Acute renal failure.

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Transcript of Acute renal failure.

  • 1. Prepared by: BSN, Level IV Sarah Jane A. Cristobal

2. Is the rapid breakdown of renal (kidney) function that occurs when high levels of uremic toxins (waste products of the body's metabolism) accumulate in the blood. ARF occurs when the kidneys are unable to excrete (discharge) the daily load of toxins in the urine. DEFINITION 3. Based on the amount of urine that is excreted over a 24- hour period, patients with ARF are separated into two groups: Oliguric: patients who excrete less than 500 milliliters per day (< 16 oz/day) Nonoliguric: patients who excrete more than 500 milliliters per day (> 16 oz/day) DEFINITION 4. Acute kidney failure almost always occurs in connection with another medical condition or event. Conditions that can increase your risk of acute kidney failure include: Being hospitalized, especially for a serious condition that requires intensive care Advanced age Blockages in the blood vessels in your arms or legs (peripheral artery disease) Diabetes High blood pressure Heart failure Kidney diseases Liver diseases RISK FACTORS 5. A detailed and accurate history is crucial for diagnosing acute kidney injury (AKI) and determining treatment. Distinguishing AKI from chronic kidney disease is important, yet making the distinction can be difficult. PHYSICAL EXAMINATION 6. A history of chronic symptomsmonths of fatigue, weight loss, anorexia, nocturia, sleep disturbance, and pruritussuggests chronic kidney disease. AKI can cause identical symptoms, but over a shorter course. PHYSICAL EXAMINATION 7. It is important to elicit a history of any of the following etiologic factors: Volume restriction (eg, low fluid intake, gastroenteritis) Nephrotoxic drug ingestion Trauma or unaccustomed exertion Blood loss or transfusions Exposure to toxic substances, such as ethyl alcohol or ethylene glycol Exposure to mercury vapors, lead, cadmium, or other heavy metals, which can be encountered in welders and miners PHYSICAL EXAMINATION 8. Urine output history can be useful. Oliguria generally favors AKI. Abrupt anuria suggests acute urinary obstruction, acute and severe glomerulonephritis, or embolic renal artery occlusion. A gradually diminishing urine output may indicate a urethral stricture or bladder outlet obstruction due to prostate enlargement. PHYSICAL EXAMINATION 9. Prerenal failure Patients commonly present with symptoms related to hypovolemia, including thirst, decreased urine output, dizziness, and orthostatic hypotension. Ask about volume loss from vomiting, diarrhea, sweating, polyuria, or hemorrhage. Patients with advanced cardiac failure leading to depressed renal perfusion may present with orthopnea and paroxysmal nocturnal dyspnea. PHYSICAL EXAMINATION 10. Elders with vague mental status change are commonly found to have prerenal or normotensive ischemic AKI. Insensible fluid losses can result in severe hypovolemia in patients with restricted fluid access and should be suspected in elderly patients and in comatose or sedated patients. PHYSICAL EXAMINATION 11. Intrinsic renal failure Patients can be divided into those with glomerular etiologies and those with tubular etiologies of AKI. Nephritic syndrome of hematuria, edema, and hypertension indicates a glomerular etiology for AKI. Query about prior throat or skin infections. PHYSICAL EXAMINATION 12. A history of prior gynecologic surgery or abdominopelvic malignancy often can be helpful in providing clues to the level of obstruction. Flank pain and hematuria should raise a concern about renal calculi or papillary necrosis as the source of urinary obstruction. PHYSICAL EXAMINATION 13. Postrenal failure Postrenal failure usually occurs in older men with prostatic obstruction and symptoms of urgency, frequency, and hesitancy. Patients may present with asymptomatic, high-grade urinary obstruction because of the chronicity of their symptoms. RISK FACTORS 14. The interaction of tubular and vascular events result in ARF. The primary cause of ATN is ischemia. Ischemia for more than two hours results in severe and irreversible damage to the kidney tubules. Significant reduction in glomular filtration rate (GFR) is a result of (1) ischemia, (2) activation of the renin-angiotensin system , and (3) tubular obstruction by cellular debris PATHOPHYSIOLOGIC MECHANISM 15. As nephrotoxins damage the tubular cells and these cells are lost through necrosis, the tubules become more permeable. This results in filtrate absorption and a reduction in the nephrons ability to eliminate waste. PATHOPHYSIOLOGIC MECHANISM 16. The clinical course of ARF is characterized by the following three phases: Phase 1. Onset ARF begins with the underlying clinical condition leading to tubular necrosis, for example hemorrhage, which reduces blood volume and renal perfusion. If adequate treatment is provided in this phase then the