Central venous catheter placement is an essential procedure in emergency medicine, with the internal jugular vein (IJV) the most commonly accessed site. However, in certain situations such as abnormal neck anatomy, presence of a cervical collar, IJV thrombosis, or active cardiopulmonary resuscitation, the subclavian vein (SCV) may be a better option.1,2 Also, because of the SCV’s fixed position under the clavicle, size variations are less common (unlike the often collapsed IJV noted in patients with severe dehydration or sepsis). Cannulation of the SCV may also improve patient comfort while reducing rates of infection and thrombosis when compared to the IJV and femoral vein.3,4
Classically, landmark-based SCV cannulation is performed below the clavicle. In contrast, ultrasound guidance allows cannulation to occur both via the infraclavicular (at the junction of the axillary vein and SCV) and supraclavicular (where the SCV meets the IJV to form the brachiocephalic vein) approaches. When compared to landmark techniques, ultrasound guidance reduces the rates of arterial puncture, pneumothorax, brachial plexus injury, and hematoma formation.5–8 With the supraclavicular approach, the SCV is often shallow and easily visualized as compared to the infraclavicular approach, making for an ideal site for central venous cannulation.9,10
- This approach may be more difficult in patients with higher BMI or short necks since it’s more difficult to probe and needle into the supraclavicular notch.
- Always clearly visualize the needle tip with the in-plane technique and remember that the SCV is anterior to the SCA.
- For more advanced sonographers, color Doppler can be used to discern between SCV and SCA.
Our two-part series will discuss both the supraclavicular and infraclavicular approaches to ultrasound-guided SCV cannulation. Before attempting either of these more challenging ultrasound-guided SCV cannulations, we recommend novice sonographers obtain comfort with both the ultrasound-guided IJV or femoral vein cannulation as well as attain proficiency with in-plane needling technique.