acute kidney failure
| Noun | 1. |  acute kidney failure - renal failure associated with burns or other trauma or with acute infection or obstruction of the urinary tract |
| 单词 | acute kidney failure | |||||||||||||||
| 释义 | acute kidney failure
acute kidney failureAcute Kidney FailureDefinitionDescriptionCauses and symptoms
Key terms
DiagnosisTreatmentHemodialysisHemofiltrationPeritoneal dialysisPrognosisPreventionResourcesPeriodicalsOrganizationsacute renal failureAn abrupt decline in renal function, marked by a rise in serum creatinine or azotemia, triggered by various processes—e.g., sepsis, shock, trauma, kidney stones, drug toxicity (aspirin, lithium, substances of abuse), toxins, iodinated radiocontrast.Clinical findings • Cardiovascular Congestive heart failure, myocardial infarction, arrhythmias, cardiac arrest occur in up to 35% of patients with ARF. The elderly with low cardiac reserve are at risk of fluid overload secondary to oliguric ARF. • Pulmonary Lung disease occurs in over half of patients with ARF and may be linked to shared pulmonary and renal syndromes—e.g., Goodpasture syndrome, Wegener granulomatosis, polyarteritis nodosa, cryoglobulinemia, sarcoidosis. Hypoxia is common during hemodialysis and attributed to white cell sequestration by the lungs and alveolar hypoventilation. • GI tract Nausea, vomiting, anorexia; GI bleeding occurs in ± one third of patients with ARF and causes nearly 10% of deaths in patients with ARF. Other GI complaints include pancreatitis, jaundice linked to hepatic congestion, blood transfusions, and sepsis. • Infections Occur in up to 33% of patients with ARF; most occur in the lungs and urinary tract, and have mortality rates of up to 72%. • Neurologic signs of uraemia occur in one-third of ARF patients, and have the expected findings of lethargy, somnolence, reversal of the sleep-wake cycle, and cognitive or memory deficits. Types • Prerenal—adaptive response to volume depletion and hypotension. • Renal/intrinsic—response to cytotoxicity, ischaemia, or inflammation with structural and functional damage to the renal parenchyma. • Postrenal—obstruction to the passage of urine. Acute renal failure by type Crescentic GN—renal vasculitis, anti-GBM disease, immune complex diseases. Acute tubular injury—ischaemic, toxic, crystals, myoglobinuria Acute tubulointerstitial nephritis. Thrombotic microangiopathy—haemolytic-uraemic syndrome, accelerated hypertension, scleroderma. acute kidney failureAcute renal failure, see there.failure(fal'yer) [Fr. faillir, fr L. fallere, to deceive]acute kidney failureAcute renal failure.acute liver failureEtiologyThe most common causes of acute liver failure are viral hepatitis, acetaminophen overdose (and other drug reactions), trauma, ischemia, acute fatty liver of pregnancy, and autoimmune disorders. SymptomsEarly symptoms are often nonspecific and mFay include nausea, vomiting, dizziness, lightheadedness, or drowsiness. As liver injury becomes more obvious, bile permeates the skin, producing jaundice. Alterations in mental status (lethargy or coma) and bleeding caused by coagulopathy may develop. DiagnosisThe diagnosis is suggested by jaundice and altered mental status in addition to elevations in liver function tests and prolongation of the protime and international normalized ratio (INR). Patient careAffected patients should be hospitalized, usually in intensive care under very close monitoring. General patient care concerns apply. Airway support and mechanical ventilation are often needed. Fluids and/or pressors, such as dopamine, may be needed to maintain blood pressure and cardiac output. Nutritional support with a low salt, protein-restricted diet, and most calories supplied by carbohydrates, blood product infusions (fresh frozen plasma and platelets), and lactulose are usually administered. Potassium supplements help to reverse the affects of high aldosterone levels; potassium-sparing diuretics increase urine volume. Ascitic fluid is removed by paracentesis or shunt placement to relieve abdominal discomfort and aid respiratory effort. Portal hypertension requires shunt placement to divert blood flow, and variceal bleeding is treated with vasoconstrictor drugs, balloon tamponade, vitamin K administration, and perhaps surgery (to ligate bleeding portal vein collateral vessels). Medications that are normally metabolized by the liver and medications that may injure the liver further should be avoided. Patients who have overdosed on acetaminophen may benefit from the administration of acetylcysteine if it can be administered within 12 hr of a single ingestion. Liver transplantation is the definitive treatment for acute liver failure. Early transplant evaluation should be carried out for every patient for whom there is a donated organ available. Without transplantation, the mortality from acute liver injury may reach 80%. The patient’s level of consciousness should be assessed frequently, with ongoing orientation to time and place. Girth should be measured daily. Signs of anemia, infection, alkalosis, and GI bleeding should be documented and reported immediately. A quiet atmosphere is provided. Physical restraints are applied as minimally as