Ultrasound in the ED Flashcards
Which side of the neck is preferred for vascular access of the neck and why?
Right side - for 2 reasons:
- to avoid trauma to the thoracic duct on the left.
puncture can lead to chylothoarx. - On the right side, IJV runs a straighter course than
the
left IJV, there is less risk of damaging the vein
What maneuvres can you perform to improve the view of a vein when trying to obtain ultrasound guided venous access in a central vein?
- valsalva maneuvre
- compress the vein with pressure from the ultrasound
probe - inspiration/expiration and positional changes ( head
down to head up )
What features are suggestive of a pneumothorax on ultrasound?
in B- mode:
*absent lung sliding
in M-mode:
- loss of sea-shore sign
- presence of barcode sign/stratosphere sign,
what 3 features on Echo ultrasound that demonstrates aortic dissection?
- dilated aortic root
- intimal flap
- pericardial effusion
What is the name of the most commonly used probe in FAST scanning and why is it not suitable for vascular access?
high frequency phased array probe.
The beam shape is convex, thus the transducer is good for examinations requiring depth. Vascular access requires high near-field resolution which is best achieved with the linear probe
You are about to perform an e-FAST scan. Describe steps you would take to improve image quality ?
- change patient position
- change operator position
- adjust the gain
- adjust the depth
- ensure sufficient gel on probe to minimize air artefact
- use the correct probe for specific tasks
- What is the upper limit of normal for a mid-aorta ultrasound?
- and can you differentiate aorta from IVC?
RCEMLearning
- less than 3
- AORTA
- Left sided
- thickened wall
- non-compressable
- pulsatile
- round in shape, constant shape
- SMA can be demonstrated
- diameter does not change with respiration
IVC:
- right sided
- thin walled
- compressible
- transmitted pulse ( double bounce )
- almond shape
What are the echocardiographic signs of pulmonary embolism?
- dilated RV & RA with strain ( limited contraction )
during systole - RV wall hypokinesia
- paradoxical RV septal movement
- tricuspid regurgitation
- Mcconells sign
What are the 3 modes used in ultrasound?
*A- mode
Amplitude modulation
used in scanning the eye
- B - mode
Brightness modulation. which is a 2 dimensional, real-time B-mode scanning
used in fast scanning - M- mode
Motion modulation
What 3 probes would you use in ultrasound?
- high frequency - Phased array ( square shape )
- high frequency - Linear array ( long rectangular )
Good for Lung sliding , vascular, abscess, MSK, - Low frequency - Curved array ( curvy- linear )
Good for abdominal organisms
What are the 3 planes you would scan a patient in?
Sagital plane
Coronal Plane
Transverse plane
What is the cine-loop feature?
The operator can scroll back over a few seconds of an image that was captured after freezing the image. this is useful in an unco-operative patient
What are the 4 views on e-Fast?
what is the 5th extending view?
- RUQ, to include Morrisons pouch and the right costo-
phrenic pleural recess - LUQ, to include the spleno-renal and the left costo-
phrenic pleural recess - Sub-xiphoid veiw of pericardial sac - from below
- Pelvic cavity in 2 planes
- upper thoracic view of the right and left lungs
How would you assess the IVC to determine hydration of a patient?
If IVC diameter is < 15mm and with complete collapsability - this suggests an underfilled IVC
When introducing a needle into the skin, what 2 technical skills should you master to be able to see the needle on the screen?
- parallelism
- Angle of approach
* angle of < 35 degrees to the skin is needed to see the needle. the smaller the angle, the better the image
What 2 ways can you use ultrasound when performing invasive procedures?
static ultrasound assisted
real-time ultrasound guided
Name 1 structure that is hyper-echoic and and 1 that is anechoic?
bright ( appears white ) structures are hyper-echoic
( bone )
Black structures are anechoic ( like blood or air )
You are adjusting the gain - how does the image appear if the gain is too high or too low?
high gain - image will apear too bright
low gain - image will apear too dark
What technical approach will you use when cannulating a patient with ultrasound?
( which probe would you select, what depth settings would you select, and what TGC setting?)
*Select Linear high frequency probe
*Set the depth at :
5cm for central vein
4cm for femoral vein
3 cm for basilic vein
*TGC should be flat
What are the 2 priorities in Echo for life support?
(i) to assess cardiac movement and
(ii) to identify remediable pathology
When performing ELS, which 2 main condition would benefit from immediate treatment if diagnosed in bedside echo?
- pericardial effusion large enough to cause tamponade
2. Massive pulmonary embolism
Emergency Medicine AAA assessment is a focused examination to answer a single question - what is this question?
Is an abdominal aortic aneurysm ( with a diameter greater than 3 cm ) present?
How do you find the SMA and the IMA when performing AAA scan?
The coeliac axis lies 1-2cm below the diaphragm.
the SMA lies 2cm below the Coeliac axis
The IMA lies 4cm above the aorta bifurcation ( aorta bifurcates at the umbilicus at the level of L4 )
When scanning the IVC- What sign on ultrasound suggests increased right atrial pressure?
In an unventilated patient - if the IVC diameter is > 25mm with minimal collapse this suggests increased right atrial pressure . eg in cor pulmonale or fluid overload
During ultrasound cannulation of the internal jugular vein - how should you position the patient and why?
position the patient 30 degree tilt head down with little neck rotation and NO extension.
this minimizes the risk of air embolism
During ELS - what 5 features will you try to identify ?
On acquisition of the best possible image :
- demonstrate the subxiphoid and long-axis parasternal
view - identify pericardial space and any fluid that is present
- identify presence/absence of any ventricular wall
motion - comment on right and left ventricular size
- identifies IVC in LS. and measures IVC diameter and
collapsibility
Where should the marker of the probe always be? which view is an exception to this?
marker of the probe should always be to the patients head or to their right. Except in the parasternal view.
