Measurement of the skin microcirculation through intact bandages using laser Doppler flowmetry

The microcirculation under compression bandages has been assessed by numerous methods; however, the measurement techniques can disrupt the bandage-skin interface, affecting the measurement. In this study, a non-invasive method for measuring cutaneous blood flow using laser Doppler flowmetry (LDF) is presented. Ten volunteers had their microcirculation assessed by a laser Doppler probe being placed on their upper forearm with and without a light-transmissive gel and with a compression bandage plus light-transmissive gel. A circulatory challenge to the bandaged forearm in two of the volunteers was also undertaken. The median (95% confidence interval) perfusion (p.u.) for the skin surface was 24 (15-33) perfusion units (p.u.), and the skin plus light-transmissive gel demonstrated a higher perfusion: 66 (50-82) p.u., (p < 0.012). The addition of the compression bandage, with additional gel allowed to permeate through to the underlying skin, decreased the perfusion to 27 (20-34) p.u. (p < 0.007). In both volunteers, the microcirculatory flow responded to the vascular challenge, resulting in flow changes related to the cuff pressure (45-27 and 14-8 p.u.). This method demonstrated that it may be possible to assess the microcirculation through intact bandages, without the need to place any sensors at the skin-bandage interface.

Interface pressure measurement: testing and selecting sensors

Interface — or contact — pressure measurements play a key role in the design of many patient support surfaces aiming to protect areas vulnerable to pressure ulceration. But testing and selecting appropriate devices can be problematic.