A 54-year-old previously healthy male was admitted to the ICU after 45% total body surface area burns. He was pulled out of his garden shed, unconscious, by the fire brigade and was intubated at the scene of the incident by ambulance personnel. He was admitted to the ICU within one hour of injury.

a) Describe your initial fluid resuscitation plan for this patient, including the type of fluid, the rationale for your choice and how you would estimate the fluid requirements.

Three hours later, the patient remains hemodynamically unstable:

Heart rate 125 beats per minute

Blood pressure 85/45 mmHg (on noradrenaline 30 μg/min and vasopressin 0.04 units/min)

b) What are the diagnostic possibilities?

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College Answer

a)

Type of fluid:
 Fluid resuscitation of patient with moderate to severe burns consists of an isotonic crystalloid
solution, such as Hartmann’s solution or plasmalyte. Large volumes of 0.9% NaCl may be
associated with hyperchloremic metabolic acidosis.
 The colloids (albumin) are more expensive, and do not improve survival, compared to
crystalloids.
 The use of hypertonic saline does not provide better outcomes than isotonic saline.

Estimating fluid requirements:
 No formula provides a precise method for determining the burn victim's fluid requirements; the
formulas described provide only a starting point and guide to initial fluid resuscitation. Patient
age, severity of burns and co-morbidities can substantially alter the actual fluid requirements
of individual patients. Patient response to fluid therapy needs careful monitoring and
adjustment as clinically indicated
 Parkland (or Baxter or consensus) Formula (most widely used):
Fluid requirement (ml) = 4 x body weight x percentage of burns. (Only deep)
One half of the calculated fluid is given over the first eight hours and the remaining over the
next 16 hours.
The rate of infusion should be as constant as possible; sharp decrease in infusion rates can
cause vascular collapse and increase in edema.
 Modified Brooke Formula:
Fluid requirement (ml) over the initial 24 hours = 2 x body weight x percentage of burns.
This formula may reduce the total volume used in fluid resuscitation without causing harm.
 Following initial resuscitation, IV fluids are administered to meet baseline fluid needs and
maintain urine output.
 Care should be taken to avoid fluid overload, as associated with multiple co-morbidities.

b)
 Unidentified blood loss / inadequate fluid resuscitation
 Distributive shock with large fluid shifts
 Cyanide toxicity
 Compartment Syndrome, including abdominal compartment
 Cardiogenic Shock (severe myocardial suppression caused by burns)
 Carbon monoxide poisoning
 Ingestion of toxins (ethylene glycol, methanol, salicylates)

Additional Examiners’ Comments:
Candidates omitted discussion on rationale for choice of fluid

Discussion

A detailed dissection of fluid resuscitation for the burns patient  is performed in the Required Reading section. Physiologic consequences of burns is also covered there.

In brief:

Fluid resuscitation end point:

Choice of fluids:

  • Resuscitation should use a balanced solution to avoid hyperchloraemic acidosis (Walker et al, 2001)
  • Most formulae recommend Ringer's Lactate; the locally available version is Hartmanns
  • The disadvantage of crystalloid is the potential need for massive volume
  • Historically, significantly more fluid is given to burns patients  then is predicted by any formula (Mitra et al, 2006). This is known as "fluid creep" and is associated with significant complications, of which the most serious is abdominal compartment syndrome.
  • Colloid (eg. albumin) is also recommended by many of the formulae
  • The advantage of colloid is that it may alleviate "fluid creep" and achieve haemodynamic goals more rapidly and with less volume
  • There is no evidence that albumin improves survival or organ dysfunction (Melinyshyn et al, 2013)
  • The theoretical advantage of hypertonic saline is earlier achievement of haemodynamic goals and the avoidance of burns-associated hypernatremia. However, hypertonic saline solutions were associated with a fourfold increase in the risk of renal failure and a twofold increase in the risk of death (Huang et al, 1995)

