An In-Shoe Laser Doppler Sensor for Assessing Plantar Blood Flow in the Diabetic Foot.

Cobb, J. E., 2000. An In-Shoe Laser Doppler Sensor for Assessing Plantar Blood Flow in the Diabetic Foot. PhD Thesis (PhD). Bournemouth University.

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Abstract

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot. Jonathan Edwin Cobb Plantar ulceration is a complication of the diabetic foot prevalent in adults with type 11 diabetes mellitus. Although neuropathy, microvascular disease and biornechanical factors are all implicated, the mechanism by which the tissue becomes pre-disposed to damage remains unclear. Recent theories suggest that the nutritional supply to the tissue is compromised, either by increased flow through the arteriovenous anastomoses ('capillary steal' theory) or through changes in the micro vascu I ature (haemodynamic hypothesis). Clinical data to support these ideas has been limited to assessment of the unclad foot under rest conditions. A limitation of previous studies has been the exclusion of static and dynamic tissue loading, despite extensive evidence that these biornechanical factors are essential in the development of plantar ulceration. The present study has overcome these problems by allowing assessment of plantar blood flow, in-shoe, during standing and walking. The system comprises a laser Doppler blood flux sensor operating at 780nm, load sensor, measurement shoe, instrumentation, and analysis software. In-vitro calibration was performed using standard techniques. An in-vivo study of a small group of diabetic subjects indicated differences in the blood flux response between diabetic neuropaths, diabetics with vascular complications and a control group. For example, following a loading period of 120s, relative increases in response from rest to peak were: Control (150% to 259%), Vascular (-70% to 242%), Neuropathic (109%-174%) and recovery times to 50% of the peak response were: Control (33s to 45s), Vascular (43s to >120s), Neuropathic (>120s). Dynamic re-perfusion rates (arbitrary units per millisecond) obtained for the swing phase of gait were: Control (6.1 a. u/ms to 7.9 a. u/ms), Vascular (4 a. u/ms to 6.2 a. u/ms), Neuropathic (2.3 a. u/ms to 4.5 a. u/ms).

Item Type:Thesis (PhD)
Additional Information:A thesis submitted in partial fulfilment, of the requirements of Bournemouth University for the degree of Doctor of Philosophy. If you feel this work infringes your copyright please contact the BURO manager.
Subjects:Technology > Engineering > General Engineering
Technology > Medicine and Health
Group:Faculty of Science and Technology
ID Code:312
Deposited By:INVALID USER
Deposited On:07 Nov 2006
Last Modified:10 Sep 2014 15:38

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