possible, with chemical restraint prohibited. If the patient is comatose, the eyes are protected from corneal injury using artificial tears and/or eye patches. The prognosis for the illness should be discussed in a sensitive but forthright fashion and emotional support provided to family members. Agency social workers, the hospital chaplain, and other support personnel should be involved in the patient’s care as appropriate to individual needs. acute renal failureAbbreviation: ARFEtiologyPrerenal: Most ARF is caused by low perfusion of the kidneys due to problems that do not at first directly damage the kidneys: hypovolemia (such as burns, cirrhosis with portal hypertension and ascites, dehydration, diarrhea, excess diuresis hemorrhage, vomiting); low cardiac output (such as arrhythmias, cardiac tamponade, massive pulmonary embolus, mechanical ventilation, myocardial diseases, pulmonary hypertension); systemic vasodilation (such as anaphylaxis, anesthesia, antihypertensives, sepsis); or bilateral renal vascular blockage (such as emboli, stenosis, thrombi). Intrarenal: A less common ARF is caused from direct damage to the kidneys. Ninety percent of these cases are caused either by ischemia (from prolonged prerenal ARF or from diseases of blood vessel walls, glomerulonephritis, hyperviscosity syndromes, malignant hypertension, thrombotic microangiopathies, or vasculitis) or by nephrotoxins. Postrenal: The least common ARF (less than 5% of cases) is caused by urinary obstruction that leads to increased back-pressure in the kidney tubules, which, in turn, decreases the glomerular filtration rate (GFR). Urinary obstruction most often occurs at the bladder neck due to anticholinergic drug therapy, neurogenic bladder, or prostatic disease. TreatmentAcute renal failure caused by urinary outlet obstruction (postrenal failure) often completely resolves when urinary flow is restored, i.e., after a urinary catheter is placed or a prostatectomy performed. Renal failure caused by prerenal conditions, i.e., from reduced blood flow to the kidneys (as in dehydration or shock), sometimes improves with fluid and pressor support but may require other therapies, including dialysis. The resolution of ARF caused by intrarenal diseases (as in acute tubular necrosis) and kidney toxins depends on the underlying cause and the duration of the exposure. For example, immunosuppressant drugs may reverse ARF due to glomerulonephritis or renal vasculitis whereas forced diuresis is the treatment for those whose disease is caused by rhabdomyolysis. Patient carePatients with ARF may stop making urine, have a sudden rise in BUN and creatinine levels, and develop metabolic acidosis and electrolyte imbalances, esp. hyperkalemia. Other complications may follow as uremia develops, e.g., altered mental status, anorexia, arrhythmias, and fluid overload. The specific cause is identified and removed if possible. The nurse instructs the patient about dietary and fluid restrictions and implements these restrictions, promotes infection prevention, and advises the patient about activity restrictions due to metabolic alterations. Neurological status is assessed, and safety measures are instituted. Intake and output and daily weights (measures of fluid status) are monitored. Daily blood tests determine acid-base and electrolyte balance. Hyperkalemia is treated with dialysis, intravenous hypertonic glucose solutions, insulin infusion, sodium bicarbonate, or potassium exchange resins administered orally or by enema, depending on its severity. The nurse should assess the patient for edema in the legs and feet, hands and sacrum, and around the eyes. It is also usual to record urine color and clarity. The patient is assessed for gastrointestinal (GI) and cutaneous bleeding and anemia; blood components are replaced, or erythropoietin therapy is administered as prescribed. Blood pressure, pulse, respiratory rate, and heart and lung sounds are regularly assessed for evidence of pericarditis or fluid overload. Cardiac monitoring is used to detect changes in cardiac conduction related to hyperkalemia. Anorexia, nausea, and vomiting result from uremia and lead to poor nutrition with loss of body muscle and mass. Nutritional support is critical to combat malnutrition, infection, and to limit electrolyte imbalances. Protein calorie malnutrition is prevalent in ARF. Renal failure diet requires careful management of total calories, protein, electrolytes, minerals, vitamins, and fluid volume. It should provide enough calories (30–35 kcal/kg) through fats and carbohydrates to limit muscle breakdown. At the same time, protein intake should be restricted to about 1.2 to 1.3 g/kg to minimize azotemia. Sodium intake should be limited to 2 to 4 g a day to limit water retention and hypertension. Potassium intake is restricted because, in renal failure, potassium is not excreted by the kidneys, and hyperkalemia may produce muscle weakness and cardiac rhythm disturbances. Oral intake of phosphorus must also be limited as prescribed; alternately, phosphorus-binding medications are taken with meals to prevent hyperphosphatemia. Oral calcium supplements are often used for this purpose. Vitamins B, C, and