While there is no clear consensus regarding the position of the tip of central venous catheters (CVC) in the superior vena cava (SVC) [2], the right atrium (RA) should definitely be avoided due to the risk of vascular/cardiac perforation. The SVC at the level of the carina is preferred by some authors, while others prefer the junction of the right atrium with the SVC (RA-SVC junction). Autopsy studies on infants have shown that the carina is almost always located above the pericardial reflection on the SVC [3]. Thus using the carina as a landmark for placement of the tip of the CVC reliably excludes placement in the RA. The carina is relatively easy to identify either by the anatomical landmark method or by radiological evaluation.

Studies in children to guide the positioning of CVC are scarce [4-6]. Andropoulos, et al. [4] used external anatomical landmarks or transesophageal echo-cardiography (TEE) to guide CVC placement in 456 children undergoing surgery for congenital heart disease (CHD) and checked the placement on the first postoperative chest X-ray. With this data, formulae for the correct insertion length for right-sided internal jugular vein (IJV) and subclavian vein (SCV) catheters were made based on the patient’s height. The formulae predicted the correct catheter length, i.e., position above the RA, in 97%. Andropoulos’ formulae found wide acceptance and are widely used. In a study on 60 preoperative infants and children by Yoon, et al. [5], right IJV catheters were positioned using TEE. They formulated a guideline to correctly position a right IJV catheter in 97.5% patients with an accuracy of 95%, in children with height between 40 and 140 cm. Similarly, in 90 children <5 years age, Na, et al. [6] placed right IJV catheters using the sternal head of the clavicle and the nipples as external landmarks to determine the position of the carina. This method required no formula or any pre-operative chest X-ray, or any other sophisticated methods like TEE or electrocardiographic guidance.

In contrast to the above studies, Witthayapraphakorn, et al. [1] have measured the actual distance from the point of insertion of a right IJV catheter to the position in the SVC to be correctly located above the RA, on computerised tomography (CT) images of 165 children. They measured the distance from the presumed skin puncture site to the SVC at the level of the carina and the RA-SVC junction. Inter-and intra-observer agreement was good and the study was adequately powered. With the data thus obtained, using regression analysis, a formula was devised to calculate the depth of the right IJV catheter based on the age in months and body surface area. Finally, for ease of recall, simple recommendations for length of catheter insertion have been made for different ages (not using the complicated formula) starting at 6.5 cm at 1 year of age and increasing by 0.5 cm till 12 years of age, 13 cm at 13 years and remaining at 14 cm beyond this age.

Unfortunately, the study gives no information for CVC placements for the left IJV/SCV or right SCV catheters. The number of children <1 yr age was only 8 and hence, the values do not represent an adequate sample. Perhaps, keeping this in mind, the authors’ recommendations start from the age of one year. External validation of the recommendations is awaited.

Funding: None; Competing interests: None stated.

1. Witthayapraphakorn L, Khositseth A, Jiraviwatana T, Siripornpitak S, Pornkul R, Anantasit N, et al. Appropriate length and position of the central venous catheter insertion via right internal jugular vein in children. Indian Pediatr. 2013; 50:749-52.

2. Vesely TM. Central venous catheter tip position: a continuing controversy. J Vasc Interv Radiol. 2003;14:527-34.

3. Albrecht K, Breitmeier D, Panning B, Tröger HD, Nave H. The carina as a landmark for central venous catheter placement in small children. Eur J Pediatr. 2006;165: 264-6.

4. Andropoulos DB, Bent ST, Skjonsby B, Stayer SA. The optimal length of insertion of central venous catheters for pediatric patients. Anesth Analg. 2001;93:883-6.

5. Yoon SZ,　Shin TJ,　Kim HS,　Lee J,　Kim CS,　Kim SD,　et al. Depth of a central venous catheter tip: length of insertion guideline for pediatric patients. Acta Anaesthesiol Scand. 2006;50:355-7.