Acute renal failure after burns

Introduction to acute renal failure after burn Hypovolemic shock after burn is the main cause of acute renal failure. In shock, the blood pressure of the arterial artery decreases or the serum sodium decreases, stimulating the renal ball device, producing a large amount of nephrotoxicity, angiotensin II, and causing renal vasoconstriction. Kidney ischemia and hypoxia, glomerular premature rate decreased, oliguria or even no urine. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: uremia stress ulcer metabolic acidosis hyponatremia

Causes of acute renal failure after burns

1, shock

Hypovolemic shock after burn is the main cause of acute renal failure. In shock, the blood pressure of the arterial artery decreases or the serum sodium decreases, stimulating the renal ball device, producing a large amount of nephrotoxicity, angiotensin II, and causing renal vasoconstriction. Kidney ischemia and hypoxia, glomerular premature rate decreased, oliguria or even no urine.

2. Toxic substances

Severe deep burns and sepsis produce toxic substances, including free hemoglobin, myoglobin, and bacteriocin, which can aggravate kidney damage directly or in unit.

3, antibiotics

Aminoglycoside antibiotics, polymyxin B, and sulfonamides have a mildew response to the kidneys.

4, other reasons

Severe diarrhea, hot wind therapy and stress diabetes caused by dehydration were not corrected in time. Before the blood volume was filled in shock, large doses of vasoconstrictor or diuretic could be used to pre-exist renal insufficiency, elderly patients and patients with kidney disease before injury. Renal failure occurs.

Prevention of acute renal failure after burn

The mortality rate of acute renal failure after burn is high, and the focus of prevention is to prevent complications:

1. Attention to high-risk factors infection is the most common complication of this disease, should be strictly monitored and take measures to prevent infection.

2. Actively correct water, electrolyte and acid-base balance disorders, timely and correct anti-shock treatment, prevent effective blood volume deficiency, relieve renal vasoconstriction, can avoid renal ARF.

3. For severe soft tissue crush injury and mis-transfusion of heterotypic blood, in the treatment of the primary disease, use 250ml of sodium bicarbonate solution to alkalinize urine, and use mannitol to prevent hemoglobin, myoglobin block renal tubule or other nephrotoxin damage kidney Tubular epithelial cells.

4. Before performing surgery affecting renal blood flow, blood volume should be expanded, and mannitol or furosemide (furosemide) should be applied during and after surgery to protect renal function. The dosage of mannitol should not exceed 100g, furosemide 1 -3g/d can convert oliguric ARF into non-oliguric type, and dopamine 0.5~2ug/(kg·min) can dilate renal blood vessels to increase glomerular filtration rate and renal plasma flow.

5. Rehydration test can be applied when oliguria occurs, which can identify prerenal and renal ARF, and may prevent the development of prerenal ARF as renal ARF.

Complications of acute renal failure after burn Complications uremia stress ulcer metabolic acidosis hyponatremia

Complications of acute renal failure after burns are similar to acute renal failure, mainly in the following categories:

(1) Infection: It is one of the most common and serious complications, especially in this disease.

(2) cardiovascular system complications, including heart rhythm disorders, heart failure, pericarditis, hypertension, etc.

(3) neurological complications: manifested as headache, lethargy, muscle twitching, coma, epilepsy, etc., neurological complications and toxins in the body retention and water toxicity, electrolyte imbalance and acid-base balance disorders.

(4) digestive system complications: manifested as anorexia, nausea, vomiting, abdominal distension, hematemesis or blood in the stool, etc., bleeding is mostly caused by gastrointestinal mucosal erosion or stress ulcers.

(5) Hematological complications: due to a sharp decline in renal function, erythropoietin can be reduced, resulting in anemia, but most are not serious, a small number of cases may have bleeding tendency due to decreased clotting factors.

(6) Electrolyte disorders, metabolic acidosis, hyperkalemia, hyponatremia and severe acidosis are one of the most dangerous complications of acute renal failure.

In the polyuria period, the daily urine volume of the patient can reach 3000-5000ml. Dehydration, hypokalemia, hyponatremia, etc. may occur due to the discharge of a large amount of water and electrolytes. If not replenished in time, the patient may die from severe dehydration. And electrolyte imbalance.

