Abstract
Small veins are a risk factor for infiltration. However, there are no data regarding the ideal vein diameter for preventing infiltration. Using ultrasound, vessel diameter and calculated ratios of the vessel diameter to the catheter gauge were measured. The relationship between the ratio and infiltration was assessed to establish a cutoff point. The mean ratio of the infiltration group was significantly smaller than that of the no-infiltration group (P < .01), and the ratio was an independent risk factor according to the multivariable analysis. The ratio of 3.3 was determined to be the cutoff point that enables health care professionals to identify veins appropriately.