Ultrasound Regional Flashcards
Advantages
- ability to see __ and __ of LA
- ability to measure __ to the nerves
- __ onset of sensory loss
- __ volume of LA
- no discomfort of __ __
Location and spread Distance Faster Less Nerve stim
USG resulted in __ procedure time, and __ block duration
Shorter, longer
Ultrasound frequencies between __-__ __
Higher number means __ __ lower number means __ __
2-15 MHz
Finer resolution, greater depth
Acoustic impedance
Resistance of tissue to absorption of ultrasound
Differences in this create reflective interfaces
Reflection occurs when what, depends on what
Ultrasound strikes 2 diff media
Texture of surface
Reverberation occurs with what
Multiple reflections from closely spaced interfaces
Absorption
Conversion of ultrasound energy to other forms of energy
Depth, measured in what
Distance away from probe, cm
Scattering
When sound wave strikes small irregular shaped structures and causes artifact
Shadowing
Reduction of ultrasound energy lying below solid objects
Echogenicity
Ability to reflect or transmit ultrasound waves in context to surrounding tissue
Anechoic
Doppler what Bart stands for
Black on screen
Detects blood flow, blue away red towards
Mode: penetrating means what, resolution means what
Depth control
- increased depth does what to image
- try to use what
Deep, superficial
Reduces width
Most superficial setting
Gain control
Adjusts what of signal
__ or __ image
Too much amplifies __
Amplification
Brighter or darker
Artifact
Color gain does what
Increase or reduce color artifact for identifying vessels
Linear probe
__-__ hz
Ideal for __ and __ structures
Used for depths __-__ cm
7-12
Vascular and nerve
6-8
High frequency linear probe
__-__ hz
Ideal for __ __ and __ structures
10-15
Superficial nerve and vascular
Curvilinear
__-__ hz
Ideal for __ __ structures of __ cm
4-7
Deep nerve, 30
Peripheral nerve stimulators
__-__ ma
__ usec
0.2-0.5
100
Nerve block needles
Blunted b bevel
__ except for tip
Allows stim of nerve with low __
Nonconductive
Current
Epineurium
Fascicles
Ct that surrounds a nerve
Nerve trunks and branches are bundled in groups of fascicles, contain a few or a hundred axons
Perineurium
Contain axons and fascicles
Endoneurium
Separates axons
Nerve tissue is what color
Perineurium is what color
Hypoechoic and dark
Hyperechoic and light
Superficial nerves best viewed with __ __ __ >__hz
High frequency linear probes 10
Deep nerves best visualized with __ __ __ probes __-_ ha
Low frequency curvilinear probes 2-5
Needle guides used more frequently with what
Central venous access
Nerve stim features
Constant __ __
Compensates for __ of tissues and __ impedance to ensure accurate delivery of current
Current output
Impedance, connection
Nerve stim
Display of __ delivered
__ control. __ ma increments in __-__ ma range
Current
Intensity
0.01, 0.0-2
Nerve stim
Stimulating frequency of __-__ hz
Pulse width of __-__ usec optimal for __ nerve fibers
2-2.5
100-200, motor
Nerve stim
Disconnect or malfunction indicator happens when
If needle disconnected or loss of positive lead to pt
