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Abstract & Commentary
Source: Alam HB, et al. Application of a zeolite hemostatic agent achieves 100% survival in a lethal model of complex groin injury in swine. J Trauma 2004;56:974-983.
Control of hemorrhage in the field is of utmost importance in improving survival from trauma. Although this is not possible for internal bleeding, a substance that can be applied to external wounds and control bleeding—in a manner that outperforms direct pressure or bandages—would be enormously useful. A number of readers may be aware of reports of two agents being used on the battlefield in Iraq QuikClot and HemCon. The authors report a study that compares these agents plus others in a swine model of uncontrolled hemorrhage.
QuikClot —a powdered mineral zeolite hemostatic agent — controls hemorrhage via a mechanism that primarily depends upon the absorption of water. This process is exothermic (i.e., it releases heat). The temperature increase can be significant and has been shown to be 65°C in vitro and between 42 and 44°C in wound models. The temperature release is dependent upon the blood-to-zeolite ratio and the residual moisture content of zeolite. The temperature increases quickly (within minutes) and is sustained for 30 minutes. There is a potential risk for this heat to cause tissue damage. HemCon is a chitosan- (deacetylated poly-N-acetyl glucosamine) based dressing that is applied in the form of a coated sponge backed with foam. It works primarily by sticking to the tissues and sealing the injury. TraumaDex is a powder-like agent that consists of bio-inert microporous particles that absorb water and promote clotting by producing a gelling action. Quick Relief is a mixture of hydrophilic polymer and potassium salt that has the appearance of coarse black sand. It interacts with the blood to form a scab. Finally, Fast Act is a hemostatic product derived from bovine clotting factors that activate factors II, V, VIII, and XIII.
The hemorrhage was created by a scalpel transection of the femoral artery and vein, just below the inguinal ligament in anesthestized swine. The exsanguination was permitted to continue for three minutes before the application of the bandage. Ten percent of the animals died as a result of this phase and were excluded. The authors applied no dressing, standard dressing, four variations of zeolite hemostat, HemCon, Quick Relief, Fast Act, or TraumaDex. In keeping with the real world concept for the animal model, Hespan resuscitation was started 15 minutes after injury. The primary outcome measurement was survival.
All of the animals treated without a dressing expired within 50 minutes. All of the animals treated with QuickClot survived (3.5 oz of the zeolite hemostat formulation with the lowest residual moisture content [1%]). Minimal histologic damage was noted in the use of all formulations of a zeolite hemostat. Wound temperatures were within the 50 to 60°C range for all zeolite formulations. HemCon achieved a 71% survival rate, the highest of the hemostatic agents that were not zeolite-based and was noted by the authors to either work well or fail completely in a way that suggested a quality control issue with individual dressings. The authors found that QuickClot was effective equally when used as a straight powder or applied in small teabags to the wound. This eliminated the need for meticulous debridement of the zeolite powder.
Commentary by Richard J. Hamilton, MD, FAAEM, ABMT
QuickClot is a very effective hemostatic agent. It should be used only for life-threatening hemorrhage, and currently is employed in Iraq when a battlefield wound does not respond to initial field methods for control of hemorrhage, such as the application of a pressure bandage. It is no stretch of the imagination to see this material implemented into emergency medical service units in the United States. There may even be a role for its use in emergency departments to stabilize hemorrhagic wounds prior to transport, computerized tomography scans, procedures, etc. Its exothermic nature means that it should be reserved for life-threatening hemorrhage, when the risk of this adverse property is quite tolerable in consideration of the benefit. HemCon also shows promise and has the added advantage of not having an exothermic quality.
Dr. Hamilton, Associate Professor of Emergency Medicine, Residency Program Director, Department of Emergency Medicine, Drexel University College of Medicine, Philadelphia, PA, is on the Editorial Board of Emergency Medicine Alert.