Measurement of skin and total blood flow to the rabbit lower limb by washout of freely diffusible radioactive tracers introduced intra-arterially.

Good agreement was obtained when measuring total (capillary) blood flow in 9 rabbit thighs using two different techniques. The 133Xenon washout technique yielded a mean value of 8.0 cm3 X min-1 X 100 g tissue-1 whilst the microsphere technique gave a mean value of 7.8 cm3 X min-1 X 100 g tissue-1. There was a significant correlation (r = 0.83, p less than 0.006). In a further 14 rabbit thighs an attempt was made to measure skin blood flow by washout of 85Kr and to compare it with the microsphere technique. 133Xe promises to be a useful tracer for measuring lower limb flow when introduced intra-arterially. Because 85Kr tends to underestimate skin blood flow, and because of problems of diffusion of the tracer between compartments, which are discussed, this tracer is not satisfactory as a technique for measuring skin blood flow.