الفهرس 
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Abstract
Acute renal failure (urine output <0.5 ml/kg/hr.) following cardiopulmonary bypass is an uncommon but highly lethal complication which arises in the setting of inadequate cardiac function and may be associated with multi-organ failure. Acute renal failure (ARF) after cardiopulmonary bypass occurs in about 8% of adult cardiac surgical patients with some preoperative renal impairment and in about 3-4%, of patients with normal preoperative renal parameters.
A raised serum urea concentration (uremia) may conveniently be classified as: Prerenal, renal, and postrenal. Prerenal acute renal failure is characterized by diminished renal blood flow (60 to 70 percent of cases). In intrinsic acute renal failure, there is damage to the renal parenchyma (25 to 40 percent of cases). Postrenal acute renal failure occurs because of urinary tract obstruction (5 to 10 percent of cases). The most commonly encountered diagnoses are prerenal acute renal failure and acute tubular necrosis (a type of intrinsic acute renal failure).
The etiology of acute renal injury post CABG is thought to be multifactorial. Ischemia-reperfusion, inflammation, and atheroembolism are three common sources of renal injury. Many risk factors are contributing in acute renal failure as advancing age, male sex, type and severity of of cardiac lesion, preoperative renal dysfunction, preoperative dehydration and excessive use of diuretics, effect premedication and induction of Anaesthesia, effect of thoracotomy and effect of cardiopulmonary bypass which include direct effect of bypass on renal function, hemo-dilution, hypothermia, hemolysis, vascular effects, osmolar and oncotic effect and microemboli.
To diagnose postoperative acute renal failure, we have to look for it in the suspicious patients with the previously mentioned predisposing and precipitating factors by the following, History and physical examination of suspected causes, Assess cardiac hemodynamics (filling pressures, cardiac output), Monitor other electrolytes, blood glucose, and acid-base balance frequently, Identify any drugs being prescribed with adverse effects on renal function, Renal Imaging and Laboratory studies which include: urine volume and composition, blood urea and serum creatinine and clearance tests.
To prevent Acute renal failure we use pharmacological and non pharmacological methods. Non pharmacological methods include good hydration, glycemic control, using OFF-pump cardiac surgery, avoidance or timely management postoperative surgical complication and avoidance or minimal exposure of nephrotoxic drugs. Pharmacological methods which include antioxidant(as Ascorbic Acid, Allopurinol and Vit E and N acetylcystiene), Calcium channel blockers, Angiotensin converting enzyme inhibitors, Theophylline, Sodium bicarbonate, Dopamine agonists (Dopamine, Fenoldopamin and Dopexamine), Loop diuretics, Mannitol, Natriuretic peptides(Anaritide and Nesiritide), Erythropiotine, Growth factors and Steriods.
Treatment of acute renal failure include: management of volume homeostasis, management of electrolyte homeostasis(as potassium, sodium, Calcium, Magnesium and phosphorus), management of acid-base homeostasis, management of uremia, nutritional management, indication and technique of dialysis in acute renal failure and drug management in acute renal failure.