Entering the recovery period of serum urea nitrogen, creatinine level returned to normal, uremia symptoms subsided, renal tubular epithelial cells were regenerated and repaired, most patients with renal function can be fully restored, a small number of patients may leave varying degrees of renal dysfunction.

Symptoms of acute renal failure after burns Common symptoms Indifferent expressions Limb numbness, oliguria, polyuria, no urine, nausea, coma, fatigue, convulsions, dehydration

1, oliguria

After supplementing blood volume and water, there is still less urine, and oliguria should identify pre-renal and post-renal.

2, low urine weight

Fixed at 1.010 ~ 1.018, urinary sediment has a granular type, epithelial cell debris, red blood cells and white blood cells.

3, azotemia

Urine urea nitrogen / blood urea nitrogen <14:1, urine creatinine / serum creatinine <10:1, blood urea nitrogen / serum creatinine <10:1

4. Determination of free water removal rate

The normal value of free water clearance is negative, the closer to zero, the more serious the damage to renal function, the free water clearance rate is more sensitive than blood chemistry (BUN, Cr), which is helpful for early diagnosis.

5, filtered sodium excretion fraction FENa

When renal insufficiency is a functional change, the renal tubules can reabsorb sodium ions in a large amount, and FENa is reduced. When the renal tubules are qualitatively changed, the reabsorption capacity of sodium ions is significantly decreased, and FENa is increased, so that FENa can be used. Predict the ability of the renal tubule to inhale sodium. Note: UNa sodium (mmol); Pna sodium (mmol); Cr creatinine clearance; PCr serum creatinine (mg / dl); V urine volume (L); GFR glomerular filtration rate; UCr urine creatinine (mg /dl); FENa normal value 1 to 3.

FENa<1 indicates that renal insufficiency is pre-renal or functional, FENa>3 suggests acute tubular damage, and renal insufficiency is renal or organic.

Examination of acute renal failure after burns

For patients with moderate to severe burns, the following checks should be performed as appropriate:

First, urine check urine, urine volume 17ml / h or <400ml / d, urine specific gravity is low, <1.014 or even fixed at 1.010 or so, urine is acidic, urine protein qualitative + ~ + + +, urine sediment microscopic examination visible Large particle tube type, a few red, white blood cells.

Second, azotemia, blood urea nitrogen and creatinine increased, but azotemia can not be used as a basis for diagnosis, due to normal renal function, patients with gastrointestinal hemorrhage can also increase urea nitrogen, increased serum creatinine, blood urea nitrogen / blood Creatinine 10 is an important diagnostic indicator, in addition, urine / blood urea <15 (normal urine urea 200-600mmol / 24h, urine / blood urea > 20), urine / serum creatinine 10 also has diagnostic significance.

Third, the blood examination of red blood cells and hemoglobin decreased, leukocytosis, thrombocytopenia, blood potassium, magnesium, phosphorus increased, normal or slightly reduced blood sodium, blood calcium decreased, carbon dioxide binding capacity also decreased.

Fourth, urinary sodium quantitative> 30mmol / L.

Determination of filtered sodium excretion fraction (FENa), the method has a certain significance for the cause, the value of > 1 for acute tubular necrosis, non-oliguric acute tubular necrosis and urinary tract obstruction, the value of <1, for the kidney Probiotic azotemia and acute glomerulonephritis.

V. Determination of pure water clearance rate This method is helpful for early diagnosis.

Pure water clearance = urine volume (1 hour) (1-urine osmotic pressure / blood osmotic pressure)

Its normal value is -30, the greater the negative value, the superior renal function; the closer to 0, the more severe the renal function.

-25 to -30 indicates that renal function has begun to change.

-25-15 indicates mild and moderate renal damage.

-15 to 0 indicate severe damage to kidney function.

Diagnosis and diagnosis of acute renal failure after burn

diagnosis

According to the history and clinical manifestations, it can be diagnosed.

Differential diagnosis

1, renal and renal X-ray abdominal plain film, B-mode ultrasound, kidney map can check for congenital malformation or obstruction. Patients with suspected renal parenchymal disease may have a renal biopsy if necessary.

2, non-oliguric acute renal failure about 10% to 30% of children with non-oliguric acute renal failure, the cause is mostly aminoglycoside poisoning, after trauma or burn, blood biochemical changes should be regularly monitored.

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