I have a very old criteria grid used to evaluate vein conditions prior to cannulation. The grid graded the veins on a scale of 0 (best) to 5(worst), Vein size was compared to IV catheter gauge ie. 14g = large vein, 16-18g = med vein etc, . The grid also evaluated vein palpability with/without a tourniquet and vein condition ranging from soft and resilient, mod. hardening, corded, sclerosed etc. Does anyone remember this " criteria for judging veins" the author, which journal and edition the article first appeared.