Peripheral Nerve Block Techniques

Question 1

What type of hormones are increased during a stress response?

Answer 1

Catabolic (cortisol and catechols)

Question 2

What types of hormones are decreased during a stress response?

Answer 2

Anabolic (human growth hormone and testosterone)

Question 3

How is glucose increased during a surgical stress response?

Answer 3

Increase in conversion of amino acids to glucose through liver gluconeogenesis

Question 4

What form of anesthesia can blunt the surgical stress responses and increased metabolic demand?

Answer 4

Regional anesthesia

Question 5

Define regional anesthesia.

Answer 5

Loss of sensation in a region of the body produced by application of an anesthetic agent to all the nerves supplying that region

Question 6

What is a significant difference between regional anesthesia and general anesthesia?

Answer 6

There is no loss of consciousness with regional anesthesia

Question 7

What is conduction anesthesia?

Answer 7

Anesthesia of an area supplied by a specific nerve, produced by an anesthetic agent applied to the nerve

Question 8

What are absolute contraindications for regional anesthesia?

Answer 8

Patient refusal
Infection at injection site
Coagulopathy

Question 9

What are relative contraindication for regional anesthesia?

Answer 9

Hypovolemia
Systemic sepsis
Preexisting neurological conditions

Question 10

If the patient has received regional anesthesia what does that indicate regarding the characteristics of the block?

Answer 10

Implies loss of all sensations –> autonomic, motor, and sensory

Question 11

If the patient has received regional analgesia what does that indicate regarding the characteristics of the block

Answer 11

Loss of pain sensations –> only sensory and autonomic

Question 12

What are the goals of local anesthetic?

Answer 12

Rapid Onset
Appropriate duration
Lowest toxicity
Adequate analgesia/anesthesia

Question 13

What type of tool can aid the provider in using less LA?

Answer 13

Ultrasound

Question 14

What type of regional anesthesia is the exception to volume equalling success?

Answer 14

Spinal, use a very small amount compared to other blocks

Question 15

What are the three components that must be balanced when administering regional anesthesia?

Answer 15

Volume
Concentration
Toxicity

Question 16

If a local anesthetic has a faster onset, what can be assumed about the duration?

Answer 16

Shorter duration

Question 17

What order do nerve fibers become blocked?

Answer 17

B
C & A-delta
A-gamma
A-beta
A-Alpha

Question 18

What is the function of A-Alpha nerve fibers?

Answer 18

Motor and proprioception

Question 19

What is the function of A-beta nerve fibers?

Answer 19

Motor, proprioception, touch and pressure

Question 20

What is the function of A-gamma nerve fibers?

Answer 20

Muscle tone

Question 21

What is the function of A-delta nerve fibers?

Answer 21

Pain, touch and cold

Question 22

What is the function of B nerve fibers?

Answer 22

Preganglionic sympathetic

Question 23

What is the function of C nerve fibers?

Answer 23

Pain, touch, warm and cold

Question 24

What drugs should be readily available prior to performing regional anesthesia?

Answer 24

Supplemental O2
Narcotics/sedatives
Resuscitation drugs –> LAST

Question 25

What is a paresthesia?

Answer 25

Occurs with direct contact of needle to nerve “electric shock”

Question 26

What is the purpose of the nerve stimulator when placing a regional anesthetic?

Answer 26

Isolated specific nerves using adjustable, low voltage stimulator

Question 27

What is the highest amplitude a nerve stimulator should go if using for purpose of regional anesthesia?

Answer 27

No more than 5mAmps (0.1-5mA)

Question 28

How will the provider know that an accurate localization of the nerve is present?

Answer 28

The lower the threshold current the more accurately the nerve is located

Question 29

What should the provider use a nerve stimulator with an insulated needle when performing regional anesthesia?

Answer 29

Reduces current leakage

Question 30

Ideally, what would the provider like the amplitude to be when locating a nerve?

Answer 30

Greater than 0.2mAmp tom make sure we aren’t in the nerve itself

Question 31

What is a major complication of regional anesthesia?

Answer 31

LAST

Question 32

In what order are the areas most likely to experience LAST?

Answer 32

Tracheal –> Intercostal –> Caudal –> Epidural –> lumbar –> brachial plexus –> Sciatic –> femoral –> Subcutaneous

Question 33

What should the provider do prior to injecting the LA?

Answer 33

ALWAYS aspirate before each injection

Question 34

How much LA should the provider inject prior to aspirating again?

Answer 34

Incremental doses of 5mL or less

Question 35

What might the patient tell the provider if there is a intramural injection?

Answer 35

Patient will be screaming in pain

Question 36

What can occur if LA is injected intraneurally?

Answer 36

Damage to the nerve can occur

Question 37

If the patient tells the provider they are feeling dull achy pain and cramps what might this indicate?

Answer 37

Pressure from volume being injected around the nerve, temperature is cold compared to body temperature

Question 38

What are the symptoms in the progression of LAST?

Answer 38

Disorientation
Metallic taste
Tingling in the mouth and tongue
Tinnitus and auditory hallucinations
Muscle spasms
Seizure
Coma
Respiratory arrest
Cardiac Arrest 
Death

Question 39

How should LAST be treated?

Answer 39

Airway –> secure airway
Breathing –> ventilation prevent acidosis
Circulation –> CV support
Drugs –> drugs to increase seizure threshold