Acute left ventricular failure in children

In children, acute left ventricular failure is most often diagnosed after anatomical correction of simple transposition of the main arteries (by the method of arterial switching), and after total anomalous drainage of the pulmonary veins. Development of left ventricular failure is associated with relative LV hypoplasia or coronary blood flow disorders in the early postoperative period. In the early postoperative period in such patients, a moderately underdeveloped LV is unable to fully provide blood flow over a large range of blood circulation. This leads to the formation of pulmonary hypervolemia (and later - to pulmonary edema), as well as to the onset of systemic hypoperfusion.

Criteria for low cardiac output:

• Peripheral spasm with symptom of capillary filling more than 4 s.
• Tachycardia, as a rule, is not sinus (more than 180 per minute), with a normal plasma concentration of potassium.
• Heart rhythm disturbances.
• Decrease in the rate of diuresis is less than 1 mlDkgxh).
• Extremely low average blood pressure (less than 40 mm Hg).
• Low pulse pressure (less than 20 mm Hg).
• Increase the filling pressure of the left and right atriums to a level exceeding 12-14 mm Hg.
• Metabolic acidosis.
• Venous hypoxemia (Py02 less than 28 mm Hg, Bu02 less than 40%), serum lactate concentration exceeds 4 mmol / l.
• Hypotension is a later manifestation of low CB in infants. The earliest signs are low pulse pressure (less than 20 mm Hg), a decrease in diuresis to 1 mlDkgxh) (and less), tachycardia more than 180 per minute, and an increase in pressure in the left atrium to 12 mm ppm (or more).

[1], [2], [3], [4], [5], [6], [7]

Drug treatment of acute left ventricular failure

[8], [9], [10], [11], [12], [13],

Sedation

To achieve a sedative effect, children are prescribed fentanyl infusions [3-10 μg / (kghh)], and for the purpose of myoplegia, pipecuronium or pancuronium is administered in age doses.

Infusion therapy

The volume of fluid administered during the first and second days after the operation is limited to 2 ml / (kghh). From the third day, the volume of fluid is increased to 3 ml / (kghh). Given the fluid retention during the time of artificial circulation, by the time of sternum and extubation, it is necessary to achieve a negative water balance, provided adequate preload (CVP and pressure in the left atrium - 5-8 mm Hg, satisfactory peripheral blood flow).

Diuretic therapy

To maintain a sufficient rate of diuresis [not less than 1 ml / (kghh)], furosemide in a dose of 1-4 mg / (ghsut) is administered bolus from the first day after the operation. Development of signs of fluid retention on this background (positive water balance for three hours or more, increased pressure in the left atrium and CVP more than 12 mm Hg, an increase in peripheral edema, an increase in liver size) is an indication to the maximum limitation of the volume of the injected fluid and the performance of infusions furosemide in a dose of 5-25 mg / (kilogram). When plasma osmolality is more than 310 mmol / l, it is recommended to administer mannitol in a single dose of 0.5 g / kg (up to a daily dose of 1 g / kg).

[14], [15]

Hemodynamic support

If LV is insufficient, a decrease in post-loading of the ventricles with maintenance of the minimum sufficient for adequate coronary blood flow and diuresis of the average BP is the basis of hemodynamic support.

The systolic blood pressure level is 50 mm minimum for adequate coronary and peripheral perfusion of the newborn. Gt; The safety level is 60 mm. Gt; the safe level of the average blood pressure is 40-45 mm. Gt; Art. Pressure in the left atrium should be maintained at 10-12 mm. Gt; Art. (but not higher). Further increase does not lead to an increase in CB and indicates a decompensation of LV deficiency. It is extremely important to exclude systemic hypertension (the level of systolic blood pressure in a patient in the state of sedation and analgesia is no more than 80 mm Hg).

Dopamine [at a dose of 2-10 μg / (kghmin)] in combination with dobutamine [2-10 μg / (kghmin)] - starting cardiotonic drugs used in acute left ventricular heart failure. All patients are recommended to administer nitroglycerin infusion at a dose of 0.5-3 μg / (kg-min) (vasodilator).

