Determination of the optimal length of insertion for central venous catheterization via axillary vein cannulation using preoperative chest X-ray- A prospective feasibility study

Background and Aims: Ensuring safe central venous catheter tip placement is important. Multiple techniques are available to estimate the length of catheter insertion for subclavian and internal jugular approaches. However, the methods to determine the length of insertion for the axillary route have not been validated. The purpose of this feasibility study was to evaluate a simple method for the calculation of catheter length to be inserted and assess whether it accurately predicts the correct tip placement. Material and Methods: A total of 102 patients requiring preoperative central venous cannulation were evaluated, out of which 60 had successful axillary vein (AxV) cannulation. The length of insertion was calculated using the formula: (2/3* A + B) +Y (A: Clavicular length on chest radiograph [CXR], B: Vertical distance between the sternal head and carina on CXR, Y: Perpendicular distance from the skin to the AxV on ultrasound). A postoperative CXR was used to assess the accurate tip placement (2 cm above the carina to 0.5 cm below it). The primary outcome of the study was the rate of successful placement of the central venous catheter (CVC) in terms of the correct position of the tip of the catheter when the length of the catheter inserted was predicted by the formula described previously. Results: Optimal placement was observed in 83.33% of the cases. A higher rate of accuracy was seen in the females (P value = 0.03) and shorter patients (P value = 0.01). A Bland-Altman plot depicted a high degree of agreement. Conclusion: Use of the formula using a CXR and ultrasound allowed P successful placement of the CVC tip at the desired location in 83.33% of the cases.