Background: Puncturing of the internal jugular vein (IJV) after placement of a laryngeal mask airway (LMA) is difficult. Overlapping of the right internal jugular vein (IJV) and common carotid artery (CCA) after placement of an LMA-Classic (Laryngeal Mask Company, Henley-on-Thames, United Kingdom) was investigated using an ultrasound scanner. A study was conducted to determine the optimal puncture site in the case of puncturing the right IJV after LMA-Classic placement.
Methods: The subjects in this study consisted of 114 patients (60 men and 54 women) scheduled to undergo LMA-Classic placement (size 4 for men and size 3 for women). Overlapping between the IJV and CCA was investigated at three points (high, middle, and low points) on the right side of the neck after LMA-Classic placement. A test puncture was also made at the right low (supraclavicular) point after LMA-Classic placement.
Results: (1) The degree of overlapping of the right IJV and CCA after LMA-Classic placement was clearly greater than before LMA placement. (2) With the exception of some measurements, there were many cases in which the right IJV and CCA were completely overlapping after LMA-Classic placement. Furthermore, the CCA was not observed in the vicinity of the right IJV at the right low point. (3) There were no complications (including pneumothorax and accidental arterial puncture) during supraclavicular IJV puncture after LMA-Classic placement.
Conclusion: After placement of the LMA-Classic, overlapping of the IJV and CCA increased at the high and middle puncture points of the IJV; however, at the lower puncture point, the position of the vessels remained unaffected. Therefore, during IJV puncture at high or middle points, ultrasound guidance is advisable to avoid CCA puncture.