Realistic approach for sub-bandage pressure appraisal

Abstract

Manufacturers estimate the specific compression levels of their products to satisfy the intended medical purposes. Medical compression bandages have different intended purposes. This means that the engineer must be able to estimate the clinical performance, referred to as the interface pressure, during product development and prior to clinical testing in humans. Unfortunately, the mathematical equations found in the literature do not result in interface pressure values that are similar to the ex vivo pressure. Therefore, the present work aims to demonstrate that the use of bandage elongation as a premise for predicting the interface pressure, as revealed new expression, can provide a reliable estimate.

Methods

Pressure of compression bandages can be discrepant when using different method or devices. This work proposes a modified equation of Pascal and Laplace, used to estimate the sub-bandage pressure, is given by: p = (2*π*F)/ (ε+1)*L0*w, where P, represents the pressure in kPa, F is the force applied on the bandage width (w), L0 is the initial length, and ε = (Δ_L/L0)*100 is the relative elongation expressed in [%].

Bandage specimens underwent a tensile test using a constant rate extension (CRE) device. The tensile test determined the elongation resulting from an arbitrary force and predicted the sub-bandage pressure. The elongation was then prescribed as the stretch required to achieve ex vivo pressure. The elongation and pressure were measured ex vivo with a ruler and the PicoPress® device, respectively, and compared to the predicted elongation and pressure.

Result

The predicted pressure (24 mm Hg), calculated for ε = 48 % in the pressure equation, is not significantly different from the ex vivo pressure (26 mm Hg), as measured by a healthcare professional using the PicoPress®. The p-value (0.102) is greater than α (0.05) and the Pearson coefficient, R = 0.529, indicates a moderate relationship between the two variables.