Page 53 - JSOM Winter 2022

TABLE 1 Surgical Cricothyrotomy Success Rates FIGURE 1 Study materials.
Successful Unsuccessful
Kit Light (95% CI) (95% CI)
TCJ R 93.8 (79.9–98.9) 6.3 (1.1–20.2)
TCK RG 90.6 (75.8–96.8) 9.4 (3.2–24.2)
BA R 87.5 (71.9–95.0) 12.5 (5.0–28.1)
BA R 93.8 (79.9–98.9) 6.3 (1.1–20.2)
Two surgical cricothyrotomy kits, the North American Rescue Tacti-
cal CricKit (TCK) and the H&H Medical Emergency Cricothyrotomy
Kit, which is bougie-assisted (BA), were tested in low light conditions
with either red (R) or red-green (RG) light. N = 32 corpsmen.

all applicable federal regulations governing the protection of
human subjects. Research data was derived from that approved
protocol. Participants were United States Navy corpsmen vol-
unteers (N = 33) possessing current TCCC certification and
without physical limitations that would prohibit participation.
The TCCC course teaches evidence-based prehospital trauma
care for use in tactical settings. For US Navy Corpsmen, cur-
rent TCCC certification is defined per Department of Defense
(DoD) Instruction 1322.24 as completion of a TCCC Tier 3 - A. The First Light Tomahawk with elastic headband was used in this
Medical Personnel course within the past 3 years. study. B. Example of R and RG light from First Light Tomahawk on
lowest intensity setting. C. Strategic Operations 6-in-1 Trainer (from
left to right) ready for use, with skin removed to see trachea placement
Light Source and detail of the silicone trachea.
The First Light Tomahawk Multicolor was used as the light
source for both R and RG light (Figure 1A). It is a light-emitting equipment and procedures involved in the study. Upon com-
diode (LED) tactical light that allows the use of four different pletion of the preevent survey, participants were given a
colors (R, green, RG, and white) and three different intensities. 15-minute instructional period on relevant anatomy and land-
In this study, the R and RG settings were used on the lowest marks and detailed, step-by-step instructions on the use of
intensity (Figure 1B). This model was chosen for the study be- both cricothyrotomy kits being used in the study. They were
cause it was able to produce both R and RG lighting from a given time to practice on the same mannequin used during the
single device, reducing confounding variables such as power study until they determined themselves to be comfortable with
output, beam width, and throw. Although it was designed to be the equipment and procedure.
mounted in a variety of ways, including on a helmet or body ar-
mor, all participants in this study used the light as a headlamp. Participants then endured 30 minutes in a dark, windowless
room to allow their eyes to adapt to low-light conditions.
Cricothyrotomy Kits This time period was chosen because the rods, which are the
Two cricothyrotomy kits commonly issued to US military primary scotopic photoreceptor, require approximately 30
personnel were used in this study: the North American Res- minutes to fully adapt, but are considerably adapted after 10
cue Tactical CricKit (TCK), which uses a traditional tracheal minutes. Thereafter, subjects remained in the low-light envi-
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hook placement technique, and the H&H Medical Emergency ronment for the duration of the study, wearing black-out gog-
Cricothyrotomy Kit, which is bougie-assisted (BA). A review gles to maintain light adaptation during transition between
of prehospital use of surgical cricothyrotomy kits involving a rooms, resetting equipment, and recording results.
limited number of patients, identified the TCK as successfully
placed more often than other methods. In a previous simu- After the adaptation period, participants were led to the study
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lated mannequin study, the TCK and the BA outperformed the area where the mannequin was positioned on the floor. Partici-
Control-Cric system, prompting the latter kit not to be chosen pants then sequentially performed the procedure four separate
for comparison in this study. 8 times – using each of the SC kits with each of the two light
conditions. The order in which they performed the procedures
Mannequin was randomized with an orthogonal Latin square design to
The mannequin used was the Strategic Operations 6-in-1 equalize the potential confounds of warm-up effects (from go-
Trainer (Figure 1C). It is a silicone trauma trainer consisting ing first) and fatigue effects (from going last).
of a torso, neck, and head and is designed to facilitate multi-
ple procedures including cricothyrotomy. The anterior neck is Each iteration began with a participant seated on the floor
covered with a replaceable sheet of silicone to simulate skin. wearing blackout goggles and the light source. The cricothy-
Underneath this layer is an anatomically correct silicone air- rotomy kit in its packaging was placed on the mannequin’s
way approximately 3 inches long, with thicker silicone rings chest. Participants were then allowed to remove the blackout
simulating the cartilaginous rings and thinner silicone to sim- goggles and given an opportunity to position themselves and
ulate the cricothyroid membrane. their light prior to commencing. The timer was started when
participants stated they were ready to begin. The iterations
Study Design were observed by two investigators, with one investigator
After being consented, participants completed a preevent sur- keeping and recording time and the other investigator (trained
vey to evaluate their previous experience with regard to train- in the procedure) observing for proper completion and noting
ing, prior operational experience, and familiarity with the any additional observations. Investigators used the same light

Surgical Cricothyrotomy in Low Light | 51