The anatomic relationship between the internal jugular vein and the carotid artery in children after laryngeal mask insertion: an ultrasonographic study.

BACKGROUND Central venous cannulation, although challenging in children and prone to complications, is frequently required for total parenteral nutrition and infusion of drugs. AIM The aim of this study was to determine the anatomic relationship between the internal jugular vein (IJV) and carotid artery (CA) before, and after, insertion of laryngeal mask airway (LMA) in children using ultrasound. METHODS Patients aged 2-16 were recruited to this prospective study and divided into three groups of 20 patients each: group 1: LMA size 2, group 2: LMA size 2½, and group 3: LMA size 3. Prior to, and following, LMA insertion, the position and depth of the vessels, and time to locate them were recorded. All measurements were taken at the level of the cricoid cartilage in a neutral head position in the spontaneously breathing patient during expiration. The IJV position in relation to the CA was noticed as anterior (A), anterolateral (AL), lateral (L), or medial (M). RESULTS The position of the IJV was found to be in the anterolateral (AL) or anterior (A) position to the CA in the majority of cases. The anatomic relationship changed in 10/120 (8.3%) following insertion of the LMA. The mean depth was 0.80 (± 0.15) cm for the right IJV before LMA insertion and 0.84 (± 0.17) cm after insertion. Similar measurements were taken on the left side [0.81 (± 0.14) cm and 0.83 (± 0.18) cm]. The diameter as well as the depth of the IJV increased with the age and weight of the patient. CONCLUSIONS This study demonstrates that the IJV is anterior or anterolateral to the artery in the majority of cases and that the anatomic relationship may change following the insertion of the LMA. It supports the need for using ultrasound-guided techniques for IJV cannulation following LMA insertion in spontaneously breathing children.