Page 163 - JSOM Fall 2020

TABLE 3 Acceptance Criteria for a Vented Chest Seal
Biological Property Value Chest Seal Test Criteria
Inspiration intrapleural pressure –5 → –8mmHg Holds –5 → –8mmHg negative pressure for ≥ 3 sec
Respiration rate 22–41 breaths/min with a reservoir volume of half total lung capacity
Exhalation intrapleural pressure at pneumothorax ~10mmHg Pressure <10mmHg (ideally close to 0) when air flow
Airflow through the chest seal 200mL/5 min is at 40mL/min
Exhalation intrapleural pressure at pneumothorax ~10mmHg
Airflow through the chest seal 200mL/5 min Pressure <10mmHg (ideally close to 0) when air flow
is at 40mL/min and blood flow is at 25mL/min
Blood flow in hemopneumothorax 25mL/min (max of 226mL)
recreated included extreme temperature conditions representa- dry conditions, volunteers at rest had the adhesive technology
tive of different global climate zones and casualties who were applied to their chest, with the side of the body noted to en-
recently been active and in dirty environments. sure dressings were not applied twice to the same area. After
a dwell time, the adhesive technology was removed, using a
In Vitro Adhesion handheld Mecmesin Force gauge, and the force required to
For the in vitro test methodology, strips of test article were cut peel the adhesive technology from the test area was recorded.
from the chest seal dressing and adhered to a stainless-steel For the sandy dry measurement, an amount of sand was ap-
plate. The plate was then clamped onto a tensiometer at a 90° plied to the chest area before application and the same test
angle to the base. The dressing strip was then folded back on procedure was applied.
itself and clamped into an upper jaw. This creates an 180°peel

test. The force to remove the dressing from the stainless-steel All volunteers then undertook an exercise class within a gym
plate was recorded. before the second application of the adhesive technology for
evaluation in a sweaty/sweaty sandy condition. The gym ses-
To recreate a sweaty environment, acidic sweat was created sion was used to establish a rise in body temperature and in-
as per ISO 105-E04:1987(E) test method 11,12 and dosed onto creased perspiration to mimic physical activity that is expected
the stainless-steel plate. The same procedure as described here on military operations. The adhesive technology was placed
earlier was then carried out. onto the volunteer, on the opposite side of the initial dry sam-
ple without allowing individuals time to cool down. This was
To mimic sandy conditions, sand was dosed onto the stain- done to ensure that the body surface was sweaty, with any
less-steel plate and the same procedure was undertaken. Fur- excess sweat being wiped off as per IFU. Corneometer read-
ther environmental conditions were then created to recreate ings were taken from three areas before each application of
the sweaty sandy/dry sandy conditions that combined the use the dressings. Once the adhesive technology was applied, all
of the acidic sweat and sand as described. volunteers underwent a cool-down period, and after a dwell
time, the adhesive technology was removed, using a handheld
For the extreme temperature conditions, the test articles were Mecmesin Force gauge. The force required to peel the adhesive
conditioned at ambient room temperature (23 ± 2°C), a cold technology away from the test area recorded. For the sweaty/
environment (at least –5°C) and a warm environment (40 ± sandy measurement, some sand was applied to the chest area
2°C) for 24 hours before testing. Following this conditioning prior to adhesive technology application.
period, the test articles were removed from the environmental
chamber and tested within 2 minutes of removal as per the It is important to note that none of the volunteers had the
described test method. area of application shaved before the adhesive technology was
applied. It is not uncommon for a medic/first aid provider to
In Vivo Adhesion have a razor in their equipment for use so shaving can take
The in vivo adhesion study assessed the adhesive technology of place before chest seal application. It is of huge benefit if this
the test article and mimicked the in vitro studies and compared is not required, to save time on application.
active, dirty, and extreme-temperature environments.
For the environmental conditions, the adhesive technology
Volunteers were selected from healthy individuals from both samples were conditioned at three environment, ambient
gender demographics. Significantly more males were recruited room temperature (23 ± 2°C), a cold environment (at least
due to the nature of military frontline workers and the expected –5°C) and a warm environment (40 ± 2°C) for a minimum of
additional challenge of chest hair to the chest seal dressing. 12 hrs. All environments were monitored via a data logged
thermometer. These temperatures were the extremes of what
Active conditions are described as sweaty skin, dirty condi- may be seen in typical military fighting operation environ-
tions described as dirt/sand contaminated skin, and extreme- ments. The adhesive technology samples were placed onto a
temperature environments as those at different temperatures volunteer within 2 minutes of being removed from its envi-
from freezing to hot. ronment for cold and warm samples. After a dwell time, the
adhesive technology was removed using a handheld Mecmesin
To validate and confirm the conditions for sweaty skin, the Force gauge and the force required to peel the adhesive tech-
difference in moisture on the volunteer’s skin was deter- nology away from the test area recorded. Each volunteer had
mined using a corneometer at three positions within the test all three adhesive technology conditions placed onto them in
site. Normal conditions were described as the moisture value one of three positions at random; left upper chest, right upper
of the skin with the volunteer at rest, whereas sweaty con- chest, left upper back. The dwell time was consistent across
ditions confirmed once the skin moisture increased. For the all volunteer studies.

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