Pathophysiology

Hypovolemic shock, a predominant concern in trauma resuscitation, involves a significant loss of blood or fluid, leading to diminished venous return, reduced cardiac output, and impaired tissue perfusion and oxygenation. The pathophysiology involves:

1. Initial Fluid Loss: Caused by hemorrhage or fluid escape, reducing intravascular volume.
2. Compensatory Mechanisms: Including tachycardia and vasoconstriction to maintain blood pressure and perfusion.
3. Progressive Deterioration: Advanced shock leads to tissue hypoxia, acidosis, and organ dysfunction.

An essential concept in the pathophysiology of trauma is the “lethal triad of death,” comprising hypothermia, acidosis, and coagulopathy. This triad is a vicious cycle that exacerbates patient morbidity and mortality:

• Hypothermia: Decreased body temperature impairs coagulation enzyme function and platelet activity.
• Acidosis: Caused by tissue hypoxia and poor perfusion, further impairing coagulation.
• Coagulopathy: A result of massive transfusions and clotting factor depletion, exacerbated by hypothermia and acidosis.

Lethal Diamond

• Hypothermia: Impairs coagulation and enzymatic reactions.
• Acidosis: Resulting from tissue hypoxia and poor perfusion.
• Coagulopathy: From massive transfusions and clotting factor depletion.
• Hypocalcemia: Often present in severe trauma, exacerbated by transfusions and resuscitation efforts, and intrinsically linked to the other components of the lethal triad. It impacts cardiac function, vascular tone, and coagulation processes, making it a crucial factor in trauma resuscitation.

This expanded view emphasizes the importance of monitoring and managing calcium levels alongside other critical factors in trauma care.

Breaking this lethal triad is crucial in trauma resuscitation, requiring integrated approaches that address all three components simultaneously.