Decreased blood flow in a papaverine-induced passive vascular bed in sclerodermal skin

Blood flow was measured in the form of 133Xenon washout rate constants in a cutaneous vascular bed made passive by intracutaneous injection of a 133Xenon-papaverine mixture. Experiments were performed using injection volumes of 0.005, 0.02, 0.1 and 0.2 ml in 7 normals and 15 patients suffering from generalized scleroderma. Blood flow was closely related to the volume of fluid injected, probably reflecting dilution of tissues and increased diffusion distances when injection volumes were increased. When using injection volumes of 0.005 and 0.02 ml, blood flow was significantly reduced in the patients, as compared with normals, probably because of a decreased capillary density in cutaneous tissue in generalized scleroderma.