To Poke or Probe the Subclavian?

Written by: Dr. Andrew Shanes

Edited by: Dr. Joann Hsu

To set the scene, here is a hypothetical case:

  • Pre-hospital notification for a 64YO male enroute via EMS for STEMI Alert as well as Trauma Bravo activation for high rate of speed MVC.

  • EMS report upon arrival to scene, patient states that prior to MVC he developed “crushing” chest pain that felt similar to his prior heart attack causing him to veer off the road, crashing into a parked car. Field 12-lead was obtained suspicious for anterolateral STEMI.

  • Upon arrival, Vitals: BP: 95/64, HR: 112, RR: 22, O2: 96%

  • Pertinent Exam:

    • Awake and alert, diaphoretic, complaining of nausea, severe chest, left arm, neck and back pain. 

    • C-collar in place

    • Obvious deformity to left wrist and forearm

    • Midline C-Spine and L-Spine tenderne


Patient’s hypotension persists and decision to obtain central access is made.


How do you decide what site to use for access?

  • Site selection is going to be patient and provider dependent. While providers should be performing the procedure they are most comfortable with, they should be able to perform central venous catheterization at all 3 sites (Internal Jugular, Femoral, Subclavian) as there may be certain situations where only one site is available. 

  • Providers may need to avoid the IJ in patients who are wearing a c-collar, have a tracheostomy, or have trauma to the head and neck.

  • Providers may need to avoid femoral sites if pelvic trauma, a large pannus, a contaminated inguinal region or preservation for cardiology procedures.

  • However even if all 3 sites are available/accessible, it’s important to know the possible complications at each insertion site.

  • 3SITES Study was a multicenter randomized, controlled trial of over 3000 ICU patients to assess risks of central venous catheterization at different insertion sites.

  • Subclavian vein was associated with a reduced risk of the combined outcome of catheter-related bloodstream infection and symptomatic deep-vein thrombosis.

  • Subclavian-vein catheterization was associated with an increased risk of mechanical complications, primarily pneumothorax.

  • However, mechanical complications associated with subclavian catheter insertion can be limited by ultrasonographic guidance and physician experience with the procedure.

Should Subclavian Access be obtained using Ultrasound Guidance?

  • Historically, subclavian access has been obtained using landmark guidance, however Ultrasound Guidance has been shown to result in a higher overall success of venous catheterization, faster procedure time and less complications when compared to landmark guidance.

The Proof:

  • A Single center blinded RCT of 194 ICU patients comparing static Ultrasound guidance* vs landmark guidance showed the ultrasound group had:

  1. A higher puncture success rate (91.7% vs. 77.6%; p = 0.007)

  2. A lower rate of complications (7.3% vs. 20.4%; p = 0.008)

  3. A lower incidence of mispuncture of an artery (2.1% vs. 14.3%; p = 0.002)

  • With no significant differences in the number of punctures and puncture time between the two groups (both, p > 0.05).

Six RCTs, looking at over 800 cannulations, were included in the quantitative analysis. These results showed:

  • Ultrasound guidance increased the success rate (RR = 1.14 [95% CI 1.06–1.23]; p = 0.0007)

  • Ultrasound guidance was associated with lower complication rates (RR = 0.32; [95% CI 0.22–0.47]; p < 0.0001)

  • Ultrasound guidance increased the success rate on first attempt (RR = 1.32 [95% CI 1.14–1.54]; p = 0.0003)

  • Overall analysis favored ultrasound guidance, with fewer attempts required for successful cannulation (MD = –0.45 [95% CI –0.57 to –0.34]; p < 0.00001)

  • The use of ultrasound guidance was associated with shorter access times: (MD = –10.14 s; [95% CI –17.34 to –2.94]; p = 0.006)


How to perform Ultrasound Guided Subclavian Central Venous Access:

  • First, obtain your short-access view of the subclavian vein and subclavian artery. You can either place the probe as shown below, but may have issues with maintaining contact with the skin with the clavicle in the way. You can also place your probe just inferior to the clavicle, along the length of the clavicle, to locate your subclavian vessels.

If unsure of vein vs artery, can attempt to compress the vein, however this may be difficult due to the location under the clavicle. 

If unable to compress the vein or for further confirmation, can use color doppler to identify the vein which will have more of a continuous flow, compared to the artery (more pulsatile).

Next, center your vein in the screen and rotate to obtain your long view of the subclavian vein. Here, you can see how close the vein lies to the rib and pleura.

Here is another nice view of the subclavian vein in long axis.

Here is a view of both artery and vein next to each other in long axis. Fan to see where the artery is in relation to the vein so you know where it is and ideally avoid hitting it.

You then proceed with central line placement as you normally would.

In the videos above you can see the minimal distance (0.5-1.5cm) between the back wall of the subclavian vein and the pleural line, emphasizing even further the importance of maintaining good visualization of your needle during the entire procedure to decrease risk of pneumothorax (or other mechanical complication).


Take Away Points:

  • Decision of which site to use is going to be situation dependent emphasizing the importance of becoming comfortable with obtaining access at all 3 sites.

  • Ultrasound Guidance > Landmark Guidance for:

    • Improved overall success rate

    • Faster procedure time/first attempt success rate

    • Decreased complications

  • It all comes down to YOUR comfort/training so don’t necessarily change your practice immediately, but maintain procedural competence with a variety of access options.

Happy scanning!

Resources:

Salim Rezaie, "REBEL Cast Episode 19: All Vascular Access", REBEL EM blog, November 12, 2015.

Mark Ramzy, "REBEL Cast Ep91: Static Ultrasound vs Landmark Placement of Subclavian Central Lines", REBEL EM blog, November 19, 2020. 

Brass P, et al. Ultrasound guidance versus anatomical landmarks for subclavian or femoral vein catheterization. Cochrane Database Syst Rev. 2015 Jan 9;  PMID: 25575245

Rezayat T, et al. Ultrasound-Guided Cannulation: Time to Bring Subclavian Central Lines Back. West J Emerg Med. 2016 Mar;17. PMID: 26973755

Parienti, J.-J. et al. (2015) ‘Intravascular complications of central venous catheterization by insertion site’, New England Journal of Medicine, 373(13), pp. 1220–1229. doi:10.1056/nejmoa1500964. 

Kannappan, A. and Chang, L. (2018) Ultrasound Guided Subclavian Central Lines -- BAVLS, YouTube. Available at: https://www.youtube.com/watch?app=desktop&v=_VYHj4sRlkc (Accessed: 05 October 2024).

Wang Q, Cai J, Lu Z, Zhao Q, Yang Y, Sun L, He Q, Xu S. Static Ultrasound Guidance VS. Anatomical Landmarks for Subclavian Vein Puncture in the Intensive Care Unit: A Pilot Randomized Controlled Study. J Emerg Med. 2020 Dec;59(6):918-926. doi: 10.1016/j.jemermed.2020.07.039. Epub 2020 Sep 22. PMID: 32978029.


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