Research and Reviews in the Fastlane 153

Research and Reviews in the Fastlane

Welcome to the 153rd edition of Research and Reviews in the Fastlane. R&R in the Fastlane is a free resource that harnesses the power of social media to allow some of the best and brightest emergency medicine and critical care clinicians from all over the world tell us what they think is worth reading from the published literature.

This edition contains 5 recommended reads. The R&R Editorial Team includes Jeremy Fried, Nudrat Rashid, Soren Rudolph, Justin Morgenstern and, of course, Chris Nickson. Find more R&R in the Fastlane reviews in the R&R Archive, read more about the R&R project or check out the full list of R&R contributors

This Edition’s R&R Hall of Famer

Airway

R&R Hall of Famer - You simply MUST READ this!
Duggan LV. Transtracheal jet ventilation in the ‘can’t intubate can’t oxygenate’ emergency: a systematic review. Br J Anaesth. 2016.PMID 27566790

  • All major guidelines for emergency airway management include the use of transtracheal jet ventilation as a mean of oxygenation. The NAP 4 study documented a high failure rate when used in the CICO setting. After a very comprehensive literature review the authors of this paper the authors identified 44 studies of both emergency and elective use of transtracheal jet ventilation and found a similar high failure rate of 42% (device failure 38%, barotrauma 39% and miscellaneous complications 9%) of transtracheal jet ventilation in emergency settings. They boldly but justifiably question the recommendation of transtracheal jet ventilation in the CICO situation
  • Recommended by Soren Rudolph

The Best of the Rest

Quirky, weird and wonderful
Thomas L. Schlenk et al. Electric Fans Don’t Cool Elders Exposed to Extreme Heat and Humidity. JAMA 2016. PMID 27599335

  • An interesting paper (‘m sure with many variables difficult to control for) about simple recommendations that probably don’t help, and living in a climate in Brisbane in summer like this, circulating hot wet air doesn’t help evaporative cooling occur.
  • Recommended by Daman Langguth

Critical care
R&R Hot Stuff - Everyone’s going to be talking about this
Sharifi M et al. Pulseless electrical activity in pulmonary embolism treated with thrombolysis (from the “PEAPETT” study). The American journal of emergency medicine. 2016. PMID 27422214

  • This is a retrospective study looking at a group of 23 patients who had all been referred to a specialist cardiovascular team after a PEA cardiovascular arrest secondary to PE (20 diagnosed by CT and 3 by right heart strain on bedside echo) and who received tPA. 4 of the 20 CTs were done after the arrest and tPA had been given. The patients all received 50mg of tPA followed by heparin. Return of spontaneous circulation and hemodynamic stability was achieved within 15 minutes for 22 of the 23 patients. At 22 month follow-up, 20 of 23 patients were still alive. There were no major or minor bleeding events recorded. This group was relatively sick, with a mean age of 72, lots of comorbidities, and 22% having a cancer history. Of course, there is no comparison group and this is a select group of patients that was actually referred, so I wouldn’t pay too much attention to the specific numbers, but these outcomes are way better than normal PEA.
  • Recommended by Justin Morgenstern

Emergency medicine
R&R Game Changer? Might change your clinical practice
Smith JD et al. Effectiveness of N95 respirators versus surgical masks in protecting healthcare workers from acute respiratory infection: a systematic review and meta-analysis. CMAJ : Canadian Medical Association journal. 2016. PMID 26952529

  • This systematic review identified 29 studies, 6 of which were appropriate for the quantitative meta-analysis. N95 masks did not appear to be protective in any of the clinical outcomes: influenza like illness, lab confirmed respiratory infection, or days off work. However, the masks do seem to work in laboratory settings, so perhaps the reason that they don’t work in the real world is that we don’t wear them properly? Also, the confidence intervals here are relatively large and all the point estimates come down on the side of N95s being better. Given the extra expense and annoyance, this probably warrants a high quality large RCT, but for now the best answer is simply: we don’t know. Bottom line: N95 masks might not be any better than surgical masks, but we really can’t be sure at this point.
  • Recommended by Justin Morgenstern

