Influence on pressure transduction when using different drainage techniques and wound fillers (foam and gauze) for negative pressure wound therapy

Abstract

Pressure transduction to the wound bed in negative pressure wound therapy (NPWT) is crucial in stimulating the biological effects ultimately resulting in wound healing. In clinical practice, either foam or gauze is used as wound filler. Furthermore, two different drainage techniques are frequently employed. One involves the connection of a non-perforated drainage tube to the top of the dressing, while the other involves the insertion of perforated drains into the dressing. The aim of this study was to examine the efficacy of these two different wound fillers and drainage systems on pressure transduction to the wound bed in a challenging wound (the sternotomy wound). Six pigs underwent median sternotomy. The wound was sealed for NPWT using different wound fillers (foam or gauze) and drainage techniques (see earlier). Pressures between 0 and -175 mmHg were applied and the pressure in the wound was measured using saline-filled catheters sutured to the bottom of the wound (over the anterior surface of the heart) and to the side of the wound (on the thoracic wall). The negative pressure on the wound bed increased linearly with the negative pressure delivered by the vacuum source. In a dry wound, the pressure transduction was similar when using the different wound fillers (foam and gauze) and drainage techniques. In a wet wound, pressure transduction was better when using a perforated drainage tube inserted into the wound filler than a non-perforated drainage tube connected to the top of the dressing (-116 ± 1 versus -73 ± 4 mmHg in the wound at a delivered pressure of -125 mmHg for foam, P < 0·01), regardless of the type of wound filler. Gauze and foam are equally effective at delivering negative pressure to the wound bed. Perforated drainage tubes inserted into the wound filler are more efficient than a non-perforated drainage tubes connected to the top of the dressing. The choice of drainage technique may be particularly important in wounds with a large volume of exudate.

Comparative effectiveness of mechanically and electrically powered negative pressure wound therapy devices: A multicenter randomized controlled trial

“…In addition to comparing two systems of NPWT, the results of this study may also add insight into the role of foam and gauze and their relative effectiveness with NPWT. These data support, for at least a subset of chronic wounds, similar efficacy for both foam and gauze interfaces, and this is consistent with some published studies . However, the specific wound types that may respond best to each form of wound interface layer during NPWT still need to be defined further clinically in additional studies.…”

“…These data support, for at least a subset of chronic wounds, similar effi- cacy for both foam and gauze interfaces, and this is consistent with some published studies. [24][25][26][27] However, the specific wound types that may respond best to each form of wound interface layer during NPWT still need to be defined further clinically in additional studies. It may be entirely plausible foam interfaces may perform better in deeper wounds with exposed structures than gauze interfaces.…”

Effects of Negative Pressure Wound Therapy on Healing of Free Full‐Thickness Skin Grafts in Dogs

“…Most NPWT publications relate to the use of polyurethane open cell foam (V.A.C., Kinetic Concepts Inc., San Antonio, TX), rather than the gauze dressing we used. For this discussion, we have made the assumption that the mechanisms of action are similar for both types of contact dressing, based on recent studies showing equally effective delivery of negative pressure and deformation with either type . The widely reported successes of NPWT are probably because of mechanisms of action that have been proven with in vivo and in vitro studies.…”

Clinical evaluation of gauze‐based negative pressure wound therapy in challenging wounds

“…The efficiency of pressure transduction to the wound from the vacuum pump depends on the structure or nature of the wound filler. In previous studies, authors have shown that interface dressings influence the delivery of negative pressure (17). However, a recent report confirmed that the type of wound filler (foam or gauze) does not affect the pressure transduction to the wound bed and they could provide similar pressure transduction to the wound bed (18).…”