Arterial catheterization for continuous hemodynamic monitoring or frequent blood sampling is a common procedure in anesthesia and critical care setting. The most commonly used site for arterial catheterization is the radial artery because of its superficial course, alternate blood supply to hand via ulnar artery and a low rate of complications. Allen test is a simple, but not reliable, method for assessing the safety of radial artery catheterization. Intraarterial catheterization has some complications such as hematoma, vasospasm, arterial thrombosis, necrosis of skin overlying. Using larger size cannula from radial artery diameter, increase rate of complications. The purpose of this study is to investigate the corelation of radial artery diameter with sex, age, height, weight and body mass index for determination of proper cannula size and investigation of correlation between Allen test and doppler ultrasonography.
In this study, the investigators will investigate how patients' radial artery diameters change according to sex, age, height, weight and body mass index by measuring radial artery diameter using ultrasonography. The correlation of Allen test with doppler ultrasonography will also be evaluated.