individual's prognosis is good. PATHOPHYSIOLOGIC MECHANISM 17. Phase 2. Maintenance A persistent decrease in GFR and tubular necrosis characterizes this phase. Endothelial cell necrosis and sloughing lead to tubular obstruction and increased tubular permeability. Because of this, oliguria is often present during the beginning of this phase. Efficient elimination of metabolic waste, water, electrolytes, and acids from the body cannot be performed by the kidney during this phase. PATHOPHYSIOLOGIC MECHANISM 18. Therefore, azotemia, fluid retention, electrolyte imbalance and metabolic acidosis occurs. The patient is at risk for heart failure and pulmonary edema during this phase because of the salt and water retention. Immune function is impaired and the patient may be anemic because of the suppressed erythropoietin secretion by the kidney and toxin-related shorter RBC life. PATHOPHYSIOLOGIC MECHANISM 19. Phase 3. Recovery Renal function of the kidney improves quickly the first five to twenty-five days of this phase. It begins with the recovery of the GFR and tubular function to such an extent that BUN and serum creatinine stabilize. Improvement in renal function may continue for up to a year as more and more nephrons regain function. PATHOPHYSIOLOGIC MECHANISM 20. If your signs and symptoms suggest that you have acute kidney failure, your doctor may recommend tests and procedures to verify your diagnosis. These may include: Urine output measurements. The amount of urine you excrete in a day may help your doctor determine the cause of your kidney failure. Urine tests. Analyzing a sample of your urine, a procedure called urinalysis, may reveal abnormalities that suggest kidney failure. DIAGNOSTIC EXAMINATION 21. Blood tests. A sample of your blood may reveal rapidly rising levels of urea and creatinine two substances used to measure kidney function. Imaging tests. Imaging tests such as ultrasound and computerized tomography (CT) may be used to help your doctor see your kidneys. DIAGNOSTIC EXAMINATION 22. Removing a sample of kidney tissue for testing. In certain situations, your doctor may recommend a kidney biopsy to remove a small sample of kidney tissue for lab testing. To remove a sample of kidney tissue, your doctor may insert a thin needle through your skin and into your kidney. DIAGNOSTIC EXAMINATION 23. Drugs that are renally excreted may need to have their doses reduced in patients with renal insufficiency or end-stage renal disease: MEDICATIONS 24. For prescribing purposes renal impairment is usually divided into three grades: Mild: GFR 20-50 ml/minute; serum creatinine approximately 150-300 mol/l. Moderate: GFR 10-20 ml/minute; serum creatinine approximately 300-700 mol/L. Severe: GFR less than 10 ml/minute; serum creatinine >700 mol/L. MEDICATIONS 25. Nephrotoxic drugs should, if possible, be avoided in patients with renal disease because the consequences of nephrotoxicity are likely to be more serious when the renal reserve is already reduced. MEDICATIONS 26. The situation may change if a patient begins dialysis, since some drugs will be removed by the dialysis. Dialysis may lead to the loss of therapeutic effect for some drugs. MEDICATIONS 27. Drugs to which particular attention must be given include many antibiotics, histamine H2- receptor antagonists, digoxin, anticonvulsants and non- steroidal anti-inflammatory drugs (NSAIDs). MEDICATIONS 28. 1. Excess Fluid Volume May be relate to Compromised regulatory mechanism (renal failure) Possibly evidenced by Intake greater than output, oliguria; changes in urine specific gravity Venous distension; blood pressure (BP)/central venous pressure (CVP) changes Generalized tissue edema, weight gain Changes in mental status, restlessness NURSING DIAGNOSIS 29. 2. Risk for Decreased Cardiac Output Risk factors may include Fluid overload (kidney dysfunction/failure, overzealous fluid replacement) Fluid shifts, fluid deficit (excessive losses) Electrolyte imbalance (potassium, calcium); severe acidosis Uremic effects on cardiac muscle/oxygenation Possibly evidenced by [Not applicable; presence of signs and symptoms establishes an actual diagnosis.] NURSING DIAGNOSIS 30. 3. Risk for Imbalanced Nutrition risk for less than body requirements Risk factors may include Protein catabolism; dietary restrictions to reduce nitrogenous waste products Increased metabolic needs Anorexia, nausea/vomiting; ulcerations of oral mucosa NURSING DIAGNOSIS 31. 4. Risk for Infection Risk factors may include Depression of immunologic defenses (secondary to uremia) Invasive procedures/devices (e.g., urinary catheter) Changes in dietary intake/malnutrition Possibly evidenced by [Not applicable; presence of signs and symptoms establishes an actual diagnosis.] NURSING DIAGNOSIS 32. 5. Risk for Deficient Fluid Volume Risk factors may include Excessive loss of fluid (diuretic phase of ARF, with rising urinary volume and delayed return of tubular reabs