Verathon AORTASCAN AMI 9700, Operation & Maintenance Manual

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SUBSTANTIAL GAS OBSTRUCTION
A substantial amount of gas in the abdomen can block ultrasound from reaching the aorta and results in an
unreadable or inappropriate scan.
A red arrow on the console and a flashing green arrow on the probe indicate bowel gas has substantially
obscured the aorta. No diameter measurement can be calculated and the results display shows a diameter of
< 3 cm, meaning the aorta was not detected.
Figure 22. Substantial Gas Obstruction
Although moving the probe 1/2 to 1 inch (1 to 3 cm) in the direction of the arrow has a low probability
of providing a successful scan, an additional scan should be attempted. In this case, the probe should be
repositioned and the patient rescanned. Gently but firmly work the probe into the tissues of the abdomen
with a side‑to‑side rocking motion to try and displace any bowel gas obscuring the aorta. Do not move the
probe while the scan is in progress as that will decrease the accuracy of the measurement.
If rescanning is not successful, the exam should be postponed and rescheduled. Have the patient fast for
12 hours prior to the exam.
OBESITY
Attenuation of the ultrasound signal by excess abdominal fat can result in a poor ultrasound image, which
affects the quality of the diameter measurement.
With obese patients, try pressing the probe firmly into the abdomen to reduce the distance to the aorta as
much as possible, while attempting to minimize patient discomfort.
In rare cases, it is possible for a patient’s abdomen to be too thick for the ultrasound to reach the aorta. If
a patient has an extra‑thick abdomen where the distance from the probe face to the aorta is greater than
18 cm (7 in), the AortaScan AMI 9700 will not detect the aorta appropriately. In these cases, alternative
imaging methods should be used.