Education
R&R Game Changer? Might change your clinical practice
Stratta EC, et al. Ethical erosion in newly qualified doctors: perceptions of empathy decline. Int J Med Educ. 2016. PMID 27608488

  • A heart-wrenching open access paper looking at the changing attitudes of junior doctors towards patients and their reflections of the care they see role-modelled by seniors. 9 doctors consented to semi-structured interviews in which they described their perceptions of empathy, its value in clinical practice and its erosion with increasing exposure to the working world of medicine. Even with the possibility of a selection bias in the respondents, the paper still leaves us with important questions; who are we, as doctors? Is this part of the medical professional’s journey essential – if not, how can we avoid it? And how can we prevent it in the first place?
  • Recommended by Natalie May

The R&R iconoclastic sneak peek icon key

Research and Reviews The list of contributors R&R in the FASTLANE 009 RR Vault 64 The R&R ARCHIVE
R&R in the FASTLANE Hall of Famer R&R Hall of famer You simply MUST READ this! R&R Hot Stuff 64 R&R Hot stuff! Everyone’s going to be talking about this
R&R in the FASTLANELandmark Paper R&R Landmark paper A paper that made a difference R&R Game Changer 64 R&R Game Changer? Might change your clinical practice
R&R Eureka 64 R&R Eureka! Revolutionary idea or concept R&R in the FASTLANE RR Mona Lisa R&R Mona Lisa Brilliant writing or explanation
R&R in the FASTLANE RR Boffin 64 R&R Boffintastic High quality research R&R in the FASTLANE RR Trash 64 R&R Trash Must read, because it is so wrong!
R&R in the FASTLANE 009 RR WTF 64 R&R WTF! Weird, transcendent or funtabulous!

That’s it for this week…

That should keep you busy for a week at least! Thanks to our wonderful group of editors and contributors Leave a comment below if you have any queries, suggestions, or comments about this week’s R&R in the FASTLANE or if you want to tell us what you think is worth reading.

Last update: Sep 29, 2016 @ 9:57 pm

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Modern-Day Burn Resuscitation: Moving Beyond the Parkland Formula

Authors: Mary Ellen Billington, MD (EM Resident Physician, Parkland Memorial Hospital, Dallas, TX) and Brett D. Arnoldo, MD, FACS (Associate Professor, Department of Surgery, Parkland Memorial Hospital, Dallas, TX) // Edited by: Erica Simon, DO, MHA (@E_M_Simon) & Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW Medical Center / Parkland Memorial Hospital)

In the midst of a busy ED shift, a patient arrives by EMS. You immediately recognize the distinctive odor: a dry and unfortunately singed smell lingers in the air. As the catecholamines surge, you recognize your own tachycardia: it’s time to see a burn victim.

Thoughts race through your mind: What’s that  formula for fluid resuscitation? What rate do I use for the lactated ringers? What are the criteria that determine the need for burn center care? Where is my co-oximetry equipment?

Step away from your MDCalc – we’re going to calm that scorching stress-induced acid reflux with an update on the emergency department management of burns.

Mental Road Map

To adequately manage the burn victim, the emergency medicine physician must remember three key guidelines:

  1. The burn patient is a special type of trauma patient.
  2. The burn patient may be a toxicological patient.
  3. The burn patient requires comprehensive evaluation and management, and is best served by transferring to a burn center in accordance with ABA (American Burn Association) guidelines.

The Burn Patient is a Special Type of Trauma Patient

Begin with the ABCs: Is the airway intact? Is there concern that the airway may be lost? What is the patient’s projected course?

