After anesthesia induction and tracheal intubation, we will prepare central venous catheterization for patients requiring it. After anesthesiologists who are blinded to this study perform central venous catheterization, an investigator measured the shortest distance from the crease line of the cricoid cartilage to the puncture site of the introducer needle.
In this observational study, we will measure the shortest distance from the cricoid cartilage level to the puncture site of the introducer needle when anesthesiologists perform central venous catheterization.