Limitations
COMPLICATIONS
The study results were obtained by five less-experienced operators, which might lead to a high rate of immediate complications, and thus cannot be directly extrapolated to sonographers with more experience. Further studies are required to assess the necessity of the x-plane approach for operators with prior experience. Moreover, the out-of-plane approach was not employed in this study. This is attributed to the use of the US-guided in-plane approach by less-experienced operators because it can real-time display the needle in-plane to ensure safety. In addition, subclavian vein was not included in this study because catheterization here is associated with higher mechanical complications and high technical difficulty which is difficult for less-experienced sonographers. Further studies including experienced operators and subclavian vein catheterization are necessary to confirm our findings.