POCUS - Lungs Flashcards
True or false: lung should not be sliding in an US.
False
Lung sliding is normal (the ants on a log are good!). If there is no lung sliding then that is pathognomonic for a pneumothorax.
B lines must be differentiated from comet tails. How can you do this?
Comet tails are shorter (B lines technically need to be 16 cm to count) and comet tails typically do not obliterate A lines whereas B lines do.
What are the rule of fours for pulmonary US?
Four positions: mid-clavicular, medial to nipple, lateral to nipple, mid axillary
What is a differential for bilateral B-lines?
CHF
Multifocal PNA
Pulmonary fibrosis
Pulmonary contusions
How much depth should you have for lung sliding?
Only enough to see the pleura and a little beyond (usually ~ 6 cm)
The definitive diagnosis of a pneumothorax is by getting what view?
The lung point, which is the point at which you can see lung sliding and then lung not sliding
Beware of scanning for lung points lower down. The liver, spleem, and heart can all mimic a lung point.
Which transducers should you use for lung evaluation?
- PTX: linear
- Pleural effusion and B lines: usually cardiac probe but can use curvilinear
It’s important to remember that the parietal pleura is ______ to the ribs.
deep
There are soft tissue lines that can appear like the pleura, but these are anterior to the ribs.
Why is it important to have the right setting for lungs?
Other settings have motion-reducing features that can eliminate lung sliding.
The interval distance of the A line is what?
The distance from the probe to the bright, hyperechoic line that produces the A lines.
Other than being an artifact, A lines can also _________-
suggest PTX (if accompanied by absence of lung sliding)
Importantly, A lines with lung sliding is good evidence that there is no interstitial syndrome such as consolidation or effusion at the spot scanned.
To speed up your thoracic exam, ______________.
put “stripes” of gel along the anterior chest wall; this allows you to pass through multiple intercostal spaces without having to pause and apply more gel
Review the BLUE (bedside lung US in emergencies) protocol.
Essentially, you look for lung sliding, B lines, and A-lines and then group into categories:
- Sliding present, B lines present = pulmonary edema, atypical PNA, or fibrosis (if lines diffuse) or PNA or contusion (if localized)
- Sliding present, A lines present = PE, PNA, COPD, or Asthma
- Sliding absent, B lines present = PNA
- Sliding absent, A lines present with lung point = PTX
- Sliding absent, A lines present without lung point = need for other imaging
- Sliding w/ A and B lines: pulmonary contusion or PNA
B lines originate from the __________ on the screen.
pleura
Many B lines that converge on the probe is called the ________ sign.
rocket
True B lines will do what to an A line?
Cross over it
Bilateral anterior B lines is highly sensitive and specific for ____________.
volume overload
You see lung that is consolidated (hepatisized). Why are air bronchograms helpful in this scenario?
Air bronchograms are seen in PNA but not atelectasis.
Importantly, lung sliding is an __________ test.
all-or-none
There is no “diminished” lung sliding.
What is the sensitivity and specificity of lung sliding for pneumothorax?
95% and 95%
A lung point is 100% specific and sensitive for PTX.