Transcutaneous oxygen tension(tcPOz) was investigated in 31 control subjects and in 134 diabetics with nor without peripheral vascular diseases on clinical examination.
With a modified Clark-type oxygen electrode, tcPOz was measured on the chest, above the knee, below the knee and the dorsum of the foot.
One hundred-thirty four diabetics were clinically classified in the following 3 groups; group 1~98 diabetics without clinical evidence of vascular insufficiency, group 2^25 diabetics with intermittent claudication and group 3--11 diabetics with rest pain or gangrene.
In order to develop tcPOz measurement into a practical method for accurate assessing peripheral vascular´ insufficiency of the diabetic foot, regional perfusion index(RPI: the ratio of foot to chest tcPOz), that was> independent of systemic oxygen delivery and accurately reflected the adequacy of foot perfusion, was examined.
In addition, tcPOz and RPI were measured with or without leg elevation and tcPOz_recovery half time after temporary arterial occulsion was also studied.
The results were as follows:
1. The tcPOz of the foot and below the knee in group 1, as well as group 2 and group 3, were significantly lower than those in control group(p<0´.01), which represented the existence of subelinical hypoxia.
2. RPI was significantly lower in the diabetics compared to control subjects. The tcPOz and RPI of control foot were high and varied little with leg elevation(p<0.01).
All values of the foot with leg elevation in group 2 were below the lower limits of those of ´control (tcPOz<30 mmHg, RPI<65,o), however all values without leg elevation in group 3 were below the lower limits of those of control.
3. The recovery half time of tcPOz after transient arterial occlusion was delayed significantly in diabetic
group compared to control group(p<0.01), and the delay was related to the severity of the hypoxia. These quantitative assessments of limb hypoxia by measuring tcP02 may provide a noninvasive and -simple screening method not only for early detection of the diabetics at risk with no clinical evidence of peripheral vascular insufficiency but also for grading the severity of diseases and evaluating progression´ of diseases in the diabetics.
|