Page 77 - JSOM Fall 2019

of midline, significance was not found (p = .06). However, the deployment. Training should be multifaceted and as realistic
large discrepancy (93% versus 68%) does suggest a carryover as possible. Most importantly, CTM localization should be the
effect with respect to markings within 5mm of midline when foundation of ESA and should by no means be assumed.
the LHM was performed after the TM. For vertical accuracy,
maximum distances past the upper border were 10.5mm for Disclaimer
the TM and 9.6mm for the LHM. The maximum distances The view(s) expressed herein are those of the author(s) and
past the lower border were 15.5mm for the TM and 8.4mm do not reflect the official policy or position of Brooke Army
for the LHM. Thus, it was found that those participants who Medical Center, the US Army Medical Department, the US
missed the upper and lower borders did so to a lesser degree, Army Office of the Surgeon General, the Department of the
but with greater frequency, when using the LHM. Air Force, the Department of the Army or the Department of
Defense, or the US Government.
Time to completion was faster for the TM than the LHM. The
minimal and maximal time values for successful TM markings Disclosures
was 7.9 and 48.9 seconds versus 11.4 and 38.4 seconds for the There are no financial disclosures to report. No funding was
LHM. Previous studies found similar marking times for the required for this study.
TM: 14 seconds overall (Bair and Chima ), 15.2 seconds for
5
nonobese males (Lamb et al. ), 10 seconds overall (Elliot et Author Contributions
10
al. ), and 12 seconds for nonobese women (You-Ten et al. ). AM and RC conceived the study concept. AM recruited vol-
7
11
The faster time compared with the LHM can reasonably be at- unteers and coordinated logistics. RC served as the ultrasound
tributed to familiarity with the TM. However, having met the subject matter expert and ensured interrater reliability. RC
30-second goal on average, both should be regarded as viable and UM collected data. AM and JA analyzed data. AM wrote
solutions to identify the CTM in a reasonable timeframe. the first draft, and JA, RC, and UM contributed with manu-
script revisions and final approval.
There were some limitations to the study design. Chiefly, the
target patient population of the average warfighter are mostly References
young, nonobese men and their CTMs are often easily palpa- 1. Levitan RM. Tips and tricks for performing cricothyrotomy.
ble due to their prominent Adam’s apple. Dr Levitan’s LHM is 2014. http://www.acepnow.com
advised for patients whose anatomy is not as readily appreci- 2. Bellamy R. How people die in ground combat. Presented to Joint
ated, such as women. Also, the unequal exposure of the partic- Health Services Support Vision 2010 Working Group, 1996.
ipants to the two identification methods negatively affects the 3. Mabry RL, Frankfurt A. An analysis of battlefield cricothyrotomy
in Iraq and Afghanistan. J Spec Oper Med. 2012;12(1):17–23.
generalizability of the study. A lengthier, more robust intro- 4. Aslani A, Ng S-C, Hurley M, et al. Accuracy of identification of
duction to the new method, such as performed by Kristensen the cricothyroid membrane in female subjects using palpation: an
et al., when introducing ultrasound identification of the CTM observational study. Anesth Analg. 2012;114(5):987–992.
to study participants, could serve as a model for a future study. 5. Bair AE, Chima R. The inaccuracy of using landmark techniques
In their study, participants received computer-based training, a for cricothyroid membrane identification: a comparison of three
20-minute lecture and 20 minutes of hands-on training. 9 methods. Acad Emerg Med. 2015;22:908–914.
6. Campbell M, Shanahan H, Ash S, et al. The accuracy of locating
the cricothyroid membrane by palpation: an intergender study.
Based on the study findings, the authors have some recommen- BMC Anesthesiol. 2014;14:108.
dations. First, military frontline healthcare providers, and com- 7. Elliot D, Baker P, Scott M, et al. Accuracy of surface landmark
bat medics in particular, should continue to be a focus of CTM identification for cannula cricothyrotomy. Anaesthesia. 2010;65:
localization and SCRIC studies and efforts until battlefield suc- 889–894.
cess rates meet or exceed those of civilian prehospital providers. 8. Hiller KN, Karni RJ, Chunyun C, et al. Comparing success rates
We also believe that the LHM still has a place in military med- of anesthesia providers versus trauma surgeons in their use of pal-
pation to identify the cricothyroid membrane in female subjects: a
icine. A future study could include female subjects and males prospective observational study. Can J Anesth. 2016;63:807–817.
with a wide range of BMI. It would also be beneficial to see the 9. Kristensen MS, Teoh WH, Rudolph SS, et al. Structured ap-
results of a study that evaluates the two methods when penetrat- proach to ultrasound-guided identification of the cricothyroid
ing trauma is simulated. Massive hemorrhage could obscure vi- membrane: a randomized comparison with the palpation method
sual landmarks, such as the laryngeal prominence, and the LHM in the morbidly obese. Br J Anaesth. 2015;114:1003–1004.
might fare better than the TM in such an instance. The same 10. Lamb A, Zhang J, Hung O, et al. Accuracy of identifying the
cricothyroid membrane by anesthesia trainees and staff in a Ca-
could be said for patients who are writhing around on a litter nadian institution. Can J Anesth. 2015;62:495–503.
in pain, instead of lying still, or when other stressors of trauma 11. You-Ten KE, Desai D, Postonogova T, et al. Accuracy of conven-
medicine are introduced such as low light and background noise. tional digital palpation and ultrasound of the cricothyroid mem-
brane in obese women in labor. Anaesthesia. 2015;70:1230–1234.
12. Tilghman A. Military data reveals obesity issue, and it’s get-
Conclusion ting worse. 2016. https://www.usatoday.com/story/news/nation
-now/2016/09/12/military-data-reveals-obesity-issue-and-s
The 78% success rate of the TM, higher than in previous stud- -getting-worse/90261454/
ies, is mostly likely the result of recent and recurrent training 13. Henderson JJ, Popat MT, Latto IP, et al. Difficult Airway Society
that is essential to good outcomes, yet there is still room for guidelines for management of the unanticipated difficult intuba-
improvement. SCRIC practice should take place on a routine tion. Anaesthesia. 2004;59:675–694.
basis. Increased frequency and quality of instruction are par- 14. Hagberg CA, Benumof J. Benumof and Hagberg’s Airway Man-
amount during the weeks leading up to and during a combat agement. Philadelphia: Elsevier/Saunders; 2013.

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