Step 2: Initial Ultrasound Survey with Anesthetic
Starting in short axis orientation (probe parallel with the spine), the
axillary vein and artery can be identified as the probe is slid closer
to the clavicle. Depth and gain should be adjusted appropriately by an
assistant to optimize visualization. The vein is more anterior (i.e.,
closer to the probe) and caudal (closer to the feet) than the artery,
collapsible with light pressure, and can sometimes contain valves that
are visible on ultrasound. In addition, if the arm IV has saline flush
infusing to keep the line open, saline bubbles can usually be visualized
flowing centrally on ultrasound.
Once the vein is identified near the clavicular shadow, the probe should
be turned 90 degrees clockwise to view it in long axis. Structures
visible in this view should be the clavicular shadow superficially (top
of the ultrasound screen), the medial axillary vein in long axis running
across the length of the screen, and the shadow of the first rib
posterior to the vein (bottom portion of the ultrasound screen).
Frequently, the cephalic vein can be visualized inserting into the
axillary vein. Long axis view allows the operator to choose whether to
enter the axillary vein medial or lateral to this intersection.
Administration of subcutaneous anesthetic with a 22-gauge needle during
long axis ultrasound imaging allows the operator a preview of the angle
of the needle course that will be needed. This is also a good time to
anesthetize the future incision line, which should be medial and a few
millimeters inferior to the skin access points (Video 2).
Step 3: Ultrasound Guided Access
After the skin has been adequately anesthetized, the access needle can
now be introduced under long axis visualization with the bevel of the
needle facing up at an angle of 45 degrees or less from the surface of
the vein to ensure a smooth angle of insertion. The operator should
focus on finding the tip of the needle on the ultrasound screen before
advancing it past the initial first 5 millimeters under the skin. If the
needle tip is not visualized, the needle should not be advanced.
Instead, the operator must tilt the ultrasound probe and/or tilt the
needle from side to side until it is found.
After identifying the needle tip, it should be slowly advanced towards
the front wall of the axillary vein until tenting of the wall is
encountered. Most operators at this point are taught to perform jabbing
motions with backwards suction on the syringe to puncture the front
wall. However, this type of aggressive motion can lead to inadvertent
backwall punctures, which in turn could lead to arterial injury or
pleural injury. Instead, once maximal tenting is achieved, a quick
back-and-forth twisting motion of the access needle will facilitate a
clean entry into the vein by taking advantage of the sharp edges of the
bevel that will cut into the vein.
Sometimes the operator will find that the needle will tend to slide
across the surface of the vein and not enter it. An advanced technique
tip here would be to withdraw the needle slightly, then dip the tip of
the needle to almost a 90 degree angle in relation to the anterior vein
wall surface to try to catch the vein wall on the tip of the needle.
When the anterior wall is caught on the tip of the needle, flattening
out the needle back to a less than 45 degree angle combined with the
twisting motion should result in a swift entry of the needle into the
vein. The needle position inside the vein can either be verified by
direct visualization on ultrasound or by aspiration of blood into the
syringe.
A standard J-wire can now be advanced into the axillary vein either by
feel or under direct ultrasound visualization. If this is a left
infraclavicular approach, it is highly recommended to perform a quick
fluoroscopic visualization of the wire at this point to ensure a normal
course of the wire to the subclavian vein, brachiocephalic vein, and
then superior vena cava. This will facilitate identification of a
persistent left superior vena cava, in which case the operator now has
the choice to either continue on with the implant or abandon the left
sided approach and switch over to a right infraclavicular approach. A
second and third access (depending on type of CIED) may now be obtained
by the same technique with the needle puncturing the skin 1-2
millimeters lateral or medial to the first wire entry point (Video 3).
Step 4: Pocket Incision
The lateral border of the pocket incision should be 3-5 millimeters just
inferior to the skin insertion points of the wires. Thus, the incision
should be started about 4-6 centimeters (depending on the size of the
CIED device) medial to this point on a horizontal line. Once the
incision is taken down to the pre-pectoral fascia layer and the
subcutaneous pocket is created through blunt dissection inferiorly and
slightly superiorly, the operator will find that the wire will be
located at the mid portion or slightly medial portion of the superior
lip of the pocket. This position allows for the CIED leads enter nicely
into the pocket and coil from there in a clockwise fashion (Video 4).