muscles looking for the left kidney, not realizing the probe has made it to the midline at the umbilicus (by drifting). No wonder you cannot find the left kidney! If you double‐check yourself by frequently looking at the screen and then at the probe's external location on your patient, you will get to where you want to go much faster! This also occurs commonly while performing Vet BLUE in standing patients. You think you are at the Caudodorsal Vet BLUE lung region but the weight of your hand has brought you close to the Middle Vet BLUE lung region.
The best way to prevent drifting is to routinely “kickstand” out a finger that solidly touches your patient’s body wall (or have another comfortable part of your hand against the patient's body wall) (Figure 5.9).
Figure 5.8. When extending the foreleg, don’t touch the paw! Gently extend the foreleg with your helper hand placed near the elbow and away from the paw. The paw is sensitive and you may create an uncooperative patient (e.g., may bite, may become resistant to restraint, may become tachycardic) by triggering a negative response. Stay near the elbow. Shown is the acquisition of the right Vet BLUE cranial lung region view.
Source: Courtesy of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.
Figure 5.9. “Kickstand” your probe hand to prevent drifting. Having some part of your probe hand in contact with the patient will prevent drifting, which is when the sonographer is focused on the screen and unaware that the weight of their probe hand has moved the probe to a different acoustic window. In (A) the probe hand is not braced against the patient, so the sonographer is susceptible to drifting. In (B) the fingers are comfortably spread in contact with the patient's body, thus preventing drifting. Common views for drifting are especially during Vet BLUE and the least gravity‐dependent SR and HR views.
Source: Courtesy of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.
Not Checking Where the Probe is Externally on the Patient
This is really Part 2 of the previous paragraph. A few years ago, while I was performing Global FAST imaging on dolphins, the concept proved most helpful. Without goggles showing the ultrasound screen, two people were needed for imaging – one on the dock monitoring the ultrasound screen and directing the sonographer who was in the water with the dolphin, unable to see the ultrasound screen. Paying attention to external landmarks helped guide the sonographer to the AFAST target organs (and all of Global FAST) efficiently and confidently.
The same holds true with our small animal and exotic patients. Pay attention to where the probe is externally on your patient, double‐checking between the ultrasound screen and the probe's external location. Look at your patient! For example, if you can't find the urinary bladder then slide toward the patient’s pubis slightly off midline in lateral recumbency or along midline when standing or sternal. Some other examples – the gallbladder is right of midline in both dogs and cats so the probe has to be directed to that side of your patient; the TFAST chest tube site (CTS) view generally takes you to the caudodorsal transition zone, thus helping to prevent mistaking abdominal structures for lung pathology; and the kidneys are close to the caudal vena cava and aorta attached by their short renal artery and veins.
Not Visualizing the Path of the Beam from the Probe Head
Mental visualization of success prior to a motor skill performance such as an athletic event is important and so is mentally visualizing the path of the ultrasound beam from the probe head (Figure 5.10). To get the “cardiac bump” at the diaphragmatico‐hepatic (DH) view, the probe's beam must be directed toward the muscular apex of the heart which requires the probe being rocked far cranially and the beam approximating being parallel to the sternum. The AFAST CC pouch is in the most gravity‐dependent region of that view so the probe should be directed toward the tabletop (when in lateral recumbency), not at the spine! Visualizing the direction in which the ultrasound beam is projecting from the probe head will contribute to your imaging success, save time, and build confidence in locating structures of interest.
Figure 5.10. Paying attention to the direction of the beam. If the sonographer is to image the heart and its cardiac bump at the DH view, then the beam must be directed where the heart would be. In (A) the beam is directed in the correct direction whereas in (B) the heart will never be imaged. The "H" and red oval represent the heart; the black arrow the ultrasound beam; and the white curved line the diaphragm.
Source: Courtesy of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.
Losing Track of the Probe Orientation Marker
Make it a habit to have a finger or thumb on the probe marker or be able to clearly see the probe marker (Figure 5.11). It is easy to lose track of the probe marker without making this habitual while imaging. It not only helps with orientation but also prevents creating confusing planes through structures by the sonographer's awareness of being in longitudinal, sagittal, transverse, and short‐ and long‐axis planes. Moreover, keep the screen orientation marker to the left so you maintain the “head to the left, tail to the right” orientation, which is the same as radiography (see Figure 1.6).
Using More than One Probe Maneuver at a Time
One of the main rules of imaging is only performing one probe maneuver at a time. The five major maneuvers are rocking, fanning, rotating, sliding, sweeping and pressure/compression (see Figures 4.5–4.11). Performing only a single maneuver at a time while optimizing your image should become habitual. When you perform multiple maneuvers at the same time, you are really doodling and nothing productive typically results. This is very common with “flashing” the abdomen, thorax, and lung (see Preface). We strongly discourage flashing but rather stick with the exact clarity of the 15 acoustic windows of Global FAST.
Figure 5.11. Be aware of the probe marker. Every probe has a marker or notch that serves as its orientation marker. Always keep track of the marker and when in longitudinal or sagittal orientation, keep it directed toward the patient’s head. Getting into the habit of holding the probe with your index finger or thumb on the marker or be able to clearly see the probe marker keeps you from making mistakes and getting confused during image acquisition and interpretation. Screen orientation is also important (see Figure
