Treatment of shock

Treatment of shock conditions in children aims to restore the delivery of oxygen to tissues and to optimize the balance between tissue perfusion and metabolic needs of tissues. To do this, it is necessary to improve blood oxygenation, increase cardiac output and its distribution, reduce tissue oxygen consumption and correct metabolic disorders. The program of intensive treatment of a patient in shock includes the following medical actions:

• replenishment of the BCC deficit and ensuring optimal pre- and post-loading;
• maintenance of contractile function of the myocardium;
• respiratory support;
• analgosediation;
• use of steroid hormones;
• antibiotic therapy;
• prevention of reperfusion injury;
• correction of violations of hemostasis (hypo- and hyperglycemia, hypocalcemia, hyperkalemia and metabolic acidosis).

Replenishment of the BCC deficit and ensuring the optimal level of preload and afterload should always be done. Absolute or relative deficiency of BCC is eliminated by infusion therapy under the control of CVP and hourly diuresis, which should normally be at least 1 ml / kgh). CVP should be 10-15 mm Hg, with preload adequate, and hypovolemia does not cause a circulatory insufficiency. Restriction of the intensity of infusion therapy and the need for inotropic drugs can be caused by the appearance of such symptoms as an increase in liver size, the appearance of a wet cough, growing tachypnea and wet wheezing in the lungs. Reduction of preload below the norm almost always leads to a decrease in cardiac output and the appearance of signs of circulatory insufficiency. Despite the fact that the neuroendocrine reactions of the child to bleeding correspond to the adult organism, the degree of hypotension and reduction in cardiac output accompanying moderate (15% of blood volume) blood loss, the child is relatively larger, so an important role is played by compensation for even moderate blood loss. The volumes of the infusion means and their interconnection largely depend on the stage of medical care and the stage of shock. Replenishment of bcc leads to an increase in venous return with a subsequent increase in blood pressure, cardiac output, which in turn increases the perfusion and oxygenation of tissues. The volume and rate of infusion depends on the estimated magnitude of hypovolemia. Infusion therapy is recommended to begin with the use of bolus injection of saline. The first bolus - 20 ml / kg - is administered for 5-10 minutes, followed by a clinical evaluation of its hemodynamic effect. With hypovolemic, distributive and obstructive shock for the first hour, the volume of infusion can be up to 60 ml / kg, and with septic shock even up to 200 ml / kg. With cardiogenic shock and poisoning (beta-blockers and calcium channel blockers), the volume of the first bolus should not be more than 5-10 ml / kg, administered in 10-20 minutes.

After the administration of isotonic crystalloids in a dose of 20-60 ml / kg and if necessary, colloidal solutions may be used, especially in children with decreased oncotic pressure (with dystrophy, hypoproteinemia).

In case of hemorrhagic shock, erythrocytes (10 ml / kg) or whole blood (20 ml / kg) are used to compensate for blood loss. Hemotransfusion increases the concentration of hemoglobin, which leads to a decrease in tachycardia and tachypnea.

On the positive dynamics of the infusion therapy says a decrease in heart rate, an increase in blood pressure and a decrease in the shock index (heart rate / blood pressure).

Preservation of arterial hypotension with every hour increases the lethality by half.

If at this speed by the end of the first hour no effect is obtained, then it is necessary to continue the infusion and simultaneously prescribe dopamine. Sometimes it is necessary to resort to jet injections of solutions, which are considered to be a speed above 5 ml Dkgmmin). It should also be taken into account that a simple compensation of the BCC deficit can be difficult on the background of a widespread vascular spasm, due to the influence of pathological afferent impulses, including the pain factor. In connection with this, a neurovegetative blockade with a 0.25% solution of droperidol at a dose of 0.05-0.1 ml / kg was shown. Normalization of microcirculation can also be achieved by the administration of antiaggregants, such as dipyridamole (quarantil) 2-3 mg / kg, pentoxifylline (trental) 2-5 mg / kg, heparin 300 U / kg.

Decreased afterload is important for improving myocardial function in children. In the stage of decentralization of blood circulation in shock, high systemic vascular resistance, poor peripheral perfusion and reduced cardiac output can be compensated by decreasing afterload. Such a combination of influence on afterload with inotropic effect can provide optimal working conditions for damaged myocardium. Sodium nitroprusside, nitroglycerin causes vasodilation, reduce afterload, generates nitric oxide - a factor that relaxes the endothelium, reduces ventilation-perfusion disorders. The dose of nitroprusside sodium for children is 0.5-10 μg / kghmin), nitroglycerin - 1-20 μg / kghmin).

