Changes of Renal Resistive Index in Critically Ill Patients Undergoing Continuous Renal Replacement Therapy.

Last updated: May 28, 2025
Sponsor: Uniwersytecki Szpital Kliniczny w Opolu
Overall Status: Active - Recruiting

Phase

N/A

Condition

Kidney Disease

Renal Failure

Kidney Failure

Treatment

Measurement of Renal Resistive Index

Clinical Study ID

NCT06174610
RICRRT_USK
  • Ages > 18
  • All Genders

Study Summary

The aim of the study is to determine whether there is a correlation between changes in the renal resistive index and the restoration of kidney function in critically ill patients undergoing continuous renal replacement therapy.

Eligibility Criteria

Inclusion

Inclusion Criteria:

  • All ICU patients undergoing CRRT due to AKI

Exclusion

Exclusion Criteria:

  • age <18 years

  • pregnancy

  • history of chronic kidney disease in stage 4 or 5

  • post-kidney transplant status

  • mechanical circulatory support

  • occurrence of one or more conditions preventing reliable RRI measurement in bothkidneys:

  • challenging technical conditions of ultrasound examination, hindering propervisualization of the kidney

  • post-kidney injury in grade III and higher, according to AAST

  • advanced parenchymal kidney pathology: atrophy, hypoplasia, cirrhosis,extensive ischemia (more than 2/3 of the parenchyma),

  • kidney diseases preventing parenchyma identification: advanced cancer (stageabove T1 according to TNM), certain forms of polycystic kidney disease

  • inflammatory kidney diseases

  • obstructive uropathy

  • renal vascular pathologies: renal vein thrombosis, significant stenosis (>60%),and renal artery occlusion.

Study Design

Total Participants: 50
Treatment Group(s): 1
Primary Treatment: Measurement of Renal Resistive Index
Phase:
Study Start date:
December 19, 2023
Estimated Completion Date:
December 18, 2026

Study Description

A significant number of critically ill patients experience acute kidney injury (AKI), an independent factor contributing to increased mortality. Prevention of AKI and monitoring kidney function are crucial. Commonly used markers such as serum creatinine and hourly diuresis are employed to assess AKI severity, but they are not ideal due to their late elevation in the disease course. Therefore, alternative methods for detecting and evaluating kidney dysfunction at an earlier stage are sought.

Previous studies have demonstrated a correlation between the risk of AKI and the resistive index of renal parenchymal arteries. Renal resistive index (RRI) is a parameter calculated from Doppler measurements, representing the difference between peak blood velocity during systole and end-diastolic velocity divided by peak systolic velocity [(Vs-Vd) /Vs]. In healthy adult kidneys, the RI typically ranges from 0.6 to 0.7. Changes in RRI can be observed much earlier than an increase in serum creatinine concentration and/or a decrease in hourly diuresis.

Some patients with acute kidney injury require renal replacement therapy. Continuous renal replacement therapy (CRRT) is commonly used in critically ill patients, causing less circulatory destabilization compared to intermittent therapies. However, adverse effects accompany renal replacement therapies, including thromboembolic complications, bleeding, infections, blood cell damage, altered drug pharmacokinetics, and loss of proteins and vitamins.

In addition to determining the appropriate initiation time for CRRT, identifying the optimal moment to end the treatment is crucial. CRRT is typically applied for several days, and during the procedure, it is challenging to ascertain whether renal function has improved and whether CRRT can be safely discontinued. The hypothesis is that there may be a correlation between changes in RRI and the recovery of kidney function. This may enable the early identification of patients who have regained kidney function, allowing for the earlier termination of CRRT.

In 1989, a study was conducted on children undergoing peritoneal dialysis due to AKI, showing a relationship between a decrease in RRI and the restoration of kidney function. However, no similar study has been conducted on adult patients undergoing continuous renal replacement therapy.

The planned project will be based on daily ultrasonographic examinations, measuring RRI of the arcuate and/or interlobar arteries of both kidneys.

Connect with a study center

  • Department of Anesthesiology and Intensive Care, Uniwersytecki Szpital Kliniczny w Opolu

    Opole, Opolskie 45-372
    Poland

    Active - Recruiting

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