The effects of varying degrees of pressure delivered by negative-pressure wound therapy on skin perfusion.

Vacuum-assisted closure (V.A.C. Therapy) uses 2 distinct types of foams, with different physical characteristics: the black polyurethane (PU) foam and the white polyvinyl alcohol (PVA) foam. This prospective, randomized study evaluates the response of cutaneous blood flow (CBF) in healthy intact forearm skin to varying V.A.C. Therapy negative pressures and both foam types. Continuous negative pressure was used in the range of 25-500 mmHg. Skin blood flow was measured with noninvasive laser Doppler probes incorporated into the foam. Significant increase in CBF was found with both foams up to negative pressure of 300 mmHg, with over 5-fold increase (mean: 5.57; SD: 3.32) with the PU foam and nearly 3-fold increase (mean: 2.87; SD: 1.29) with the PVA foam. Comparison of blood flow at baseline and at a negative pressure of 300 mmHg showed a statistically significant difference (P < 0.001). No decrease in blood flow below baseline was observed during the experiments.