FAST techniques: standard ultrasound machines can be used
but, in general, hand-held machines are easier to use and less
expensive. Four transducer positions are used.
Subxiphoid – the transducer is angled upward and slightly to the
left shoulder in order to identify haemopericardium. Consider the
transverse left intercostal position in the third or fourth interspace
if poor views are obtained.
Right upper quadrant – the transducer is placed in the final
intercostal space in the anterior axillary line with a slightly oblique
posterior orientation to image the liver and right kidney. Fluid
accumulates in Morrison’s pouch between the two (Figure 3).
Left upper quadrant – the transducer is placed far posteriorly
in a low intercostal space (two spaces higher than on the right)
and the probe angled anteriorly to visualize the left kidney, spleen
and the space between the two where fluid accumulates. The left
subdiaphragmatic space and lower thorax (for pleural effusion/
haemothorax) may also be visualized.
Pelvic – the probe is placed transversely suprapubically to
identify the bladder and turned 90° in order to show fluid behind
the bladder. Saline may be instilled (via a urinary catheter) to
provide an acoustic window if the bladder is empty.