Page 22 - JSOM Summer 2023

function within the harsh combat environment. For example, TABLE 2 List of All MIL-STD-810H Test Methods
devices may be stored and used in extremes of temperatures Test Method
for prolonged periods of time. These extremes include heat Low Pressure (Altitude) Acoustic Noise
(e.g., deserts of Kuwait and Iraq) and cold (e.g., arctic combat
locations). There are other environmental factors to be con- High Temperature Shock
sidered, and it remains unclear which airway devices are resil- Low Temperature Pyroshock
ient under which conditions. Therefore, we sought to perform Temperature Shock Acidic Atmosphere
testing of marketed airway devices in a MIL-STD-type setting. Contamination by Fluids Gunfire Shock
Solar Radiation (Sunshine) Combined Environments
Methods Rain Icing/Freezing Rain
Humidity Ballistic Shock
We tested 10 models of SGA devices according to nine MIL- Fungus Vibro-Acoustic/Temperature
STD-810H test methods. The tested models are listed in Table 1. Salt Fog Freeze/Thaw
MIL-STD-810H contains a total of 30 test methods (Table 2).
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Sand and Dust Time Waveform Replication
Explosive Atmosphere Rail Impact
TABLE 1 Supraglottic Airway Models Subjected to MIL-STD-810H
Testing Immersion Multi-Exciter Test
Company Acceleration Mechanical Vibrations of Shipboard
Model Company Headquarters Location Equipment (Environmental)
Vibration Mechanical Vibrations of Shipboard
air-Q Cookgas LLC, Mercury Clearwater, FL
Medical Equipment (Internally Excited)
AuraGain Ambu Ballerup, Denmark all devices to serve as a baseline. We used the RespiTrainer sys-
AuraStraight Ambu Ballerup, Denmark tem and corresponding software as described in Berard et al
12
King LTS-D Ambu Ballerup, Denmark (Figure 1). The RespiTrainer system consists of a lung model,
LMA Classic Laryngeal Mask Henley-on-Thames, UK a base integrated into the patient interface (intubation trainer/
Company mannequin head), and a computer. With this system, we re-
LMA Fastrach Laryngeal Mask Henley-on-Thames, UK corded the peak inspiration, average inspiration, peak expi-
Company ration, and average expiration of ventilation attempts during
LMA Supreme Intavent Orthofix Maidenhead, UK each operational check. Additionally, the RespiTrainer software
i-gel Intersurgical Ltd. Wokingham, UK provides a graphic display of the lung filling and emptying with
Solus Intersurgical Ltd. Wokingham, UK each ventilation attempt and a bar graph that identifies op-
13
Baska mask Logikal Health Morisset, NSW, timal ranges of ventilation (Figure 1). The bar graph’s red
Products PTY Ltd. Australia section represents over-ventilation, the violet section represents
under-ventilation, and the green section represents the appro-
According to MIL-STD-810H, the test plan should be tailored priate ventilation level. Along with the inspiration and expira-
based on the test methods applicable to the testing device. We tion values, we used the bar graph and graphic display of the
were unable to identify other sources informing the use of lungs to determine whether the test device could provide the
MIL-STD-810H tests on similar medical devices. To establish appropriate ventilation levels. After each test, we performed
test applicability, five military (four active duty, one retired) another operational check to determine any damage caused by
and civilian emergency medicine SMEs selected the nine test the test.
methods in this study using a systematic selection process.
Each SME listed the relevance of each test and the results com- FIGURE 1 RespiTrainer system and corresponding software.
piled. The test methods we chose included the high tempera-
ture, low temperature, freeze/thaw, humidity, contamination (A) (B)
by fluids, sand and dust, solar radiation (sunshine), and the
shock and low pressure (altitude) tests. We followed each test
method according to MIL-STD-810H standards. For each test,
the parameters (e.g., temperature, humidity) were tailored to
ensure the devices were subjected to the environmental condi-
tions expected in the military combat setting.
We completed all tests, with n=3 for each model, with the ex-
ception of the LMA Classic (n=2) because of stock unavail-
ability resulting from the Covid-19 pandemic-related material
shortage. Each device of the same type was labeled as A, B, (A) QuickLung RespiTrainer Advance system, including mannequin,
or C to distinguish between devices of the same model. For lung model, and PC software. (B) RespiTrainer software with a graphic
instance, the i-gel devices were labeled as i-gel A, i-gel B, and display of the lungs and a bar graph for determining the appropriate
level of ventilation.
i-gel C. In keeping with industry standards, tests were not
blinded or randomized. We conducted visual examinations before and after every test,
as well. The procedure consisted of visually determining any
Operational Checks and Visual Examinations operational or aesthetic damage to the test device. Examples of
Before testing, we (CB, DZ, MG, SS) performed an operational potential damage include distortion or deterioration of seals,
check using the IngMar Medical QuickLung RespiTrainer Ad- discoloration, cracking of plastic components, alteration of
vance RespiTrainer Advance Airway Management Trainer on material properties, blockage of the airway tube, tearing of the

20 | JSOM Volume 23, Edition 2 / Summer 2023