Quantitative Analysis of Autonomic Neuropathy in Diabetic Patients Using a Periflux Laser Doppler Flowmeter

With Special Reference to the Valsalva Test

Abstract

The skin blood flow (Periflux blood flow: PBF) in the finger tip was measured with a Periflux laser doppler flowmeter (PLDF). PLDF is a new instrument for the direct, continuous and noninvasive measurement of blood flow in skin capillaries. A 2 m W He-Ne laser was used as a light source. In the present study, the pattern of PBF was evaluated as a measure of autonomic neuropathy in diabetic patiens. Response to the Valsalva maneuvre was studied in 80 normal subjects and 93 diabetic patiens. PBF decreasing velocity (PDV) was chosen as an index of the PBF response. The results obtained were as follows.
1) In normal subjects, PDV value was decreased significantly by atropine sulfate, but it was not affected by age, sex or the duration of breath holding.
2) PDV value (mV/sec) was 134 ±41 (mean ± SD) in normal subjects, and 75±50 (mean ± SD) in diabetic patients. The frequency with which abnormal PDV occurred in diabetic patients was 45%(42/93 cases).
3) Twenty-one diabetic patients were examined with regard to Beat-to-beat variation (BBV). There was significant correlation between PDV and BBV (r=0.802. p<0.001).
These results suggest that measurement of PBF observed by the Valsalva maneuvre is clinically useful for evaluating parasympathetic nerve dysfunction in diabetic patients.