Acute Renal Failure Treatment

General Therapy for Acute Renal Failure
Treatment of acute renal failure usually should be conservative and largely supportive. It requires careful and precise management. All patients will require close monitoring, many of them within intensive care settings.
Supportive care includes stabilizing the patient, monitoring input and output strictly, weighing daily, determining electrolyte values frequently, preventing sepsis via reducing the number of intravenous lines and removing an indwelling urinary catheter, culturing periodically, and using antibiotics when indicated clinically. It is important to adjust medication dosage according to renal function and to avoid nephrotoxins whenever possible. Because serum creatinine values increase daily, it is best to calculate drug doses based on GFR <10 style="font-weight: bold;">THERAPY FOR PRERENAL FAILURE
Rapid volume replacement and treatment of the underlying condition that resulted in prerenal failure are the cornerstones of therapy. Initial fluid administration of isotonic saline (0.9%) or 5% albumin (10 to 20 mL/kg per dose) should be used to restore intravascular volume. This can be both a diagnostic and a therapeutic trial. Fluid administration also can convert oliguric to nonoliguric renal failure in its early stage.
Unless a patient is suffering congestive heart failure (CHF), fluid administration should be repeated, followed by the use of loop diuretics, including furosemide (2 to 5 mg/kg per dose) or bumetanide (0.25 to 0.5 mg/dose IV). After each bolus, the patient's volume needs to be reevaluated. Response to the therapy will be indicated by a urine output of greater than 1 to 3 mL/kg per hour.
Patients who have CHF will need inotropic support, such as dopamine (5 µg/kg per minute IV), dobutamine (5 to 20 µg/kg per minute), or digoxin. Therapeutic digitalis values should be achieved slowly and the maintenance dose reduced as dictated by renal function (Table 6).
THERAPY FOR POSTRENAL FAILURE
Therapy for postrenal failure includes removal of obstruction by decompression or diversion of the urinary tract, stabilization of electrolyte abnormalities, management of postobstructive diuresis, and therapy for voiding dysfunction and for urinary tract infection. Surgical intervention will require urologic consultation. The site of the obstruction will determine the approach: placement of a Foley catheter, vesicostomy, ureteral catheters (stents), or nephrostomy tubes. Prompt relief of a partial obstruction is indicated in cases of severe pain, where the possibilities for severe renal damage predominate, and whenever there is a history of frequent urinary tract infections.
Postobstructive diuresis is characterized by marked polyuria. The excessive excretions of salt and water may result in hypokalemia, hyponatremia, and hypotension and lead to collapse. Fluid replacement should be guided by what is excreted and based on frequent measurements of urine volume, urinary electrolytes, and serum electrolytes, including calcium and phosphorus.
THERAPY FOR ESTABLISHED RENAL FAILURE
Maintaining Balance of Fluid and Electrolytes
In a euvolemic state, fluid intake, including water generated from endogenous metabolism (insensible fluid gain), is balanced by fluid output. Most of the fluid output involves sensible fluid losses by urine, stool, and sweat and insensible losses by water evaporation from the skin and respiratory tract. Only small amounts of water normally are lost in the stool (100 to 150 mL/d), and fluid loss by sweat is minimal. Therefore, patients who are in ARF should have fluid restricted to net insensible water loss (insensible losses minus endogenous water production, which is 400 mL/m² per day or 25% to 30% of caloric expenditure) plus all measured fluid losses (urine output, gastrointestinal losses, chest tube drainage). Net insensible loss should be restored with 5% to 10% dextrose in water (D5%W - D10%W). Urine output should be replaced with fluid that has the composition and quantity of these losses. Usually, normal saline (0.45% NS) mL for mL of losses every 4 to 6 hours is appropriate. If this therapy is sufficient, the patient will lose 0.5% to 1% of body weight per day over the initial few days. The patient should be weighed at leastonce daily, and input and output should be monitored strictly, with clinical status assessed constantly. Once urine output begins to rise, fluid intake should be increased. Fluid balance is easier to manage in children who have nonoliguric renal failure. Dialysis is indicated in the case of a severe fluid overload
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