Assessing the barrier and physical properties relevant to clinical performance of commonly-used barrier films

Lead Presenter

Presented At

Abstract

Introduction
Healthy skin serves as a barrier to protect the body from outside irritants and microorganisms. When barrier function is damaged, such as in dry skin, moisture escapes, integrity is compromised, and the skin becomes susceptible to irritation and damage
from external factors. Skin damage constitutes:

  • Negative clinical outcome
  • Poor patient experience
  • Healing potential is compromised
  • Increased infections
  • Increased in the cost of care
  • Moisture on skin contributes to pressure ulcer

Barrier films commonly used in daily patient care can demonstrate different barrier and physical performance although they are visually similar. In this study, we utilized several bench tests to simulate performance features of the barriers on skin. These included their ability to provide barrier protection, film breathability or moisture vapor permeability, effect on adhesion of medical tapes and dressings, coefficient of friction, compatibility with chlorhexidine gluconate (CHG) and the elasticity of the film. These physical tests were conducted on six commercially available barrier films. These in vitro tests allow for performance measurements of the barriers which would not be possible in the clinical setting.

Results

Barrier Integrity using Dye Penetration Test
We utilized an in vitro dye penetration test as a bench test to simulate the performance of the barrier properties on skin. Barrier integrity or similarly barrier breakdown was tested using a dye penetration challenge in which each barrier film was challenged with dyed water and quantified using image analysis software. Less dye penetration or subsequent staining through film indicates superior barrier performance.

% barrier remaining after water wash. Typical stained image is placed
above the individual bar.

On average Product 2, 3, 4, 5 and 6 had 70, 66, 76, 70 and 86 % less
barrier remaining than Product 1. Clinicians should be aware that
visually similar looking barrier film may perform significantly
different in clinical setting.

Coefficient of Friction (CoF)
Patients with limited mobility, are exposed to friction and shear stress when their skin comes in immediate contact with bedding, clothing, or wound dressings. The effect of high friction and shear loading may lead to significant skin injuries. Reduction in frictional forces between the skin and stationary surfaces reduces the effect of shearing and potential detrimental consequence.

A sliding sled model was used to measure CoF. A piece of 100% cotton cloth was placed on the platen of an IMASS SP-2100 Slip/Peel Tester. A chlorhexidine gluconate (CHG) gel (2.5 inches square) was applied to the IMASS sled and then covered with polyurethane film (0.9 mil thick). Barrier films were then applied to polyurethane film and moved against cotton cloth. The resulting frictional force and coefficient of friction (CoF) were measured and calculated. Control was polyurethane film moved against cotton cloth without any barrier film.

Static and Kinetic CoF for six barrier films and control

Values for product 1 barrier film static and Kinetic CoF are statistically lower than control indicating that application of product 1 may significantly reduce friction when applied on patient skin.

Adhesion to Steel
Skin injury related to medical adhesive usage is a prevalent that occurs across all care settings and among all age groups. If proper technique is not used, superficial layers of the skin are removed along with the adhesive product, which not only affects skin integrity but can cause pain and the risk of infection, increase wound size, and delay healing, all of which reduce patients’ quality of life. However, under certain circumstances, adhesive products can also cause deeper tissue injuries beyond loss of superficial skin layers. In this test method, we tried to evaluate the peel force after medical tape being applied in presence of barrier film.

Each barrier film was applied to a steel plate and let dry for two minutes. A transparent polyurethane film (0.9 mil thick) dressing was applied over the barrier film, pressed on for adhesion and left in place for 24 hours in CTH room. The dressing was removed using an instrument, Zwick calculating the force required. Five replicates were tested for each barrier film and were compared with control which was without any barrier film.

The average adhesion to steel value for substrates treated with product 1 was statistically lower than products than control, 2,3,4,5 and 6. Adhesion to steel data indicates that application of
product 1 may significantly reduce medical adhesive
related skin injury when applied on patient skin.

Elongation Failure
This test method is based on the principle that barrier films undergoes elastic deformation after application to skin. Skin undergoes elastic deformation with patient’s movement. Elastic gels containing chlorohexidine gluconate (CHG) gel pads were coated with barrier films, allowed to dry and subsequently stretched at 50% & 100% of their original length on horizontal axis. The stretched gels were treated with bleach. Fractured barrier film will allow the bleach to pass through interaction with CHG, which changes the color of the gel to brown as a result of interaction between CHG and bleach. CHG analyzer was used to record the brown area as failure area.

The ability to resist cracking with elongation correlates with product flexibility and durability on skin. No film failure (0%) indicates high flexibility and durability, whereas 100% failure, indicates poor barrier function, flexibility and durability. Products 3 and 6 had 100% failure at 50% elongation indicating poor flexibility and elasticity.

Chlorhexidine gluconate (CHG) Compatibility
It is important to know the compatibility of CHG with barrier film formers. A colorimetric method was used to determine the compatibility. Dilute solutions of CHG can be colorimetrically quantified by the addition of bleach, which forms a brownish color with CHG. Brownish color formation confirms the CHG is still active.

All test samples were individually added to a dilute solution of chlorhexidine and bleach. These samples were assessed for color change after 5 minutes.

All test samples resulted in orange brown color formation, indicating CHG Compatibility.

Conclusion
This series of tests explored the variety of performance features customers are requiring their barrier films to provide. These features range from barrier performance, moisture breathability, friction reduction, reduction of tape or dressing trauma to skin, compatibility with CHG and the durability of the barrier on strained skin. Obviously it is challenging for facilities to maintain products specifically optimized for each of these features. Having a single product which covers a broad range of performance features is ideal for medical facilities. These results indicate that the most versatile product in this list is Product 1 and that not all barrier films are equivalent.

Footnote
This study was sponsored and supported by 3M Health Care. Data on file at 3M. Polyurethane film used is Tegaderm™ Film and CHG gel is Tegaderm™ gel

Products tested:

  1. 3M™ Cavilon™ No Sting Barrier Film
  2. Smith & Nephew™ No-sting SkinPrep
  3. Aplicare ™ One Skin Protectant Swabstick
  4. Medline ™ SurePrep Rapid Dry No-Sting Barrier Film
  5. Cutimed ™ PROTECT Medical Skin Protection
  6. ConvaTec ™ SensiCare Sting Free Skin Barrier