There are two primary 2D ultrasound (US) methods used for central venous cannulation (CVC): the out-of-plane (transverse) and in-plane (longitudinal) approaches. When the US probe is positioned transversely to the vessel (out-of-plane), a "short-axis" view is displayed on the US screen, showing a cross-sectional image of the vessel. Alternatively, positioning the US probe parallel to the vessel's direction (in-plane) yields a "long-axis" view, providing a longitudinal depiction of the vessel on the screen.
The out-of-plane ultrasound technique presents challenges, especially for those new to the procedure. Novices often find it non-intuitive to track the needle tip using the US probe, as the needle typically isn't visible until it passes through the axial imaging plane. This method necessitates either sliding or tilting the transducer to monitor the needle tip in real-time and visualize its trajectory, tasks that can be complex for inexperienced users. There's a notable risk associated with this technique: unintended needle penetration of vital structures, like the posterior venous wall and adjacent arteries. Such inadvertent penetrations can lead to complications, including the formation of hematomas, guidewire fractures, misplacement of the wire, or significant bleeding.
The in-plane technique for central venous cannulation (CVC) offers better needle tip tracking, enhancing precision. However, maintaining the needle within the narrow ultrasound beam requires practice. Clear imaging can be challenging in areas like a short neck or curved groin. Additionally, this method might obscure the relationship between the target vessel and nearby critical structures, potentially raising mechanical complication risks.
Which ultrasound approach do you prefer for central line insertion?
0%In-plane approach (longitudinal or long axis)
0%Out-of-plane approach (transverse or short axis)
An innovative x-plane technique has been introduced, a real-time 3D imaging method using a matrix array probe, combining strengths of the earlier techniques while mitigating their limitations. It allows simultaneous imaging of both transverse and longitudinal views without needing to rotate the probe. Utilizing the real-time biplane imaging technique provides two perspectives: the trajectory of the needle tip via the long-axis and its position within the vessel lumen alongside the proximity to nearby structures through the short-axis.
In a study conducted between October 2022 and March 2023 involving 256 critically ill patients requiring central venous cannulation (CVC), the real-time biplane ultrasound-guided approach demonstrated superior outcomes compared to the single-plane method for internal jugular vein cannulation (IJVC) and femoral vein cannulation (FVC). The biplane approach achieved higher first-puncture success rates (91.6% vs. 74.7% for IJVC; 90.9% vs. 68.3% for FVC), greater single-pass catheterization success, fewer undesired punctures, reduced cannulation times (205s vs. 311s for IJVC; 228s vs. 340s for FVC), and fewer immediate complications (10.5% vs. 28.7% for IJVC; 9.1% vs. 34.1% for FVC) [1].
In conclusion, for critically ill patients needing CVC, the biplane ultrasound-guided method is notably superior to the single-plane technique. It delivers higher first-puncture success rates and shorter catheterization times, making it the preferred choice when accessible.
REFERENCES:
Li YY, Liu YH, Yan L, Xiao J, Li XY, Ma J, Jia LG, Chen R, Zhang C, Yang Z, Zhang MB, Luo YK. Single-plane versus real-time biplane approaches for ultrasound-guided central venous catheterization in critical care patients: a randomized controlled trial. Crit Care. 2023 Sep 23;27(1):366. doi: 10.1186/s13054-023-04635-y. PMID: 37742018; PMCID: PMC10517529. [PubMed]