1. Determining Properties of Wound Dressings for Negative Pressure Wound Therapy Lora Aboulmouna, Lisa Lewicki, Ryan Frye

2. What is NPWT? The application of sub-atmospheric pressure to a sealed wound for the purpose of removing fluid and stimulating a cellular response through the mechanical stretching of wound tissue. Process: Material inserted into wound bed Material inserted into wound bed Sealant drape Sealant drape Fluid drain tube Fluid drain tube Vacuum Applied Vacuum Applied -50 to -120 mmHg -50 to -120 mmHg

3. Pioneer Technology Aims to discover and create solutions in the healthcare community beginning with advancements in wound care while bridging the gap between healthcare technology and nature Aims to discover and create solutions in the healthcare community beginning with advancements in wound care while bridging the gap between healthcare technology and nature Green healthcare Green healthcare Discover the benefits of Sorbact and likelihood of commercial success Discover the benefits of Sorbact and likelihood of commercial success Mentor: Josh Smith, Vice President of Pioneer Technology Mentor: Josh Smith, Vice President of Pioneer Technology Advisor: Dr. Jack Fisher, Associate Clinical Professor of Plastic Surgery at Vanderbilt University Advisor: Dr. Jack Fisher, Associate Clinical Professor of Plastic Surgery at Vanderbilt University

4. Wound Dressings Sorbact Gauze KCI Foam

5. Project Goals To determine To determine Material resistance Material resistance Flow rate Flow rate Pressure gradient Pressure gradient Saturation points Saturation points of the three materials in a negative pressure environment. of the three materials in a negative pressure environment. Build a model that provides a controlled environment Build a model that provides a controlled environment

6. Equating the Materials Procedure: Procedure: Obtained three materials with equal masses Obtained three materials with equal masses Measured water displacement in a graduated cylinder of each sample Measured water displacement in a graduated cylinder of each sample Mass and volume were used to determine the density of each material Mass and volume were used to determine the density of each material MaterialDensity (g/ml) Gauze1.48 KCI Foam0.62 Sorbact1.36

7. Preliminary Experiment: Material Behavior in NP Environment Used skin analog in mold to simulate wound bed Used skin analog in mold to simulate wound bed Inserted appropriate material amount Inserted appropriate material amount Covered with sealant drape Covered with sealant drape Applied pressure of Applied pressure of 180 mmHg 180 mmHg Observed material compression Observed material compression

8. Results of Preliminary Experiment All materials compressed under negative pressure All materials compressed under negative pressure SorbactGauzeKCI Compression (mm)161913

9. Design Setup Clinical Pressure Ranges: -50 to -120 mm Hg Bernoulli’s Principle: Height of water Fluid velocity Vacuum Pressure Density Head losses Pipe h Q P = -180 mm Hg

10. Design Obstacles Resistance of tubing Resistance of tubing Flow meter range accuracy (o.4 to 40 mL/min) Flow meter range accuracy (o.4 to 40 mL/min) Small flow rates may cause readings to not be significantly different Small flow rates may cause readings to not be significantly different All flow travels through materials All flow travels through materials Varying Pressure Varying Pressure

11. Future Directions Obtain accurate flow measurements Obtain accurate flow measurements Awaiting shipment of proper flow meter Awaiting shipment of proper flow meter Test flow while varying pressure Test flow while varying pressure Test saturation Test saturation Weigh materials before and after saturation Weigh materials before and after saturation

12. References Borgquist O, Ingemansson R, Malmsjö M. Wound edge microvascular blood flow during negative pressure wound therapy: examining the effects of pressures from -10 to -175 mmHg. Plast Reconstr Surg In press. Borgquist O, Ingemansson R, Malmsjö M. Wound edge microvascular blood flow during negative pressure wound therapy: examining the effects of pressures from -10 to -175 mmHg. Plast Reconstr Surg In press. Ljungh, A, N Yanagisawa, and T Wadström. "Using the principle of hydrophobic interaction to bind and remove wound bacteria." Journal of Wound Care 15.4 (2006): n. pag. Web. 6 Nov 2010. Ljungh, A, N Yanagisawa, and T Wadström. "Using the principle of hydrophobic interaction to bind and remove wound bacteria." Journal of Wound Care 15.4 (2006): n. pag. Web. 6 Nov 2010. Smith, Jan, and Peter Robertsson. Method for Dressing a Wound., 2010. Web. 27 Oct 2010. Smith, Jan, and Peter Robertsson. Method for Dressing a Wound., 2010. Web. 27 Oct 2010. "Science Behind the Therapy — KCI." Science Behind The Therapy. Web.. "Science Behind the Therapy — KCI." Science Behind The Therapy. Web..