NCT05214729: UF CHALLENGE

A Net Ultrafiltration Challenge to Predict Preload-dependence (UF CHALLENGE)

Completed NA Results posted Last updated 13 February 2026

What this trial tests

NA trial testing Fast ultrafiltration challenge in Acute Kidney Injury in 20 participants. Completed in 2 January 2025.

Timeline

14 July 2022

Primary endpoint
2 January 2025

2 January 2025

Quick facts

Lead sponsor	Hospices Civils de Lyon
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	crossover
Masking	none
Primary purpose	diagnostic
Enrollment	20
Start date	14 July 2022
Primary completion	2 January 2025
Estimated completion	2 January 2025
Sites	1 location across France

Drugs / interventions tested

• Fast ultrafiltration challenge
• Slow ultrafiltration challenge

Conditions studied

• Acute Kidney Injury — all drugs for Acute Kidney Injury →

Sponsor

Hospices Civils de Lyon — full company profile →

Who can join

18 and older, any sex, with Acute Kidney Injury. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Diagnostic Performance of the Net Ultrafiltration (UF NET) Challenge to Detect de Novo Preload Dependence Primary · Baseline and immediately at the end ot each UF NET challenge (approximately 15-30 minutes, 1 day apart)

The diagnostic performance was assessed using the area under the receiver-operating curve (AUROC) of the relative variation in calibrated cardiac index, measured at baseline and at the end of the challenge, and compared to the reference standard consisting in the result of a postural maneuver (passive leg raising or Trendelenburg) evaluating preload dependence using pulse-contour continuous cardiac index variation (positive if \> 10% or negative if ≤ 10%) performed at the end of the challenge.

Group	Value	95% CI
All UF NET Challenges	0.74	0.58 – 0.88

Respective Diagnostic Performance of the Fast and Slow Net Ultrafiltration (UF NET) Challenge to Detect de Novo Preload Dependence Secondary · Between baseline and end of the UF NET challenge

The respective diagnostic performance of fast and slow challenges was assessed using the area under the receiver-operating curve (AUROC) of the relative variation in calibrated cardiac index, measured at baseline and at the end of fast and slow challenges, and compared to the reference standard consisting in the result of a postural maneuver (passive leg raising or Trendelenburg) evaluating preload dependence using pulse-contour continuous cardiac index variation (positive if \> 10% or negative if ≤ 10%) performed at the end of the challenge.

Group	Value	95% CI
Fast UF NET Challenge	0.71	0.49 – 0.91
Slow UF NET Challenge	0.69	0.36 – 1.00

Preload Dependence Prevalence After a UF NET Challenge Secondary · At the end of the UF NET challenge

The rate (in %) of UF NET challenges after which a preload-dependence status was identified using the reference diagnostic method, consisting of a postural maneuver (passive leg raising or Trendelenburg maneuver) during which the relative variation in pulse-contour continuous cardiac index was assessed over 1 minute. The test was positive if the relative variation in pulse-contour continuous cardiac index increased by more than 10% during the maneuver, and negative otherwise.

Group	Value	95% CI
All UF NET Challenges	9
Fast UF NET Challenge	6
Slow UF NET Challenge	3

Adverse events — posted to ClinicalTrials.gov

Time frame: From enrollment until end of follow-up (8h after the end of the second challenge, that is within a maximum time range of 56 hours avec enrollment). Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Fast UF NET Challenge

Serious: 11/19 (58%)

Deaths: 0/10

Slow UF NET Challenge

Serious: 13/17 (76%)

Deaths: 0/10

Serious adverse events (3 terms)

Reaction	System	Fast UF NET Challenge	Slow UF NET Challenge
Hemodynamic instability episode during the 8h follow-up period after the challenge	Cardiac disorders	—	—
Norepinephrine increase during the UF NET challenge	Cardiac disorders	—	—
Change in sedation dose	Nervous system disorders	—	—

Most-reported serious reactions: Hemodynamic instability episode during the 8h follow-up period after the challenge, Norepinephrine increase during the UF NET challenge, Change in sedation dose.

Data from ClinicalTrials.gov NCT05214729 adverse events section.

Sponsor's own description

Hemodynamic instability episodes are a frequent complication of renal replacement therapies in critically ill patients, and their incidence is associated with worse survival. Hypovolemia, identified by the existence of biventricular preload dependence, is responsible for one episode out of two, and may justify a decrease in or cessation of fluid removal by net ultrafiltration (UF). To date, preload dependence is most frequently identified by evaluating the effects on cardiac output of postural changes (passive leg raising), impact of cardio-pulmonary interactions in ventilated patients, or fluid challenge. However, none of these tests may help identify a patient whose cardiac output is at risk of becoming preload dependent, that is situated at the inflexion point of the Frank Starling curve.

Our study aims to evaluate the effects on cardiac output (measured by a transpulmonary thermodilution technique) of 2 net ultrafiltration challenges, consisting fast removal of 250 ml of ultrafiltrate over 15 and 30 minutes respectively, and compare their diagnostic performance to the reference technique of preload dependence assessed by postural changes (passive leg raising) performed after the UF challenge.

Enrolled participants will undergo both UF challenges, following a randomized crossover design, in which the order of UF challenge duration (15 or 30 minutes) is randomized, separated by a washout period of 24 hours.

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

1. 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.
   Biscarrat C, Deniel G, Chivot M, Yonis H, et al · · 2025 · cited 1× · PMID 41121412 · DOI 10.1186/s13054-025-05674-3