Final- Ultrasound [7/16/24] Flashcards
what is ultrasound?
the idea of “seeing” using sound waves
S3
Where was ultrsound first used?
- in nature
- bats
- dolphins…. spallanzani (1794)
- in the military
- submarines
- in medicine
- When was ultrasound first used in medicine?
- What was it popular in?
- Why was it popular?
- 1950’s
- Popular first in obstetrics
- It was popular because there was no ionizing radiation.
S3
Advantages of ultrasound.
- Identify anatomical structures
- Relationship of the needle to tissues is visualized
- Increases accuracy
- “See” spread of LA
- May decrease time performing pain blocks/assessments
- May decrease complications
S4
Ultrasound waves travel between what Mhz?
- 2-20 Mhz
- travels differently in different structures
S5
What is the range of audible sounds?
- 20-20,000 Hz
S5
What can ultrasound waves do when they encounter a surface?
- Transmit through the surface
- Reflect on the surface
- Something in between
S5
The sound waves that are reflected back to crystals create ____ recorded by the computer.
impulse
S5
What is the result when ultrasound waves are transmitted through fluid?
- No signal
- Anechoic
- Dark
S6
What is the result when ultrasound waves are reflected on bones/stones?
- Lots of signals
- Hyperechoic
- Bright
S6
What results when ultrasound waves encounter soft tissue, muscles, and fat?
- Iso/hypoechoic
- Shades of grade
S6
What is echogenesis?
- Google: the ability to bounce an echo, e.g. return the signal in medical ultrasound examinations.
- In other words, echogenicity is higher when the surface bouncing the sound echo reflects increased sound waves.
S7
Differentiate hyper-echoic and hypo-echoic?
- Hyper-echoic: solid tissues reflect sound waves…appear bright
- Hypo-echoic: soft/hollow tissues reflect less sound waves… apear dark
S7
- Which picture represents a solid?
- Which picture represents fluid?
- Picture A: Solid
- Picture B: Fluid
S8
- Piezo electric crystals are located where?
- what do they do?
- Location: inside head of the transducer
- change shape with electric impulse:
- startes to vibrate
- generates sound waves
S9
these are specific to exam performed and allow you to penetrate shallower or deeper tissue
transducers
S10
What are the three types of transducers used in POCUS?
- Linear Array
- Curve Array
- Phased Array
S10
- Linear Array
- Frequency?
- Resolution?
- Used for?
- High frequency (7-15 MHz)
- Better resolution at a superficial depth
- Examples: Great to use to start a central line , IJ, IV
For things that are close to the surface of the body
S10
Curve Array:
* Frequency?
* Resolution?
* used for?
- Low frequency (2-5 MHz)
- Poorer resolution
- Great for deeper tissue
- Ex: Used to look at gallbladder or stomach to assess NPO, kidney, liver, spleen, bladder rupture
S10
- Phased Array
- Frequency?
- Used for?
- Lowest frequency (1-3 MHz)
- Useful for echocardiography
- windows of the ribs, subxiphoid view
S10
What do we need to pay attention to for ultrasound orientation?
- patient orientation
- axial plane
- sagittal plane
- probe orientation
S11/12
- What is gain?
- How do you adjust gain?
- Gain is the brightness signal quality usually
- adjusted with a knob.
- Twist the knob back and forth until fluid is black and soft tissue is mid-grey
S18
- how many buttons are there for depth?
- where can you see depth measurment?
- how do you adjust depth?
- often 2 buttons [up and down]
- depth measures are shown in cm on side of screen
- start at high depth then work to bring object of interest into middle of screen
S20
What does In-plane vs. Out-of-plane refers to?
- the relationship of needle to the ultrasound plane.
S22
In in-plane vs out-of-plane, what is the orientation of the needle for each?
- In plane: needle parallel to transducer
- Out of plane: needle cross sectional to the transducer
S22 lecture
- What is the advantage of in-plane ultrasound?
- Disadvantage?
- Advantage: See the whole needle
- Disadvantage: Easy to be off plane. Needle could be in front or back of the vessel and not IN the vessel.
S23
- What is the advantage of out-of-plane ultrasound?
- Disadvantage?
- Advantage: The needle is positioned directly under the plane of an ultrasound
- Disadvantage: Unclear where tip of the needle is
S25
What do you look for to determine that your guidewire is in the vessel’s lumen?
- Vanishing Sign
- as you scan from high to low on the vessel, the needle will get closer.
- get artifact
- see better needle/wire then it goes away. The needle/metallic part moves.
- its looking at the wire/tip of the needle. As you get deeper its gets better.
- its a way to prove the needle is in the vessel.
S26
- Indications to use a FAST.
- contraindications?
- Indication: To rule out free fluid in the abdomen and pericardium
- CI: none :)
S31
What are the assessment points for FAST?
- (1) RUQ- Morison’s pouch (Liver, Right Kidney)
- (2) LUQ- Peri-splenic view (Spleen, Left Kidney)
- (3) Pelvic view- Suprapubic (Bladder rupture)
- (4) Cardiac view (Pericardial sac)
Look at 4 quadrants + pericardium
S32
- what does free fluid around the kidney look like?
- what view would you use?
- RUQ- morisons pouch [pic on left bc liver]
- LUQ- peri-splenic view [pic on right bc spleen]
S33/34
- what does bladder rupture look like?
- what view would you use?
Pelvic view- Suprapubic (Bladder rupture)
S35
- what does pericardial effusion look like?
- what view do you use?
Cardiac view (Pericardial sac)
S36
Steps to perform USG peripheral nerve blocks
- pre-block scan to plan route
- use “heeling” to help maintain parallel alignment
- line the probe with nerve bundle not the skin .
- await fascial pop
- verify nerve doesnt move with needle
S37
Grade the Antrum
- Grade 0 Antrum: Empty Stomach [NPO]
- Bull’s Eye
S39/40
Grade the Antrum
- Grade 1 Antrum: < 1.5 ml/kg
- Clear liquids
- rounder more disteneded
- starry night
- peristalsis starts
- Milk, thick fluids:
- thinner walls
- increased echogenicity
- low aspiration risk
S39/40
Grade the Antrum
- Grade 2 Antrum: > 1.5 ml/kg
- Solid Food
- hyperechoic
- High Risk of Aspiration
S39/40
chart on estimating gastric volume
S40
