Influence of Negative-Pressure Wound Therapy on Tissue Oxygenation in Diabetic Feet

OBJECTIVE: Negative-pressure wound therapy (NPWT) has become a common wound care treatment modality for a variety of wounds. Several previous studies have reported that NPWT increases blood flow in the wound bed. However, NPWT might decrease tissue oxygenation in the wound bed because the foam sponge of NPWT compresses the wound bed under the influence of the applied negative pressure. Adequate tissue oxygenation is an essential consideration during diabetic foot management, and the foot is more sensitive to ischemia than any other region. Furthermore, the issue as to whether NPWT reduces or increases tissue oxygenation in diabetic feet has never been correctly addressed. The aim of this study was to evaluate the influence of NPWT on tissue oxygenation in diabetic feet. PARTICIPANTS: Transcutaneous partial oxygen pressures (TcPo₂) were measured to determine tissue oxygenation levels beneath NPWT dressings on 21 feet of 21 diabetic foot ulcer patients. DESIGN: A TcPo₂ sensor was fixed at the tarsometatarsal area of contralateral unwounded feet. A suction pressure of-125 mm Hg was applied until TcPo₂ reached a steady state. The TcPo₂ values for diabetic feet were measured before, during, and after NPWT. MAIN RESULTS: The TcPo₂ levels decreased significantly after applying NPWT in all patients. Mean TcPo₂ values before, during, and after therapy were 44.6 (SD, 15.2), 6.0 (SD, 7.1), and 40.3 (SD, 16.4) mm Hg (P <.01), respectively. CONCLUSION: These results show that NPWT significantly reduces tissue oxygenation levels in diabetic feet.