Journal Article

Diagnostic performance of a 250-ml net ultrafiltration challenge to identify risk of preload-dependence in critically ill patients undergoing continuous renal replacement therapy: a randomized, cross-over trial

Richard, Jean-Christophe, Chauvelot, Louis, Deniel, Guillaume, Yonis, Hodane, Biscarrat, Charlotte, Mezidi, Mehdi, Chivot, Matthieu, Bitker, Laurent

2025

Overview

Introduction During continuous renal replacement therapy (CRRT), preload-independent patients risk of becoming preload-dependent in case of excessive net ultrafiltration (UF NET ). We aimed to evaluate the ability of a UF NET challenge to identify de novo preload-dependence in preload-independent patients undergoing CRRT. Materials and methods We conducted a single-center, randomized, cross-over trial, enrolling adult patients with CRRT, calibrated continuous cardiac index (CCI) monitoring, and preload-independent at time of enrolment. The diagnostic test consisted of 250-ml UF NET removal over 15 (fast challenge) or 30 min (slow challenge), preceded and followed by a postural maneuver (PM) evaluating preload-dependence using CCI relative variations. Patients underwent both types of challenges, starting with either fast or slow challenges as determined by randomization, separated by a wash-out period of 24 h. We evaluated the performance of UF NET challenges to diagnose de novo preload-dependence using the area under the receiver operating curve (AUROC) of the relative change in calibrated cardiac index between before and after the challenge (∆CI UFC ), based on the result of the PM performed after the challenge (responder if positive, non-responder if negative). NCT05214729. Results We included 20 patients, comprising 36 UF NET challenges (19 fast and 17 slow challenges). In intention-to-treat (ITT), the rate of preload-dependence after the challenge was 33% (12/36, 95% confidence interval: 19% to 51%). In ITT, the AUROC of ∆CI UFC to identify de novo preload-dependence was 0.74 (95% confidence interval: 0.58–0.88), with the respective AUROCs of fast and slow challenges not reaching statistical significance. After exclusion of 5 challenges a posteriori identified as being preload-dependent before challenge start (modified intention-to-treat [mITT], N = 31), the AUROC of ∆CI UFC was 0.83 (0.66–0.99), with ∆CI UFC not significantly differing between fast and slow challenges. In mITT, CCI variation during the PM preceding the challenge predicted de novo preload-dependence with an AUROC of 0.82 (0.65–0.98), at an optimal threshold of + 5%. Conclusions A 250-ml UF NET challenge had acceptable diagnostic performance to identify preload-independent patients becoming preload-dependent during CRRT, with no detectable difference between fast and slow challenges. A CCI variation ≥ 5% during a PM in preload-independent patients may help identify those at risk of becoming preload-dependent.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Aged / Anesthesia / Clinical trials / Continuous Renal Replacement Therapy - adverse effects / Continuous Renal Replacement Therapy - methods / Continuous Renal Replacement Therapy - standards / Critical Care Medicine / Critical Illness - therapy / Cross-Over Studies / Diagnostic tests / Emergency Medicine / Female / Hemodynamics / Humans / Intensive / Intensive care / Male / Medicine / Medicine & Public Health / Middle Aged / Patients / Personalized medicine in the ICU / Renal replacement therapy / Ultrafiltration - methods / Ultrafiltration - standards