The Predictive Performance of Renal Ultrasound on Changes in Renal Clearance

Study Overview
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Brief Summary
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The study will examine the ability of renal ultrasound (Doppler and Contrast Enhanced Ultrasound (CEUS)) in distinguishing ICU patients who exhibit increases in glomerular filtration rate (GFR) in response to fluid loading, from those for whom fluid loading is without benefit of directly harmful.

Detailed Description
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The study will examine the ability of renal ultrasound (Doppler and Contrast Enhanced Ultrasound (CEUS)) in distinguishing ICU patients who exhibit increases in GFR in response to fluid loading, from those for whom fluid loading is without benefit of directly harmful. Patients available for inclusion will receive a baseline administration of Tc-99-DTPA for precise determination of GFR/renal function by blood and urine samples. Baseline values of ultrasound measures will be obtained, including renal arterial, renal venous, portal venous and hepatic venous Doppler measures and renal contrast enhanced ultrasound (CEUS) will also be recorded. After two hours, baseline values of GFR are finished. The patient is then exposed to passive leg raising and ultrasound measures are repeated, including renal arterial, renal venous, portal venous and hepatic venous Doppler measures. The participant then receives a standardised fluid bolus of 7 ml/kg (ideal body weight) Once the fluid bolus administration is complete, renal ultrasound is repeated, including renal arterial, renal venous, portal venous, hepatic venous Doppler measures and renal CEUS. Follow-up determination of GFR/renal function based on Tc-99-DTPA after fluid therapy is repeated with blood and urine samples.

Official Title
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The Predictive Performance of Renal Ultrasonographic Perfusion Measures on Changes in Renal Clearance in Response to Fluid Therapy.

Conditions
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Acute Kidney Injury, Hypoperfusion, Fluid Overload

Intervention / Treatment
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* Drug: IV crystalloid fluid bolus


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients ≥ 18 years admitted to the ICU, Aarhus University Hospital. Patients who are assessed by their attending physician as having need for fluid therapy. Exclusion Criteria: Insufficient ultrasound imaging of the kidneys. Pregnancy. Intolerance to any ultrasound contrast agent or isotopes, including intolerance for human albumin. Prior enrolment in a conflicting research study. Known morphological kidney disease. Need for dialysis. Need for extracorporeal membrane oxygenation (ECMO). Prior participation. Severe pulmonary hypertension (systolic pulmonary pressure > 90 mmHg)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ICU patients<br>ICU patients who are assessed by their attending physician as having need for fluid therapy and are planned to receive IV crystalloid fluid due to oliguria and/or to improve GFR. | Drug: IV crystalloid fluid bolus<br>* The participant receives IV fluid as a standardised bolus of 7 ml/kg (ideal body weight).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in renal function in response to a standardised fluid bolus. | Renal function is measures as Tc-99-Diethylenetriaminepentaacetic acid (DTPA) clearance. | 6 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Renal venous flow classification | normal - abnormal (pulsatile/biphasic/monophasic | 6 hours | 
| Renal venous impedance index | (maximum flow velocity - minimum diastolic flow velocity) / maximum flow velocity | 6 hours | 
| Renal venous stasis index | (index cardiac cycle time - venous flow time) / index cardiac cycle time | 6 hours | 
| Renal arterial resistive index | (maximum flow velocity - minimum diastolic flow velocity) / maximum flow velocity | 6 hours | 
| Portal venous pulsatility fraction | (maximum flow velocity - minimum diastolic flow velocity) / maximum flow velocity | 6 hours | 
| Contrast enhanced ultrasound 1 | Mean transit time (mTT) | 6 hours | 
| Contrast enhanced ultrasound 2 | Perfusion Index (PI) | 6 hours | 
| Contrast enhanced ultrasound 3 | Relative Blood Volume (rBV) | 6 hours | 
| Contrast enhanced ultrasound 4 | Wash-in Rate (WiR) | 6 hours | 
| Contrast enhanced ultrasound 5 | Quality Of Fit (QOF) | 6 hours | 
| Continuous recordings of hemodynamic variables 1 | arterial pressure | 6 hours | 
| Continuous recordings of hemodynamic variables 2 | Central venous pressure | 6 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ultrasound, Renal perfusion, Fluid treatment, Venous congestion, Renal function