Venous Oxygenation in the Feet of Diabetics with Neuropathic foot Ulceration

Cho, Chung Gu

Abstract

BACKGROUND: Diabetic patients with non-infected neuropathic foot lesions frequently have prominent pedal arteries and distended dorsal foot veins, both in the ulcerated and in the non-ulcerated foot. Such patients also have increased blood flow in the lower limbs as suggested by plethysmographic and ultrasound studies. Accordingly, the aim of this study was to evaluate the venous oxygenation, as determined by partial pressure of oxygen(PO), in the feet of diabetics with and without foot ulceration and neuropathy in order to confirm the arteriovenous(A-V) shunting in the diabetic neuropathic foot may be important in the pathogenesis of ulceration.
METHODS
Venous PO was measured in the feet and hands of four subject groups: 8 diabetics with neuropathy and foot ulceration(group 1); 10 diabetics with neuropathy but no ulceration(group 2); 10 diabetics with no evidence of neuropathy(group 3); and 9 non-diabetic controls(group 4). After an initial 30-min period of stabilization, veins on the dorsum of each foot and on the back of the hand were cannulated using a Butterly infusion set, 0.8mm gauge. Blood was withdrawn from each site into a heparinized glass syringe for immediate analysis of PO using a blood gas analyser.
RESULTS
The mean venous PO2 in the feet of diabetic subjects with neuropathy and foot ulceration (group 1: 60.7+6.3mmHg)was significantly higher than in controls(group 4: 44.3+6.0mmHg) or the other two diabetic groups(group 2: 52.3+9.0mmHg, group 3: 46.1+5.5mmHg). Venous PO2 in the feet of the diabetic subjects with ulcers was also significantly higher than in their hands(45.4+5.8mmHg) or in the hands of the other groups(group 2:.46.6+6.3mmHg, group 3: 44.5+4.9mmHg, group 4: 44.9+5.1mmHg).
CONCLUSION
These results provide further evidence of abnormal blood flow in the diabetic neuropathic foot and are compatible with arteriovenous shunting.