Diabetic Foot

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Diabetic foot and occlusive arterial disease
Reactive Hyperemia
Inspiratory Gasp
Surgery planning of amputations

Diabetic foot and occlusive arterial disease

Pathogenesis of diabetic foot syndrome includes mainly ischemic tissue damage that results from circulatory disorders caused by a macro- and microangiopathy, oxygen utilisation problems caused by altered vessel wall structure and properties of hemoglobin, peripheral neuropathy, and an increased disposition for infections.
With measurements that assess vessel function and oxygen utilisation, O2C can

Likewise effects of artheriosclerotic vessel alterations on nutritive supply of tissue can be judged, possible collateral growth taken into account, clinical stages objectified and progress and therapy controlled.

By simple provocations like occlusion or work vessel function can be tested.

Reactive Hyperemia

Length and height of reactive hyperemia can be used for judgment of endothelial function and perfusion reserve.


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Figure 1: Complete occlusion of arm and reactive hyperemia
Blood flow (green) and blood flow velocity (yellow) decrease during occlusion rapidly, whereas oxygen saturation (blue) decreases slowly. After opening of the occlusion (second marker) you can see the reactive hyperemia with increased blood flow, blood flow velocity and hemoglobin amount (red).

Inspiratory Gasp

During a deep breath reflex vasoconstriction can be observed. In diseases with neuropathies this test is negative.


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Figure 2: Deep breath
The first marker was set when the volunteer took a deep and fast breath. You can see the following decrease of blood flow (green) and blood flow velocity (yellow).

Surgery planning of amputations

If efforts to maintain peripheral perfusion by vascular surgery remain unsuccessful, often amputation of the affected extremity is the last remaining possibility. Mainly, the affected areas are the feet and legs of patients with diabetes mellitus and occlusive arterial disease with not healing wounds and pain. In Germany, with about 4 million diabetics, there are still approximately 23,000 amputations per year, thereof 14,000 amputations of the foot that are so called major amputations above the ankle. Withal it means a big difference for rehabilitation which joint can be saved or how long the stump can be shaped respectively. Until now, the effort to amputate in a way, that as much tissue as possible is saved however with unsure vitality of the tissue, resulted in the so called "salami technique" , where revising surgeries had to be performed again and again. By use of oxygen measurements, a prognosis of healing potential of tissue can be made and areas necessary for amputation can be defined [1]. Therein it was also determined that mean oxygen values over 30% with no values below 15% are the criteria for successful tibia amputations [2]. This method is already used routinely by University Hospital of North Durham [3].

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