BURNS Early management issues. Epidemiology. Approx 135 000 total burn injuries in Oz in 2001. 2% of all injury hospitalisations 6000 children to A&E with burns each year 20-25 children die each year from burns 13 000 hosp. in NSW between 95 and 99, 40% children.
A burn patient is a trauma patient; therefore, other injuries should be expected and sought
Dramatic physiologic and metabolic changes over the course of the injury state.
1) Resuscitation phase (0 to 36 hours)
characterised by cardiopulmonary instability
2) Post resuscitation phase (2 to 6 days)
3) Inflammation / infection phase (7 days to wound closure)
Pathophysiology of early changes
1) Inhalation injury complex
2) Burn injury (external) to face and neck
3) Burn injury (external) involving the thorax
How to diagnose?
Treatment cyanide toxicity
Third degree burn of the neck is particularly bad
Minimal external oedema due to the non-elastic burn
No external expansion.
Massive intraoral / pharyngeal oedema
How to determine degree of involvement?
The unconscious patient loses airway protective mechanisms, resulting in a more severe injury to the lower airways when continuing to inspire.
Symptoms may be absent on admission. The magnitude of the degree of injury evident after 24 to 48 hours.
Increased WOB to maintain functional residual capacity and an adequate tidal volume.
Symptoms may not be clearly evident until oedema formation peaks at about 10 to 12 hours.
Summary of early management
30-70% of patients with inhalational injury will develop ventilator-associated pneumonia.
When can the patient be extubated?
ARDS (low pressure) typically occurs later (after the 1st week).
Pathophysiology of initial changes
Most oedema occurs locally at the burn site and is maximal at 24 hours post injury.
24 hour fluid requirement =
3-4 ml/kg * body wt * %TBSA burnt.
First half to be adm. over initial 8 hours after injury. Consider deficits. Hartmann’s solution / Ringer’s.
Modified Parkland (Hartmann’s)
Maintenance fluids (4%D 1/5 NS)
Evaporation from the surface of the burn becomes a major source of water loss that persists until the wound is closed. This loss is related to the water vapour pressure at the surface.A reasonable estimate of loss can be obtained from the following formula:
EVAPORATIVE WATER LOSS =
( 25 + % TBSA burnt ) * TBSA in m2
Blood volume can be restored more effectively as the leakage decreases at about 24 to 36 hours.
Tachycardia, ranging from modest to significant (100 to 120 beats per minute), is seen frequently and results partly from persistent elevation of catecholamine levels. Systemic vascular resistance begins to decrease. The vasodilatation results in an increase in the capacity of the vascular space and, therefore, an increased need for colloid and red blood cells.