  • If the airway is not protected: intubate.
  • Signs of impending airway compromise include: stridor, wheezing, subjective dyspnea, and a hoarse voice.1
    • Severe burns to the lower face and neck may develop significant edema predisposing to airway obstruction.1
    • A history of the inhalation of superheated air, or steam in a confined space, is concerning for severe bronchial injury.1
    • Keep in mind that perioral burns and singed nasal hairs mandate an examination of the oropharynx for mucosal injury, however, these findings alone do not indicate airway involvement.2
    • Smoke inhalation victims may develop delayed respiratory failure: when in doubt, admit for observation and bronchoscopy.3
  • Projected Course: patients with burns involving >60% total body surface area (TBSA) tend to deteriorate rapidly: consider immediate intubation.1
  • Keep in mind that patients possessing burns involving a lower percentage of TBSA (e.g. < 40%), may require intubation if significant volume resuscitation is required.1
  • If the airway is intact, and the history and physical are not consistent with inhalational injury, it is prudent to administer oxygen by nasal cannula or face mask.1

Aside from airway concerns, complete your primary and secondary surveys and treat life-threatening emergencies as appropriate:

  • Consider a cervical collar if the mechanism is appropriate (blast injuries), or when doubt surrounds the circumstances of the injury.
  • Remember that full-thickness burns to the chest wall may lead to mechanical restriction of ventilation: consider escharotomy.1,3
    • Note: It is advised that escharotomies be performed in cooperation with a burn surgeon.4

In terms of fluid resuscitation:2

  • Burns <15% TBSA generaly require only PO fluid resuscitation.
  • Obtain large bore PIV access: two sites recommended for burns >40% TBSA.
  • Despite popular belief, IV access may be obtained through burned skin; ensure that lines are  well secured.
  • Obtain IO access if unable to obtain IV access.
  • Central lines equipped with invasive monitoring devices may provide useful volume-status metrics to guide resuscitation.

The What, When, and How Much of Fluids

  • In order to determine the volume of fluid resuscitation required for a burn patient, the Rule of Nines for adults and the Lund and Browder chart for children should be utilized (Figures 1 and 2 below).1,2
  • Remember: do not include first degree burns in the calculation of % TBSA.2
  • The over-estimation of % TBSA may result in hypervolemia, predisposing to a number of dangerous conditions:4
    • abdominal compartment syndrome
    • extremity compartment syndrome(s)
    • intraocular compartment syndrome
    • pleural effusions
Figure 1. Rule of Nines (Reference 5)
Figure 1. Rule of Nines (Reference 5)
Figure 2. Lund & Browder Chart (Reference 5)
Figure 2. Lund & Browder Chart (Reference 5)

Fluid Formulas:

  • The Parkland (or Baxter) Formula is possibly the most well-known and widely utilized formula:
    • 4 mL x weight in kg x % TBSA (up to 50%) = total volume of lactated ringers (LR) required for resuscitation
      • Half of the total volume is administered over the first 8 hrs post injury; the remaining, over the following 16 hours.
    • It is important to note that this formula is not universally accepted. Current trends in burn management literature emphasize a clinical assessment of volume status as essential in guiding fluid administration.1,2 Early consultation with a burn center is advised.1,2
  • The Advanced Burn Life Support (ABLS) handbook recommends the following for fluid resuscitation:
    • 2-4mL x kg body weight x % TBSA burn = volume of LR required for adult resuscitation (formula adjusted to 3-4mL x kg body weight x % TBSA burn for pediatric patients).6
      • Half of the total resuscitation volume is given over the first 8 hours, with administration of the remaining half titrated to patient response (urine output of 0.5mL/kg/hr for adults and 1mL/kg/hr for children).6
  • Inhalation injuries most commonly increase fluid resuscitation requirements.2
  • All resuscitation measures should be guided by perfusion pressure and urine output:4
    • Target a MAP of 60 mmHg, and urine output of 0.5-1.0ml/kg/hr for adults and 1-1.5mL/kg/h for pediatric patients.
    • The placement of a radial or femoral catheter is advised.4
    • Heart rate, pulse pressure, capillary refill, and mental status should also be assessed when determining resuscitation adequacy.
    • Additional markers, i.e. – lactate, base deficit, intestinal mucosal pH, and pulmonary arterial catheters are of limited use, and demonstrate varied mortality benefit.

