POCUS - Abdominal Flashcards
According to a 2005 meta-analysis, what is the sensitivity and specificity of eFAST for hemoperitoneum?
Sens: 79%
Spec: 99.2%
Why is eFAST not perfectly sensitive for hemoperitoneum?
A couple of reasons:
- Adhesions could cause trapping of blood in non-FAST views
- There are anatomic gutters that blood can accumulate in that are not seen on FAST
- Position of patient can cause false negatives
FAST will miss hemoperitoneum below what threshold of bleeding?
Thought to be 250 mL
It’s important to note that FAST will miss what type of abdominal trauma?
Solid-organ injury without hemoperitoneum
Describe the usual path of bleeding in the peritoneum.
- Bleeding from the spleen typically collects in the sub-phrenic space. Overflow will go down along the transverse colon to the liver (because of the ligament at the splenic flexure).
- Bleeding from the liver will collect in Morrison’s pouch and usually go down the ascending colon to the pelvis.
- Bleeding from the pelvis will typically stay in the pelvis. If there is overflow it will go first to the liver.
True or false: blood on FAST will always be anechoic.
False
It can be mildly echogenic.
About _____% of patients with cholecystitis have stones in the CBD.
15
Because of this, the decision to operate in cholecystitis should only be done after the CBD is assessed.
The gallbladder is normally ___ cm long.
7
The common bile duct is made by the fusion of the cystic duct with the _______________ duct.
common hepatic
To begin the sagittal view of the gallbladder, place the probe ______________.
in the mid-clavicular line, just below the costal margin, with the probe indicator pointed to the patient’s R shoulder
From there, you may need to fan and slide to find the gallbladder.
The gallbladder lies _________ and _________ to the R kidney.
anterior; medial
The _____________ is a landmark that connects the portal vein to the gallbladder. It can be used to help identify the gallbladder.
main lobar fissure
It is typically seen in the sagittal (longitudinal) view of the gallbladder.
The ideal patient position for finding the gallbladder is ____________.
supine (deep inspiration can help) and tilted slightly to the left
If you see stones in the gallbladder neck, you must _________________.
repeat the views with the patient in a different position (so that you can see if it is stuck)
There are three things to consider when you can’t find the gallbladder. What are they?
- Surgical absence (look for surgical clips)
- Contracted to the point of not being recognizable
- Full of stones (and thus looking like bowel artifact)
True or false: the transverse gallbladder view should be taken from the R side.
False
It can be done that way if that is the only obtainable view, but it is preferably done from the anterior aspect.
The hepatorenal space has what eponym?
Morrison’s pouch
The haustra on small bowel are called ___________.
plicae circularis
In pediatric patients, list the most frequent places blood will collect.
1) RUQ
2) Pelvis
3) Dome of the spleen
The most sensitive area for detection of free fluid in the abdomen is _______________.
the caudal tip of the liver
What are the sensitivity and specificity of the FAST exam for intraabdominal bleeding?
- Sensitivity: 66%
- Specificity: 95%
What’s the minimum amount of fluid needed for a FAST to be positive?
200 mL
Where does fluid first collect in the LUQ?
Between the spleen and diaphragm
What studies should you obtain in the gallbladder US?
- Long axis showing neck
- Short axis
- Anterior wall thickness
- CBD (w/ color if uncertain)
- Gallbladder length
The CBD is right on top of the _______________.
portal vein
True or false: the CBD has hyperechoic borders and appears bright white on both sides.
False
The portal vein appears this way.
Always look in the ___________ in the gallbladder US.
neck
Be sure to look for shadowing that may indicate a stone.
The portal vein is ___________ to the hepatic artery and CBD.
deep/posterior
This is why the CBD is “on top” of the portal vein from the transverse view.
The CBD is usually ____________ to the hepatic artery.
lateral
How many lung views do you need in an eFAST?
6 total (3 each side)
Where do you put the probe in the perihepatic view of the FAST exam?
Mid axillary line in the 8th-11th intercostal spaces with the probe marker pointed to the patient’s head
__________ capsule surrounds the liver.
Glisson’s
When doing a search for bleeding (such as the FAST) beware of ___________ that will not appear anechoic.
clotted blood
It’s rare to develop pyloric stenosis after what age?
12 weeks
True or false: use the curvilinear probe to identify pyloric stenosis.
False
Use the linear
US is actually more sensitive than ____________ in detecting pneumoperitoneum.
plain radiographs
One study showed that US can detect as little as 1 mL of air.
What locations (and patient positions!) are best for detecting free air in the abdomen?
- RUQ, curvilinear probe, patient in left-lateral decubitus position looking for air above the dome of the liver: 83%
- Epigastric area, curvilinear probe, patient supine: 81%
What should you look for in detecting pneumoperitoneum?
A lines that do not vary with respiration with distortion behind the A lines (that is, distortion where there should not be distortion such as over the liver)