Study results show warming heals faster

No adverse effects reported

Tests of a new electronic device described as a non-contact, thermal wound care system have thus far shown positive results.

In a pilot study at the Milwaukee Veterans Administration Hospital, the effects of Warm-Up Active Wound Therapy on wound healing, pain, and adverse effects were evaluated on 10 males with pressure ulcers.

Patients in the study had suffered their wounds for at least a month; most for far longer. Standard wound care had been administered, which included moist wound dressings, debridement, and pressure relief. During the four-week investigation, heat was applied for two hours a day, totaling 40 treatment hours.

Average wound size decreased by more than 48%, says Luther Kloth, MS, PT, a professor in the physical therapy department at Marquette University in Milwaukee. "A few patients had some initial wound-related pain, but indicated that their pain decreased as measured by visual analog scale," he adds. "None of the patients experienced any adverse effects."

Kloth then undertook a second, larger study to observe and measure the same criteria, this time adding a control group. Ten patients, each with a stage 3 or 4 pressure ulcer, underwent the treatment for two one-hour periods Monday through Friday for four weeks. During non-heated periods, patients received standard wound care. In the control group of five patients, standard wound care was administered 24 hours a day for four weeks.

Heated wounds showed significant improvement

Temperatures inside and outside of the dressing were measured every 30 minutes to ensure that uniform heat was administered throughout the study. Wound evaluations were digitized by computer and statistically analyzed. After four weeks, control ulcers underwent a mean reduction in surface area of 13.5%, compared with a 48.2% reduction for heat-treated wounds.

The system, which received FDA approval last summer, consists of four components: a disposable wound cover, a warming card, a control unit, and an AC adapter. (See diagram of this device, p. 43.)

Wound covers comes in three sizes (4.75 inches X 4.75 inches, 6.75 inches X 6.75 inches, and 6.75 inches X 8.75 inches) and adhere to the peri-wound area but do not touch the wound. Their borders are designed to absorb exudate.

The transparent, semiocclusive top surface is permeable to both oxygen and water and allows for visual inspection of the wound without the need to remove the dressing. Because of its occlusive nature, the dressing creates condensation build-up within its confines, thereby creating a moist environment.

The warming card, a metallic transducer, slides into the top of the wound cover during therapy. A typical therapy regimen consists of three one-hour sessions per day, five days per week. The warming card produces infrared radiation that heats to the wound to approximately 38 degrees C.

The control unit, a microprocessor, monitors and maintains temperature levels and therapy duration. The entire system is compact and weighs only a few pounds.

The disposable dressings cost from $20 to $30, depending on size, and are designed to be changed every three to five days. The heating unit card can be used over a patient's entire treatment period and costs from $100 to $175. The control unit is usually leased for $23 to $25 per day, according to the manufacturer.

One advantage of this type of treatment is that it does not disturb the wound bed, says Jeff Kauffman, vice president of Augustine Medical, Eden Prairie, MN. "Many times people stuff dressings down into the wound. When they take the material out they often rip out the new cell growth and disturb the wound bed." He also notes that many wounds, because of their distal locations on limbs, may be exposed to outside air and therefore face higher risk of hypothermia, which decreases blood flow and is believed to impede healing. Kauffman estimates that 300 to 500 patients in the United States have been treated with Warm-Up.