Resuscitation formulae

Formulae to Estimate Fluid Resuscitation Requirements in Adult Burns
Formula First 24 hours Next 24 hours  
Choice of fluid Volume Choice of fluid Volume
Parkland Ringer's Lactate 4ml/kg/%
first half in 8 hrs
second half in 16 hr
Colloids only.
No more  crystalloids.
20–60% of calculated plasma volume.
Modified Parkland Ringer's Lactate 4ml/kg/%
first half in 8 hrs
second half in 16 hr
5% albumin 0.3–1 ml/kg/% burn/16 per hour
Brooke Ringer's Lactate 1.5 ml/kg/% Ringer's Lactate 1.5 ml/kg/%
Colloids 0.5 ml/kg/% Colloids 0.25 ml/kg/%
Dextrose 5% 2000ml Dextrose 5% 2000ml
Modified Brooke Ringer's Lactate 2 ml/kg/% Colloids 0.3–0.5 ml/kg/%
Evans Crystalloid 1 ml/kg/% Crystalloid 0.5 ml/kg/% burn
Colloid 1 ml/kg/% Colloid 0.5 ml/kg/% burn
Dextrose 5% 2000ml    
Monafo 250 mEq Na
150 mEq lactate
100 mEq Cl.
titrate to u/o 250 mEq Na
150 mEq lactate
100 mEq Cl.
titrate to u/o
1/3 saline titrate to u/o

It is probably worth adding that this patient is at high risk of inhalational injury. He was unconscious, and sharing a small enclosed space with his fire. Naver et al (1985) demonstrated that patients with smoke inhalation injury and airway burns require a larger volume of fluid resuscitation. The total volume is increased up to 35% - 65%.

Causes of shock in the unconscious burns patient:

Let this be an exercise in generating differentials.

  • Wrong BP measurement (eg. arterial line is not zeroed)
  • Cardiogenic shock
    • Due to cytokine storm of severe burns
    • Due to carbon monoxide toxicity (i.e. severe tissue hypoxia)
    • Due to cyanide toxicity (i.e. mitochondrial failure)
    • Due to a myocardial infarction (due to increased myocardial oxygen consumption in context of burns, on top of pre-existing ischaemic heart disease)
  • Abdominal compartment syndrome (over-resuscitation)
  • Tension pneumothorax (explosion)
  • Spinal injury neurogenic shock (unrecognised due to unconsciousness)
  • Blood loss from some internal injury or due to DIC
  • Under-resuscitated burns shock (i.e. fluid shifts)
  • SIRS vasoplegia
  • Anaphylaxis to some drug given in hospital

In more detail:

Causes of Shock in the Acute Burns Patient
Type of shock Cause Diagnostic strategy Management
Artifact of measurement Arterial blood pressure measurement is inaccurate Compare with non-invasive measurement and physical examination
  • Re-zero and recalibrate the arterial line
  • Resite arterial line or change the transducer
Cardiogenic Cytokine-induced myocardial dysfunction
Alternatively, cardiac dysfunction can be associated with cyanide and carbon monoxide toxicity
TTE, ECG, cardiac output measurement by PiCCO or PA catheter
  • Fluid resuscitation
  • Commence inotrope infusion
  • Correct rhythm if in AF
  Myocardial infarction TTE, ECG, cardiac enzymes
  • Consider IABP
  • Thrombolysis or anticoagulation likely contraindicated given the potential need for escharotomy or debridement
Obstructive Abdominal compartment syndrome Measure the intra-abdominal pressure;
calculate total fluid resuscitation (it is associated with over-resuscitation)
  • Maintain MAP with vasopressors
  • Consider opening the abdomen
  • Consider diuresis (although, at this stage the urine output is limited by poor renal perfusion)
 

Massive pulmonary embolism (unlikely - too early - more likely in the chronic recovery from burns)

