Interface pressures

A bandage is also defined by the interface pressure that it exerts on the limbs, i.e. the pressure measured in vivo between the bandage and the skin (sub-bandage pressure) (read more...)

In the past, only technical data produced using laboratory measurements were taken into account to compare bandages. However, in the last few years, the position of international experts has shifted and new international recommendations tend towards in vivo measurement of interface pressures.
Largely overlooked until recently, the interface pressure is now recognised as being the most important biophysical property of compression systems applied to patients.

This pressure varies depending on the type of bandage and whether the limb on which the measurement is being taken is :

  • immobile, giving rise to a resting pressure (RP) produced directly by the passive tension exerted by the compression system
  • mobile, giving rise to a working pressure (WP) produced intermittently on exertion when the muscle is exercised.

The difference between these 2 pressures corresponds to the static stiffness index of the bandage.

The higher this index is, the more rigid the bandage and the more it fits into the short-stretch (low-elasticity) category.
The lower this index is, the more elastic the bandage it and the more it fits into the long-stretch category.
(Read more...)

Since the interface pressures depend on the extensibility of a product ant the resistance it provides, short and long-stretch bandages do not therefore offer the same in vivo interface pressure profiles.
These characteristics will have a direct influence on the expected result of the veno-lymphatic system.
(see chapter on compressive effects as a function of different bandage types)