Wound Healing System Development: V.A.C. Therapy

1. Wound Healing System Development: V.A.C. Therapy Marybeth Jewell*, Melissa Kopacz*, Ian Sando*, Cary Berdy† Advisor: Dr. Naji Abumrad *Department of Biomedical Engineering, Vanderbilt University †Department of Mechanical Engineering, Vanderbilt University INTRODUCTION V.A.C. OPERATING PROCEDURES SAFETY 2. Foam is placed over or in wound. Catheter tubing is positioned within the foam dressing. 1. Foam cut and altered in accordance with specific wound characteristics. • - Promotes granulation tissue formation through the promotion of wound healing. • - Uniformly draw wounds closed by applying controlled, localized negative pressure. • - Removes interstitial fluid allowing tissue decompression. • - Removes infectious materials. • - Provides a closed, moist wound healing environment. • - Treats Chronic open wounds, Diabetic ulcers, Pressure ulcers, Acute and traumatic wounds, Flaps and grafts, Dehisced Wounds, and Partial Thickness Burn V.A.C. Therapy V.A.C. Therapy is the controlled application of sub-atmospheric pressure to a wound using a therapy unit to intermittently or continuously convey negative pressure to a specialized wound dressing to help promote wound healing. • Future work to improve safety Implement a benign failure design that would cause the device to shut off if the pressure exceeds -200 mmHg (note: normal operating range is between -25 and – 200 mmHg) Also, we wish to design the automated device to be battery operated so that in the case of a power failure, the negative pressure would not be lost by the supply of an alternative energy source • Replace/sanitize components after each use Be sure to replace canister, catheter tubing, and adhesive drape, after every dressing change to decrease any change of infection • Sponge placement Carefully confine the sponge to the wound tissue and avoiding the overlap of normal skin. The technique is contraindicated in patients with an allergy to any of the components which contact the skin such as the polyurethane sponge, the adhesive, or the plastic film applied to seal the system to the skin around the wound. • Other patient considerations Patients whose skin is thin and easily damaged will not tolerate the pulling off of the adhesive film, which is done at the time of sponge removal/change. Also, patients who are fully anticoagulated or patients with large wound surface areas (e.g., burns) may need careful monitoring of electrolytes, hematocrit, and/or fluid balance in an intensive care or burn unit setting. 4. Adhesive drape is placed over the foam-filled wound and negative pressure is applied. Dressing is changed every 48 hours. 3. Catheter tubing is connected to the V.A.C. device. Sterile canister for exudate collection is positioned. Operating Procedures: - Foam is placed over or in wound - A large piece of transparent tape/ dressing is placed over the wound and surrounding healthy tissue - Catheter tubing connects vacuum source and dressing - Negative pressure of vacuum draws excess fluid that may hinder wound healing into a canister PROTOTYPE I DESIGN CONCLUSIONS • Our two prototypes proved to be more cost effective than current KCI technology as they are seen to be either less or approximately equal to KCI’s V.A.C. one-day rental costs. Moreover, their rental costs do not include the cost of dressings, canisters, sponges, catheter tubing, etc. Our first prototype also provides the option of having two different variable pressures from a single device. This allows for the ability to apply different negative pressures at different wound sites without the need of renting a second device. The ability to provide different pressures at different sites is beneficial if the two wounds require different pressure for optimal healing. Our second prototype also has the ability of providing negative pressures by hanging different weights from the handle. This design also provides continuous pressure until 296 cc of fluid is removed, after which another pass of negative pressure must be made. Also, although KCI’s base patents in the U.S. do not expire until 2013 and although they have many issued patents in Europe, Canada, Australia and Japan, there is still a large market for V.A.C devices. Our target market where those third-world countries whose healthcare systems could not afford the expensive devices that KCI produces. This was our motivation for designing an even cheaper, second prototype. We hope that our business can provide these countries with V.A.C. therapy to help reduce patient time in the hospitals and reduce the chance of infection. Some future improvements on our design would be to have an alarm and automatic shutoff if the pressure exceeds -200 mmHg. It would also be beneficial to have battery powered devices since many of the hospitals in third-world countries do not have the convenience of electricity. • Cost Breakdown • 1 3/8” Crimp Tee: $2.57 • 2 Case Enclosures: $12.00 • 1 Roll Electrical Tape: $0.79 • 8 ft. Vinyl Tubing: $1.60 • 4 1/2” x 3/8” Brass Coupling: $6.12 • 2 ½” Barb Ball Valve: $16.82 • 1 800 cc Suction Canister: $15.30 • 1 21.3” Hg Single-Head VacuumPump: $194 • - Labor costs: $45.00 • Total: $294.20 PROJECT OBJECTIVES Project Goals: Toprovide an affordable medical instrumentation device to improve patient health by assisting in wound closure.  Currently, there are few devices on the market that use Vacuum Assisted Closure (V.A.C) therapy to remove interstitial fluid from the wound and facilitate its closure.  We hope to design a device that is less expensive and more efficient that current methods.  Design Parameters: - Inexpensive - Portable - Durable - Efficient PROTOTYPE II DESIGN MARKET ANALYSIS • Cost Breakdown • Four feet of 1 inch diameter PVC pipe: $2.70 • Four feet of ½ inch diameter PVC pipe: $2.10 • One foot of ¾ inch (thin wall) PVC: $2.55 • One 1 inch diameter PVC check valve: $7.40 • One ½ inch diameter PVC "T" fitting: $2.20 • One foot clear vinyl hose: $2.40 • One ½ barb fitting to match hose: $3.75 • One foot of ½ PVC to fit barb fitting: $1.12 • One elbow to mate 1 inch to ½ inch PVC: $1.90 • One rubber "O" ring:$0.10 • Labor Costs: $22.50 • Total: $48.72 KCI’s Patent • KCI’s base V.A.C. patents do not expire until 2013. They not only have over 100 V.A.C.- related patents in the U.S. but, internationally, they have more than 75 issued patents and more than 100 pending patents, with protection in Europe, Canada, Australia, and Japan KCI Monopoly: • - Daily costs of V.A.C. exceeds that of the traditional, twice-a-day dressing changes with a topical antimicrobial with regard to dressing and nursing costs ($282/day versus $75/day). • Nonetheless, V.A.C. decreases costs when considering the added costs of increased operative time for complex reconstructions as well as for the treatment of associated complications. • We are attempting to design a device that is very cost effective to provide KCI with competition so as to decrease patient and hospital costs related to V.A.C. therapy. ACKNOWLEDGEMENTS • Dr. Naji Abumrad • Chairman, Deptartment of Surgery, Vanderbilt University Hospital • Dr. Paul KingDr • Associate Professor of Biomedical Engineering, Vanderbilt University • Carolyn Watts • MSN, RN, CWCNand Senior Associate in the Surgical Sciences, Vanderbilt University Hospital • Design Characteristics: • Design for even cheaper • Weights added to end of PVC hook to vary negative pressure • O-ring slides back and forth to allow for air escape and suction • - Manual, but better than the JP-drain