PNB EXAM QUESTIONS WITH 100%
CORRECT ANSWERS
What immediate effect should an injection of 1 to 2 mL of local anesthetic have if the
needle tip is correctly placed at the nerve site? - Answer- It will immediately abolish
nerve stimulation and muscle contraction.
What is the key advantage of using ultrasound imaging for nerve blocks? - Answer- It
allows for real-time visualization of nerves, muscles, vessels, bone, and local anesthetic
spread.
What component within an ultrasound probe detects the reflection of sound waves to
create an image? - Answer- A piezo-electric crystal.
What is the term for the density of tissue and its ability to reflect ultrasound waves back
to the transducer? - Answer- Echogenicity.
In ultrasound terminology, how do hypo-echoic tissues appear and why? - Answer-
They appear as dark areas because they are less dense and allow sound waves to
pass through them more readily.
Provide an example of a structure that typically appears hypo-echoic on an ultrasound. -
Answer- Blood, lung, or nerves above the clavicle.
To reduce infection rates during PNB, a new _____ should be worn for each new case.
- Answer- facial mask.
Systemic toxicity of local anesthetic most commonly occurs due to an inadvertent _____
injection. - Answer- intravascular.
What action should be performed carefully and frequently during the injection of local
anesthetic to prevent intravascular injection? - Answer- Aspiration.
If nerve stimulation is obtained with a current intensity of <0.2mA, what should be done
before injecting local anesthetic? - Answer- The needle should be pulled back slightly to
obtain the same response with a current >0.2mA.
What is the primary function of a peripheral nerve stimulator in regional anesthesia? -
Answer- To assist in identifying the location of peripheral nerves that have motor fiber
components.
, In a peripheral nerve stimulator setup, the anode (+) terminal is usually colored _____
and connected to an electrode on the patient's skin. - Answer- red
To which component is the cathode (-) terminal (usually black) of a peripheral nerve
stimulator connected? - Answer- The stimulating needle.
What is the typical initial output setting for a peripheral nerve stimulator when searching
for a nerve? - Answer- 1 to 2 mA.
What happens to nerve stimulation as the needle tip approaches a nerve and then
passes it? - Answer- Stimulation increases as the needle approaches the nerve and
then decreases as it passes the nerve.
To what level is the stimulator's current output decreased to confirm proximity to a nerve
before injection? - Answer- The lowest output that results in nerve stimulation and
muscle contraction, usually less than 0.5 mA.
In ultrasound terminology, how do hyper-echoic tissues appear and why? - Answer-
They appear bright because they are dense and poor conductors of sound.
Provide an example of a structure that typically appears hyper-echoic on an ultrasound.
- Answer- Bone, needle, vessel wall, muscle tissue, or nerves below the clavicle.
Are nerves above the clavicle typically hypo-echoic or hyper-echoic? - Answer- Hypo-
echoic.
Are nerves below the clavicle typically hypo-echoic or hyper-echoic? - Answer- Hyper-
echoic.
Which axis orientation is most often used for peripheral nerve blocks? - Answer- Short
axis.
Which axis orientation is particularly useful for central line placement? - Answer- Long
axis.
An in-plane needle orientation generates what kind of view of the needle? - Answer- A
long-axis view of the needle.
What is the main advantage of an in-plane needle approach in ultrasound-guided
procedures? - Answer- It allows for full visualization of the shaft and tip of the needle.
An out-of-plane needle orientation generates what kind of view of the needle? - Answer-
A short-axis view of the needle (a dot).
CORRECT ANSWERS
What immediate effect should an injection of 1 to 2 mL of local anesthetic have if the
needle tip is correctly placed at the nerve site? - Answer- It will immediately abolish
nerve stimulation and muscle contraction.
What is the key advantage of using ultrasound imaging for nerve blocks? - Answer- It
allows for real-time visualization of nerves, muscles, vessels, bone, and local anesthetic
spread.
What component within an ultrasound probe detects the reflection of sound waves to
create an image? - Answer- A piezo-electric crystal.
What is the term for the density of tissue and its ability to reflect ultrasound waves back
to the transducer? - Answer- Echogenicity.
In ultrasound terminology, how do hypo-echoic tissues appear and why? - Answer-
They appear as dark areas because they are less dense and allow sound waves to
pass through them more readily.
Provide an example of a structure that typically appears hypo-echoic on an ultrasound. -
Answer- Blood, lung, or nerves above the clavicle.
To reduce infection rates during PNB, a new _____ should be worn for each new case.
- Answer- facial mask.
Systemic toxicity of local anesthetic most commonly occurs due to an inadvertent _____
injection. - Answer- intravascular.
What action should be performed carefully and frequently during the injection of local
anesthetic to prevent intravascular injection? - Answer- Aspiration.
If nerve stimulation is obtained with a current intensity of <0.2mA, what should be done
before injecting local anesthetic? - Answer- The needle should be pulled back slightly to
obtain the same response with a current >0.2mA.
What is the primary function of a peripheral nerve stimulator in regional anesthesia? -
Answer- To assist in identifying the location of peripheral nerves that have motor fiber
components.
, In a peripheral nerve stimulator setup, the anode (+) terminal is usually colored _____
and connected to an electrode on the patient's skin. - Answer- red
To which component is the cathode (-) terminal (usually black) of a peripheral nerve
stimulator connected? - Answer- The stimulating needle.
What is the typical initial output setting for a peripheral nerve stimulator when searching
for a nerve? - Answer- 1 to 2 mA.
What happens to nerve stimulation as the needle tip approaches a nerve and then
passes it? - Answer- Stimulation increases as the needle approaches the nerve and
then decreases as it passes the nerve.
To what level is the stimulator's current output decreased to confirm proximity to a nerve
before injection? - Answer- The lowest output that results in nerve stimulation and
muscle contraction, usually less than 0.5 mA.
In ultrasound terminology, how do hyper-echoic tissues appear and why? - Answer-
They appear bright because they are dense and poor conductors of sound.
Provide an example of a structure that typically appears hyper-echoic on an ultrasound.
- Answer- Bone, needle, vessel wall, muscle tissue, or nerves below the clavicle.
Are nerves above the clavicle typically hypo-echoic or hyper-echoic? - Answer- Hypo-
echoic.
Are nerves below the clavicle typically hypo-echoic or hyper-echoic? - Answer- Hyper-
echoic.
Which axis orientation is most often used for peripheral nerve blocks? - Answer- Short
axis.
Which axis orientation is particularly useful for central line placement? - Answer- Long
axis.
An in-plane needle orientation generates what kind of view of the needle? - Answer- A
long-axis view of the needle.
What is the main advantage of an in-plane needle approach in ultrasound-guided
procedures? - Answer- It allows for full visualization of the shaft and tip of the needle.
An out-of-plane needle orientation generates what kind of view of the needle? - Answer-
A short-axis view of the needle (a dot).