folate supplements are often given. Fluids are usually limited to the amount of the patient's urine output plus 500 to 700 ml for metabolic needs. Oral hygiene and misting provide relief for dry mucous membranes and help to prevent inflammation and infection. All stools are tested to monitor for GI bleeding. Aseptic technique is used in caring for this patient, who is extremely susceptible to infection. Other therapies include incentive spirometry, coughing, passive range-of-motion exercises, antiembolism stockings or pneumatic leg dressings, and ambulation. Acute renal failure often results in a protracted illness. Many patients with ARF requiring intensive care will die. As a result, the patient and family require continuous emotional support, and education about the treatment regimen (including dialysis if it is employed), nutritional restrictions, and the use of medications. Because some patients will eventually need to have arteriovenous fistula constructed for dialysis, intravenous access should be limited to the dorsal aspects of the hands whenever possible. If ARF is not reversed but progresses to chronic (end-stage) renal failure, follow-up care with a nephrologist is arranged, and evaluation and teaching are provided for maintenance dialysis and/or possible kidney transplant. Referral is made for vocational or other counseling as needed.
acute respiratory failureTreatmentIn most cases the patient will need supplemental oxygen therapy. Intubation and mechanical ventilation may be needed if the patient cannot oxygenate and ventilate adequately, i.e., if carbon dioxide retention occurs. Treatment depends on the underlying cause of the respiratory failure, e.g., bronchodilators for asthma, antibiotics for pneumonia, diuretics or vasodilators for congestive heart failure. Patient carePatients with acute respiratory failure are usually admitted to an acute care unit. The patient is positioned for optimal gas exchange, as well as for comfort. Supplemental oxygen is provided, but patients with chronic obstructive lung disease who retain carbon dioxide are closely monitored for adverse effects. A normothermic state is maintained to reduce the patient's oxygen demand. The patient is monitored closely for signs of respiratory arrest; lung sounds are auscultated and any deterioration in oxygen saturation immediately reported. The patient is also watched for adverse drug effects and treatment complications such as oxygen toxicity and acute respiratory distress syndrome. Vital signs are assessed frequently, and fever, tachycardia, tachypnea or bradypnea, and hypotension are reported. The electrocardiogram is monitored for arrhythmias. Serum electrolyte levels and fluid balance are monitored and steps are taken to correct and prevent imbalances. If mechanical ventilation or noninvasive support is needed, ventilator settings and inspired oxygen concentrations are adjusted based on arterial blood gas results. See: ventilation To maintain a patent airway, the trachea is suctioned after oxygenation as necessary, and humidification is provided to help loosen and liquefy secretions. Secretions are collected as needed for culture and sensitivity testing. Sterile technique during suctioning and change of ventilator tubing helps to prevent infection. Use of the minimal leak technique for endotracheal tube cuff inflation helps prevent tracheal erosion. Positioning the nasoendotracheal tube midline within the nostril, avoiding excessive tube movement, and providing adequate support for ventilator tubing all help to prevent nasal and endotracheal tissue necrosis. Periodically loosening the securing tapes and supports prevents skin irritation and breakdown. The patient is assessed for complications of mechanical ventilation, including reduced cardiac output, pneumothorax or other barotrauma, increased pulmonary vascular resistance, diminished urine output, increased intracranial pressure, and gastrointestinal bleeding. All tests, procedures, and treatments should be explained to the patient and family to improve understanding and help reduce anxiety. Rationales for such measures should be presented, and concerns elicited and answered. If the patient is intubated (or has had a tracheostomy), the patient should be told why speech is not possible and should be taught how to use alternative methods to communicate needs, wishes, and concerns to health care staff and family members. adult failure to thrivefailure of artificial pacemakerbackward heart failurecardiac failureHeart failure.chronic respiratory failurePatient careThe focus of patient care is to relieve respiratory symptoms, manage hypoxia, conserve energy, and avoid respiratory irritants and infections. The nurse, respiratory therapist, primary care physician, and pulmonologist carry out the prescribed treatment regimen and teach the patient and family to manage care at home. Patients may require supplemental oxygen. The patient is taught how to use the equipment and the importance of maintaining an appropriate flow rate. Low flow rates (1–2 L/min) are often best for patients with chronic obstructive lung disease. Drug therapy can include inhaled bronchodilators (if bronchospasm is reversible), oral