Page 19 - JSOM Spring 2025

Comparison of Novel Chest Seal Designs to
Commercially Available Chest Seals at
Relevant Physiological Pressures

Nathan Wells, MS *; Johnathon M. Aho, MD, PhD 2
1

ABSTRACT
Background: Tension pneumothorax is a leading cause of blood filled the chest cavity in about half of the identified tho-
preventable death in combat scenarios. When treating a chest racic injuries, highlighting the importance of draining both air
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wound with the potential for open hemopneumothorax us- and blood for effective treatment of an open chest wound.
ing a chest seal, it is important that it efficiently drain fluid While recent data show progress in outcomes, there is signifi-
from the chest cavity. We tested the ability of commercial and cant room for improvement. 5
novel chest seal designs to drain fluid from a simulated chest
wound. Methods: Eight novel laminar chest seal designs were The treatment of a chest wound with potential for open trau-
created and compared to six commercially available chest matic hemopneumothorax in the prehospital setting is of high
seals. Closed-cell foam with a hole was used to simulate a chest urgency. Once the chest wall is punctured and the lung col-
wound. Fluid pressures of 10, 30, and 100cmH O were tested. lapses, there is a threat of developing a tension pneumotho-
2
Mean flow rate through the chest seals was calculated. The per- rax or hemothorax as air and fluid fill and become trapped in
centage of the laminar channels completely saturated with fluid the pleural space. The diameter of the chest wall injury must
was also measured. The effect of laminar channel width and only be two-thirds the diameter of the trachea before air will
quantity on the dependent variables was determined. Results: preferentially enter the pleural space through the chest wound
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Novel chest seals with the highest flow rates were comparable instead of the trachea. Treatment options have included com-
to commercial chest seals with the highest flow rates at all pres- pletely sealing the chest wound with an occlusive dressing,
sures. Channel saturations were also similar between novel and securing a dressing only on three sides, or using a more com-
commercial chest seals. As the width of the laminar channels plex chest seal to create a one-way valve. This valve allows
increased so too did flow rate (p=.048), while the percentage for air and fluid drainage from the chest cavity, while keeping
of channel saturation decreased (p=.006). As the quantity of air from entering through the chest wound. Evidence suggests
channels increased, the flow rate tended to increase (p=.02), occlusive dressings initially restore respiratory mechanics but
and percentage of channel saturation decreased (p=.03). eventually lead to development of tension pneumothorax and
Conclusions: Laminar vented chest seals with wider channel respiratory failure if air continues to accumulate in the chest
8,9
widths and more channels had higher flow rates and lower per- cavity. Current guidelines in treatment of an open chest
centages of channel saturation. Certain novel chest seal designs wound are to apply a vented chest seal, if available and is man-
used in this study were comparable to commercial designs in datory in open pneumothorax with a sucking chest wound to
flow rate and percentage of channel saturation. prevent tension physiology. 10
Keywords: chest seal; tension pneumothorax; There are several vented chest seals currently available on the
hemopneumothorax; thoracic trauma; prehospital care market, each with a unique design of laminar channels or one-
way flutter valves. Although few studies have been done to
assess each design’s capacity to effectively act as a one-way
vent and restore respiratory function, early studies showed
Introduction
that the different commercial chest seals had similar abilities
In 2022 over 225,000 deaths occurred as a result of prevent- to evacuate air from the chest cavity. 9,11 A more comprehen-
able trauma in the United States. According to some reports, sive study involving a selection of five commercially available
1
thoracic injuries account for 25%–32% of all traumatic inju- vented chest seals found that there were significant differences
ries. Mortality rates for these injuries in civilians range from in performance, especially between laminar and flutter valve
2,3
around 8%–32%. Thoracic injuries are also a major threat in designs. Both flutter valve designs tested in a swine model
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combat scenarios. During the recent U.S. Military operations were unable to effectively drain blood from a hemopneumo-
in the Middle East, thoracic injuries accounted for 4.9%–9.9% thorax, with some designs becoming unusable due to blood
of all combat-related injuries, around 10% of which proved to clotting the valves. It was also shown that certain laminar de-
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be fatal. A study of a large combat casualty database from the signs were unable to properly drain blood. While in the case
5
Vietnam War estimated 3%–4% of all combat casualties were of a hemothorax, the standard treatment would be drainage
a result of tension pneumothorax, many of which may have of the blood through a tube thoracostomy, this may not be
been treatable. It was also found that a significant amount of available in many treatment settings. Although the primary
*Correspondence to nathan.wells@wichita.edu
2
1 Nathan Wells is affiliated with the Department of Biomedical Engineering, Wichita State University, Wichita, KS. Dr. Johnathon M. Aho is
affiliated with the Sanford School of Medicine, University of South Dakota, Vermillion, SD.
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