Final- Ultrasound (7/24/23) Flashcards
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.
Advantages of ultrasound.
- Identify anatomical structures
- Relationship of the needle to tissues
- Increases accuracy
- “See” spread of LA
- May decrease time performing pain blocks/assessments
- May decrease complications
Ultrasound waves travel between these Mhz.
- 2-20 Mhz
What is the range of audible sounds?
- 20-20,000 Hz
What can ultrasound waves do when they encounter a surface?
- Transmit through the surface
- Reflect on the surface
- Something in between
What is the result when ultrasound waves are transmitted through fluid?
- No signal
- Anechoic
- Dark
What is the result when ultrasound waves are reflected on bones?
- Lots of signals
- Hyperechoic
- Bright
What results when ultrasound waves encounter soft tissue, muscles, and fat?
- Iso/hypoechoic
- Shades of grade
Which picture represents a solid?
Which picture represents fluid?
- Picture A: Solid
- Picture B: Fluid
What is inside the transducer’s head that changes shape with an electric impulse?
- Piezo Electric Crystals
What are the three types of transducers used in POCUS?
- Linear Array
- Curve Array
- Phased Array
Describe a Linear Array
- High frequency (7-15 MHz)
- Better resolution at a superficial depth
- Great to use to start a central line with to look for an IJ
Describe a Curve Array
- Low frequency (2-5 MHz)
- Poorer resolution
- Great for deeper tissue
- Used to look at gallbladder or stomach to assess NPO
Describe a Phased Array
- Lowest frequency (1-3 MHz)
- Useful for echocardiography
Static vs Dynamic Approach for Ultrasound
Static: Identifying the target vessel, assessing the patency, marking an appropriate insertion site, and cannulating blindly.
Dynamic: Performing the procedure in real-time and viewing the needle puncturing the vessel wall.
Tips and Tricks for using Ultrasound.
- Proper Ergonomics
- Use Conductive gel
- Hold the Transducer probe like a pencil
- Focus using gain and depth buttons
What is 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
In-plane vs. Out-of-plane refers to the relationship of ______ to the ultrasound plane.
- needle
What is the advantage of in-plane ultrasound?
Disadvantage?
- Advantage: See the whole needle
- Disadvantage: Easy to be off plane
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
What do you look for to determine that your guidewire is in the vessel’s lumen?
- Vanishing Sign
Common anesthesia use for ultrasound.
- Guided IV Access
- Focused Assessment with Sonography for Trauma
- Ultrasound-guided Nerve Blocks
- Gastric Ultrasound
What are the indications for using USG IV Access?
- History of difficult cannulation
- Multiple failed attempts
- Best to use a linear probe, if the patient is obese, use the curve probe
What are the contraindications for using USG IV Access?
- Does not substitute for IO access in life-threatening situations
Indications to use a FAST.
- To rule out free fluid in the abdomen and pericardium
What probe is used for a FAST?
- Curvilinear probe
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)
When performing a USG peripheral nerve block, what can be done to the transducer to maintain parallel alignment with the US monitor?
- Heeling
What are the indications for the gastric US?
- Lack of adherence to fasting instructions
- Unclear fasting history
- Potential delay in gastric emptying
Grade the Antrum
- Grade 0 Antrum: Empty Stomach
- Bull’s Eye
Grade the Antrum
- Grade 1 Antrum: < 1.5 ml/kg
- Aspiration Unlikely
Grade the Antrum
- Grade 2 Antrum: > 1.5 ml/kg
- Solid Food
- High Risk of Aspiration
