Ultrasonographic Assessment of Anatomic Relationship Between the Internal Jugular Vein and the Common Carotid Artery in Infants and Children After ETT or LMA Insertion: A Prospective Observational Study

Background: Central venous catheterization is used for fluid management and infusion of drugs, but it is difficult to perform and carries a high incidence of complications in infants and children. In adults, the anatomic relationship and the overlap index between the internal jugular vein (IJV) and the common carotid artery (CCA) changed significantly after laryngeal mask airway (LMA) placement. However, there are conflicting results regarding the anatomic relationship between the IJV and the CCA after endotracheal tube (ETT) or LMA insertion in pediatric populations. Aim: The aim of this study was to compare the overlap index and anatomic relationship between the IJV and the CCA in infants and children after ETT or LMA insertion by ultrasonography. Method: This single-center, prospective, observational study including 92 infants and children, aged 1 month to 6 years, were grouped according to the airway devices placed: Group ETT (n = 44) and Group LMA (n = 48). The overlap index and anatomic relationship between the IJV and the CCA before and after airway device insertion at neutral and 30° head rotation position were evaluated by ultrasonography. Results: Before airway device insertion, as the head was rotated 30° to the contralateral side, the overlap index increased significantly on the right side of the neck compared to the neutral head position. In Group ETT, there was no significant difference in the overlap index after intubation in the neutral head position or 30° head rotated position on either side. In Group LMA, the overlap indexes were increased significantly after LMA insertion in the neutral head position on both sides. Likewise, the overlap indexes were increased significantly after LMA insertion in the 30° head rotated position on both sides. The most common positional relationship between the IJV and the CCA was anterolateral (AL) in both the right side and left side in the neutral head position. In Group ETT, the AL position was still the most common position relationship between the IJV and the CCA before and after intubation in the 30° head rotated position. In Group LMA, the anterior (A) position increased significantly after LMA insertion in the left side. In the 30° head rotated position, there was a significant increase to the A position after LMA insertion in both the right side and left side. The change from AL to A was increased after LMA insertion, especially in the 30° head rotated position. Conclusions: The overlap indexes of the IJV and the CCA increased significantly in both sides of the neck after LMA placement in the neutral head position, especially in 30° head rotated position. The IJVs after LMA placement had a tendency to become anterior to the CCA when the head of the patient rotated to the opposite direction in infants and children.