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216 Burns

by sepsis and pneumonia. Ventilator-associated lung injury may be an of the urine may be necessary (add bicarbonate to the IV fluid). When
important contributing iatrogenic factor. available, electrocardiogram (ECG) monitoring and measurement
Fluid Resuscitation of cardiac muscle enzymes and urine myoglobin levels are useful
Advancements in fluid resuscitation of critically burned patients have indicators of muscle damage. Urine output is the single most useful
made a major impact on patients’ survival and have led to a general index of adequate intravascular replacement. In this regard, systemic
decrease in complication rates. Burn injury leads to a combination of blood pressure (BP) and central venous pressure (CVP) are unreliable.
hypovolaemic and distributive shock by means of generalised micro- However, an overaggressive protocol may lead to complications, such
vascular injury and interstitial third-space fluid accumulation. as compartment syndromes and pulmonary oedema. Serial serum
Fluid resuscitation formulas are based on the child’s weight and potassium and sodium levels are needed to monitor electrolyte changes.
percentage of the TBSA burned. The goal is to replace ongoing fluid Secondary Survey
losses during the early postburn period. For burns larger than 15% Following initial resuscitation, a detailed history and head-to-toe exami-
TBSA, significant fluid losses occur and must be replaced aggressively. nation should be conducted. The possibility of associated nonburn inju-
The most widely used fluid regimen is probably the Parkland formula ries or a precipitating event (e.g., epilepsy) should always be considered.
or one of its several adaptations. Numerous resuscitation formulae History
are in use as guides to the initial resuscitation in hypovolaemic shock
following thermal injury. Most use various combinations of crystalloid In addition to the history obtained during the primary survey, more
and colloid solutions, but they differ widely in the ratio of crystalloid detailed information is needed to determine:
to colloid as well as the rate of administration. Most formulae give • the cause of the burn injury (hot liquid, hot object, chemical, open
approximately 0.52 mmol of sodium/kg body weight per % TBSA burn. flame, etc.);
Although no single fluid replacement formula is perfect, physicians • the time since injury;
should aim for a urine output of 1.0–2.0 ml/kg body weight per hour.
This is proof of adequate resuscitation and perfusion. • the duration and location of contact/exposure (a closed-space flame
With the Parkland formula, the child is given 2–4 ml/kg per % burn suggests a coexistent inhalation injury);
TBSA burn over the first 24 hours, with half administered in the first • any preexisting medical conditions, such as epilepsy, diabetes, men-
8 hours and the second half in the next 16 hours. Different physiologic tal handicap, and so forth;
demands in children of various ages and the size of the burn require • other coexisting injuries; and
even more modification of the guideline formula. For children with
burns of more than 15% TBSA and weight less than 20 kg, an additional • a vaccination history.
maintenance fluid containing glucose should be administered. Physical Examination
For burns of less than 10% TBSA, oral fluids or maintenance (IV)
fluid are usually sufficient. Children with burns between 10% and Assessment of the burn wound should include the age, height, and
15% TBSA generally respond appropriately to 1.5 times the normal weight of the patient; the depth of the burn wound; the extent (total
calculated maintenance fluid. Maintenance glucose infusion should body service area) of the burn; and the anatomical location of the injury.
be given to children younger than 2 years of age, as they may easily Age, height, and weight
become hypoglycemic due to limited glycogen stores. The age, height, weight, and calculated TBSA are needed to determine
Frequent measurements of vital signs, hourly urine output, and the appropriate doses of fluid and medications.
observation of general mental and physical response are best used to Depth of burn
judge the adequacy of resuscitation. If available, monitoring of the The depth of the burn may be determined by clinical wound inspection
central venous pressure is also a helpful guide to the adequacy of and the pinprick test (see Table 33.1). The depth of the burn is the pri-
intravascular volume.
mary determinant of the patient’s long-term appearance and function. It
Children require more fluid for burn shock resuscitation than do
is critical to differentiate between superficial and deep second-degree
adults with similar burns. The presence of inhalation injury increases
burns. Whereas superficial second-degree burns heal within 2–3 weeks,
the fluid requirements for resuscitation from burn shock after thermal
deep second-degree burns require early tangential excision and skin
injury. Continuous colloid replacement may be required to maintain
grafting to permit relatively uncomplicated healing and a return to
colloid oncotic pressure in very large burns and in the paediatric burn
normal life.
patient. Serum albumin levels should be maintained above 2.0 g/dl.
Extent of burn
Failure of Burn Shock Resuscitation
The extent of the burn surface involved is determined by careful obser-
In some patients, failure of burn shock resuscitation still occurs despite
vation, and should be graphically represented to aid in diagnosis, treat-
administration of massive volumes of fluid. Such patients are charac-
ment, prognosis, and epidemiologic surveillance. It is calculated as a
terised by extreme age, extensive tissue trauma, major electrical injury,
percent of total body surface area (% TBSA) using any of the following:
major inhalation injury, a delay in initiating adequate fluid resuscita-
• Wallace’s “rule of nines” (Table 33.2), which allows rapid estimation;
tion, or underlying disease that limits metabolic and cardiovascular
reserve. In such patients, refractory burn shock and resuscitation fail- • Lund and Browder normogram for a more precise estimation (this
ure remain major causes of early mortality. Additional data implicate table is described in several references);
a myocardial depressant factor as a contributor to early burn shock,
• the “rule of tens”, which is more appropriate for estimation of pae-
despite adequate volume resuscitation.
diatric burns; or
The Parkland formula, discussed in the last subsection, is well known
and is used as an example in this chapter. Crystalloids are preferred • the patient’s palm (~ 1% of their body surface area), which is useful
with this formula, as they are also cheaper than other fluids, but some for children with smaller burns.
centres use colloids or even hypertonic saline. Because of the increased Anatomical location
capillary leak, colloids may potentially worsen postburn oedema.
The location of burns has an important bearing on specific treatment,
In electrical injuries (high-voltage, including lightning strikes), the
reconstruction, and rehabilitation. The hands, feet, face, eyelids, perine-
goal for urine output should be 2.0 ml/kg per hour, and alkalinisation