You are required to read and agree to the below before accessing a full-text version of an article in the IDE article repository.

The full-text document you are about to access is subject to national and international copyright laws. In most cases (but not necessarily all) the consequence is that personal use is allowed given that the copyright owner is duly acknowledged and respected. All other use (typically) require an explicit permission (often in writing) by the copyright owner.

For the reports in this repository we specifically note that

  • the use of articles under IEEE copyright is governed by the IEEE copyright policy (available at http://www.ieee.org/web/publications/rights/copyrightpolicy.html)
  • the use of articles under ACM copyright is governed by the ACM copyright policy (available at http://www.acm.org/pubs/copyright_policy/)
  • technical reports and other articles issued by M‰lardalen University is free for personal use. For other use, the explicit consent of the authors is required
  • in other cases, please contact the copyright owner for detailed information

By accepting I agree to acknowledge and respect the rights of the copyright owner of the document I am about to access.

If you are in doubt, feel free to contact webmaster@ide.mdh.se

Non-invasive techniques for assessment of peripheral blood flow at different vascular depths

Authors:


Research group:


Publication Type:

Licentiate Thesis


Abstract

Missing or reduced blood flow can lead to pressure ulcers. Monitoring blood flow in areas prone to pressure ulcer development would be a valuable tool for prevention of pressure ulcers. PPG and LDF are both established non invasive optical techniques that can be used to estimate the changes in blood flow in different tissue volumes. The aim of this thesis was to combine the established techniques, LDF and PPG, into one flexible silicon probe intended for evaluation of peripheral blood flow in tissue volumes prone to pressure ulcer development. Further, a temperature sensor was integrated. Two probe configurations combining LDF and PPG has been evaluated regarding the ability to separate between shallow, medium and deep blood flow variations, and skin temperature changes. Further, techniques to reduce or totally avoid interference between LDF and PPG have been investigated. The probes can be used to discriminate between blood flows at different vascular depths. The vascular depths reached by the different channels correspond to the depths of interest when investigating pressure ulcer aetiology. The probe itself has shown not to affect the skin surface temperature, neither due to the silicon sheet or the light. The skin temperature can be expected to rise and approach the body core temperature by lying in supine position alone, which has to be taken into consideration when designing studies. By switching between the different light sources, interference can be totally avoided. When rapid blood flow variations at several vascular depths are of interest to evaluate, a peripheral placement of the LDF-fibre and an increased illumination power of the PPG-LEDs might be used to minimize the interference between LDF and PPG. Both probes have shown potential to be used for investigation of the processes in pressure ulcer development.

Bibtex

@misc{Hagblad2094,
author = {Jimmie Hagblad},
title = {Non-invasive techniques for assessment of peripheral blood flow at different vascular depths},
month = {May},
year = {2011},
url = {http://www.es.mdu.se/publications/2094-}
}