Clinicians

Everything you need to know about compression

The material science of compression

Multilayer wrap systems lose a significant percentage of their compression within 5 hours

Multi-Layer compression wraps contain elastic (long stretch) materials or nonelastic (short stretch fabrics) or a combination of both.

  • Elastic materials (long stretch) contain the ability to apply various amounts of compression using the stretch (elastomer) fiber spandex. In addition, the elastomer allows the fabric to apply therapeutic interface compression levels with changes in local circumference changes due to loss or increases in edema. These fabrics stretch in excess of 100%. When the tension is released the elastic fabric should return to its original length.
  • Inelastic materials (short stretch) contain few spandex or elastomeric fibers producing minimal amounts if any elongation or degree of stretch. They therefore require considerable amount of tension to be applied and can only produce minimal if any elongation or degree of stretch.

Creep is defined as the deformation of a material, in this case fabric, due to an applied amount of tension or stretch. A fabric that has significant creep loses compression when wrapped around the limb. For example a fabric that is stretched 100% from 8 inches in length to 16 inches in length should return to his normal configuration of 8 inches length after the release of any tension or stretch. The degree to which it does not return to 8 inches (possibly to 10 inches or 11 inches) is reflective of the degree of creep. This deformation of the fabric is due to the amount of tension and the length of time during which the tension was applied. The clinical results of creep can be shown by research by Hegarty et al which demonstrated that two layer multilayer wrap systems can lose as much as 25% of their compression in five hours of time. They also demonstrated that four-layer multi-layer wrap systems can lose as much as 10% of their compression in only five hours [2]. These findings illustrate the creep found in these systems, reducing the amount of applied compression and contributing to the wrap not remaining in place on the lower leg. After a few days of application, wrap systems can slide down to the middle of the leg. This creates friction and bunching of the fabric which and can lead to secondary ulceration often located on the anterior tibial crest.

Proposed interface pressure measurement guidelines

  • During initial application to obtain selected therapeutic pressure
  • During each subsequent visit
  • Prior to removal of bandage dressing for wound inspection
  • During application of a fresh new dressing
  • Prior to removal of wound dressing at the end of treatment

US compression standards for hosiery

  • 15-20 mmHg - Improves circulation, reduce swelling, controversial treatment telangiectasia/varicosities
  • 20-30 mmHg - Chronic venous insufficiency, Treatment/prevention of varicosities
  • 30-40 mmHg - Treatment of chronic venous insufficiency and ulcers
  • 40-50 mmHg - Treatment of chronic venous insufficiency and ulcers

References:

  1. Characterizing the pressure profiles of medical compression hosiery: an investigation of current techniques, The Journal of the Textile Institute. 2014. 106: 757-767
  2. Hegarty-Craver, M., Grant, E., Kravitz, S., Reid, L., Kwon, C., Oxenham, W. Research into compression fabrics used in compression therapy and assessment of their impact on treatment regimens, Journal of Wound Care, Academy of physicians in wound healing supplement. 2014. 23: S14-S22