Bhattacharjee S, et al. - Researchers analyzed data from prospective randomized controlled trials in adult patients comparing ultrasound guided radial artery cannulation with digital palpation technique. Trials conducted in operating room, emergency department, cardiac catheterization laboratory were searched from PubMed and Cochrane Central Register of Controlled Trials (CENTRAL)(from 1946 to 20th November 2017) and included in the analysis, with a focus on overall cannulation success rate, first attempt success rate, time to cannulation and mean number of attempts to successful cannulation. This meta- analysis included data of 1895 patients from 10 studies. Relative to digital palpation technique, radial artery cannulation by ultrasound guidance may increase the first attempt success rate but not the overall cannulation success.