Emergency conditions in circulatory collapse

The place of collapse in the structure of vascular failure

The syndrome of acute vascular failure is always based on a common pathogenetic foundation: a drop in arterial and venous pressure with subsequent impairment of tissue blood supply. However, the depth and reversibility of these hemodynamic disorders vary, allowing three main clinical forms to be identified.

Classification of collapse

For the proper selection of emergency therapy, it is important to understand which specific mechanism triggered the cascade of vascular failure. According to the leading pathogenetic factor, collapse is divided into three types:

1. Cardiogenic — the pumping function of the heart suffers primarily, leading to an acute decrease in cardiac output.
2. Vasodilatory (vascular) — occurs due to a sudden and sharp drop in the tone of the vascular wall.
3. Hypovolemic — develops as a result of a rapid decrease in the circulating blood volume (CBV).

In addition to the pathogenetic classification, there is also an etiological classification. It includes infectious (toxic), orthostatic, hypoxic, and pancreatic collapse, as well as conditions in acute poisonings. It is important to understand that any of these etiological forms ultimately manifests through one of the three pathogenetic pathways described above.

Emergency care algorithm

The fundamental principle of resuscitating a patient from collapse is simultaneous restoration of cardiovascular activity and elimination of the etiological factor. The standard protocol includes the following non-pharmacological and pharmacological steps:

• Positioning: the patient is immediately placed in a horizontal position with legs elevated (Trendelenburg position). This mechanically improves venous return to the heart and stimulates cerebral perfusion.
• Securing breathing: it is necessary to unbutton restrictive clothing, ensure a fresh air supply and airway patency. If signs of hypoxia are present, oxygen therapy is initiated.
• Thermoregulation: if peripheral vasoconstriction with marked cooling of the skin is observed, the patient is warmed (e.g., heating pads are applied to the extremities).
• Infusion therapy: administration of crystalloid and colloid solutions to restore circulating blood volume. This is especially relevant in the hypovolemic variant. It is performed under strict control of blood pressure and central venous pressure (CVP).
• Etiotropic support: the cause is simultaneously eliminated (stopping bleeding, detoxification in infection, management of arrhythmia).

Differentiated pharmacotherapy

The choice of specific drugs is dictated by the type of hemodynamic disorders. If infusion therapy in vasodilatory collapse is insufficient, vasopressors (sympathomimetics) are added to increase vascular tone. In the cardiogenic variant, where myocardial weakness dominates, cardiotonic and inotropic drugs are prescribed. If the collapse has a toxic, infectious, or anaphylactic nature, glucocorticoids are indicated — they stabilize the vascular wall and enhance the effect of vasopressors. In anaphylaxis involving the respiratory system (stridor, dyspnoea) or a marked drop in blood pressure, immediate administration of epinephrine is an absolute indication.

It is critically important on the exam and in practice to distinguish the tactics in collapse from the therapy of acute left ventricular failure (pulmonary edema, cardiac asthma). In left ventricular failure, doctors strive to relieve the pulmonary circulation: they administer morphine to reduce sympathetic nervous system tone, diuretics (furosemide), and vasodilators (nitroglycerin). In collapse, vasodilators and diuretics are strictly contraindicated! In conditions of hypovolemia and reduced venous return, they will only fatally worsen hypotension.

Class and exam questions

What else to study on this topic

• Anaphylactic shock: etiology, pathogenesis, and key triggers
• Acute left ventricular failure: pulmonary edema and cardiac asthma
• Acute decompensated heart failure (ADHF)
• Principles of differential diagnosis of shock states
• Etiotropic therapy of toxic and infectious collapse

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