Evaluation of Surface Landmarks and C-length as Predictors of the Depth of Right Internal Jugular Venous Catheter Insertion: A Transesophageal Echocardiography-Guided Study
Authors: Hakim Sameh Michel , Elgendy Hanaa Abdallah , El-Din Doaa Mohammed Kamal , Awad Mohamed Mohsen Mohamed , Eldin Ghada Ramadan Mohamed Mohamed Sharaf 
Published: October 2021

Abstract

Background
Central venous catheterization is a standard clinical practice for infusion of fluids, blood products, or vasoactive drugs to the central circulation and to monitor central venous pressure during perioperative periods. However, this procedure can lead to significant complications, including cardiac arrhythmia, vascular injury, hydrothorax, hemothorax, hydromediastinum, and cardiac tamponade. Such complications can occur when the catheter tip is inserted within the heart chamber or when it abuts the vascular wall at a steep angle.

Objectives
The primary aim of the current study is to examine the accuracy of the C-distance or surface landmarks in determining the length of CVC that is required to place the catheter tip at the mid-SCV as confirmed by transesophageal echocardiography (TEE). A secondary aim is to derive an equation or formula to calculate the depth of the CVC that is required in order to have the catheter tip placed at the mid-SVC.

Patients and Methods
After obtaining the approval from research ethical committee of Ain Shams University and obtaining informed consent from patients the study was conducted in The Academic Institute for Cardiothoracic and Vascular Surgery, Ain Shams University hospitals. 30 adult patients scheduled for elective cardiac surgeries were enrolled in the study after being selected by random simple method.

Results
We used the TEE to visualize the CVC tip 3 cm above SVC-RA junction and use this actual depth to compare between the accuracy of the expected depth by C-length method and expected measured depth by surface landmarks method; we found out that the two methods were nearly the same to the actual depth guided by TEE. The mean ± SD surface landmarks distance was 142 ± 12 mm (range, 120 - 162 mm) and the mean ± SD by C-length was 128 ± 18 mm (range, 95 - 174 mm). The mean ± SD TEE-guided CVC length needed to place CVC tip at mid-SVC was140 ± 13 mm (range, 110 - 162 mm). Also in none of the patients was the CVC tip placed below the carinal level on postoperative plain AP chest x-ray. The CVC tip was placed at a mean ± SD height of 12 ± 2 mm (range, 5 to 16 mm) above the carinal line, which concludes that the mid SVC region lies above the carina level by 0.5-1.5 cm and it’s a reliable landmark for postoperative confirmation of optimum placement of CVC tip.

Conclusion
TEE can be used to effectively determine the proper fixed catheter insertion depth for a patient through the right internal jugular vein. This study showed that both C-length and surface landmarks methods are accurate to determine the depth of the central venous catheter in the mid SVC region (3-3.5 cm) above SVC-RA junction above pericardial reflection. Another conclusion is that the mid SVC region is above carinal level in all cases by 5 mm -15 mm. From this study we formulated two regression equations depending on the expected surface landmarks and C-length with an accuracy of ± 11.662 mm and ± 10.643 mm respectively.