The pulmonary vascular bed plays a pathogenetically important role in patients with hemodynamic disorder in shock combined with high pulmonary hypertension against a background of certain congenital heart defects, respiratory distress syndrome, sepsis. Careful monitoring and maintenance of BCC are necessary when using vasodilators to reduce pulmonary vascular resistance. Drugs that block calcium channels, such as nifedipin and diltiazem, can reduce pulmonary vascular resistance, but at present the experience of their use for children is negligible.

One of the most important problems in the treatment of shock conditions is the maintenance of the contractile function of the myocardium. The cardiac index should be at least 2 l / min ² ) in case of cardiogenic and 3.3 to 6 l / min ² ) with septic shock. At present, for this purpose, various means are widely used that affect the inotropic function of the heart. The most rational of these drugs is dopamine, which stimulates a-, B- and dopaminergic sympathetic receptors and has a variety of effects. In small doses -0.5-2 μg / kg hmin) - it primarily causes expansion of the kidney vessels, supporting renal perfusion, reduces arteriovenous shunting in tissues. Increasing peripheral blood flow, improving coronary and mesenteric circulation. Effects of small doses persist even when exposed to a small circle of blood circulation, which contributes to the elimination of pulmonary hypertension. In medium doses - 3-5 μg / kghmin) - its inotropic effect is manifested with an increase in stroke volume and cardiac output, and the contractile ability of the myocardium increases. In such a dose, dopamine slightly changes the heart rate, reduces the venous return of blood to the heart, that is, reduces preload. Dopamine, having vasoconstrictive activity, reduces peripheral and renal perfusion, increasing afterload on the myocardium. The prevalence of systolic and diastolic blood pressure increases. The degree of manifestation of these effects is individual, so careful monitoring is needed to assess the patient's response to dopamine. As an inotropic vasodilator, dobutamine, used at a dose of 1-20 μg / kg hmin, is also used). Since dobutamine is a beta1-adrenergic antagonist with a positive inotropic and chronotropic effect. It expands the peripheral vessels in the systemic and pulmonary circulation, weakens spasm of pulmonary vessels in response to hypoxia. In doses greater than 10 μg / kg hmin), especially in children under 2 years of age, dobutamine can cause hypotension due to a significant decrease in post-loading caused by a _2- mediated blockade of norepinephrine release from presynas. Dobutamine does not possess the properties of a selective stimulator of renal perfusion, and now it is considered the drug most appropriate to the concept of a "purely inotropic drug".

Epinephrine (adrenaline) at a dose of 0.05-0.3 μg Dkgmmin) stimulates alpha and beta ₁ -, B ₂ -adrenoceptors, causing a generalized sympathetic response: this increases the cardiac output, blood pressure, increases oxygen consumption, increases pulmonary vascular resistance and there is kidney ischemia.

Epinephrine increases myocardial contractility and causes a contraction of the stopped heart. But its use for extreme cases limits a host of adverse actions, such as anaphylactic shock and cardiopulmonary resuscitation. Large doses of epinephrine can slow blood circulation in the heart or even worsen blood flow to the myocardium. Parasympathomimetics (atropine) in the treatment of shock in children are usually useless, although they increase sensitivity to endogenous and exogenous catecholamines, especially when restoring cardiac activity through the slow rhythm phase. Currently, atropine is used to reduce bronchorrhea with the administration of ketamine. The use of active calcium preparations (calcium chloride, calcium gluconate) to stimulate cardiac activity, which has been used traditionally in resuscitation practice, is currently questionable. Only with hypocalcemia calcium preparations give a distinct inotropic effect. With normocalcemia, intravenous bolus administration of calcium causes only an increase in peripheral resistance, contributes to the intensification of neurological disorders in the background of cerebral ischemia.

Cardiac glycosides, such as digoxin. Strophantine, lily of the valley glycoside (korglikon), are able to improve blood circulation in shock due to a positive effect on cardiac output and chronotropic effect. However, in the development of acute heart failure and arrhythmia in shock, cardiac glycosides should not be first-line drugs due to their ability to increase myocardial oxygen demand, causing tissue hypoxia and acidosis, which dramatically reduces their therapeutic efficacy and increases the likelihood of intoxication. Cardiac glycosides can be prescribed only after the initial therapy of shock and restoration of homeostasis. In these cases, faster digitalization is used. At which half of the dose of the drug is administered intravenously and half - intramuscularly.

