ACUTE RENAL FAILURE
Description
- Acute renal failure (ARF) is the rapid loss of kidney function from renal cell damage.
- Occurs abruptly and can be reversible
- ARF leads to cell hypoperfusion, cell death, and decompensation of renal function.
- The prognosis depends on the cause and the condition of the client.
- Near-normal or normal kidney function may resume gradually.
Causes
- Prerenal: Outside the kidney; caused by intravascular volume depletion, dehydration, decreased cardiac output, decreased peripheral vascular resistance, decreased renovascular blood flow,
- and prerenal infection or obstruction.
- Intrarenal:Within the parenchyma of the kidney; caused by tubular necrosis, prolonged pre renal ischemia, intrarenal infection or obstruction, and nephrotoxicity
- Postrenal: Between the kidney and urethral meatus, such as bladder neck obstruction, bladder cancer, calculi, and postrenal infection
Phases of ARF and interventions
Onset:
Begins with precipitating event
Oliguric phase
- For some clients, oliguria does not occur and the urine output is normal; otherwise the duration of oliguria is 8 to 15 days; the longer the duration, the less chance of recovery.
- Sudden decrease in urine output; urine output is less than 400 mL/day.
- Signs of excess fluid volume: Hypertension, edema, pleural and pericardial effusions, dysrhythmias, congestive heart failure (CHF), and pulmonary edema
- Signs of uremia: Anorexia, nausea, vomiting, and pruritus
- Signs of metabolic acidosis: Kussmaul’s respirations
- Signs of neurological changes: Tingling of extremities, drowsiness progressing to disorientation, and then coma
- Signs of pericarditis: Friction rub, chest pain with inspiration, and low-grade fever
- Laboratory analysis
- Restrict fluid intake; if hypertension is present, daily fluid allowances may be 400 mL to 1000 mL plus the measured urinary output.
- Administer medications as prescribed, such as diuretics (furosemide [Lasix]), to increase renal blood flow and diuresis.
Diuretic phase
- Urine output rises slowly, followed by diuresis (4 to 5 L/day).
- Excessive urine output indicates that damaged nephrons are recovering their ability to excrete wastes.
- Dehydration, hypovolemia, hypotension, and tachycardia can occur.
- Level of consciousness improves.
- Laboratory analysis (see Box 62-4)
- Administer IV fluids as prescribed, which may contain electrolytes to replace losses.
Recovery phase (convalescent)
- Recovery is a slow process; complete recovery may take 1 to 2 years.
- Urine volume returns to normal.
- Memory improves.
- Strength increases.
- The older adult is less likely than a younger adult to regain full kidney function.
- Laboratory analysis (see Box 62-4)
- ARF can progress to chronic renal failure (CRF). The signs and symptoms of acute renal failure are primarily caused by the retention of nitrogenous wastes, the retention of fluids, and the inability of the kidneys to regulate electrolytes.
Assessment:
Assess objective and subjective data noted in the phases of ARF
Other interventions
- Monitor vital signs, especially for signs of hypertension, tachycardia, tachypnea, and an irregular heart rate.
- Monitor urine and intake and output (hourly in ARF) and urine color and characteristics.
- Monitor daily weight (same scale, same clothes, same time of the day), noting that an increase of ½ to 1 lb/day indicates fluid retention.
- Monitor for changes in the BUN, serum creatinine, and serum electrolyte levels.
- Monitor for acidosis (may be treated with sodium bicarbonate).
- Monitor urinalysis for protein level, hematuria, casts, and specific gravity.
- Monitor for altered level of consciousness caused by uremia.
- Monitor for signs of infection because the client may not exhibit an elevated temperature or an increased white blood cell count.
- Monitor the lungs for wheezes and rhonchi and monitor for edema, which can indicate fluid overload.
- Administer a prescribed diet, which is usually a low- to moderate-protein (to decrease the workload on the kidneys) and high-carbohydrate diet.
- Restrict potassium and sodium intake as prescribed based on the electrolyte level.
- Administer medications as prescribed; be alert to the mechanism for metabolism and excretion of all prescribed medications.
- Be alert to nephrotoxic medications, which may be prescribed (see Box 62-3).
- Be alert to the health care provider’s adjustment of medication dosages for renal failure.
- Prepare the client for dialysis if prescribed; continuous renal replacement therapy may be used in ARF to treat fluid volume overload or rapidly developing azotemia and metabolic acidosis.
- Provide emotional support by allowing opportunities for the client to express concerns and fears and by encouraging family interactions.
- Promote consistency in caregivers.
- Also refer to the section in this chapter on special problems in renal failure and interventions.