or inhaled corticosteroids, oral or inhaled sympathomimetics, inhaled mucolytic therapy, and prompt use of oral antibiotics in the presence of respiratory infection. The patient and family are taught the order and spacing for administering these drugs, as well as how to use a metered-dose inhaler (with spacer if necessary). They are taught the desired effects, serious adverse reactions to report, and minor adverse effects and how to deal with them. Patients are taught care of inhalers and other respiratory equipment and are advised to rinse the mouth after using these devices to help limit bad tastes, dryness, and Candida infections. Unless otherwise restricted, the patient will benefit from increased fluid intake (to 3 L/day) to help liquefy secretions and aid in their expectoration. Deep-breathing and coughing techniques are taught to promote ventilation and remove secretions. The patient also may be taught postural drainage and chest physiotherapy to help mobilize secretions and clear airways. Such therapy is to be carried out at least 1 hr before or after meals. Incentive spirometry may help to promote optimal lung expansion. A high-calorie, high-protein diet, offered as small, frequent meals, helps the patient maintain needed nutrition, while conserving energy and reducing fatigue. Daily activity is encouraged, alternating with rest to prevent fatigue. Patients may benefit from a planned respiratory rehabilitation program to teach breathing techniques, provide conditioning, and help increase exercise tolerance. Diversional activities also should be provided, based on the patient's interests. The patient is assessed for changes in baseline respiratory function; restlessness, changes in breath sounds, and tachypnea may signal an exacerbation. Any changes in sputum quality or quantity are noted. The patient is taught to be aware of these changes. Patients need help in adjusting to lifestyle changes necessitated by this chronic illness. Patients and their families are encouraged to ask questions and voice concerns; answers are provided when possible, and support is given throughout. The patient and family should be included in all care planning and related decisions. The patient also is taught to avoid air pollutants such as automobile exhaust fumes and aerosol sprays, as well as crowds and people with respiratory infections. Patients should obtain influenza immunization annually and pneumonia immunization every 6 years. The patient also may benefit from avoiding exposure to cold air and covering the nose and mouth with a scarf or mask when outdoors in cold, windy weather. Patients who smoke tobacco are advised to abstain, using nicotine replacement therapy, hypnotism, support groups, or other methods. circulatory failurefailure of compensationcongestive heart failureAbbreviation: CHFHeart failure. extubation failureforward heart failurefulminant hepatic failureAcute liver failure.heart failureDiagnosisHeart failure is easily diagnosed in a patient with typical symptoms and signs, esp. when these findings are accompanied by a chest x-ray that shows an enlarged heart and pulmonary edema. In patients with an uncertain presentation, elevated levels of B-type natriuretic peptide (BNP) may aid in the diagnosis. SymptomsDifficulty breathing is the predominant symptom of heart failure. In patients with mild impairments of ejection fraction (45% to 50%), breathing is normal at rest but labored after climbing a flight of stairs or lifting lightweight objects. Patients with advanced heart failure (ejection fraction 20%) may have such difficulty breathing that getting out of bed or taking a few steps is very tiring. Difficulty breathing while lying flat (orthopnea) or awakening at night with shortness of breath (paroxysmal nocturnal dyspnea) are also hallmarks of heart failure, as are exertional fatigue and lower extremity swelling (edema). EtiologyHeart failure may result from myocardial infarction, myocardial ischemia, arrhythmias, heart valve lesions, congenital malformation of the heart or great vessels, constrictive pericarditis, cardiomyopathies, or conditions that affect the heart indirectly, including renal failure, fluid overload, thyrotoxicosis, severe anemia, and sepsis. Of the many causes of heart failure, ischemia and infarction are the most common. TreatmentDiuretics (including furosemide and bumetanide), neurohormonal agents (such as angiotensin-converting enzyme inhibitors or angiotension receptor blockers), beta blockers (such as carvedilol or bisoprolol) are often combined in the acute and chronic treatment of heart failure. Other drugs that have been shown to be effective are nitrates with hydralazine, and aldosterone (a potassium-sparing diuretic). All of these medications must be monitored closely for side effects. In patients with heart failure caused by valvular heart disease, valve replacement surgery may be effective. Cardiac transplantation can be used in advanced heart failure when donor organs are available. Patient careIn the patient who presents for medical attention in heart failure, signs and symptoms are assessed, and vital signs, cardiac rhythm, and neurological status are closely monitored. A 