Correction of metabolic acidosis allows improving the function of the myocardium and other cells, reducing systemic and pulmonary vascular resistance, reducing the need for respiratory compensation of metabolic acidosis. It should be remembered that metabolic acidosis is only a symptom of the disease, and therefore all efforts should be aimed at eliminating the etiologic factor, normalizing hemodynamics, improving renal blood flow, eliminating hypoproteinemia, improving tissue oxidation processes by introducing glucose, insulin, thiamine, pyridoxine, ascorbic, pantothenic and pangamic acids. The acidosis that persists in the background of shock treatment with signs of insufficient tissue perfusion may indicate inadequate therapy or continued bleeding (with hemorrhagic shock). Purposeful correction of CBS by administration of buffer solutions should be carried out only after elimination of hypovolemia and hypoglycemia in the presence of decompensated acidosis at pH less than 7.25 and in the case of metabolic acidosis with a low anion interval associated with large renal and gastrointestinal bicarbonate losses. In case of shock, correction of acidosis with sodium hydrogen carbonate should be carried out cautiously, since the transfer of acidosis to alkalosis worsens the oxygen transport properties of blood due to the shift of the oxyhemoglobin dissociation curve to the left and promotes the accumulation of sodium in the body, especially with reduced renal perfusion. There is a danger of developing hyperosmolar syndrome, which can cause intracranial hemorrhages, especially in newborns and premature babies. In children of the first months of life, the sodium load is not compensated by the increase in natriuresis, the delay in sodium leads to the development of edema, including edema of the brain. Sodium bicarbonate is administered slowly intravenously, at a dose of 1 -2 mmol / kg. In newborns, a solution at a concentration of 0.5 mmol / ml is used to avoid an acute change in the osmolarity of the blood. Often the patient needs 10-20 mmol / kg in order to correct deep acidosis. The appointment of sodium bicarbonate is acceptable with mixed respiratory and metabolic acidosis in the background of mechanical ventilation. Correction of metabolic acidosis also shows the use of trometamol (trisamine), which is an effective buffer, eliminating extra- and intracellular acidosis. It is used in a dose of 10 mlDkgxh) with the addition of sodium chloride and potassium chloride and glucose, as trometamol increases the excretion of sodium and potassium from the body. The newborn is injected with trometamol supplemented with only glucose. Trometamol is not indicated in central respiratory distress and anuria.

Over the years, steroid hormone therapy has been widely used in the treatment of shock. The most commonly used drugs are hydrocortisone, prednisolone and dexamethasone. The basis of the theory of treatment of HA is a variety of effects, including the property of these drugs to increase cardiac output. They have a stabilizing effect on the activity of lysosomal enzymes, antiaggregational effect on platelets, a positive effect on the transport of oxygen. Antihypertensive action together with membrane stabilizing and anti-edema effects, as well as the effect on the microcirculation and inhibition of the release of lysosomal enzymes form the basis of their anti-shock action and the ability to prevent the development of multiple organ failure. Determining the indications for the use of glucocorticoids, it is necessary to evaluate the etiology of shock. So anaphylactic shock serves as an absolute indication for glucocorticoid therapy after the administration of epinephrine and antihistamines. With hemorrhagic and septic shock, glucocorticoids are used against a background of specific therapy. Substitution therapy or stress-doses of corticosteroids in these types of shock will be necessary. With adrenal insufficiency, physiological [12.5 mg / kgsut] are used or stress doses of 150-100 mg / (kilogram) | hydrocortisone. Relative contraindications in shock states are minimal, since the readings are always vital. The dependence of the success of steroid therapy on the time of its onset is obvious: the earlier treatment with steroid hormones is started, the less symptoms of polyorganic insufficiency are. However, along with the positive effects of steroid therapy, in septic shock, negative aspects of their action are also being noted. It is noted that massive steroid therapy contributes to the development of extravascular infectious factor, as the inhibition of polymorphonuclear cells slows their migration into the extracellular space. It is also known that steroid therapy contributes to the occurrence of gastrointestinal bleeding and reduces the tolerance of the patient's body in a shocked state to a glucose load.

