Page 33 - JSOM Summer 2023

TABLE 5 Final Score for Each Model of SGA Device Discussion
SGA Device Model Final Score The LMA Classic had the highest total score, but the model
LMA Classic 25.9 is a first-generation SGA device without a gastric channel or
AuraGain 25.5 bite block and requires cuff inflation. The AuraGain had the
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i-gel 25.2 second highest score; the model is a second-generation SGA
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Solus 24.4 device with a gastric channel but still requires cuff inflation.
LMA Fastrach 24.4 The i-gel scored third; the model is a second-generation SGA
AuraStraight 24.1 device with a gastric channel and bite block and does not re-
King LTS-D 22.1 quire cuff inflation. 17,18 Time and ease of insertion of these
LMA Supreme 21.0 three devices has been previously studied, demonstrating no
air-Q 20.1 significant difference between these devices with respect to
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Baska mask 18.1 these performance measures. Although these devices scored
SGA, supraglottic airway highest overall, they showed some limitations on specific tests.
The AuraGain and i-gel performed poorly during the sand and
King LTS-D dust tests. The LMA Classic was the best performing device;
The cuff of the King LTS-D tore during the shock test, and however, failure conditions may not have been detected be-
the tear became worse during the sand and dust test. The cuff cause of the fewer number of devices available for testing.
would not inflate, which slightly reduced the ventilation level
until the contamination by fluids test prevented the appro- This study evaluated the durability of SGA devices in a mili-
priate ventilation level from being reached. Additionally, the tary environment setting, which has significant crossover with
freeze/thaw test caused all King LTS-D devices to become rigid civilian care in austere or first-responder scenarios. For future
and made insertion into the mannequin difficult. studies, a wider selection of MIL-STD-810H tests should be
conducted. This will allow further examination of the dura-
LMA Supreme bility of the SGA devices. Additionally, testing will focus on
The contamination by fluids test caused the devices to be- individual tests with a larger sample size to further examine
come more flexible, resulting in difficult insertion and dam- the effects of each test. The structural integrity and mechan-
age to one cuff of the device. Also, operational checks after ical properties of each device would also be explored by im-
the low-pressure (altitude) and low-temperature tests showed plementing mechanical tensile testing. Further testing should
that appropriate ventilation levels were difficult to reach after focus on the top three performing devices to examine more
those tests. Finally, the humidity test caused cuff discoloration possible failure modes.
and moisture inside the cuff.
Limitations
air-Q This study has several important limitations. The nine MIL-
The contamination by fluids and high-temperature tests made STD-810H tests selected by our expert panel do not represent
the devices more flexible, resulting in difficulty inserting the the full breadth of tests available. The scoring system, while
devices into the airway model. Similarly, the devices became systematic and technically justified, may contain systematic
more rigid during the low-temperature test. During the sand biases. Future work should explore independent validation of
and dust test, the devices contained significant amounts of the selected standards and our scoring system. Initially, we had
particulate in the airway tubes after the 10-second cleaning planned a sample size of 20 and a pristine device for each test.
period. For the humidity test, the cuffs became discolored and However, because of delays in obtaining the devices, attribut-
received deformation damage. able to the COVID-19 pandemic shutdowns, we were able to
obtain only three devices of each model. A larger sample size
Baska Mask would allow for more robust statistical testing, as in Bielski
21
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The devices became more flexible during the contamination et al (2019) and Gupta et al (2015). Lastly, we solicited
by fluids and high temperature tests, resulting in difficult in- military and emergency medicine SME input to inform the se-
sertion. The operational check after these tests also showed lection of SGA device models and MIL-STD-810H test meth-
difficulty in providing the appropriate ventilation level. Fur- ods utilized in this study. Additional models and test methods
ther, the operational check after the freeze/thaw test showed could have been implemented but were outside the scope of
that Baska Mask C failed to provide the appropriate ventila- this study.
tion level. During the sand and dust test, the devices contained
significant amounts of particulate in the airway tubes after the Conclusions
10-second cleaning period.
Although the LMA Classic, AuraGain, and i-gel scored the
Exploratory Tests Results best, the variation of scores among the top six performers
The results from the visual examination of the exploratory is small, and the clinical and practical significance of score
tests (vibration, acceleration, and blast chamber) showed little differences is not established. Therefore, it is not possible to
to no damage on most of the models (Table S11). No damage select a single optimal device for all situations. However, the
was noticed on any of the models after the vibration and ac- performances of the models in each test provide insight into
celeration tests. The blast chamber caused damage to the LMA which models should be avoided in certain situations. For in-
Fastrach, LMA Supreme, and i-gel models. The test destroyed stance, the Solus performed poorly during the low temperature
the plastic handle on the LMA Fastrach, warped and fractured and freeze/thaw tests, suggesting that the model should not
the vent connector on the LMA Supreme, and cracked the gas- be used in arctic environments. The AuraStraight performed
tric channel connection piece on the i-gel. poorly during the high temperature and solar radiation tests,

Testing SGA Devices in Military Combat | 31