12-lead ECG is examined for evidence of acute coronary syndromes and cardiac monitoring is instituted. Hemodynamic monitoring is initiated based on the severity of patient symptoms. The chest is auscultated for abnormal heart sounds and for lung crackles or gurgles. Daily weights are obtained to detect fluid retention, and the extremities are inspected for evidence of peripheral edema. If the patient is confined to a bed, the sacral area of the spine is assessed for edema. Fluid intake and output are monitored esp. if the patient is receiving diuretics. Blood urea nitrogen and serum creatinine, potassium, sodium, chloride, and bicarbonate levels are monitored frequently. The complete blood count, liver function tests, thyroid function tests, and kidney functions should be evaluated to determine whether any comorbid conditions such as anemia, nephrotic syndrome, cirrhosis, or hyperthyroidism are contributing to or worsening heart failure. Echocardiography helps measure ejection fraction, a key component in distinguishing between systolic heart failure and diastolic dysfunction. It is also used to estimate ventricular dysfunction, measure intracardiac pressures and wall motion, assess ventricular relaxation and compliance, and demonstrate abnormal chamber sizes, valve deformities, pericardial effusions, and ventricular thrombi. Multiple gated acquisition (MUGA) scans may be used as an alternative. Cardiac catheterization, recommended for patients with angina or large ischemic areas, can exclude coronary artery disease as a cause of HF. Cardiopulmonary exercise testing, employing computers and gas analyzers to determine maximal oxygen consumption, evaluates ventricular performance during exercise. Acceptable total oxygen uptake is 20 ml/kg/m or higher. A result of less than 12 indicates severe HF. Continuous ECG monitoring is provided during acute and advanced disease stages to identify and manage dysrhythmias promptly. The patient's blood pressure and pulse are assessed while the patient is supine, sitting, and standing to detect orthostasis, esp. during diuretic therapy. The legs are assessed for symmetrical pitting edema, a common finding. The patient is placed in high Fowler's position and on prescribed bedrest, and high concentration oxygen is administered as prescribed to ease the patient's breathing. Prescribed medications, such as carvedilol, candesartan, digoxin, furosemide, lisinopril, spironolactone, and potassium, are administered and evaluated for desired responses and any adverse reactions. All patient activities are organized to maximize rest periods. To prevent deep venous thrombosis due to vascular congestion, the caregiver assists with range-of-motion exercises and applies antiembolism stockings or uses heparins or warfarin. Any deterioration in the patient's condition is documented and reported immediately. To help curb fluid overload, the patient should avoid foods high in sodium content, such as canned and commercially prepared foods and dairy products, restricting dietary sodium to 2 to 3 grams a day and fluid intake to 2 liters a day. The importance of regular medical checkups is emphasized, and the patient is advised to notify the health care practitioner if the pulse rate is unusually irregular, falls below 60, or increases above 120, or if the patient experiences palpitations, dizziness, blurred vision, shortness of breath, persistent dry cough, increased fatigue, paroxysmal nocturnal dyspnea, swollen ankles, decreased urine output, or a weight gain of 3 to 5 lb (1.4 to 2.3 kg) in 1 week. Patients and their families and other care givers must understand the action of each of the medications prescribed, along with their possible adverse reactions and actions to be taken if a dose is missed. The importance of renewing prescriptions in a timely manner so that doses are available when needed should be stressed. Patient activity as tolerated is encouraged with tasks divided into small segments to avoid shortness of breath. Annual influenza vaccines and a pneumococcal vaccine (repeated every 5 years) help patients minimize the risk of systemic infections. Smokers are encouraged to quit. Frequent rehospitalizations are the rule rather than the exception in heart failure. Effective treatment may depend on a multidisciplinary approach that includes active participation by the patient, the primary care provider and nurse educator, case managers, pharmacists, dietitians, and social workers, among others. Evidence-based clinical pathways for managing heart failure are available from the American Heart Association and other agencies. high output heart failureintestinal failurekidney failureRenal failure.left ventricular heart failureliver failurelow output heart failuremetabolic failuremultiple systems organ failureMultiple organ dysfunction syndrome.multisystem organ failureMultiple organ dysfunction syndrome.organ failureovarian failurepump failurerenal failurerespiratory failureSee: acute respiratory failure; chronic respiratory failureright ventricular heart failurefailure to thriveAbbreviation: FTTSee AKF acute kidney failure
Synonyms for acute kidney failure
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