Preservation or appearance of clinical signs of a decrease in CB with a high OPSS against the background of infusion of two catecholamines [at a rate of administration of each drug more than 10 μg / (kghmin)], with an optimal heart rate and adequate preload indicates an increase in acute left ventricular heart failure. This condition is considered an indication for the onset of infusion of inodilators - inhibitors of phosphodiesterase type III or levosimendan.

The introduction of enoximone (perfane) begins with a dose of saturation of 1-2 mg / kg for 10 min followed by infusion of 3-15 μg / (kg-min).

For milrinone (primakor), the saturation dose varies from 25 to 75 μg / (kg-min), the maintenance dose does not exceed 0.25-0.8 μg / (kg-min) [up to 1.0 μg / (kg-min)].

If the clinical symptoms of low CB are preserved for 5-6 h against infusion of phosphodiesterase III inhibitors, and if it is needed for two days (or more), this preparation is replaced with levosimendan.

In view of the absence of phosphodiesterase III inhibitors in Russia, levosimendan (simdax) is considered the drug of choice in the treatment of acute left ventricular failure in children, but experience with the use of drugs in this category of patients is limited. The administration of levosimendan is started with a saturation dose of 12-24 μg / kg for 10 min followed by infusion of 0.1-0.24 μg / (kg-min). The maximum effect is noted 6 hours after the initial application of the drug. In the case of a good saturation dose effect and an insufficient maintenance dose effect, a repeated dose of saturation is possible. The duration of infusion of levosimendan is 24-48 hours. The active metabolite of OL-1896 possesses the same properties as levosimendan, ensuring the preservation of the hemodynamic effects of the drug for at least 1-2 weeks after the end of its use.

The only indication for the appointment of adrenomimetics [adrenaline or norepinephrine at a dose of 0.03-0.2 μg / (kghmins)] in acute left ventricular congestive heart failure is the need to increase OPSS to increase blood pressure with adequate CB, including intravenous phosphodiesterase III inhibitors or levosimendana.

All patients immediately after the operation begin to digitize (30-40 μg / kg digitalis for six administrations for two days). Patients with a clinic of low CB on a background of normal potassium concentration in blood plasma can perform rapid digitalization (the first 3 doses are administered within 3-6 hours).

All patients with low CB are prescribed creatine phosphate (neoton) at a dose of 1-2 g / day. After prolonged (more than 180 min) artificial circulation at low SV, and also with bleeding, it is necessary to make infusion of aprotinin (trasilol) at a dose of 10 000 U / kgkg, and also to introduce inhibitors of the proton pump (for example, lobe 1 mg / kg 2 times a day) for 1-3 days.

To reduce the symptoms of CVD and prevent distant restenosis in the area of vascular anastomoses, glucocorticoids (2-4 mg / kg prednisone per day) are prescribed 1-3 days after the operation. To restore or increase the sensitivity of adrenoreceptors to catecholamines use thyroxin at a dose of 5 μg / (kghsut) (for three days).

Non-pharmacological treatment of acute left ventricular failure

Renal replacement therapy

The indication for PD is a decrease in the rate of diuresis [less than 1 ml / (kghh) for 6 hours or less 0.5 ml / (kghh) for 3 hours], persistence of fluid retention characteristics (despite the dehydration therapy described above for the previous 24 h) and hyperkalemia (more than 5 mmol / l). Dialysis is performed when one of the indications or their combinations is detected.

Respiratory support

The ventilation is performed in the normal ventilation (pH 7.4-7.45, paCO2 - 30-45 mm Hg), eliminate hyperoxia (SaO2 - 95-98%, p02 less than 100 mm Hg) and Hyperinflation (DO - 5-9 ml / kg), PEEP is 3-4 mBar. With the progression of signs of acute left ventricular heart failure, it is recommended to increase PEEP to 6-8 mBar.