How is acute renal failure treated?

Therapeutic measures in oliguria should begin with the introduction of a catheter to detect obstruction of the lower urinary tract, reflux diagnosis, collection of urine for analysis and monitoring of urine. In the absence of intrarenal obstruction and congenital heart disease as the cause of oliguria, it is necessary to suspect prerenal acute renal failure and begin the introduction of fluid.

[1], [2], [3], [4], [5], [6]

Sample with a water load

If suspected of prerenal acute renal failure in children, treatment should begin as soon as possible without waiting for the results of laboratory tests. To restore bcc, the infusion load is recommended with isotonic sodium chloride solution or 5% glucose solution in a volume of 20 ml / kg for 2 hours. The liquid load serves both as a diagnostic and therapeutic procedure. When hypovolemia is the only cause of the observed oligoanuria, the diuresis normalizes, usually within a few hours. In the absence of diuresis and the preservation of hypovolemia [central venous pressure (CVP) of less than 10-20 cm of water, arterial hypotension, tachycardia], infusion therapy should be continued using FFP or a starch solution in a volume of 20 ml / kg for 2 hours. Diuresis indicates a prerenal oliguria. The absence of diuresis when reaching normovolemia (within 18-24 h) indicates an organic acute renal failure. Carrying out infusion therapy without proper control and in an inadequate volume against the background of organic Oostri of kidney failure can lead to overload with body fluids (pulmonary edema, brain, arterial hypertension, heart failure).

A timely correction of prerenal disorders in acute conditions and adequate surgical tactics for postrenal causes, maintenance of normal homeostasis parameters for the completion of reparative processes in the kidney are necessary.

Later, the patient's admission to the hospital (with the preservation of oliguria and azotemia more than 24-48 hours) with a greater degree of probability indicates a current in the child, especially the elderly, renal acute renal failure.

Renal Replacement Therapy

The basis of treatment of patients with organic acute renal failure is renal replacement therapy, including intermittent hemodialysis, hemofiltration, hemodiafiltration, continuous low-flow extracorporeal techniques and peritoneal dialysis. The most important factors affecting the choice of the type of dialysis are indications for dialysis and the general condition of the patient.

Absolute indications for the beginning of dialysis treatment are organic (renal) renal failure, the clinical sign of which is anuria.

Indications for emergency dialysis

• Anuria is more than 1 day.
• Oliguria, complicated:
  • hyperhydration with pulmonary edema and / or respiratory insufficiency, uncontrolled arterial hypertension;
  • disorders of the central nervous system;
  • heart failure;
  • hyperkalemia more than 7.5 mmol / l;
  • decompensated metabolic acidosis (BE <12 mmol / l);
  • increase in creatinine more than 120 μmol / day.
• The need for adequate nutrition with a long oliguria.

Dialysis is necessary when conservative treatment is not able to provide correction for these disorders.

Therefore, the decision to start dialysis depends not so much on criteria such as urea or plasma creatinine, but primarily relies on the general condition of patients, taking into account the clinical course of acute renal failure. These symptoms not only indicate the need for renal replacement therapy, but more serve as a signal to stop intensive infusion therapy and stimulation of diuresis, as its continuation can be life threatening.

