Burns injury - PACT - ESICM

Fluid resuscitation (0–24 hrs)
Burns exceeding 20% TBSA (10% TBSA in children) are characterised by an early phase
of massive capillary hyperpermeability proportional to the extent of the burn injury.
[Images in interactive version]
The transient increase in permeability is caused by the massive liberation of
numerous substances such as histamine, serotonin, cytokines, prostaglandins,
leukotrienes, lipid peroxides, free radicals, myeloperoxidase, and complement.
Studies in animals show that the leakage lasts 24–72 hrs, peaking between 12 and 24
hrs. The only similar clinical condition is anaphylaxis.
The resultant fluid leak causes an interstitial extravasation of intravascular fluid,
potentially resulting in hypovolaemic shock which requires sodium containing isotonic
crystalloids for treatment. During the first 24–48 hrs, molecules up to 100 kdalton in
size escape into the interstitium. Colloids are discouraged in the early phase after
injury because they will remain dispersed in the interstitium at the end of the
hyperpermeability phase (their removal being dependent on an effective lymphatic
transport).
According to recommendations, one should fluid resuscitate the burn patient with 2–4
mL/kg/%TBSA (the Parkland formula) using crystalloids. As a small burn size is
frequently overestimated on scene, this formula may cause pre-hospital fluid
overload. Other factors that contribute to the fluid creep (see Complications of fluid
management) are over-sedation and volume guided fluid therapy. Dynamic protocols
for fluid resuscitation managed by nurses may reduce fluid overload in the early
phase.
The primary goal of fluid resuscitation is to maintain adequate tissue perfusion to the
end-organs and the skin in an effort to conserve organ function/skin survival and to
avoid ischaemic injury.
Some supplementary critical care signs of
fluid overload
Polyuria > 1.0 mL/kg/hr
cardiac preload (elevated CVP or ITBVI and
PAOP if invasive monitoring instituted)
PaO2/FiO2 ratio
Intra-abdominal pressure >20 mmHg
Abdominal compartment syndrome manifested
by
- Acute kidney injury
- Visceral ischaemia
CVP: Central venous pressure, ITBVI intrathoracic blood volume index, PAOP
Pulmonary artery occlusion pressure
Remember, CVP (and PAOP) are more useful when used dynamically rather than as
single stand alone measurements – see PACT module on Haemodynamic monitoring.
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