367 Role of Pressure Magnitude in Compression Garment Therapy

Abstract

Pressure garments are commonly employed to reduce scarring following burn injury, with varying efficacy rates reported. A possible mechanism for this variability is the range of pressures utilized. The optimum magnitude of pressure necessary to achieve the greatest benefit is unknown, though it has been suggested that pressure should exceed capillary pressure, 25–30 mmHg. Unfortunately, higher pressures are associated with increased risk of side effects such as deformation of skeletal features or constricted breathing. To better understand the role of pressure magnitude on therapy efficacy, pressure garment therapy and scar development was studied in a porcine model. Full-thickness burns (1 x 1 in) were created on female, red Duroc pigs (8 burns per pig), excised, and autografted with split-thickness autografts. Custom adjustable pressure garments were applied 1 wk after grafting and maintained at either 10, 20, or 30 mm Hg for 11 wks. Scar properties were monitored over time, including contraction, scar height, erythema, and biomechanics. All pressure-treated groups were significantly less contracted than controls. Scars in the 30 mm Hg group were 46% larger than controls and 13% larger than the 20 mm Hg group 6 wks post-grafting (p < 0.05). This trend persisted throughout the study with a 56% greater scar area in 30 mm Hg treated group vs. controls and 16% increase vs. the 20 mm Hg group (p < 0.05). Pressure therapy, at all magnitudes, significantly improved the scar elasticity and pliability. Pressure garment therapy, delivered at 30 mm Hg, was the most effective at reducing scar contraction compared to 20 or 10 mm Hg. In addition, all levels of pressure (10, 20 and 30 mm Hg) resulted in statistically significant benefits to scar pliability and elasticity with the greatest improvement observed when scars were treated with 30 mm Hg. Fabrication of garments to apply 30 mm Hg pressure to underlying scars results in scars that are thinner, more pliable and less contracted than garments exerting lower pressures. While higher pressures led to superior outcomes in our study, we did note that higher pressures led to increased garment fatigue and were overall less comfortable. If higher pressures cannot be tolerated or begin to cause detrimental effects, scar improvements can still be obtained with lower pressures.