Bi-Layer Wound Dressing System for Combat Casualty Care

Burn injuries remain a significant cause of morbidity and mortality during modern military conflicts and peacekeeping operations. Considering that commercially available dressings are not designed to meet the challenges of treating combat burn wounds, DRDC Toronto has designed a novel, absorbent and medicated bi-layer wound dressing to address key requirements for treating external war wounds. In the present report, we assessed our dressing’s bactericidal efficacy, wound healing properties, and skin-cooling characteristics using various pre-clinical models. Biopsies taken from full-thickness, pig wounds infected with Ps. aeruginosa and Staph. epidermidis showed a 2to 5-log reduction in the bacterial load of antiseptic-treated wounds compared to those of control wounds. Though increasing the frequency of dressing changes led to a greater reduction in the wound bacterial load, the contamination levels of all antiseptic-treated wounds remained below 105 CFU/g of wound. Our results also show that 97% of partial-thickness, non-contaminated porcine wounds treated with the DRDC dressing healed within 7 days. In contrast, 92% of the wounds treated with commercial dressings healed within 9 days. Finally, the application of a moist DRDC dressing (to simulate a condition of exudate absorption; DRDCmoist) on a scald burn covering 25% of the dorsal area in rats reduced skin temperature (Tskin) by 1.7oC for 5 min, Tskin in DRDCmoist being comparable to that of control burned rats (BURN) after 25 min. While there were no significant differences between the body temperature (Tip) in BURN and DRDCmoist throughout the 90-min experiment, application of a commercial hydrogel dressing markedly decreased Tip after 90 min (3.03±0.55 oC). These data show that the DRDC dressing is effective in: a) delivering medications, such as an antimicrobial agent, to the wound bed; b) promoting faster healing of the treated wound; and c) providing a transient, but beneficial cooling effect to the skin contact-site, without the adverse effect of inducing whole-body hypothermia.