WOUND DRESSINGS

While wet-to-dry dressings are a mainstay for the management of open traumatic wounds, negative pressure wound therapy (NPWT) has become the more common and frequently preferred method for large soft tissue wounds. The principals of wound care are cleanliness and micro debridement. Wet-to-dry dressings, when done properly, achieve both; dressings keep the wound moist and provide mechanical debridement when removed. If the wound is too wet, it will not debride. If the wound is too dry, then it will impede healing. Optimal wound care management with wet to dry dressing requires the dressing to be changed every 12-24 hours; more frequent dressings may be needed, depending on the wound’s size, exudate burden, contamination, and vascularity. The use of either normal saline, sterile water, or potable water for the dressing are equally efficacious. This strategy for wet-to-dry dressings may need be adapted to a dry-to-wet dressing in a highly exudative/weeping wound. For highly contaminated wounds, the use of Dakin’s solution has been suggested to decrease the rates of invasive fungal infections (IFI); however, the sodium hypochlorite may be toxic to macrophages, fibroblasts and neutrophils.10,11

NPWT with Reticulated Open Cell Foam (NPWT/ROCF), commonly referred to as the VAC (vacuum assisted closure therapy system) dressing, is a commonly used alternative to wet-to-dry dressings. NPWT dressing can be left in place up to 72 hours depending on the extent and acuity of the wound. Utilization of NPWT requires a hemostatic wound bed and absence of purulence. The VAC Therapy System comes with a default negative pressure setting of 125mmHg. For large wound volumes, the pressure setting can be increased and/or an additional suction pad may be placed and connected with a “Y” connector. NPWT may aggravate bleeding in wounds with challenging hemostasis or venous hypertension. Clotted blood visible through the plastic covering or high amounts of dark sanguineous output indicate a need to return to the OR for hemostasis. Foam should not come into physical contact with exposed vessels. Use of VAC therapy has been proven safe and stable for long range air evacuation transports.12

The use of NPWT offers several advantages over wet-to-dry dressings. NPWT allows for accurate measurement of fluid loss from the wounds, prevents fluid soilage on linens and gurneys, obviates the need for painful bedside dressing changes, and promotes granulation tissue. However, there are many pitfalls that must be avoided with the placement of NPWT. It is imperative in large or deep wounds that all the ROCF is in contact with the suction source. If a piece of sponge in the wound is isolated from suction, bacteria will grow from fluid stasis. This especially applies to amputations from blasts where cavities track between muscle groups. In the unanticipated event of prolonged care at a Role 2 location, NPWT can be improvised without needing to stock commercial VAC supplies. NPWT can be devised using any suction source, Kerlex roll gauze, a conduit like a nasogastric tube (with the blue sump port tied in a knot), and an occlusive dressing like Ioban. The improvised VAC technique is further described in the JTS Acute Traumatic Wound Management in the Prolonged Field Care Setting CPG.9