Use of Fluoride as a Marker Solute to Quantify the Current Effective Delivered Dose in Continuous Renal Replacement Therapy: An “in vitro” Study

Abstract

Background: The current effective delivered dose is a quality indicator for continuous renal replacement therapy. Its periodic assessment might enable physicians to deliver personalised treatments. Yet, its quantification as by extracorporeal urea clearance (Cl) is cumbersome and thus often neglected in routine practice. The aim of this in vitro study is to demonstrate the non-inferior effectiveness of assessing the current effective delivered dose using a simpler, cheaper and faster approach based on measurement of fluoride rather than urea extracorporeal Cl. Methods: We compared urea and fluoride removal in 3 post-dilution continuous veno-venous haemofiltration (CVVH) and 3 continuous veno-venous haemodialysis (CVVHD) in vitro experimental models. Experiments ran for 180 min, using 3 L of human blood, heparin anticoagulation and a machine dose of 30 mL/kg/h. Urea and fluoride were measured in the inflow, outflow and effluent lines to compare sieving coefficients (SC), saturation coefficients (SA) and transmembrane Cls. Results: In CVVH, the median SC values were 1.

Methods for dose quantification in continuous renal replacement therapy: Toward a more precise approach

“…In a recent “in vitro” study, Villa et al evaluated the use of fluoride as a possible marker solute for CRRT dose measurement. 19 Fluoride is retained during renal dysfunction and exhibits similar properties to urea in terms of sieving (SC) and saturation coefficients (SA), transmembrane clearance, and solute mass lost in the effluent during treatment. The authors found that measured SA/SC and extracorporeal clearance of urea and fluoride yielded negligible differences at each assessment point in time.…”

“…Moreover, use of fluoride showed several advantages compared to urea, such as simple bedside measurement, lower costs, and direct quantification. 19 Future directions related to this study would be to identify a solute that is similar to fluoride in terms of bedside management and costs, but is present in biological fluids and therefore represents a measurable and evaluable biomarker of the current effective delivered dose in CRRT.…”