Acute burns

Definition
A burn is damage caused by pathological excesses of energy within the tissues. This
can occur through a number of mechanisms but for the purposes of this chapter, we
will limit the discussion to thermal burns. Heat causes protein denaturation at 43°C
and cell damage at 45°C. Burn injuries lead to the release of inflammatory mediators
that increase capillary permeability—the fluid shift that then occurs may lead to hypovolaemic
shock and death.
Jackson’s burn model
This theoretical model of burn injury divides the tissue damage into zones depending
on the distance from the contact area and is helpful in appreciating the dynamic and
three-dimensional nature of a burn:
• Zone of coagulation. Tissue at the contact area is dead.
• Zone of stasis. Adjacent tissue is hypoperfused and oedematous and in a precarious
condition; with adequate resuscitation to improve perfusion, it may recover,
but continuing inflammation, superimposed infection or ischaemia can cause irreversible
damage.
• Zone of hyperaemia. Tissue furthest away is minimally injured and will recover
quickly (in 7–10 days).
Effective burns management aims to maximize the survival of tissue in the zone of stasis.