Renal Doppler Ultrasound in Early Detection of Acute Kidney Injury in Critically Ill Patients

2019-04-09 10:58:35 | BioPortfolio


Acute kidney injury is a common complication of critical illness and is associated with high morbidity and mortality .Acute kidney injury is a syndrome that is characterized by a rapid decline in renal function and urine output, resulting in retention of waste products such as urea, nitrogen, and serum creatinine. Life-threatening consequences include volume overload, hyperkalaemia, and metabolic acidosis . In its severe form, Acute kidney injury requires renal replacement therapy, which is applied in 5±13% of Intensive Care Unit patients


The incidence of Acute kidney injury in intensive care unit patients is rising due to the population age increasing, more comorbidities, and a higher prevalence of risk factors. Improved Intensive Care Unit management has, however, significantly diminished morbidity and the mortality of patients who develop Acute kidney injury I. Despite an increase in the number and severity of comorbidities, in-hospital mortality has declined, but the incidence of Acute kidney injury ,and Acute kidney injury requiring renal replacement therapy has increased over time .

There is still some dispute over the characterization of the different types of Acute kidney injury. Classically there are three types of Acute kidney injury: pre-renal, intrinsic renal, and post-renal failure. These are characterized as decreased renal blood flow (in 40-70% of the patients), direct (intrinsic) renal parenchymal damage (in 10-50% of the patients), and obstruction of urine flow which is less common in the ICU (10%), respectively..

In critically ill patients, sepsis and acute kidney injury are very common diseases and are associated with increased hospitalization and elevated in-hospital mortality rates Acute kidney injury is a dynamic process that evolves from an early reversible condition to an established disease and leads to sustained renal impairment, cell death ,and delayed renal recovery .Consequently, prompt resuscitation of the circulation and optimal perfusion pressure are the primary therapies for critically ill patients with Acute kidney injury. These methods are based principally on the appropriate management of intravenous fluid replacement and vasopressor administration under strict hemodynamic monitoring .

Mechanisms of Acute kidney injury comprise renal hypo-perfusion, intra-renal vasoconstriction, inflammation,oxidative stress and nephrotoxicity .An important pathophysiological pathway includes intra renal vasoconstriction and endothelial damage of the microvessels, leading to impaired macro- and microvascular flow, which further aggravates ischemia .

Renal vasoconstriction is an early manifestation of Acute kidney injury. More specifically, ultrasound imaging of the renal arteries can be instrumental in the early detection of Acute kidney injury. Indeed, renal blood flow is decreased at a nearly stage during acute tubular necrosis as a consequence of protracted intra renal vasoconstriction. The renal resistive index , which is used for assessing arterial pulsatility, was shown to correlate with renal vascular resistance . Renal Doppler ultrasound can measure the renal resistive index , a sonographic index that reflects alterations in blood flow profile of the intrarenal arcuate or interlobar arteries. It reflects the relation between the decline in speed loss of flow (flow velocity) between the peak of systole and the end of diastole in (renal) blood vessels: RRI = (peak systolic velocity _end diastolic velocity)/(peak systolic velocity). Normal values are reported between 0.60 and 0.70 with the difference between both kidneys mostly being less than 5% .

The Doppler renal resistive index has been used for years in a variety of clinical settings . Doppler imaging identifies changes in blood flow at the micro-vascular level. Evaluation of the vascular impedance at different sites of the renal parenchyma could provide useful diagnostic and prognostic information. An increase in renal vascular resistance may be an early sensitive sign of hemodynamic deterioration, even in seemingly stable patients.

Measuring flow resistance in the renal circulation, Renal resistive Index (RRI), could become part of vital organ function assessment using Doppler ultrasound. An increased Doppler Renal resistive Index is suggested to not only reflect changes in intra renal perfusion, but also in systemic hemodynamics .

Renal resistive index (RI), determined by Doppler ultrasonography, directly reveals and quantifies modifications in renal vascular resistance .

Aim of the work

The aim is to

1. Determine if the resistive Renal Index on ICU admission patients predicts the development of Acute kidney injury during the first week.

2. Determine whether resistive Renal Index is related to the severity of Acute kidney injury or not.

Patients and Methods 80 patients of critically ill patients including acute ischaemic insults, patients presenting with septicaemia, hypertension, respiratory failure, coagulation/ haemorrhagic disorders, shock, and liver disease and shock.

This study will be performed in the 24-bed mixed medical and surgical intensive care unit of the Assiut University Hospital.

