Original contributionExperience with Chitosan Dressings in a Civilian EMS System
Introduction
Hemorrhage is the second leading cause of death in civilian trauma and the leading cause of death from battlefield trauma in the military (1, 2, 3, 4). There has been little advancement in the control of external hemorrhage, as evidenced by our reliance on gauze dressings and direct pressure, which has remained unchanged for hundreds of years. As such, there recently has been a significant interest in the development of new external hemostatic agents to achieve hemostasis when conventional methods fail. One of these products is the HemCon® Bandage (HemCon Medical Technologies, Inc., Portland, OR), which is a 10 cm × 10 cm × ∼2 mm-thick square bandage (Figure 1) composed of chitosan and a non-absorbable backing in a vacuum-sealed pouch.
Chitosan is a biodegradable, non-toxic, complex carbohydrate derivative of chitin (poly-β[1→4]-N-acetyl-D-glucosamine), a naturally occurring substance (5). Numerous animal studies have demonstrated its effectiveness as a hemostatic agent in controlling bleeding from both arterial and venous sources, as well as in coagulopathic subjects (6, 7, 8, 9, 10, 11). There are several factors that are thought to contribute to the hemostatic function of chitosan, the most important being its inherent mucoadhesive properties. Additional mechanisms thought to be involved include platelet activation, vasoconstriction, and interactions with red blood cells through ionic forces and cell surface proteins (12, 13, 14, 15, 16). Other possible beneficial attributes of chitosan have been proposed as well, including antimicrobial activity and improved wound healing compared with standard dressings (17).
The military has been the first to employ many new hemostatic agents in humans and the HemCon® Bandage has been distributed to medical personnel involved with combat operations in Iraq and Afghanistan. A retrospective review of 64 uses from these two conflicts suggests that the HemCon® Bandage is an effective hemostatic agent for pre-hospital combat casualties when standard methods are unsuccessful (5). Given that significant morbidity and mortality also can result from uncontrolled external hemorrhage in civilian emergency medical services (EMS) systems, it was hypothesized that a chitosan-based dressing also may control hemorrhage in wounds not responding to direct pressure.
Section snippets
Study Design
Data for this case series were obtained through a retrospective chart review of prospectively completed data collection forms after each HemCon® Bandage use, as well as the accompanying pre-hospital case record. The data form was adapted from the one used by the military. The institutional review board at the Oregon Health & Science University (OHSU) approved the study, and waived the requirement of informed consent.
Study Setting and Population
The HemCon® Bandage was added to the trauma kits of all 22 frontline
Results
Thirty-seven uses of the HemCon® Bandage were reported within the 15-month study time period. Complete data on the primary outcome variable were present for 34 cases (Table 1). In three cases, the time to cessation of bleeding after HemCon® Bandage application was not recorded and these cases were eliminated from further analysis.
Of the 34 uses analyzed, no adverse events or complications were reported. Most of the wounds were extremity wounds (53%) with lacerations to the head, neck, and face
Discussion
In recent years, the U.S. Food and Drug Administration has approved several hemostatic agents and bandages for hemorrhage control. Unfortunately, human clinical data are lacking and most of these products have been tested only in animal models of severe hemorrhage. Chitosan-based dressings have been successfully used in swine models of splenic trauma, liver lacerations, and aortic perforation. (7, 8, 10). The only reported human experience to date comes from use in Operation Iraqi Freedom and
Limitations
Due to the observational nature of this study, there are several limitations that deserve attention. Our findings are limited by the small sample size and factors inherently present in EMS studies. Data collection was based on written accounts by the EMS providers and could not be independently verified. For example, we could not confirm whether the sources of bleeding were indeed venous or arterial. In addition, the amount of pressure and duration of compression used with gauze dressing
Conclusions
The chitosan-based HemCon® Bandage is beneficial in stopping uncontrolled external hemorrhage in the civilian EMS setting when traditional methods such as pressure and gauze fail. Proper training in the use of the bandage is essential because user error was a contributing factor in most of the documented failures. Future trials should attempt to address the differences in morbidity and mortality using traditional methods vs. the HemCon® Bandage.
Acknowledgment
We thank Tualatin Valley Fire EMS Chief Mark Stevens, Alec Belman, md, and Staci McAdams of HemCon Medical Technologies, Inc. for their collaborative efforts with this study.
References (18)
- et al.
Lethal injuries and time to death in a level I trauma center
J Am Coll Surg
(1998) - et al.
The effect of chitosan (poly-N-acetyl glucosamine) on lingual hemostasis in heparinized rabbits
J Oral Maxillofac Surg
(1999) - et al.
Chitosan enhances platelet adhesion and aggregation
Biochem Biophys Res Commun
(2003) - et al.
Synergistic platelet integrin signaling and factor XII activation in poly-N-acetyl glucosamine fiber-mediated hemostasis
Biomaterials
(2005) - et al.
Healing at skin graft donor sites dressed with chitosan
Br J Plast Surg
(2000) - et al.
Epidemiology of trauma deaths: a reassessment
J Trauma
(1995) - et al.
The epidemiology of traumatic deathA population-based analysis
Arch Surg
(1993) The causes of death in conventional land warfare: implications for combat casualty care research
Mil Med
(1984)- et al.
A special report on the chitosan-based hemostatic dressing: experience in current combat operations
J Trauma
(2006)