Basic principles of treatment and prevention of acute renal failure

• Identification of children with an increased risk of developing acute kidney failure and providing them with adequate fluid intake, cardiovascular and respiratory support, creating an optimal microclimate around the child (temperature comfort and oxygenation).
• Elimination of the causes of reduced renal perfusion - normalization of bcc, hemodynamics, and with congestive heart failure - the conduct of ultrafiltration.
• In the case of a positive sample with a liquid load (i.e., with an increase in diuresis), the continuation of measures to compensate for a deficient fluid while reducing the infusion rate under the control of CVP.
• When treating premature infants, it is necessary to consider that they have hemodynamic "interests" of the kidneys and the brain are opposite. Medical measures aimed at improving renal perfusion ( dopamine administration, rapid increase of bcc, transfusion of colloidal solutions), can lead to rupture of vessels in the area of the hermetic matrix and hemorrhage in the cavity of the ventricles of the brain.
• The absence of diuresis increase after a fluid load in a newborn with normal cardiac output and, consequently, normal kidney perfusion indicates the presence of parenchymal damage to the kidneys, therefore, hemodialysis is necessary.
• Maintaining a fluid balance is the basis for the treatment of a patient in the pre-dialysis period and when it is impossible to conduct it. The weight of the patient should be reduced by 0.5-1% per day (the result of caloric loss, not inadequate infusion therapy).
• When assessing the needs of a child in a fluid, it is necessary to take into account physiological losses, metabolic needs and the preceding liquid balance. Infusion therapy is strictly controlled to achieve normovolemia, the criteria of which are normalization of CVP, arterial pressure, heart rate, elimination of dryness of the skin and mucous membranes, normalization of tissue turgor and restoration of diuresis. In the future, the flow of fluid in the sum should be equal to the unaccounted plus the measured losses (with urine, stool, drainage, etc.). Unrecorded losses are normally 1/3 of the estimated fluid demand, they can be determined based on energy needs, for example, 30-35 ml per 100 calories per day. However, patients who receive moisturized air through the intubation tube or steam inhalations have a reduced need for unaccounted losses. If the patient has a high temperature or is located under a heater or in a cuvette, the unaccounted losses will be much greater than the calculated ones.
• When the condition is severe, these factors change rapidly for newborns, which requires a dynamic approach to infusion therapy. After the introduction of the baseline volume of fluid for 4-8 hours, depending on the nature of the pathology, the effectiveness of treatment is evaluated based on urine output, urine concentration and biochemical parameters of urine and blood, assess the fluid balance and response to the treatment, then calculate the liquid load for the following 4- 8 hours. With the proper administration of the volume of the injected liquid, the plasma sodium level should remain stable (130-145 mmol / l). Rapid weight loss, increased sodium plasma indicate inadequate infusion therapy. Adding weight in combination with a decrease in the level of sodium plasma indicates an increase in hyperhydration.
• Correction of deficiency of volume in anuria must be carried out very carefully and those components whose deficiency is most pronounced (erythrocyte mass with severe anemia - hemoglobin <70 g / l, SZP with DIC syndrome, etc.).
• In connection with hyperkaliemia often observed in acute renal failure, it must be remembered that the level of potassium in the plasma does not serve as an accurate criterion for the content of potassium in the body, the interpretation of this indicator is possible only taking into account the CBS of the patient. Thus, the plasma potassium concentration of 7.5 mmol / L is less dangerous in metabolic acidosis (for example, at a pH of 7.15 and a bicarbonate level of 8 mmol / L) than with alkalosis (for example, at pH 7.4 and a bicarbonate level of 25 mmol / l).
• In acute renal failure may develop hyponatremia and metabolic acidosis. A decrease in the amount of serum sodium below 130 mmol / l is usually the result of excessive sodium loss or increased hyperhydration, so the introduction of concentrated sodium solutions is not indicated because of the possibility of increasing intravascular volume, the development of hypertension and congestive heart failure. Metabolic acidosis is an inevitable consequence of impaired renal function due to delay in hydrogen ions, sulfates, phosphates. Usually respiratory mechanisms can compensate for an easy degree of acidosis. If the ability to respiratory compensation is impaired, a special treatment for respiratory failure is necessary.
• Heart failure in acute renal failure develops due to overload or toxic myocarditis and causes a significant decrease in cardiac output, so inotropic support is required during dialysis and in the interdialysis period (dopamine, dobutamine, adrenaline hydrochloride). The traditional appointment of diuretics can not be used to treat heart failure, even with hyperhydration and hypervolemia due to anuria. Cardiac glycosides can be prescribed taking into account the severity of impaired renal function, but their effectiveness is usually small.
• Arterial hypertension often occurs with acute renal failure, especially against the background of acute glomerulonephritis and hemolytic-uremic syndrome. The main drugs for the treatment of hypertension are ACE inhibitors and peripheral vasodilators (hydralazine). If necessary, blockers of slow calcium channels are added to them, and if the diastolic blood pressure (> 100 mm Hg) is primarily increased, it is rational to add beta or a-adrenergic blockers. Usually a combination of these drugs can achieve a reduction in blood pressure in the absence of edema. Impossibility of achieving the effect is an indication for conducting ultrafiltration.