Sample size calculations will be based on the assumption that patients not developing Acute kidney injury would have an RRI of 0.72 and patients developing Acute kidney injury would have an Acute kidney injury of 0.79 with a standard deviation of 0.11. These calculations were based on the results of other previous studies that reported median values for Acute kidney injury and no Acute kidney injury

AKI was defined according to the Kidney Disease Improving Global Outcome (KDIGO) classification using both creatinine and urine output criteria [20] KDIGO takes changes in creatinine within 48 hours, or a decline in the glomerular filtration rate (GFR) over 7 days, into account. AKI is defined as an increase in sCreat ≥0.3 mg/dL within 48 hours, or an increase in sCreat ≥1.5-times baseline, which is known or presumed to have occurred within the prior 7 days, or a Urine Out put of <0.5 mL/kg/h for 6 hours

Laboratory tests:

1. Complete blood count

2. Kidney function

3. Electrolytes including sodium,potassium, calcium,Phosphorus and uric acid

4. Urine analysis 5-24 hrs sodium in urine

Radiological test:

Doppler of both renal arteries with abdominal ultrasound. Renal resistive index was measured with ultrasound-Doppler

Study Design


Acute Kidney Injury


renal doppler ultrasound


Not yet recruiting


Assiut University

Results (where available)

View Results


Published on BioPortfolio: 2019-04-09T10:58:35-0400

Clinical Trials [6277 Associated Clinical Trials listed on BioPortfolio]

Doppler Ultrasound for Prediction of Reversibility of Acute Kidney Injury in Septic ICU Patients

Purpose: The aim of this study was to assess the ability of early discrimination between transient and persistent Acute Kidney Injury (AKI) using the color Doppler Ultrasound derived Renal...

Effects of Red Blood Cells Transfusion on Renal Blood Flow

The renal Doppler resistive index (RRI) is a noninvasive tool that has been used to assess renal perfusion in the intensive care unit (ICU) setting. It is associated with the occurrence of...

The Predictive Performance of Renal Ultrasound on Changes in Renal Clearance

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 ...

Diagnostic Accuracy of Doppler Resistive Indices for Early Diagnosis of Acute Kidney Injury .

To determine if ultrasound measurement of renal and carotid arterial resistive indices are associated with post-cardiac surgery acute kidney injury.

Predictive Value of Renal Venous Flow Profiles for Acute Kidney Injury After Cardiac Surgery

The prospective single-center study investigates whether preoperative Doppler-based renal venous flow profiles predict risk of acute kidney injury after cardiac surgery.

PubMed Articles [15651 Associated PubMed Articles listed on BioPortfolio]

Renal replacement therapy for acute kidney injury in intensive care.

Acute kidney injury is a common occurrence on the intensive care unit and is associated with incremental risk of death and chronic kidney disease. Renal replacement therapy has become an essential too...

NAG: a potential biomarker for early detection of acute kidney injury (AKI) in acute chest pain.

Acute kidney injury (AKI) is often underdiagnosed due to several limitations of the renal marker creatinine. Tubular urinary biomarkers may substantially contribute to diagnose acute kidney injury AKI...

Reversibility of Acute Kidney Injury in Medical ICU Patients: Predictability Performance of Urinary Tissue Inhibitor of Metalloproteinase-2 x Insulin-Like Growth Factor-Binding Protein 7 and Renal Resistive Index.

Urinary biomarkers and renal Doppler sonography remain considered as promising tools to distinguish transient from persistent acute kidney injury. The performance of the urinary biomarker, tissue inhi...

Early versus late initiation of renal replacement therapy for acute kidney injury in critically ill patients: A systematic review and meta-analysis.

Acute kidney injury is associated with high mortality, and is the most frequent complication encountered in patients residing in the intensive care unit. Although renal replacement therapy (RRT) is th...

Drug-induced acute kidney injury: diverse mechanisms of tubular injury.

Medications are a relatively common cause of acute kidney injury (AKI), especially in hospitalized patients who are exposed to numerous agents. Drug-related acute tubular/tubulointerstitial injury is ...

Medical and Biotech [MESH] Definitions

Abrupt reduction in kidney function defined as an absolute increase in serum CREATININE of more than or equal to 0.3. mg/dl, a percentage increase in serum creatinine of more than or equal to 50%, or a reduction in urine output. Acute kidney injury encompasses the entire spectrum of the syndrome including acute kidney failure; ACUTE KIDNEY TUBULAR NECROSIS; and other less severe conditions.

Acute kidney failure resulting from destruction of EPITHELIAL CELLS of the KIDNEY TUBULES. It is commonly attributed to exposure to toxic agents or renal ISCHEMIA following severe TRAUMA.

Ultrasonography applying the Doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. (Stedman, 25th ed)

Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.

Conditions in which the KIDNEYS perform below the normal level in the ability to remove wastes, concentrate URINE, and maintain ELECTROLYTE BALANCE; BLOOD PRESSURE; and CALCIUM metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of PROTEINURIA) and reduction in GLOMERULAR FILTRATION RATE. The most severe form is KIDNEY FAILURE. Renal function may deteriorate slowly (RENAL INSUFFICIENCY, CHRONIC) or precipitously (RENAL INSUFFICIENCY, ACUTE).

More From BioPortfolio on "Renal Doppler Ultrasound in Early Detection of Acute Kidney Injury in Critically Ill Patients"

Quick Search

Relevant Topic

Benign Prostatic Hyperplasia (BPH) Erectile Dysfunction Urology Urology is the branch of medicine concerned with the urinary tract and diseases that affect it. Examples include urethritis, urethrostenosis and incontinence. Urology is a su...

Searches Linking to this Trial