Impact of Reticulated, Open-cell Foam Based Negative Pressure Wound Therapy Dressing Change Frequency on Force Required to Peel Dressing from Wound

Introduction: During the treatment of open wounds with negative pressure wound therapy (NPWT), reticulated, open-cell foam (ROCF) dressings, without interfacial layers, are changed every 2-3 days.  More recently, perhaps because of increased confidence in NPWT and an understandable desire to lower costs, some clinicians are considering leaving these dressings in place for a longer period of time prior to changing them. The goal of this porcine study was to evaluate the impact of dressing change frequency on the peel strength of NPWT foam-dressings.

Methods: 6cm x 6cm full thickness dorsal (paraspinal) wound were created in each of 6 pigs.  These wounds were treated with ROCF-based NPWT§ (-125 mmHg). After 3 days of therapy, the dressings were evaluated with a peel tester set (direction: ~180o; strain rate: 10 cm/s; peak load: 2kgf). to estimate to generate initial granulation tissue.  Dressings were then replaced and therapy continued for an additional 4 days after which the dressings were again similarly peel-tested. 

Results: At the first dressing removal on Day 3, all 6 dressings were peeled out of the wound, with a mean peel force per unit width of 1.9N/cm±0.2N/cm.  After the further 4 days of therapy, only 2 of the 6 dressings were able to be removed (2.9N/cm±0.4N/cm); the other 4 dressings could not be removed and the highest force measured before the testing system was at an impasse was 3.06N/cm±0.01N/cm.

Discussion and Conclusion: The results in this healthy, porcine model underscore the reason for foam-dressing change directions of every 2-3 days.  Increasing the duration without dressing change beyond the standard instructions of 2-3, increases the possibility of the foam dressing integration with the wound bed and the issues associated with surgical removal of the dressing.

§V.A.C. THERAPY™ with V.A.C.® GRANUFOAM™ Dressing (KCI, San Antonio, TX)