Role of Renal Artery Doppler In Critically Ill Children With Acute Kidney Injury

Critically ill child is defined as a child whose baseline state of health has significantly changed and whose life is at risk as a result of an illness or injury and they in big need for intensive care whether medicallyor surgically.

Acute kidney injury (AKI) is characterized by a sudden and generally revertible renal function impairment , involving inability to maintain the homeostasis, and may or not be accompanied by reduced diuresis. (1) Acute kidney injury (AKI) is highly prevalent among hospitalized children, with incidence rates ranging from 5% in non-critically ill children to 50% in those admitted to pediatric emergency units (2). This disease is strongly associated with worse outcomes, including increased mortality, increased use of mechanical ventilation, and prolonged hospital stay (3). AKI prevalence due to sepsis ranges from 9% to 40%, involves poor prognosis, and is associated with a 70% mortality rate (4). Among critically ill renal impaired patients, about 6% the septic shock, is one of the main causes of AKI. may need renal replacement therapy (RRT), with a mortality rate increased by 50 to 80%, particularly associated with sepsis, septic shock, and multiple organ and systems dysfunction MODS (5).

During the childhood, the main AKI causes are sepsis, nephrotoxic drugs, and renal ischemia in critically ill patients (1) .These patients, particularly those staying in intensive care units , are exposed to a number of conditions which may result in renal impairment ,thus significantly increasing the morbidity and mortality rate. (6).

Among the main causes that should be mentioned : hypovolemia leading to hypoperfusion and consequent hypoxia; inflammatory and thrombotic events caused by bacteremia ; systemic inflammation from trauma, major surgeries, extracorporeal circulation ;use of vasodilator drugs such as phosphodiesterase inhibitors, sedatives, epidural blockade; vasopressors; and use of nephrotoxic drugs as aminoglycosides, amphotericin B, radiological contrasts, and drugs interfering with the renal hemodynamics such as angiotensin converting enzyme inhibitors and angiotensin II receptor blockers (3).

In 2004, a consensus definition for AKI was proposed by the Acute Dialysis Quality Initiative (ADQI) : the RIFLE criteria (risk, injury ,failure, loss, end-stage renal disease) (7) .The adult-derived RIFLE definition was modified, and then applied and validated in pediatric patients and renamed as the pediatric RIFLE criteria. pRIFLE stratifies AKI from mild (RIFLE R, risk) to severe (RIFLE F, failure) based on changes in SCR or estimated creatinine clearance and urine output .Similar to adult studies AKI defined by these criteria was an independent risk factor for both increased hospital length of stay and mortality.