Comparison of tissue damage, cleansing and cross-contamination potential during wound cleansing via two methods: lavage and negative pressure wound therapy with instillation.

The use of lavage was compared to negative pressure wound therapy (NPWT) with instillation (NPWTi) to assess extent of soft tissue damage, debris removal and environmental cross-contamination susceptibility in three distinct models. Scanning electron microscopy in an ex vivo model showed increased visible tissue trauma from lavage treatment at low and high pressures versus NPWTi, with the degree of trauma relative to the pressure of the irrigant. These results were corroborated in granulating full-thickness excisional swine wounds coated with dextran solution to simulate wound debris. Both low-pressure lavage and NPWTi demonstrated effective cleansing in this model, reducing debris by >90%. However, using three-dimensional photography to evaluate tissue damage by measuring immediate tissue swelling (changes in wound volume and depth) showed significantly greater (P < 0.05) swelling in low-pressure lavage-treated wounds compared with NPWTi-treated wounds. Lastly, bench top wound models were inoculated with fluorescent bacterial particles to assess environmental cross-contamination potential and collected at measured distances after treatment with low-pressure lavage and NPWTi. No evidence of cross-contamination was found with NPWTi, whereas one-half of the particles became 'aerosolised' during low-pressure lavage (P < 0.05). Collectively, these studies demonstrate the effective wound cleansing capabilities of NPWTi without the tissue damage and environmental contamination associated with lavage.

Burst strength testing of porcine intestinal anastomoses following negative pressure therapy.

The effect of negative pressure therapy (NPT; The ABThera™ Open Abdomen Negative Pressure Therapy System, KCI USA, Inc., San Antonio, TX) on the integrity of small intestinal anastomoses was evaluated using in situ burst strength testing in a domestic pig model. In each of 3 swine, 8 anastomoses were created, 4 using sutures and 4 using staples. After 24 hours of continuous NPT, each anastomosis was subjected to burst strength testing in situ. Mean ratios of burst strength of sutured anastomoses to baseline intraluminal pressure were 9.0 to 10.9. Stapled anastomoses had significantly lower burst strength than sutured anastomoses, but mean values were still at least 4.6 times greater than baseline. No differences were seen between anastomoses that were located in close proximity with treatment and those remotely placed or when measured with negative pressure on or off at burst assessment. NPT had no acute adverse effect on intestinal anastomoses in swine.