Page 55 - JSOM Winter 2022

set to 1, to “complete confidence,” which was set to 5. Sub- was overwhelmingly in favor of the TCK. The TCK is used in
jects scored their confidence to perform SC a median 4 (IQR: the Naval Medical Center Portsmouth TCCC training course,
3–5) under R light. Subjects scored their confidence to per- and the increased familiarity with this kit could have contrib-
form SC a median of 5 (IQR: 5–5) under RG light, which was uted to its success in this participant population. Our results
significantly greater compared to R light (p < .001) (Figure also contradict previous studies demonstrating faster place-
3). Subjects rated difficulty in SC under each lighting choice ment using a BA technique compared to a traditional tech-
12
on a 5-point Likert-scale from “very high difficultly,” which nique. The BA technique was shown to be faster and more
was set to 1, to “very low difficulty,” which was set to 5. Sub- successful in a sheep model of simulated morbid obesity with
jects scored their perceived difficulty to perform SC a median active hemorrhage. These results are more likely to translate to
3 (IQR: 3–4) under R light and a median of 5 (IQR: 4.3–5) situations with loss of palpable anatomy or visible landmarks,
under RG light. Subjects perceived that it was more difficult such as in low-light environments. 13
to perform SC under R light compared to RG light (p < .001)
(Figure 4). Review of observer notes demonstrated that 23% In keeping with the guiding principle of TCCC, the tactical
of BA iterations were complicated by issues specific to manne- suitability of different lights warrants consideration. When
quin design such as friction from silicone and/or dislodgement strict-light discipline must be observed, use of light sources at
of the silicone airway. night, especially white light, is restricted. Enforcement of light
discipline is standard practice among tactical units, impacting
how medical personnel within these units operate. 14,15 There
Discussion
are limited data on the suitability of these light sources, spe-
The use of RG light increased procedural confidence and de- cifically RG light, in tactical settings. There is a critical need
creased perceived difficulty in performing SC on a mannequin to determine if RG light can prevent enemy detection and pre-
in low-light conditions when compared to R light alone. There serve night vision more effectively than white light.
was no significant difference in success rates between light
sources, with high levels of success across all groups. Study Limitations
The biggest limitation in our study is the use of a mannequin
The high success rates observed during this mannequin study model. The model lacks fidelity, which likely resulted in over-
(87.5–93.75%) were not consistent with previous reports us- estimation of the success rates that would be experienced
ing the same kits and mannequin model (76% success for BA; by a similar cohort in a tactical setting. Future work could
40% success for TCK). Higher failure rates were expected be- address these limitations by incorporating artificial blood or
cause of the challenging low-light conditions. In our study, all body fluids as well as simulated combat sounds to make the
participants had prior training experience in SC either in a experimental setting more realistic and challenging. Alterna-
classroom or simulated combat setting, and 50% of our par- tively, live tissue models performed under low light may be
ticipants had experience in both training environments. This more translatable.
contrasts with Dorsam et al., in which only 64% of partici-
pants had prior experience with SC.8 Because SC is a challeng- Additionally, our study population consisted of very few
ing procedure, prior experience could explain these differences corpsman with combat or in field low-light procedure expe-
in success rates in the same mannequin model. rience. A broader population of corpsman may have different
perceptions of difficulty and procedural confidence under the
More importantly, the success rates in our study were also different lighting conditions based on their past experiences.
much higher than the reported 77% success rate of SC on casu- Future work could address this by enrolling a more diverse or
alties in Iraq and Afghanistan. Additionally, a prospective trial larger cohort.
3
in the prehospital combat setting reported an SC success rate of
82%. However, a majority of the procedures were performed Conclusion
by the helicopter medic in which increased lighting, supplies,
10
and training could have improved success. Although the cause This study demonstrates that RG light is subjectively preferred
of the majority of failures was unspecified, some failures were in the performance of SC over R light alone with increased
attributed to subcutaneous passage and left mainstem intuba- procedural confidence and decreased perceived difficulty.
tion. The performance of SC on a mannequin that does not However, RG light did not demonstrate a significant differ-
10
bleed and has clear and simplified tissue planes, coupled with ence in success rates or time to placement. Further research is
the inability to duplicate the physical and emotional stress of needed prior to recommendation of adoption of RG lights on
being in a combat environment, likely contributed to our in- a large-scale basis. However, RG light could be considered for
creased rates of success compared to the reported clinical and use in individual circumstances based on provider preference
operational findings. The addition of blood or other fluids or if deemed tactically acceptable.
the use of live tissue models may confer larger differences be-
tween the two light groups as seen in previous studies evaluat- Acknowledgments
ing procedures under RG light and R light. 5,11 We thank our colleagues at the Combat Trauma Research
Group and the Naval Medical Center Portsmouth Emergency
Although our study also found that TCK was faster to place Medicine Residency Program.
than BA, these results warrant further scrutiny. Participants
observed issues specific to mannequin design including friction Funding
and dislodgment of the replaceable airway that possibly intro- This work was supported by funding from RDT&E 6.6 fund-
duced bias against the BA technique. Furthermore, although ing in support of Clinical Infrastructure, Naval Medical Cen-
the two SC kits tested are both commonly issued to US military ter Portsmouth and by the CIP1 Funds from the Navy Surgeon
personnel, prior training and experience in study participants General Grant.

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