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The speed of sound: a subcla… : Emergency medicine news

ultrasound, subclavian, supraclavicular, subclavicular lines:

Placement of the transducer for a supraclavicular approach. Some tilting of the transducer toward the collarbone (forward tilt) will be required in most patients.


I’ve written before about using ultrasound for subclavian lines, both the standard infraclavicular approach and my favorite, the supraclavicular approach. (REM. 2017;39[6]:1;; REM. 2013;35[7]:8;

But how do these ultrasound-guided approaches compare? Which approach is best, easiest and safest for patients?

A recent study by our anesthetist friends compared the two approaches. (Anesthesia. 2022;77[1]:59; Patients undergoing elective surgery who required central venous access were randomized to receive an ultrasound-guided infraclavicular (using a short-axis approach) or supraclavicular (using a long-axis approach) line.

Anesthesiologists performing the procedure were allowed three attempts to place the line via the chosen approach, and a second anesthesiologist took over if those attempts were unsuccessful. The procedure was deemed a failure after three attempts by the second physician and then an internal jugular approach was used. The primary outcome was any complications, but they also looked at the time it took to place the line.

The insertion time in the 401 patients evaluated was similar (nine seconds on average for the supraclavicular versus 13 seconds for the infraclavicular). But the supraclavicular approach had a complication rate of 3%, while that of the subclavicular approach was 13.4%.

Complications were in most cases improper placement of the catheter (two in the supraclavicular group versus 21 in the infraclavicular group). Only 10 mechanical complications occurred in these 401 patients, six in the infraclavicular group (three arterial punctures, one hematoma, two pneumothorax) versus four in the supraclavicular group (all arterial punctures).

Warnings ? The average BMI of the patients in the study was 24, which may be different from our typical patient. The anesthesiologists placing the lines had also done at least 10 previous lines with each technique.

The bottom line here is that experienced physicians can successfully use either of these approaches quickly and with minimal mechanical complications. Reducing delays by reducing cases of malposition is important and could influence the choice of the supraclavicular approach.


Visualization in the plane (long axis) of the needle entering the subclavian vein in the supraclavicular approach.

Using the long axis orientation in the supraclavicular approach is much less stressful than the out-of-plane (and steep!) approach of the infraclavicular procedure, which is why I prefer to stay supraclavicular.

Watch a video

demonstrating in-plane (long axis) visualization of a needle entering the subclavian vein in the supraclavicular approach to

Dr. Buttsis Director of the Division of Emergency Ultrasound and Clinical Associate Professor of Emergency Medicine at Louisiana State University in New Orleans. Follow her on Twitter@EMNSpeedofSound, and read its past columns at