The scope of this research is to examine how different wound dressing materials can be used in addition to negative pressure wound therapy to aid in wound healing. We are trying to answer whether additional wound dressing materials affect pressure and fluid collection during the use of negative pressure wound therapy. Some recent advancements in negative pressure wound therapy systems include improvements to modes of negative pressure delivery, more efficient and compact pumps, advanced interface dressings, and improvements to adhesive dressings.
There are a few benchtop models available to test the different factors of negative pressure wound therapy systems. Therefore, it is hard to test how other wound dressings, types of wounds, or types of foam, positively or negatively affect pressure and fluid collection on patients. Most existing models for testing negative pressure wound therapy devices are limited to short-term experiments.
These models involve placing a fluid in a simulated wound site before testing, but often fail to replicate the continuous fluid movement and pressure changes in the site. Our protocol enables long-term testing to better reflect clinical uses and evaluate wound dressing materials, and other treatment factors. And how they affect the pressure dynamics and fluid collection in the negative pressure wound therapy system.
Our protocol offers the ability to use a clinical wound vac negative pressure wound therapy machine in a lab setting with our design benchtop model. This protocol also uses an inexpensive and easily obtained tissue analog that has similar properties to human tissue to determine how pressure and fluid collection is different from different types of wound defects during the use of negative pressure wound therapy. To begin, obtain a test box with all the desired features for the procedure.
Use commercially available salted pork belly, referred to as tissue, to simulate muscle and fat tissue for negative pressure wound therapy testing. Using a number 21 blade scalpel, create an approximately 1.5 inches wide and 0.75 inches deep circular wound defect in the tissue surface. Fenestrated the tissue through the fat on each side using the same scalpel.
After creating the wound defect, wipe down the tissue to remove excess fat from the skin and soak the tissue overnight in deionized water to remove excess salt. The tissue should be placed in the fridge for overnight soaking. Then prepare one liter of the simulated body fluid with all the required components.
Combine the simulated body fluid with bovine serum in a three to one ratio. Mix the final solution to have 5%of a 10 X antibiotics antimycotic solution composed of penicillin, streptomycin, and amphotericin B for microbial control. Then store it in a refrigerator.
Fill the bottom of the test chamber with 1.5 inch thick open cell foam, and place the tissue on top of the foam. For the experimental groups, insert the additional wound dressing into the wound defect, ensuring that the bottom and sides of the defect are covered. Fill the remaining wound defect with open cell foam.
Insert the pressure tube connected to the pressure gauge on the testing chamber into the open cell foam filling the defect. Now, cover the tissue with adhesive wound dressing and create a small cut in the dressing directly above the center of the open cell foam filling the defect. Thread the vacuum nozzle through the lid of the testing chamber and place it on the adhesive dressing, aligning it with the cut.
Close the lid of the testing chamber to press down the adhesive dressing and vacuum nozzle, creating a seal. Next, connect a 500 milliliter fluid collection canister to the vacuum pump and attach the vacuum nozzle to it. After attaching the fluid collection canister and vacuum nozzle, add the final simulated body fluid into the test chamber.
Adjust the vacuum pump pressure settings according to the test condition. Then place the vacuum pump settings on intermittent or continuous pressure, and run all samples for 72 hours. Record the pressure on the pressure gauge, and the amount of fluid in the fluid collection canister every 12 hours for a total period of 72 hours.
If the amount of body fluid analog drops below 75%of the top of the testing chamber, remove the secondary pressure gauge and replenish the chamber with the complete solution. After 72 hours, turn the vacuum pump off and disconnect the fluid collection canister from the vacuum nozzle. Remove the fluid collection canister from the vacuum pump.
Take the tissue out from the testing chamber, and pull off the adhesive wound dressing. Finally, remove the open cell foam and observe whether the additional wound dressing remains intact. At maximum pressure, there was no significant difference between the control and experimental groups for the continuous test condition.
But there was a significant difference between the experimental and control groups under intermittent conditions. At minimum pressure, there was a significant difference in pressure readings between the experimental group and control for the continuous test condition. Whereas there was no significant difference between the experimental and control groups under intermittent conditions.
Fluid collection was observed to be similar across all groups, indicating no impact of the wound care device on fluid collection efficiency. While this experiment tested one specific type of wound dressing material, the system may be used to evaluate the compatibility of other dressing materials with negative pressure wound therapy.
