Question 14

A 37-year-old male has been admitted to your ICU following an explosion in his garage. He has suffered a mixture of partial and deep burns estimated at 35% total body surface area, and he has been intubated in the Emergency Department. After one hour of resuscitation in your unit he remains hypotensive with a blood pressure of 80/50 mmHg.

List the potential causes and outline how you would diagnose and manage them.

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College answer

Spurious
1. Damped or poorly functioning, zeroed, arterial line
2. Inappropriate sized cuff
  1. Check line, cuff size
  2. Measure second site, alternative modality

Hypovolemia
1. Review volumes of administered fluids to date
2. Confirm size and depth of burn
3. Check calculations for fluid resuscitation are correct
4. Rising haematocrit, ECHO findings
  1. Increase fluid resuscitation rate

Bleeding from occult/missed injury
1. Review/repeat trauma imaging
  1. Blood product resuscitation, correction of coagulopathy
  2. Operative/Interventional radiology interventions to treat cause

Sepsis
1. Too early for burn sepsis – possible intraabdominal or thoracic blast injury
  1. Broad spectrum antibiotics and source control

Distributive
1. High cervical spine injury
  1. Review imaging, vasopressors
2. Anaphylaxis to drugs
  1. Review history, examine for rash/bronchospasm, adrenaline
3. Cyanide toxicity
  1. Mixed venous oxygen, empirical antidote administration

Cardiogenic
1. Takustubo, underlying cardiac disease, blast injury, myocardial toxins
  1. ECHO, ECG, Inotropic support

Obstructive
1. Tension pneumothorax
  1. CXR, drainage
2. Abdominal compartment syndrome
  1. Bladder pressure, escharotomies, laparotomy/laparostomy
3. Tamponade
  1. Echo and pericardiocentesis

Examiners Comments:

Frequently poorly structured answer, with a list of causes of hypotension, then repeated with diagnosis and management. Worked better when candidates classified each category of shock, then described individual diagnosis and management within each category. Often the question had not been carefully read, and the time already spent in ED and ICU was ignored; then a simplistic EMST initial approach to trauma was given.

Discussion

This question resembles Question 26 from the second paper of 2016, except the patient is not unconscious and there is no ABG to interpret.

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

If one were to offer more detail, one would have to tabulate one's answer, which would handily answer complaints about a lack of structure, because nothing says "structure" like a table.

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

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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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Arlati, S., et al. "Decreased fluid volume to reduce organ damage: a new approach to burn shock resuscitation? A preliminary study." Resuscitation 72.3 (2007): 371-378.

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.

Cooper, Andrew B., et al. "Five percent albumin for adult burn shock resuscitation: lack of effect on daily multiple organ dysfunction score." Transfusion 46.1 (2006): 80-89.

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

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