Written by Clay Smith
Lumbar elevation resulted in the greatest increase in subclavian vein (SCV) and internal jugular (IJ) vein diameter on ultrasound in healthy volunteers.
Why does this matter?
Trendelenberg and Valsalva maneuver can increase cross sectional diameter of the SCV or IJ. Also a prior study has shown that turning the head 30 degrees toward the side of SCV insertion increased the diameter. What if your patient is on a bed that does not allow for Trendelenberg positioning or your patient cannot cooperate with Valsalva?
Of all the positions to plump up the central veins for central line placement, lumbar elevation (LE) was best when Trendelenberg was not an option. See the figure. This technique (Image F) resulted in the most dilation and greatest increase in diameter of the SCV and IJ on ultrasound in 30 healthy volunteers. It beat out all the other positions shown in the figure. The IJ was 9.8mm with LE compared to 8.7mm supine (p=0.001). The SCV was 10.7mm with LE and 10.1mm supine, almost significant (p=0.08). Surprisingly, lifting the legs did not increase SCV or IJ diameter and trended toward making them smaller.
Effect of lumbar elevation on dilatation of the central veins in normal subjects. Am J Emerg Med. 2018 Jul 18. pii: S0735-6757(18)30591-6. doi: 10.1016/j.ajem.2018.07.032. [Epub ahead of print]
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Reviewed by Thomas Davis