Stages and criteria of traumatic shock
The development of shock in trauma goes through several stages, the transition between which depends on the effectiveness of compensatory mechanisms and the timeliness of medical care.
- Precursors of decompensation: the Allgöwer index rises to 1.2, diuresis drops but remains at least 30 ml/h. There are no signs of cerebral and cardiac hypoxia yet.
- Decompensated reversible shock: compensation through peripheral vascular resistance becomes exhausted. Hypotension develops, and the blood volume deficit (BCC deficit) reaches 25–35%. Tachycardia up to 120 bpm, oliguria, and signs of internal organ ischemia appear.
- Decompensated irreversible shock: profound disorders with a BCC deficit of 50% or more. Characterized by hypotension, anuria, and acrocyanosis. The Allgöwer index exceeds 1.5, and there is no response to vasopressor therapy. The condition is considered irreversible if decompensation lasts for more than 12 hours.
| Shock grade | Systolic BP, mmHg | Allgöwer index | BCC deficit, % |
|---|---|---|---|
| I | > 90 | 0,7 — 0,8 | 10 |
| II | 70 — 90 | 0,9 — 1,2 | 20 |
| III | 50 — 70 | > 1,2 | 30 |
| IV (agony) | < 50 or unmeasurable | - | - |
Prognostic factors and features in different patients
The prognosis in shock depends on the timely elimination of hypovolemia, respiratory failure, bleeding, and pain. A delay in care of 2–4 hours critically worsens survival chances.
The course of shock varies among different groups:
- Elderly patients: due to chronic diseases, shock occurs with a smaller loss of blood volume; normal BP (against the background of hypertension) may mask the severity of the condition.
- Children: maintain normal BP for a long time due to strong centralization of blood flow, after which a sudden and hard-to-manage hemodynamic collapse occurs.
- Pregnant women: maternal homeostasis is maintained at the expense of the fetus. Infusion therapy must be increased by 25%, and transportation should be performed in the lateral position to prevent inferior vena cava syndrome.
Acute respiratory failure (ARF) and "shock lung"
Severe trauma inevitably affects the respiratory system, causing traumatic ARF syndrome. It is based on hypoxia, which can be respiratory, hemic (due to blood loss), circulatory (due to shock), or toxic.
A key complication is the development of "shock lung" (in international classification — ARDS or ARDS).
The pathogenesis of ARDS is associated with the destruction of surfactant, a substance that maintains the shape of the alveoli. Due to microthrombosis of pulmonary capillaries and bronchioloconstriction, unoxygenated blood is shunted into the veins (intrapulmonary shunting). If the shunt volume reaches 50%, mortality approaches 100%.
Causes of ARDS are divided into primary (direct alveolar damage from aspiration, lung contusion) and secondary (endothelial damage due to hypovolemia, intoxication, or fat embolism).
Briefly: answers to topical questions
Which pathogenetic links are characteristic of crush syndrome?
Pathogenetic factors include pain irritation, traumatic toxemia (absorption of tissue breakdown products), as well as plasma and blood loss. Against the background of ischemic muscle necrosis, intoxication with necrosis products and multiorgan pathology develop, with acute renal failure taking the leading place. Local changes consist of "self-isolation" of the focus, when rapidly developing edema causes the muscles to "crush themselves" within fascial compartments, causing secondary ischemia.
What changes occur in the kidneys during crush syndrome?
Crush syndrome leads to the development of multiorgan pathology, among which acute renal failure occupies the leading place in terms of timing and mortality.
What local symptoms develop in the injured limb during crush syndrome?
The affected limb shows increased pain signaling and cyanosis. The edema acquires a "woody" density without forming an indentation upon pressing and spreads beyond the compressed area. Blisters with serous or serosanguineous contents appear on the skin. Active movements of the limb are hindered, passive movements become painful, and all types of skin sensitivity are impaired.
What is the formula for calculating the Allgöwer index?
The Allgöwer index is calculated as the ratio of pulse rate to systolic blood pressure: Index = Pulse (bpm) / SBP (mmHg). The normal range is 0.5–0.6, and an increase in the index to 1.5 and higher indicates the development of irreversible shock.
Class and exam questions
Normotension combined with agitation in severe traumatic brain injury often indicates escalating cerebral hypoxia rather than a stable condition.
Normotension combined with agitation in severe traumatic brain injury often indicates escalating cerebral hypoxia rather than a stable condition.
ARDS (acute respiratory distress syndrome) is a synonym for the term "shock lung". This is damage to the pulmonary parenchyma due to surfactant dysfunction, developing against the background of severe shock and microthrombosis.
ARDS (acute respiratory distress syndrome) is a synonym for the term "shock lung". This is damage to the pulmonary parenchyma due to surfactant dysfunction, developing against the background of severe shock and microthrombosis.
Ominous harbingers of irreversibility are the appearance of acrocyanosis against the background of pallor, persistent hypotension, anuria, and lack of response to the administration of vasoconstrictor drugs.
Ominous harbingers of irreversibility are the appearance of acrocyanosis against the background of pallor, persistent hypotension, anuria, and lack of response to the administration of vasoconstrictor drugs.
What else to study on this topic
- Pathogenesis of hemodynamic disorders and centralization of blood circulation
- The role of surfactant and the mechanisms of its destruction in ARDS
- Differential diagnosis of types of hypoxia in polytrauma
- The impact of the pulmonary shunt on gas exchange and methods for its evaluation
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