TTE, CVP trace, ECG, CTPA
  • Consider emergency embolectomy
  • Thrombolysis or anticoagulation likely contraindicated given the potential need for escharotomy or debridement
  Tension pneumothorax
(likely, if there the patient was in some sort of  explosion)

Physical examination;

CXR

  • Emergency decompression
  • Chest drain
Neurogenic Spinal injury due to fall; may have gone unrecognised given that the patient was found unconscious Physical examination features, CT, MRI
  • Commence vasopressor infusion
Hypovolemic Blood loss Examination of the patient, FBC, DIC screen
  • Replace blood products and red cells
  • Fluid resusiciation
  • Maintain normal acid-base balance and normothermia
  • Correct coagulopathy
  Under-resuscitated burns shock Compare fluid resuscitation with predicted expectations as based on the formulae
  • Replace appropriate volume
  • Aim for urine output 0.5-1.0ml/kg
  • Consider albumin, and to hell with the evidence
Distributive Vasoplegia due to SIRS SVRI measurements by PiCCO
  • commence vasopressor infusion; consider methylene blue
  Anaphylaxis Physical examination findings suggestive of angioedema
  • Adrenaline IM or as infusion
  • Withdrawal of the trigger substance
  • Corticosteroids and antihistamines
Cytotoxic Cyanide toxicity due to smoke inhalation Lactate levels; cyanide levels
  • hydroxycobalamin
  • dicobalt edetate
  • sodium thiosulfate
  • methaemoglobinaemia

References

References

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Haberal, Mehmet, A. Ebru Sakallioglu Abali, and Hamdi Karakayali. "Fluid management in major burn injuries." Indian journal of plastic surgery: official publication of the Association of Plastic Surgeons of India 43.Suppl (2010): S29.

Fodor, Lucian, et al. "Controversies in fluid resuscitation for burn management: Literature review and our experience." Injury 37.5 (2006): 374-379.

Bak, Zoltan, et al. "Hemodynamic changes during resuscitation after burns using the Parkland formula." Journal of Trauma and Acute Care Surgery 66.2 (2009): 329-336.

Blumetti, Jennifer, et al. "The Parkland formula under fire: is the criticism justified?." Journal of burn care & research 29.1 (2008): 180-186.

Baxter, Charles R., and Tom Shires. "Physiological response to crystalloid resuscitation of severe burns." Annals of the New York Academy of Sciences 150.3 (1968): 874-894.

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Bittner, Edward A., et al. "Acute and Perioperative Care of the Burn-Injured Patient." Survey of Anesthesiology 59.3 (2015): 117.

Melinyshyn, Alex, et al. "Albumin supplementation for hypoalbuminemia following burns: unnecessary and costly!." Journal of Burn Care & Research 34.1 (2013): 8-17.

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Wilkes, NICHOLAS J. "Hartmann's solution and Ringer's lactate: targeting the fourth space." Clinical Science 104.1 (2003): 25-26.

MONAFO, WILLIAM W. "The treatment of burn shock by the intravenous and oral administration of hypertonic lactated saline solution." Journal of Trauma and Acute Care Surgery 10.7 (1970): 575-586.

Huang, Peter P., et al. "Hypertonic sodium resuscitation is associated with renal failure and death." Annals of surgery 221.5 (1995): 543.

Sun, Ye-Xiang, et al. "Effect of 200 mEq/L Na+ hypertonic saline resuscitation on systemic inflammatory response and oxidative stress in severely burned rats." Journal of Surgical Research 185.2 (2013): 477-484.

Paratz, Jennifer D., et al. "Burn Resuscitation—Hourly Urine Output Versus Alternative Endpoints: A Systematic Review." Shock 42.4 (2014): 295-306.

Walker, Steven C., et al. "Balanced Electrolyte Solution Reduces Acidosis as Compared to Normal Saline in the Resuscitation of Perioperative Burn Patients." Anesthesiology 95 (2001): A375.