EQUINE | CPD Article
very important 12 to identify areas of possible lung
involvement and in particular to locate dull ventral
areas with loud radiating cardiac sounds 3 which
would indicate effusion6 . Pleural friction rubs
indicating pleural inflammation 11 are often heard at
the end of inspiration and beginning of expiration
before an increase of pleural effusion volume reduces
all sounds heard 3 . A re-breathing bag to detect
abnormal lung sounds, although useful in suspected
early acute presentations, may cause additional
dyspnea and should be used cautiously 13 . A lack
of lung sounds in the ventral region and a painful
response to chest percussion with a dull resonance
indicates the presence of pleural effusion 11 . The most
practical diagnostic test is thoracic ultrasonography 12 15
to confirm the presence of pleural effusion and assess
fluid volume 15 This can be easily performed patient-
side in the stable, thereby allowing a rapid definitive
diagnosis to be made 17 and aids the client in making
an informed treatment decision.
Thoracic ultrasonography may be performed
preferably with a 3.5 – 5 MHz sector scanner or
linear probe and the following is assessed 3 15 :
1. Free fluid within the thorax – approximate volume
and appearance – loculated / hypoechoic /
anechoic
2. Pleural thickening
3. Pulmonary consolidation
4. Fibrinous adhesions
5. Fluid within airways
6. Lung field – lungs can be displaced dorsally and
axially due to large effusions
7. Free gas
Ultrasound images showing a pleural effusion
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