Canadian Journal of Cardiology



      While subclavian vein (SCV) cannulation offers many advantages over alternative sites for central venous access, ultrasound (US)-guided cannulation of the internal jugular (IJ) vein has become the standard of care in most critical care settings. This is mostly attributable to the higher rates of mechanical complications from the traditional landmark (LM)-approach of SCV cannulation and the widespread availability of point-of-care ultrasonography (POCUS). However, there is limited literature exploring the feasibility of US-guided SCV cannulation in the critical care setting. This proof-of-concept study aims to determine the applicability of this technique in a critical care setting.

      Methods and Results

      Informed consent was obtained from forty-one patients in a critical care setting to participate in the study and to undergo SCV cannulation. The procedure was performed with real-time US guidance. Attempts, success rate, and complications were recorded. These parameters are compared directly to the operator’s IJ cannulation database that included 156 IJ cannulations. For the SCV group, ultrasound images of their SCV and IJ were taken along with a formal assessment of their IVC and analyzed to identify the determinants of a safer SCV cannulation. Finally, Coronary Care Unit (CCU) nurses were surveyed anonymously on their personal preference in central access positions. All forty SCV cannulations successful with on average 1.2 attempts. In contrast, IJ cannulation saw 6 failures to cannulate (4%) and on average 1.1 attempts. Three SCV cannulations (7.5%) resulted in mispositioning of the catheter tip compared to 4% in the IJ group. There were zero pneumothorax or hemothorax in both groups. The ultrasound data showed that SCV runs deeper than IJ by 1 cm on average. Both vessels are similar in size and their maximal diameter do not change significantly with volume status. Both vessels also remain relatively patent (collapse < 50% on inspiration) with an estimated right atrial pressure (RAP) of 8 or 15. At a lower RAP, IJ tends to be more patent than SCV. Finally, 13 of 15 surveyed CCU nurses prefers SCV access for its convenience and patient comfort.


      Overall, while US-guided SCV cannulation is slightly more complicated, both can be achieved in a timely manner with minimal number of attempts. The complication rates are similar, except for a higher likelihood of catheter malposition, which can be mitigated with modifications in technique. Finally, expertise garnered from this study is instrumental in informed decision making in instituting SCV cannulation in a critical care setting.
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