Bio-Hemostat - Acute Treatment Modality for High Pressure Hemorrhage

摘要

Bleeding from an artery is difficult to control due to the high pressures found in the arterial system. Hemorrhage is especially problematic in penetrating wounds where the bleeding source may not be apparent. Tourniquets that are routinely used to treat such wounds can cause multiple complications. We are developing a device which, when exposed to aqueous solutions, rapidly generates pressure in a confined space. In this report, we summarize the design and testing of a prototype device. The 'biohemostat' is composed of a flexible outer membrane, which surrounds a hydrophilic, super-absorbent polymer. The outer bag is made from an electrospun mat of Ethylene-vinyl acetate co-polymer. The electrospun mat is very flexible, durable (stretching to 10 times its original length), biocompatible and porous. Its relative degree of hydrophobisity is overcome by incorporating a percentage of EVOH either as a blend or composite. The hydrophilic polymer used in the prototype device is composed of polyacrylic acid derivatives or copolymers. When the device is placed in aqueous solutions it rapidly absorbs fluid, expands and develops significant pressure in a confined space. Although swelling of such polymers is dependent on the nature of the aqueous solution (i.e. Varies with pH, ionic strength, protein content, etc.) the decreases in absorption caused by these parameters have been easily overcome by increasing the amount of hydrophilic polymer. We have met all engineering goals and can develop 90 mm Hg pressure within 180 seconds in a confined space. The goal is to place this device directly into a wound and develop counter pressure to aid in hemorrhage control. By developing pressure directly on the bleeding site, it may be possible to avoid the crush injuries and ischemic damage associated with tourniquet use.