A bloodless study with a Photoplethysmographic test of the limb's blood circulation among haemodialyzed patients with arteriovenous fistula and the influence of Flunarizine treatment was performed. All patients showed a blood reduction flux on the hand with fistulas in front of the controlateral limb. Three patients affected by Raynaud Syndrome were identified. The Flunarizine treatment did not show significative blood flux variations among among those patients with low Photopletysmographic index (P.I.) in the limb with arteriovenous fistula, while a significative increase of P.I. was registered in the limb of the patients affected by Raynaud Syndrome. Concluding, the Photopletysmographic test is useful to follow the limb's blood circulation of haemodialyzed with arterio-venous fistula, being it bloodless, sure and repeteable test to follow the influence of vasoactive therapy.