We saw that the Parkland Formula and ABLS handbook recommend the use of LR, but are there recommendations regarding the use of other fluids for burn resuscitation?

  • Generally crystalloid solutions should be infused during the initial 18-24 hrs of resuscitation.1,4
  • It is recommended that 5% dextrose be added to maintenance fluids for pediatric patients weighing < 20kg.1
  • Hypertonic solutions tend to decrease initial resuscitation volumes, but are associated with increased renal failure and death, and therefore should be avoided.2,4,8
  • Colloid administration is a topic of debate.
    • Extensive heterogeneity exists regarding the recommendation for albumin utilization:
      1. Previous studies assessing albumin delivery in burn resuscitation (the most recent >15 years ago) demonstrated no statistically significantly improvement in patient outcomes.3  Today, however, a number of burn experts argue the value of albumin administration in the post capillary leak time frame (>18-24 hours post injury)given it’s ability to decrease third spacing.Further large scale, randomized control trials are needed.3
    • Blood transfusion is considered immunosuppressive, and is associated with increased mortality in burn patients. Blood products should be withheld unless there is an apparent physiologic need.2,4

The Burn Patient May be a Toxicological Patient

 In the evaluation of a burn patient, be sure to obtain a thorough history from EMS or from the patient. Victims of enclosed-space fires may be exposed to toxic levels of carbon monoxide and cyanide:

Your patient is the victim of an apartment fire. He has what appears to be red-tinged skin in areas absent burn; he is neurologically depressed, and suddenly decompensates into cardiac arrest. What toxic exposure do you suspect? How do you confirm your diagnosis? How will you treat your patient?

  • Carbon monoxide (CO) poisoning may manifest with persistent neurologic symptoms or even as cardiac arrest. Despite the board-style vignette stated above, cherry-red skin is a neither sensitive nor specific finding.3
  • If you suspect CO poisoning, order a carboxyhemoglobin level.1 In a patient with CO poisoning, pulse oximetry readings will be falsely normal, and the PaO2 and % hemoglobin saturation on ABG will be unaffected.1
  • How do you use a carboxyhemoglobin level? Subtract the carboxyhemoglobin level from the pulse oximetry level to determine true oxygen saturation.
    • Interpreting levels:3
      • Non-smokers: up to 1% normal
      • Smokers: 4-6% common
      • Any reading >10% = concern for significant exposure
    • To treat the toxic exposure administer 100% O2. Hyperbaric oxygen may be also be considered.2

Your burn patient, despite initial resuscitative efforts, maintains a persistent lactic acidosis and develops S-T elevation on EKG. What toxic exposure do you suspect? How do you treat your patient? 

  • The spectrum of the clinical presentation of cyanide poisoning varies from mydriasis,  to tachypnea and central apnea, to hypotension, to loss of consciousness and seizures.1
  • If concerned for cyanide toxicity, initiate 100% O2 therapy and administer hydroxocobalamin, with consideration for sodium thiosulfate (slower mechanism of action).1 Note: The commercially available cyanokit contains hydroxycobalamin, amyl nitrate, and sodium thiosulfate.
  • Be sure to rule out other etiologies of lactic acidosis: under-resuscitation, CO poisoning, or missed traumatic injury.2

Additional Resuscitative Therapies and Considerations for Transfer

 What other resuscitative treatments may be indicated? When should you transfer a burn patient to a designated burn center?

