center data analysis, we evaluated COVID-19 patients undergoing CRRT and admitted to critical care between March 2020 and December 2021. We assessed the proportional incidence of clogging surrogates in the overall population and subgroups based on the specific CRRT devices employed at our institution, including multiFiltrate (Fresenius Medical Care) and Prismaflex System (Baxter). Moderate and severe clogging were defined as Na > 145 or ≥ 150 mmol/l and HCO₃^- > 28.0 or ≥ 30 mmol/l, respectively, with a total albumin-corrected calcium > 2.54 mmol/l. A mixed effect model was introduced to investigate factors associated with development of clogging.

Results: Fifty-three patients with 240 CRRT runs were analyzed. Moderate and severe clogging occurred in 15% (8/53) and 19% (10/53) of patients, respectively. Twenty-seven percent (37/136) of CRRTs conducted with a multiFiltrate device met the criteria for clogging, whereas no clogging could be observed in patients dialyzed with the Prismaflex System. Occurrence of clogging was associated with elevated triglyceride plasma levels at filter start (p = 0.013), amount of enteral nutrition (p = 0.002) and an increasing white blood cell count over time (p = 0.002).

Conclusions: Clogging seems to be a frequently observed phenomenon in critically ill COVID-19 patients. The presence of hypertriglyceridemia, combined with systemic inflammation, may facilitate the development of an impermeable secondary membrane within filters, thereby contributing to compromised membrane patency.

Keywords: COVID-19; CRRT; Dialysis; Hypertriglyceridemia; ICU.