• The development of respiratory failure in children with encephalopathy of mixed genesis (moderate and severe form) with concomitant hydrocephalic-hypertensive and convulsive syndromes indicates the need for mechanical ventilation.
• Hyperhydration in children with acute renal failure often leads to interstitial edema of the lungs - "rigid lung", ventilation is necessary.
• In children with hemolytic-uremic syndrome, microthrombosis of small branches of the pulmonary artery can lead to imbalance of ventilation and perfusion, which requires ventilation.
• Nutrition of children with acute kidney failure is an extremely important problem due to the prevalence of catabolism. An adequate intake of calories is needed to enhance energy metabolism. At the same time, the restriction of fluid intake in patients with severe oliguria reduces the intake of calories and nutrients. Intravenous administration of essential amino acids (aminostearyl, aminovene, neframine) and glucose results in a positive nitrogen balance, improved repair, weight maintenance, decreased urea levels, and alleviation of uremic symptoms in patients with acute renal insufficiency.
• The pharmacokinetics of all drugs that are eliminated with urine varies significantly in the anuric stage of acute renal failure, which determines the need for dose changes and multiplicity of drug administration. When dialysis treatment is also necessary to adjust the dose of those drugs that are able to penetrate through the dialyzer membrane.
• Antibacterial treatment for acute renal failure is used with caution, taking into account the nephrotoxicity of most antibiotics. In the case of development of acute renal failure against the background of septic conditions or bacterial infection, the dose of antibiotics is selected taking into account the clearance of endogenous creatinine, depending on the group membership of the antibacterial drug. These recommendations can only be indicative and the doses should be selected individually, since elimination during hemodialysis or hemofiltration is not well understood for all drugs, and in most cases differences in dialysis technique are not taken into account. Preventive prescription of antibiotics is acceptable at the beginning of peritoneal dialysis on the background of the course of intestinal infection.

[7], [8]

Evaluation of the effectiveness of treatment of arthritis in children

The effective treatment of acute renal failure is indicated by restoration of diuresis, normalization of the levels of nitrogen metabolism products, electrolytes in blood and CBS, absence or elimination of complications, improvement of the general condition of patients.

[9], [10], [11], [12], [13], [14], [15],

The most common mistakes and unreasonable appointments

• The appointment of furosemide against the background of an unconfined BCC.
• Persistent increase in furosemide dose in the absence of effect.
• Appointment of mannitol.
• Intensive and uncontrolled infusion therapy against oligoanuria.
• Continuation of conservative treatment in the presence of indications for dialysis.
• The use of ganglion blockers (azamethonium bromide (pentamine)) with an antihypertensive purpose.

Prognosis for acute renal failure in children

The outcome of acute renal failure depends on many factors. Very important is the nature of the underlying disease. Mortality in acute renal failure is higher in children who have undergone heart surgery, with sepsis, multiple organ failure, and with late onset of treatment (up to 50%).

High mortality in newborns with congenital heart failure or with abnormal development of the urinary system, low - in children with reversible conditions, such as hypoxia or shock. Among surviving newborns with acute renal failure, more than 40% have decreased GFR and tubular dysfunction. With urological abnormalities, the frequency of residual renal dysfunction increases to 80%.

The work of morphologists showed that after acute renal failure complete structural restoration of the kidney does not occur and there are always warts of sclerotic changes. The prognosis for neo-ligular acute renal failure is usually better than in acute renal failure with oliguria: complete restoration of kidney function occurs in more than half of patients, the rest - the development of interstitial nephritis. Neoliguric acute renal failure, apparently, reflects moderate damage to the kidneys. Timely treatment with dialysis significantly improves prognosis and reduces mortality.