Ultrasound Basics (lecture 1) Flashcards
Needle is placed in line with and parallel to the transducer.Both the needle shaft and tip are visualized.
IN Plane
3 things necessary to perform safe peripheral block:
- U/S
- Nerve Stimulation
- Injection Pressure Monitoring
Needle is placed perpendicular to the transducer.
Needle shaft and tip are visualized as a hyperechoic dot on ultrasound.
Out-of-Plane
3 types of regional anesthesia
- Neuraxial
- Peripheral Nerve Block
- Intravenous regional Anesthesia (IVRA)
one example of IVRA
Bier’s Block
3 types of neuraxial anesthesia
- spinal
- Epidural
- Caudal
Types of Peripheral nerve blocks:
- Upper Limb (Cervical Plexus, Brachial Plexus)
- Trunk
- Lower Limb (Lumbar Plexus, Sacral Plexus)
List upper limb blocks:
- Cervical Plexus
- Interscalene
- Supraclavicular
- Infrclavicular
- Axillary
- Peripheral Nerves
- Bier Block
Types of Trunk blocks
- Paravertebral /ESP/MTP
- Pecs
- Serratus Anterior
- Rectus Sheath
- TAP/QL
- Ilioinguinal/Iliohypergastric
Types of Lower Limb blocks
- Fascia Iliaca
- Femoral
- Adductor Canal
- Sciatic (Sub-Gluteal)
- Popliteal Sciatic (Tibial/Common Peroneal)
- IPACK (Interspace between the Popliteal Artery & the Capsule of the posterior Knee)
- Ankle (5 individual nerves)
Ultrasound imaging uses the transmission and reflection of high-frequency ____, ____ waves (“ultrasonic sound” waves) in tissues
longitudinal
mechanical
Steps of U/S image formation
- The electricity is sent to the probe.
- The crystals converts electricity into sound waves
- The sound waves propagate through tissue
- The returning waves hit the crystals which amplify the wave.
- This then gives you a 2D image
Example of strong reflection
Bone (white dot)
Example of weaker reflections
Solid organs (gray dot)
Example of no reflection
Full bladder/blood (black dot)
characterised by a signal void behind structures that strongly absorb or reflect ultrasonic waves
Acoustic Shadowing
Acoustic Shadowing
Acoustic Shadowing
Enhancement
an area of increased brightness underneath fluid resulting from the lack of impedance when sound waves pass through fluid and increased echoes from underlying structures
IOW, the U/S thinks that it needs to amplify the signal because its first encounter is fluid filled (which elicits no reflections), so everything beyond the fluid will be brighter.
Enhancement
Color Doppler mode is intended to add color-coded qualitative information about ____ and ____.
- Velocity
- Direction of Fluid Motion
Mnemonic for color doppler
BART
Blue Away Red Towards (the probe)
What option can you select/utilize on the U/S after turning it on to expedite your on-screen view?
choose a preset anatomical selection
(will present a standardized initial image)
High frequency =
GOOD resolution/BAD Penetration
Low Frequency =
BAD resolution/GOOD penetration
Overall Gain adjusts:
brightness uniformly to all depths
Time Gain Compensation (TGC) adjusts:
brightness/amplification of echos at different depths
What was adjusted here:
GAIN
What was adjusted here:
depth
When applied the ____ narrows the effective beam width and in this region lateral resolution is optimised
focus
Outside of the focus region the effective beam width is ____ and lateral resolution is reduced
wider
What was adjusted hers:
Focus