Immunotherapeutic approaches to the treatment of septic shock are constantly progressing. For the purpose of detoxification, a polyclonal FFP with a high titer of antiendotoxic antibodies is used, immunoglobulin preparations are normal human immunoglobulin (pentaglobin, intraglobin, immunovinin, octagam). Pentaglobin is administered intravenously to newborns and infants at a dose of 1.7 ml / (kghch) using a perfusor. Children older than 0.4 ml / kgh) continuously until a dose of 15 ml / kg for 72 hours.

A recombinant analog of human interleukin-2 (rIL-2), in particular a yeast recombinant analogue - a domestic drug, Roncoleukin has proved to be an effective immunotherapy for severe purulent-septic pathology. In children, Roncoleukin is drip intravenously. Schemes of use of Roncoleicin in children and adults are the same. The drug is diluted in isotonic sodium chloride solution for injection. A single dose of the drug in children depends on the age: from 0.1 mg for newborns to 0.5 mg in children older than 14 years.

Such targeted immunocorrection allows to achieve the optimal level of immune defense.

Shock conditions in children are accompanied by oppression of the reticuloendothelial system, so antibiotics should be included in the treatment package, but it should be remembered that their appointment is not so vital in the first hours of urgent measures compared to directed immunotherapy. Treatment is started with third-generation cephalosporin drugs (cefotaxime 100-200 mg / kghs), ceftriaxone 50-100 mg / kghs), cefoperazone / sulbactam 40-80 μg / (kghmin)] in combination with aminoglycosides [amikacin 15-20 mg / kgsut)]. Of particular interest is the defeat of the intestine in shock, since the syndrome of general reactive inflammation leading to multiple organ failure is associated with the intestine. Use the method of selective intestinal decontamination and enterosorption as a variant of antibacterial therapy. Selective decontamination with the use of enteric mixture from polymyxin, tobramycin, amphotericin selectively allows to suppress nosocomial infection. Enterosorption using such drugs as doktahedral smectite (smectite), silicon dioxide colloid (polysorb), wowlene, chitosan, allows to reduce not only the activity of nitrogenous slags, but also the degree of endotoxemia.

Pain relief and sedation are necessary components of a treatment program for many types of shock, in which the pain and hyperactivity factors of the CNS play a significant role. In these cases, the use of inhalation and non-inhaling anesthetics is indicated. From a vast arsenal of non-inhaling drugs use sodium oxybate (sodium oxybutyrate) and ketamine. The dignity of these drugs is associated with an antihypoxic effect and the absence of a depressing effect on blood circulation. Sodium oxybate is injected against a background of constant oskigenotherapy at a dose of 75-100 mg / kg. Ketamine at a dose of 2-3 mg / kg [0.25 mg / kghch] further] causes dissociated anesthesia - a condition in which parts of the brain are depressed and others are excited. In the treatment of shock, it is important that the manifestation of this process is a pronounced analgesic effect in combination with superficial sleep and with stimulation of the circulation. In addition, ketamine, releasing endogenous norepinephrine. Has an inotropic effect on the myocardium, and also, by blocking the production of interleukin-6, reduces the severity of the systemic inflammatory reaction. As first-line drugs with pain syndrome, combinations of fentanyl with droperidol and metamizole sodium (baralgin) are also used. Opioid analgesics: omnopon and trimiperidine (promedol) - as a method of analgesia in children with shock are much more restrictive than indications due to the ability to increase intracranial pressure, depress the respiratory center and the cough reflex. Avoid inclusion in the analgesic mixtures of papaverine, which can cause violation of the heart rhythm and increased arterial hypotension.

The high effectiveness of such antioxidants as vitamin E (tocopherol *), retinol, carotene, allopurinol, acetylcysteine, glutathione is clearly shown in intensive shock therapy.

