Page 147 - Journal of Special Operations Medicine - Winter 2014

equaled 100% of the animal’s estimated total lung ca- of time patients spend in areas of direct threat and in
pacity. The study found that while vented chest seals subsequent transport to definitive care are shorter. In
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prevented the development of tension physiology in the the latter, the likelihood of a patient developing a fa-
model, occlusive chest seals with no valve resulted in the tal tension pneumothorax prior to being reassessed by
development of a tension pneumothorax. However, it is medical personnel is low. This is an important consid-
also important to note that application of an occlusive eration, especially when taken in context of the find-
chest seal improved work of breathing, reestablished ings by Kheirabadi and colleagues demonstrating the
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negative intrapleural pressure, and restored most respi- improved of respiratory effort and hemodynamics with
ratory and circulatory measures. Not until insufflation application of either type of chest seal.
of 1.4L under positive pressure ventilation was a differ-
ence in respiratory status noted. Further, it is often the case on the battlefield that a
single medic is tasked with treating multiple critically
In the study by Kotora et al., a surgical thoracostomy ill patients. There is a greater potential for providers
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was created in the swine model, then sealed, and fol- to become distracted by other casualties or contingen-
lowed by an infusion of a combination of air and blood cies and fail to notice the signs and symptoms of a ten-
into the chest cavity. The authors found that the stud- sion pneumothorax in a casualty who has previously
ied commercial vented-chest-seal products all prevented had an open pneumothorax treated with a nonvented
development of tension physiology. These animal stud- chest seal. Conversely, in the civilian setting, there are
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ies raise significant and potentially broad implications typically multiple EMS providers available to man-
for civilian, prehospital trauma care practice. In addi- age, receive, and reassess patients, thereby increasing
tion to dedicated tactical medicine programs, increasing the likelihood of identifying the development of a ten-
numbers of conventional EMS personnel are providing sion pneumothorax. Acknowledging these fundamen-
tactical medical support or are deployed as part of res- tal operational considerations, the C-TECC Guidelines
cue task forces responding to active assailant and im- Committee could not definitively conclude that a clear
provised explosive device attacks. However, there are superiority exists in terms of clinical outcome compar-
fundamental differences when comparing battlefield ing vented versus nonvented chest seals when combined
and civilian trauma care environments that must be con- with a comprehensive decompression strategy.
sidered when formulating recommendations for vented
versus nonvented chest seals. Placement of a chest seal is the first step in the field man-
agement of open chest wounds and presumed pneumo-
First, the incidence of tension pneumothoraces as a cause thoraces. Independent of whether the seal is vented, a
of death in the civilian first-responder community is un- chest seal provides initial treatment of respiratory com-
clear. A 2011 report from Mark et al. reviewed the Fed- promise associated with the violation of the chest cav-
eral Bureau of Investigation Law Enforcement Officers ity and resultant hypoxia. It is the position of C-TECC
Killed and Assaulted database. Of the 533 line deaths, that for agencies that are developing new policy, proce-
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108 met inclusion criteria: 90 cases involved penetrat- dures, and protocols for the management of penetrating
ing chest trauma and 18 involved the upper back. Sixty chest trauma, vented chest seals likely confer additional
cases were ultimately evaluated, of which zero identi- clinical benefit without a significant difference in cost or
fied tension pneumothorax as a direct or contributing compromise in durability. Alternatively, if an agency is
cause of death. This study has obvious limitations, the already deploying a nonvented chest seal device or other
most notable of which is that it did not address near occlusive dressing, C-TECC currently recommends us-
misses of those who survived penetrating chest trauma. ing a tiered approach for chest decompression that in-
The second confounding factor is an absence of data cludes serial reassessments, burping applied dressings,
demonstrating that open pneumothoraces alone result and needle decompression, when signs and symptoms
in fatalities. Finally, all recommendations for changing indicating tension physiology develop. 9
acquisition and purchasing of equipment must take into
account local budgets and cost–benefit ratios. Though Disclosures
vented chest seals have been shown to prevent tension
pneumothoraces better than nonvented chest seals in the The author has nothing to disclose.
laboratory, the clinical implications of these findings in
the civilian operational environment are yet unstudied. References
1. Haynes B. Dangers of emergency occlusive dressing in
Battlefield injuries often occur in locations remote from sucking wounds of the chest. JAMA.1952;150:1404.
comprehensive medical care and in the context of pro- 2. Sellors T. Chest injuries. Br Med J. 1957;2:1097.
tracted operational engagements. This is in contrast to 3. Committee on Tactical Combat Casualty Care. TCCC
most civilian environments, in which the overall duration minutes 0807. July 2008. http://www.naemt.org/Libraries

Vented Versus Nonvented Chest Seals 137