Page 73 - JSOM Fall 2019

A Comparison of the Laryngeal Handshake Method
Versus the Traditional Index Finger Palpation Method in
Identifying the Cricothyroid Membrane, When Performed
by Combat Medic Trainees

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Amy Moore, MPAS, PA-C *; James K. Aden, PhD ; Ryan Curtis, DSc, PA-C ;
Mohamad Umar, DSc, PA-C 4

ABSTRACT
Background: The laryngeal handshake method (LHM) may FIGURE 1 Illustration of the LHM. (A) The index finger and thumb
be a reliable standardized method to quickly and accurately grasp the top of the larynx at the lateral edges of the hyoid bone and
identify the cricothyroid membrane (CTM) when performing roll it from side to side. (B) The fingers and thumb slide down over
the lateral larynx along the thyroid laminae. (C) The middle finger
an emergency surgical airway (ESA). However, there is cur- and thumb rest on the lateral aspects of the cricoid cartilage, with the
rently minimal available literature evaluating the method. index finger palpating the cricothyroid membrane (CTM) at midline. 1
Furthermore, no previous CTM localization studies have fo-
cused on success rates of military prehospital providers. This
study was conducted with the goal of answering the question:
Which method is superior, the LHM or the traditional method
(TM), for identifying anatomical landmarks in a timely man-
ner when performed by US Army combat medic trainees?
Methods: This prospective randomized crossover study was
conducted at Ft Sam Houston, TX, in September 2018. Two
Army medic trainees with similar body habitus volunteered as
subjects, and the upper and lower borders and midline of their
CTMs were identified by ultrasound (US). The participants (A) (B) (C)
were also recruited from the medic trainee population. After
receiving initial training on the LHM and refresher training TM, which uses the nondominant hand to stabilize and only
on the TM, participants were asked to localize the CTMs of the index finger of the dominant hand to palpate the CTM
each subject with one method per subject. Success was defined (Figure 2).
as a marking within the borders and 5mm of midline within
2 minutes. Results: Thirty-two combat medic trainees partici- Multiple studies have been conducted analyzing the success
pated; 78% (n = 25) successfully localized the CTM using the of physicians and specialty providers in manually locating the
TM versus 41% (n = 13) using the LHM (p = .002). Conclu- CTM; however, there is minimal research evaluating Dr Levi-
sion: Findings of this study support that at present the TM is a tan’s LHM. Furthermore, no known CTM localization studies
superior method for successful localization of the CTM when have focused on frontline military healthcare providers’ pro-
performed by Army combat medic trainees. ficiency in doing so. This study sought to identify the more
successful of the two methods and could be used as a basis for
Keywords: laryngeal handshake method; cricothyrotomy future studies, which may ultimately affect training curriculum
landmarks; cricothyrotomy palpation; austere cricothyrot- and practices.
omy; prehospital cricothyrotomy; military cricothyrotomy
Study Background
Airway compromise is the third leading cause of preventable
Introduction
death on the battlefield. A 22-month review of ESA per-
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The first step in performing an ESA is identifying the CTM. formed during Operation Enduring Freedom (OEF) and Oper-
Army medics are currently trained to localize the CTM us- ation Iraqi Freedom (OIF) revealed a 68% success rate among
ing the traditional index finger palpation method (TM). The all medical providers on the frontlines and battalion aid sta-
LHM, introduced in 2012 by airway expert and inventor of tions, including 85% success by junior physicians and phy-
the Airway Cam , Dr Richard Levitan, offers an alternative sician assistants (PAs) and 67% success by combat medics.
®
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approach. With the LHM, the entire dominant hand is used to The extra stressors of battlefield medicine include a tactical
identify the laryngeal landmarks (Figure 1), in contrast to the environment, the reliance on an individual or a small team
*Address correspondence to Amy Moore, MPAS, PA-C, 3551 Roger Brooke Dr, Ft Sam Houston, TX 78234 or Amy.m.moore66.mil@mail.mil
1 MAJ Moore is with the Department of Emergency Medicine, Brooke Army Medical Center, Fort Sam Houston, TX. Dr Aden is with the
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Department of Statistics and Epidemiology, Brooke Army Medical Center. LTC Curtis is program director, Army-Baylor Emergency Medicine
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Fellowship, Department of Emergency Medicine, Brooke Army Medical Center. LTC Umar is program director, BAMC Emergency Medicine
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Fellowship, Department of Emergency Medicine, Brooke Army Medical Center.
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