The development of the HemCon™ hemostatic bandage (HemCon Inc., Portland, Oregon, USA) (www.hemcon.com) is a major advancement in emergency care. The bandage is made of chitosan which is a highly hemostatic agent. The bandage rapidly stops bleeding of wounds from severe trauma. A sponge version of the bandage can be packed into larger wounds, stopping bleeding and stabilizing the patient.

The ability of the bandage to adhere to a bleeding wound depends on its porosity and ultrastructural architecture. Quality control during manufacture would benefit from a rapid non-invasive optical technique for assessing the ultrastructure of the bandages. This report describes our efforts to characterize the ultrastructure of the bandage using optical coherence tomography (OCT).

The key feature that appears to characterize a "good" bandage is a porous surface layer that can absorb the fluids of the blood. If the bandage cannot adsorb blood fluid, it will not effectively adhere to the wound. In contrast, a "bad" bandage presents a laminar layer near the surface that appears to seal the bandage surface and prevent absorption and good adherence to the wound. OCT depicts this laminar layer as a continuous strongly reflective layer.

OCT is able to distinguish "good" from "bad" bandages, and to contribute on-line quality control during manufacturing.

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