Date:  May 13th, 2014 

Guest Skeptics: Dr. Steve Carroll is an active duty Emergency Medicine Physician with the US Army.  He runs the EM Basic podcast which reviews core EM topics at the level of a medical student or intern.  Steve is currently on the clinical staff at Darnall Army Community Hospital in Fort Hood Texas. However,  this summer he will be moving back to San Antonio Military Medical Center to be Emergency Medicine Faculty where he did his residency.

Dr. Carroll’s views are his own and do not represent those of the Department of Defense or the US Army.  He also has no conflicts of interest to disclose about any of the devices discussed on the podcast or in this blog. I too have no conflicts of interest with what we are discussing on today’s podcast.

Case Scenario: You are working on a Saturday overnight shift when you get a trauma patient from a rollover motor vehicle accident.  The patient is a 21 year old male who had “just two beers” and was speeding at over 90 miles per hour (~160km/hr).  He arrives to the ED combative and its clear he has a bad head injury along with several extremity fractures and a surgical abdomen.  It’s also clear that he needs to be intubated and as Cliff Reid likes to say, he has a lack of ketamine in his blood.  You set up your equipment for the intubation and one of the nurses asks you “Are you going to use DL or the GlideScope”  You ponder this for a second as your prep your other equipment.

Question: Which is better for intubation in trauma patients, video or direct laryngoscopy?

Background: Emergency Medicine owns the acute airway. A paper by Walls et al in 2011 showed that 87% of intubations from the National Emergency Airway Registry were performed by emergency physicians. More than two thirds of the time rapid sequence intubations (RSIs) were performed. The initial attempt had a 95% success rate.

716px-Glidescope_02There have been a number of advances in the last few years. Many of these advances have been in new airway management devices. There are a variety of video laryngoscopy (VL) tools which are displacing traditional direct laryngoscopy (DL).

For an excellent discussion on the complexities of DL vs. VL check out the paper by Levitan et al in the Annals of Emergency Medicine 2011. Another good resource to review is by Levitan and Weingart from Annals of Emergency Medicine 2012. They discuss pre-oxygenation and prevention of desaturation during emergency airway management.

There are some great FOAM sources which you can review for free on this topic. One is from ALiEM and the other is a PRO/CON discussion about DL vs. VL from LITFL.

Article: Yeatts et al. Effect of video laryngoscopy on trauma patient survival: A randomized controlled trial.  J Trauma Acute Care Surg. 2013 Aug;75(2):212-9.

  • Population: Trauma patients at Shock Trauma in Baltimore, Maryland, USA
  • Intervention: Video  laryngoscopy (Glidescope)
  • Comparison: Direct Laryngoscopy
  • Outcome:
    • Primary- Mortality
    • Secondary- Survival among subgroups, duration of intubation attempt, desaturation during procedure, first pass success rates

Authors’ Conclusion: “Video laryngoscopy (VL) and direct laryngoscopy (DL) similar for mortality, post-hoc analysis showed possible increased mortality in those with the most severe head injuries who were randomized into the VL group.”

Quality Check List for Randomized Control Trials:checklist-cartoon

  1. Were these ED patients? – YES, but only the most injured get transferred to Shock Trauma so may have higher ISS scores than the average ED
  2. Were the patients adequately randomized? YES
  3. Was the randomization process concealed? YES
  4. Were the patients analyzed in the groups to which they were randomized? YES
  5. Were patients recruited consecutively? NO
  6. Were patients in both groups similar with respect to prognostic factors? YES
  7. Were participants unaware of group allocation? NO
  8. Were groups treated equally except for the intervention? YES
  9. Was follow-up complete? YES
  10. Were all patient-important outcomes considered? YES
  11. Was the treatment effect large enough and precise enough to be clinically significant? NO

Key Results: 

Primary Outcome: No statistical difference in survival to hospital discharge

  • Primary Outcome:
    • Mortality was 9% (28/303) in the VL group and 8% (24/320) in the DL group (p = 0.43)
  • Secondary Outcomes:
    • VL resulted in a longer time to intubation- 56 seconds vs. 40 seconds
    • Post-hoc analysis showed that those with the most severe head injuries had a higher mortality and more frequent desaturations below 80% (50% in VL vs. 24% in DL); however this was not included in the original study design
    • First pass succeess was the same in both groups at 80%

Screen Shot 2015-04-25 at 3.11.12 PM

This was a well done study with one significant weakness.  The strengths include the fact that it was a randomized trial, all patients were followed up for the primary endpoint, and the study used video to record the resuscitation to avoid any bias inherent in a chart review.

The one weakness is that attending physicians were permitted to not enroll patients if they did not want to take part of this study, even if they were eligible.  This could have introduced significant selection bias as the more difficult airways may not have been included due to the attending physician wanting to use the technique that they were more comfortable with.

According to the authors, those excluded did not differ significantly from ther enrolled patients.  The treating physicians knew the treatment assignments but this is not a concern since there is no possible way to blind the clinicians given VL and DL are different procedures that required different equipment.

This study leads support that VL is at least as useful as DL when intubating trauma patients.

The Bottom Line: VL leads to the same outcome as DL in trauma patients.  VL takes longer to accomplish and may be associated with higher mortality in patients with severe head injuries, however this relationship will require more study to confirm.

Dr. Steve Carroll

Dr. Steve Carroll

Case Resolution: You decide to use the glidescope in this case because you feel as if it might be better in this case since the patient is in a cervical collar.  Knowing that the glidescope may take a little longer to pass the tube you make sure to properly pre-oxygenate the patient with high flow oxygen with a non-rebreather mask at 30-60 liters per minute and use a nasal cannula set at 15 liters per minute kept on during your intubation attempt.  You get an excellent view with the GlideScope and pass the tube on your first attempt.

Clinical ApplicationThis study supports the use of video laryngoscopy in trauma patients.

What Do I Tell Patients: Video laryngoscopy is at least as good as direct laryngoscopy.

Keener Kontest: Last weeks winner was Jake Turner. He knew the most common cause of scapula winging is paralysis of the serratus anterior muscle.

If you want to play the Keener Kontest this week then listen to the podcast for the question. Email me your answer at TheSGEM@gmail.com with “keener” in the subject line. The first person to correctly answer the question will receive a cool skeptical prize.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.