VAC原理.ppt

* * This classic experiment was performed in full-thickness wounds in swine. An invasive laser Doppler technique was used to measure perfusion. Settings of -125 mmHg was determined in this experiment to lead to an optimal perfusion (PU foam) Click on hyperlink area of 3rd green Bullitt point regarding ‘Intermittent therapy’ to show the mechanism of action: ‘Intermittent Therapy’ * Improved perfusion leads to A better host defence against infection Improved nutrition for tissue repair Supply of cells important for repair Improved tissue oxygenation Removal of waste and toxic products. * * As indicated previously, one of the ways V.A.C.? Therapy works is by controlling localized edema. In a study published by Kamolz et al in 2004, seven patients with bilateral burns had the more severely injured hand exposed to V.A.C.? Therapy. The less injured hand was treated conservatively with silver sulphadiazine. The authors reported “reduction of edema formation (up to 500 ml) within the burn wound in the group with the application of sub-atmospheric pressure.” They also observed “…a noteworthy amount of fluid was removed from the burn wound and a clinically obvious edema reduction was observed in comparison to the contra lateral side” (Kamolz et al, 2004). This decrease in edema was associated with increases in perfusion. At day 0, and at each of the first 3 days of treatment, the extent of perfusion in each hand was measured using an indocyanine green label and a special camera that could measure the amount of label. The local perfusion was calculated by obtaining the V.A.C.? Therapy treated perfusion units and subtracting the values from the contra lateral at each time point. As you can see here, perfusion was lower in the V.A.C.? Therapy treated hand before the start of the treatment. It improved over the next 24 hours and after days 2 and 3 the V.A.C.? Therapy treated hands had significantly (p 0.05) greater perfusion as the edema was reduced. You can see