Biomedical subjects
Publications and source records attributed to M Chauveau.
In large arteries distributing blood to an area (hind leg of dog), local heat induces a vasodilatation. The mechanical reactions (variations of mean velocity of flow and amplitude of pulsatile flow) express a distal dilatation. Radial expansion responds in original way (pulsation become uniform).
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Digital plethysmography records digital pulsation and measures blood flow by occlusion and perfusion pressure. The pulsatile curve is modified in vasomotor disorders of the extremities, and is delayed and flattened in obstructive arteriopathy. In Raynaud's phenomenon, the basal flow (at 22 degrees C) decreases with clinical severity, and suppression of post-ischemic blood flow by cold seems to be an attribute of Raynaud's disease. Digital perfusion pressure is usually greater than or equal to 70% of the humeral systolic pressure. When it decreases under hot conditions, organic obstructive arteriopathy is indicated; decreases due to local cooling allow quantification of hyperreactivity to cold of the digital artery.
The authors report on a case of intermittent venous claudications in a 76-year-old man, who three months previously suffered a sudden acute attack of phlebitis in the right upper limb. The Doppler exam showed post-phlebitic failure of the humeral valve and diminished permeability of the axillobrachial axis of the vein, with sub-clavicular obstruction. The discussion provides an opportunity for reviewing the various anatomo-pathological definitions and explanations of the mechanism of intermittent venous claudications.
After medium physical exertion, twelve athletes had their venous reflux measured using a Doppler fluxometer. A rise in the speed of the blood flow was recorded. This is due to the hyperactivity of the thoraco-abdominal and cardiac pumps, whose efficiency is boosted by arteriocapillary vasodilation. In some cases, this happens only in the deep system. But in others, this "arterialization" is apparent in the superficial system too, and especially in the region of the short saphenous vein. This occurs in such a way as to suggest that the deep course becomes saturated and so the reflux is redirected along the superficial course. This hypothesis is an argument in favour of the existence of vein to vein anastomosis.