One of the main goals in shock therapy is to guarantee the optimal delivery of oxygen. Saturation of mixed venous blood (from the pulmonary artery) is recognized as an ideal method for estimating oxygen consumption. Saturation of venous blood from the superior vena cava is more than 70% equivalent to 62% of the saturation of mixed venous blood. Saturation of blood from the superior vena cava can be used as a surrogate marker for oxygen delivery. Its value is more than 70% with hemoglobin above 100 g / l, normal blood pressure and capillary filling time of less than 2 s may indicate adequate delivery and consumption of oxygen. In a shocked state, hypoxia in children develops not only as a result of tissue perfusion disorders, but also due to hypoventilation and hypoxemia due to a decrease in the function of the respiratory muscles, as well as intrapulmonary shunting due to respiratory distress syndrome. There is an increase in blood filling in the lungs, there is hypertension in the system of pulmonary vessels. Increased hydrostatic pressure against the background of increased vascular permeability promotes the passage of plasma into the interstitial space and into the alveoli. As a result, there is a decrease in the extensibility of the lungs, a decrease in the production of the surfactant, a violation of the rheological properties of the bronchial secretion, and micro-telecaptation. The essence of the diagnosis of acute respiratory failure (ODN) in the shock of any etiology consists in the sequential solution of three diagnostic problems:

• evaluation of the degree of ODN, as this dictates the tactics and urgency of medical measures;
• Determination of the type of respiratory failure required to select the nature of the interventions;
• Assessment of the response to primary measures for the forecasting of a threatening state.

The general scheme of treatment consists of restoring airway patency by improving the rheological properties of sputum and tracheobronchial lavage; providing gas exchange function of the lungs by oxygenation in combination with a constant positive exhalation pressure. If other methods of treating respiratory failure are ineffective, IVL is indicated. IVL is the main component of replacement therapy, used for complete decompensation of the function of external respiration. If the victim is unable to eliminate the arterial hypotension during the first hour, this is also an indication for transferring him to the ventilator with FiO ₂ = 0.6. In this case, it is necessary to avoid high concentrations of oxygen in the gas mixture. It is important to note that carrying out inadequate respiratory therapy also poses a potential threat to the development of severe neurological disorders. For example, prolonged ventilation using high oxygen concentrations without control of pO ₂ and pCO ₂ can lead to hyperoxia, hypocapnia, respiratory alkalosis, against which a pronounced spasm of cerebral vessels develops followed by cerebral ischemia. Significantly worsens the situation combination of hypocapnia and metabolic alkalosis, the development of which contributes to the unreasonably frequent use of furosemide (lazix).

Analgesia and IVL, in addition, reduce the consumption of oxygen.

It is necessary to note the peculiarities of treatment of such types of shock as obstructive, anaphylactic and neurogenic. Recognizing and eliminating the causes of obstructive shock is the main goal of therapy, along with infusion therapy. Restoration of shock volume and tissue perfusion occurs after pericardiocentesis and drainage of the pericardial cavity with cardiac tamponade, puncture and drainage of the pleural cavity with intense pneumothorax, and thrombolytic therapy (urokinase, streptokinase or alteplase) in thromboembolism of pulmonary arteries. Immediate continuous round-the-clock infusion of prostaglandin E1 or E2 in newborns with ductus-dependent heart defects prevents the closure of the arterial duct, which, with such vices, preserves their life. With a functioning arterial duct and suspicion of a ductus-dependent defect, the administration is initiated with low doses of 0.005-0.015 μg Dkgmmin). If signs of closure of the arterial duct or if the arterial duct is reliably closed, infusion begins with a maximum dose of 0.05-0.1 μgDkgmmin). Subsequently, after the opening of the arterial duct, the dose is reduced to 0.005-0.015 μg / (kg-min). In anaphylactic shock, adrenaline in a dose of 10 mcg / kg, antihistamines (more effective combination of H2 and H3-blockers of histamine receptors) and glucocorticoid hormones are injected primarily in / m. To stop bronchospasm through the nebulizer inhaled salbutamol. To eliminate hypotension, infusion therapy and the use of inotropic agents are necessary. In the treatment of neurogenic shock, several specific points are distinguished:

• the need to put the patient in the Trendelenburg position;
• use of vasopressors with refractory to infusion therapy shock;
• heating or cooling if necessary.

Objectives of treatment

The principles and methods of intensive therapy of shock in children developed and implemented in clinical practice contribute to optimization and improvement of treatment results. The immediate goal in the therapy of shock is to achieve normalization of blood pressure, the frequency and quality of the peripheral pulse, warming of the skin of the distal limbs, normalization of the capillary filling time, mental status, saturation of venous blood more than 70%, the appearance of diuresis more than 1 ml / (kghh) lactate and metabolic acidosis.