Acute kidney injury

Acute kidney injury is a well-known risk factor for increased morbidity and mortality in hospitalized adults and children. Understanding the interaction between the heart and the kidneys is paramount in order to successfully manage the pediatric patient in the perioperative period. Acute kidney injury can be due to a broad range of causes, and the differential diagnosis must be considered in a systemic fashion to avoid missing multiple factors that may be contributing to the condition. Traditionally, acute kidney injury is divided into prerenal, renal, and postrenal causes. Prerenal acute kidney injury is secondary to any disease process that results in intravascular volume depletion. If the injury is severe, prerenal acute kidney injury can evolve into acute tubular necrosis. Although renal ischemia is the most common etiology for acute kidney injury, patients with congenital heart disease often have multiple causes for renal injury. These include sepsis, altered autoregulation, use of cardiopulmonary bypass, and various patient-specific risk factors. In addition, reperfusion injury may play a prominent role in the development of acute kidney injury in this patient population. In the postoperative period, the degree of cardiac performance is critical for the preservation of kidney function after cardiac surgery. Ultimately, invasive therapies such as renal placement therapy may be warranted in those patients with acute fluid overload unresponsive to conventional diuretic therapies and/or life-threatening electrolyte abnormalities.