  • In the evaluation of a burn patient, screening laboratory studies are appropriate.
    • Consider: ABG and CXR; cardiac enzymes, and a carboxyhemoglobin level.1,3
  • Administer a tetanus vaccination in the emergency department if indicated.
  • Control pain and administer anxiolytics as required.
  • Monitor resuscitation: bedside ultrasound is useful in the assessment of intravascular volume. Place a foley catheter or perform suprapubic cystotomy to monitor urine output and reduce the risk of abdominal compartment syndrome.3
  • Avoid hypothermia: warm the resuscitation room, administer warm inspired air, apply warm blankets, infuse warmed fluids, and cover wounds with clean dry sheets.2,4
  • Treat inhalation injury as indicated: intubate, order aggressive pulmonary toilet + bronchodilator (albuterol) +/- N-acetylcysteine, aerosolized heparin, aerosolized TPA, recombinant human antithrombin, surfactant, inhaled NO, or ECMO if required (the majority of this will be addressed in an ICU setting).2
  • Consider escharotomy or lateral canthotomy if concern for hypoventilation or compartment syndromes.4
  • After initial stabilization, follow the American Burn Association (ABA) Guidelines for the transfer of patients to designated burn centers. Suggested criteria for transfer can be found on the ABA webpage: http://www.ameriburn.org/BurnCenterReferralCriteria.pdf

A few words on steroids and antibiotics – Today there is no data to support steroid administration in the setting of inhalation injury.2 Prophylactic antibiotics are also withheld in the setting of burn injuries as several studies have demonstrated their administration as promoting systemic fungal infection.2

Morality – The Baux Score (% TBSA + Age) has historically been utilized as a predictor of mortality.2

Summary

In treating a burn patient:

  1. Follow ATLS guidelines in the initial evaluation and resuscitation of the burn patient, with special attention to unique airway considerations.
  2. Evaluate the patient for signs of toxic exposures, particularly carbon monoxide and cyanide.
  3. The burn patient requires comprehensive care. Follow ABA guidelines when considering transfer.

References

  1. DeKoning E. Thermal Burns. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e. New York, NY: McGraw-Hill; 2016. http://accessmedicine.mhmedical. com.foyer.swmed.edu/content.aspx?bookid=1658&Sectionid=109438787.
  2. Friedstat J, Endorf FW, Gibran NS. Burns. In: Brunicardi F, Andersen DK, Billiar TR, Dunn DL, Hunter JG, Matthews JB, Pollock RE. eds. Schwartz’s Principles of Surgery, 10e. New York, NY: McGraw-Hill; 2014. http://accessmedicine.mhmedical. com.foyer.swmed.edu/content.aspx?bookid=980&Sectionid=59610849.
  3. Drigalla D, Gemmill J. Chapter 45. Burns & Smoke Inhalation. In: Stone C, Humphries RL. eds. CURRENT Diagnosis & Treatment Emergency Medicine, 7e.New York, NY: McGraw-Hill; 2011.http://accessmedicine.mhmedical.com.foyer.swmed.edu/content.aspx?bookid=385&Sectionid=40357261.
  4. Latenser BA. Critical Care of the Burn Patient. In: Hall JB, Schmidt GA, Kress JP. eds. Principles of Critical Care, 4e. New York, NY: McGraw-Hill; 2015.http://accessmedicine.mhmedical.com. foyer.swmed.edu/content.aspxbookid=1340&Sectionid=80027724.
  5. Remote Primary Health Clinic Manuals. Burns. 2014. Available from: https://rphcm.allette.com.au/publication/cpm/Burns.html
  6. American Burn Association. Advanced Burn Life Support Course Provider Manual. American Burn Association 2007.
  7. Lawrence A1, Faraklas I, Watkins H, Allen A, Cochran A, Morris S, Saffle J. Colloid administration normalizes resuscitation ratio and ameliorates “fluid creep”. J Burn Care Res. 2010 Jan-Feb;31(1):40-7. doi: 10.1097/BCR.0b013e3181cb8c72. PMID 20061836.
  8. Saffle JI. The phenomenon of “fluid creep” in acute burn resuscitation. J Burn Care Res. 2007 May-Jun;28(3):382-95. PMID 17438489

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Delayed Complications of Sternal Fractures – SGEMHOP

Sternal fractures are a rare sequela of blunt thoracic trauma (Recinos et al.) and most often occur due to motor vehicle collisions. They are also often associated with other chest injuries such as rib fractures and contusions. This week on the Skeptics Guide to Emergency Medicine – Hot off the Press, we had the chance to […]

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