Rotation
Generally, a slight rotation of the transducer, so the OM aims more towards the mattress, can improve image quality (counter-clockwise on right side, clockwise on left side).

Fluid follows gravity
Always make sure that the transducer is placed as posterior as possible – your hand needs to touch the mattress.

That hard left side
On the left side it is generally more difficult to obtain good images than on the right side – but the tips for optimising the image are the same:

In the posterolateral pleural view, the following structures can be seen:

Right side
Liver
Kidney (not seen in the image to the right)
Diaphragm
Spine

Left side
Spleen
Kidney
Diaphragm
Spine

At this point, you should feel confident about how to obtain the lung images.

If you do not feel confident, please review the slides.
If you do feel confident – now move on to answering the focused questions.

The focused questions in focused ultrasonography of the lungs are:

Pleural line
If the pleural line and the lung signs cannot be clearly separated from the surrounding structures:

A high frequency linear transducer or a curved (abdominal) transducer can be used for focused lung ultrasonography.

A linear high-frequency transducer is recommended if the purpose is only to visualise the pleural line (described later). The linear transducer has an optimal balance between resolution and depth for visualising superficial structures. It cannot be used for evaluating pleural fluid.

A lower-frequency transducer (abdominal or cardiac) permits the deep penetration that is needed for evaluation of pleural fluid (described later). The curved abdominal transducer also generates usable images for visualising the pleural line.

Tips
The ‘abdominal’ transducer can be used as an all-round transducer for focused lung ultrasonography.
Some cardiac transducers also allow fair imaging – but test your own equipment.

Learning objectives for focused ultrasonography of the lungs

Obtain
– Anterior intercostal view (‘bat-sign’)
– Posterolateral pleural view

Answer the focused questions
– Can pneumothorax be confirmed or excluded?
– Are signs of pulmonary edema present or can pulmonary edema be excluded?
– Can pleural fluid be confirmed or excluded?