Development of a Benchtop Model for Evaluating the Compatibility of Wound Dressing Materials with Negative Pressure Wound Therapy Systems

Summary

This study presents a benchtop model designed to evaluate the compatibility of wound dressing materials with negative pressure wound therapy systems by assessing pressure and fluid collection over 72 h under continuous and intermittent pressure settings.

Abstract

Negative pressure wound therapy (NPWT) systems facilitate wound healing by applying sub-atmospheric pressure to the wound bed, which promotes granulation tissue formation and reduces inflammation. Wound dressings can be used with these systems to enhance healing; however, the effects of dressings on NPWT device performance are challenging to assess. The purpose of this study was to develop a benchtop flesh analog model for testing the compatibility of wound dressing materials with NPWT devices. In this study, a chitosan-based advanced wound care device was evaluated for its effects on NPWT performance under maximum and minimum therapy pressures. The goal was to use the model to compare pressure readings and fluid collection for samples with and without the chitosan wound care device. The benchtop model was constructed using a plastic box connected to multiple pressure gauges. A circular defect was created on a piece of pork belly, used as the flesh analog, and inserted into the box. The defect was filled with standard NPWT foam or foam combined with the wound dressing. Simulated body fluid containing bovine serum was added to the box, which was then tested at either maximum (-200 mmHg) or minimum (-25 mmHg) pressures for 72 h. Pressure and fluid collection were recorded every 12 h. The NPWT system successfully maintained pressure over the 72 h test period, both with and without the test dressings. The addition of the wound dressings did not impact fluid collection. The test box proved effective as a benchtop model, as it could be sealed and maintained vacuum conditions over the 72 h testing period. This model successfully demonstrated its utility in evaluating the compatibility of wound dressing materials with NPWT systems.

Introduction

Different therapeutic approaches exist to aid in the management and healing process of wounds. Such therapeutic approaches include advanced wound dressings, growth factors, hyperbaric oxygen therapy, skin substitutes, and negative pressure wound therapy (NPWT)¹. NPWT refers to wound dressing systems that continuously or intermittently apply sub-atmospheric pressure to the system, which provides negative pressure to the surface of the wound. NPWT has become a popular treatment modality for the management of acute or chronic wounds². The NPWT system consists of an open cell foam, adhesive wound dressing, a fluid collection....

Protocol

The details of the reagents and the equipment used in this study are listed in the Table of Materials.

1. Creation of the test box

1. Obtain a 3.2-cup plastic container.
2. Create a 2-inch diameter hole in the center of the container lid. Also, make two 3/8 holes in two corners of the container lid approximately 1/2 inch from the edge seal. Use a hole saw to create the holes.
   NOTE: A schematic showing the overall testing setup using a commercial NPWT machine connected to a lab-built benchtop flesh analog box is shown in Figure 1. This schematic outlines h....

Results

The goal of the study was to develop a benchtop model for NPWT that uses a tissue analog and to use the model to investigate the compatibility of wound dressing materials with a negative pressure wound therapy machine. The model was used to study if the NPWT machine was able to maintain pressure over time with the addition of a wound care device. The model was also used to determine if the pressure generated and fluid collected by the NPWT machine in the presence of a wound care device were different as compared to the a.......

Discussion

There are a few benchtop models for NPWT, but they have significant limitations. Loveluck et al. developed an FEA computer model to determine how NPWT affected sutured incision sites but did not account for additional wound dressing materials⁶. Rycerz et al. developed agar-based models to evaluate instillation solution distribution to wounds during NPWT⁷. While the agar provided a medium for assessing the distribution of water-soluble materials/dyes in the different models,.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
100x antibiotics/mycotics	Gibco	15240062	This is the 100X antibiotics/antimycotics used in the simulated body fluid
3 M KCI ACTIV.A.C Therapy System	KCI Mdical Products	VFTR006619	This is the vacuum pump used in the study.
3 M KCI InfoV.A.C Canister w/Gel 500 mL	eSutures.com	M8275063	These are the fluid collection canisters used in the study
3 M KCI V.A.C GranuFoam Medium Dressing Kit, SensaT.R.A.C	eSutures.com	M8275052	These are the wound dressing packs with the vacuum nozzle including the open cell foam.
Bovine Serum	Gibco	16170086	This was used to mix with the simulated body fluid and the antibiotics/antimycotics
Calcium Chloride	Fisher Scientific	C614-500	This was used to create the simulated body fluid
Excel/Powerpoint	Microsoft Office	N/A	This was used to run the statistics and create the schematic for Figure 1
Foundation DRS Solo	BioNova Medical	N/A	This is the advanced chitosan wound care device used in the study.
Hydrochloric Acid	Fisher Scientific	SA54-1	This was used to create the simulated body fluid
Magensium Chloride	Fisher Scientific	M33-500	This was used to create the simulated body fluid
Phosphate buffered saline	Thermo Scientific	J62036.K3	This was used to dilute the 100x antibiotic/antimycotic to 10x
Potassium Chloride	SIGMA	P-3911	This was used to create the simulated body fluid
Potassium Phosphate Dibasic	Fisher BioReagents	BP363-500	This was used to create the simulated body fluid
PRM Vacuum Gauge 0 to -10 in Hg	PRM Filtration	PGCNBTY630652J10HG	Two pressure gauges are needed for the testing chamber.
Salted Pork Belly	Hormel Food Corporations	UPC: 0003760037988	Salted pork belly can be bought from Kroger. It cannot be sliced. It is best to pick samples that have less fat, and more muscle.
Sodium Bicarbonate	SIGMA	S5761-500G	This was used to create the simulated body fluid
Sodium Chloride	Fisher Scientific	S640-500	This was used to create the simulated body fluid
Sodium Sulfate	Fisher Scientific	BP166-100	This was used to create the simulated body fluid
Tris(hydroxymethyl) aminomethane	Fisher Scientific	BP152-500	This was used to create the simulated body fluid
Tupperware Brands Corp, Kissimmee , FL	Tupperware	N/A	This is the box used as the testing chamber.