Silver from Polyurethane Dressing Is Delivered by Gradient to Exudate, Tissue, and Serum of Patients Undergoing Negative-Pressure Wound Treatment

OBJECTIVE: This study aimed to evaluate the distribution and concentration of silver eluted from silver-coated polyurethane dressing (V.A.C. GranuFoam Silver Dressing; KCI, San Antonio, Texas) in vitro and in patients undergoing negative-pressure wound therapy (NPWT). DESIGN: This was a descriptive study of the effect of silver-coated polyurethane dressing in patients undergoing NPWT. PARTICIPANTS: Six patients with infected wounds undergoing NPWT using silver-coated polyurethane dressing. INTERVENTIONS: To evaluate silver release in vitro, the authors soaked dressing fragments in water and human serum for different lengths of time and performed atomic absorption spectroscopy. For patient evaluation, the authors obtained exudate, serum, and wound tissue at different time points from 6 patients undergoing NPWT and measured silver levels by atomic absorption and dispersed x-ray spectroscopy. MAIN RESULTS: Silver from the dressing was immediately released in vitro at a rate 3 times greater in serum than in water. In vivo, silver was delivered to wound exudate at rates 102 to 104 times greater than in corresponding serum. Few surface silver deposits were detected in treated tissue. CONCLUSION: The high concentration of silver found in wound exudate reflects not only the affinity for silver in serum components and wound fluids, but also that most silver ions are not distributed systemically in the patient; instead, they are transported by the vacuum created by therapy.