[Experimental principles of the V.A.C.-therapy -- pressure values in superficial soft tissue and the applied foam].
OBJECTIVE
Measurement of the pressure during V.A.C.(R)-therapy in superficial parts of the affected soft tissue as well as at the soft tissue/foam-interface, measurement of pressure values along bigger distances in the foam and the comparison of pressure transfer between polyurethane and polyvinyl-alcohol foams.


METHODS
A multi-channel electronic transducer-tipped catheter system based on the piezo-resistant principle was used. Measurement was performed on a plain table surface, at a bovine muscle as well as in human tibial anterior muscle of a patient after fasciotomy. Applied pressure values by V.A.C.(R)-therapy-units were 50 to 200 mm Hg (continuous suction modus).


RESULTS
100 % pressure transition through vacuum-therapy-foams to wound surface, almost 100 % pressure transition even along 60 cm in very large polyurethane-foams using only one trac-pad connector. Pressure values > 125 mm Hg using polyvinyl-alcohol-foams showed a reduction of up to 25 % in distances > 15 cm from trac-pad-connector. On the surface of the affected soft tissue there are negative and positive pressure values (25 % quartile: - 25 mm Hg; 75 % quartile: + 15 mm Hg).


CONCLUSIONS
Pore walls of the foam can produce positive pressure conditions resulting in soft tissue compression and consecutively hypoperfusion or ischemia. V.A.C.(R)-therapy seems to produce an heterogeneity of pressure distribution at the wound ground leading to pressure gradients and facilitating drainage of interstitial fluid. This mechanism could explain the anti-edema effects of V.A.C.(R)-therapy resulting indirectly in an increased nutritive perfusion.
Willy
C
C
Bundeswehrkrankenhaus Ulm, Chirurgische Klinik, Ulm/Donau. pddrmedchristianwilly@bundeswehr.org
von Thun-Hohenstein
H
H
von Lübken
F
F
Weymouth
M
M
Kossmann
T
T
Engelhardt
M
M
D000818:Animals; D001274:Atmospheric Pressure; D002417:Cattle; D004487:Edema / Q000503:physiopathology / Q000628:therapy; D045604:Extracellular Fluid / Q000502:physiology; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D066298:In Vitro Techniques; D008365:Manometry; D008953:Models, Anatomic; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000503:physiopathology; D009779:Occlusive Dressings; D011140:Polyurethanes; D011145:Polyvinyls; D012815:Signal Processing, Computer-Assisted; D012867:Skin / Q000503:physiopathology*; D015503:Surgical Sponges; D013529:Surgical Wound Dehiscence / Q000503:physiopathology / Q000628:therapy; D014618:Vacuum
D011140:Polyurethanes; D011145:Polyvinyls; C026699:ivalon sponge; C028279:polyurethane foam