Tag Archives: probe

Subxiphoid window

sub x Subxiphoid window

The subxiphoid four chamber view is commonly used in cardiac assessments and the FAST exam and for many is the initial “go-to” view of the heart. Difficulty obtaining this window can frustrate novice and seasoned operators, and there are a few tips which can help optimize the view.

  1. It’s called SUB-xiphoid for a reason. Don’t jam the probe up against the xiphoid process. Imaging through bone is difficult, the patient will be in pain, and the angle is too steep. Instead, place the probe a few centimeters south of the xiphoid process and work up from there.
  2. Get a good view of the liver, THEN use that to get a good view of the heart. You may find that starting to the patient’s right of midline gives a better liver window, since the stomach tends to obscure the subxiphoid view as you go further left.

This video illustrates the huge difference that left vs. right can make. It was taken with the probe in a midline subxiphoid position. Starting with the probe angled towards the patient’s left, the entire screen is obscured by gas in the stomach. As the operator changes the angle towards the patient’s right, we see the liver come into view. This yields an excellent window through which the heart can be visualized.

The figure below, taken from the midpoint of the video, illustrates the point a bit more clearly. To the right of the green line (patient left), superficial stomach gas (arrow) obscures everything behind it, creating a terrible view. On the other side of the green line, liver (L) is visualized which creates a good window for viewing the heart behind it.

subxsplitlabels 500x370 Subxiphoid window

NYSORA Winter Symposium 2011

Fellows Leila PoSaw and Gene Chan attended the NYSORA (New York School of Regional Anesthesia) Winter Symposium held on December 17-18, 2011 at the Marriott Marquis Hotel on Broadway.

In addition to the expected excellent lectures and educational sessions, there was a new needle guidance system being demonstrated which may be of benefit to clinicians performing ultrasound-guided procedures.

The SonixGPS system by Ultrasonix uses a sensor in the ultrasound transducer and another in the needle to track the needle’s trajectory and tip placement. The system can work in any direction: in-plane or out-of-plane. Needle trajectory is displayed as a graphic on the main screen, and orientation with respect to the transducer is modeled in the lower right. The system promises the ability to plan out their trajectory before needle placement as well, thus facilitating decisions regarding optimal entry points.

Please note that no members of our ultrasound division have a financial relationship with Ultrasonix.

 

Tips and Tricks: Probe Rotation

Probe 500x312 Tips and Tricks: Probe Rotation

Probe Manipulation – Rotation from Sinai EM Ultrasound on Vimeo.

How do you obtain that nice long image of the peripheral blood vessel for a longitudinal approach? It is easy to say ‘rotate the probe 90 degrees from the transverse view,’ but there are many subtleties to probe rotation. Many times when we rotate the probe, we do not get the desired longitudinal view, but rather the vessel is seen in part, or obliquely sectioned. Also, the vessel may appear on the left side of the screen or the right side and further fine rotation often makes the vessel disappear. How do we correct for this?

The trick is to understand the many different axes of probe rotation. See the video for an example of :

(i) probe rotation along an axis that goes through the proximal end of the probe (incorrect)

(ii) probe rotation along an axis through the distal end of the probe (incorrect)

(iii) CORRECT probe rotation along an axis through the central portion of the probe (through the transducer wire)

In order to move from a transverse to longitudinal view of a blood vessel without losing track of it, you must:

  1. Visualize the vessel in the center of the screen (thus, directly beneath the center of the probe)
  2. Rotate the probe on its CENTRAL axis (through the wire)
  3. Watch as the vessel transitions from a circle (transverse) to an ellipse (oblique) to two parallel lines (longitudinal)

Go try this on a phantom and with some practice, everyone can get that nice elongated view of the vessel.

Holding the probe

righthandprobe Holding the probe

Figure 1. Holding the probe for general scanning

Novice sonographers often hold the ultrasound probe like a dead mouse they found under the sink.

Many people seem afraid to get gel on their hands or make physical contact with patients, both of which are just part of scanning.
Instead of treating the probe like an alien object, hold it like something you hold everyday: a pen. Continue reading