Effect of material and structure of compression bandage on interface pressure variation over time

Background: Compression bandage consists of fibrous materials which are viscoelastic in nature due to which the internal stress developed in the compression bandage under wrapped position may decay over time. The viscoelastic behaviour of a textile material depends on the fibre type as well as on its structure, and hence these factors could play a prominent role in interface pressure variation over time. Objective: To explore the influence of different materials and varying structures on the interface pressure profile generated by the bandages over time during static state of the limb. Method: The material and construction of several compression bandages were engineered first and based on that different knitted bandages were prepared using several yarns (cotton, viscose, polyethylene terephthalate [PET], cotton-Lycra and PET-Lycra) and varying thread density in the structure. Three important factors, namely the material type, the applied tension and the tightness of the structure, were selected to examine their influence on interface pressure variation over time. The interface pressure measurement over time was done using a leg-segment prototype, which allows continuous online measurement of interface pressure over a static mannequin leg. Results: More than 40% reduction of interface pressure was obtained for bandages made of spun yarns (cotton or viscose) in eight hours. Reduction of interface pressure for these bandages was higher when wrapped at a higher tension level. Lower reduction of interface pressure was obtained for the sample having higher thread density as compared with lower thread density in the structure, for the same applied tension level during wrapping. Bandages containing elastomeric yarn in the structure showed good sustenance of pressure for longer period. Conclusion: Bandages made up of elastic core spun yarns are effective for maintaining uniform interface pressure for longer period due to sustained compression developed by the elastic filament and tight structure of these bandages.