Regional Anesthesia – Questions With Correct
Solutions
MOA of local anesthetic Right Ans - molecules selectively bind to sodium
channels in the inactivated state, thus preventing membrane depolarization
For sensory blockade Right Ans - use lower % of local anesthetic
For motor blockade Right Ans - use higher % of local anesthetic
Potency Right Ans - is directly related to lipid solubility
- Only the lipid soluble form diffuses across the epineurium (neural sheath)
and the nerve membrane
Duration of action Right Ans - is correlated to plasma protein binding,
specifically a1-acid glycoprotein
Role of NaHCO3 Right Ans - - Adding NaHCO3 alkalinizes the local
anesthetic
o Hastens onset
o Improves quality of the block
o Improves neural blockade by increasing the amount of available free base
Dose of NaHCO3 Right Ans - - Use 1 mEq per 10 ml of solution
o Not clinically relevant with Bupivicaine or Ropivicaine
Role of Epinephrine Right Ans - - Adding Epinephrine causes
vasoconstriction
o Decreases absorption
o Prolongs duration of action
o Limits toxic side effects
o Enhances neural uptake
Clonidine Right Ans - alpha-2 adrenergic receptor agonist often used in
conjunction with local anesthetics
- Mechanism of action unknown as it relates to peripheral nerve blocks
- Postulated that there is decreased plasma absorption of local anesthetic at
the site of injection
,- Prolongs block for up to 24 hours
- Not effective if used alone
o For some reason it seems to work synergistically with the local anesthetic
Clonidine Dose Right Ans - - Dose = 0.1-0.5 mcg/kg
Local anesthetic dosing for regional blocks Right Ans - 30-40 ml
Alpha Fibers Right Ans - Proprioception/motor
Beta Fibers Right Ans - Touch Pressure
Gama Fibers Right Ans - Muscle Tone
Delta Fibers Right Ans - Pain, Cold,Temp, Touch
Type B Right Ans - Preganglionic Autonomic Vasomotor
Type C Right Ans - Postganglionic Vasomotor
Pain, Warm, Cold, Temp, Touch
Regional Blocks Indications Right Ans - - Perioperative pain control
- Decreased opioid use
Regional Blocks Contraindications Absolute Right Ans - o Patient refusal
o If neural blockade would hinder surgical procedure (i.e. intraoperative
nerve testing)
Uncorrected coagulation deficiencies
Systemic anticoagulation
Long term ASA or NSAIDs
Infection at the site of the block
Intraoperative/immediate post-op nerve testing
Severe or potential bleeding
Severe Hypovolemia
Severe Aortic or Mitral Valve Stenosis
Increased ICP
Regional Blocks Contraindications Relative Right Ans - Uncooperative
patient
, Septicemia/bacteremia
Preexisting neurologic disease
Chronic head or back ache
Stenotic valvular disease
Severe spinal deformity
Block Complications Immediate Right Ans - Related to Intravascular
Injection
CV
Local anesthetic toxicity reaction (LAST)
Block Complications Delayed Right Ans - Nerve injury
Pneumothorax
CV
Local Anesthetic Toxicity Right Ans - Tinnitus
Metallic Taste
Tongue & Circumoral Numbness
Lightheaded
Tremors
Obtundation
Seizures
Coma-Respiratory Depression-Cardiac Arrest
Local Anesthetic Toxicity Management Right Ans - DC injection
ABCs administer 100% O2
Intubate if needed
Give anti-seizure medications
Be prepared to began ACLS
Treat bradyarrhythmias with atropine
Intralipid 20% 1.5ml/kg bolus followed by a 0.25ml/kg/min infusion over 60
min
Intralipid dose Right Ans - Intralipid 20% 1.5ml/kg bolus followed by a
0.25ml/kg/min infusion over 60 min
Universal Block Setup Right Ans - Patient consent
IV access
O2
Solutions
MOA of local anesthetic Right Ans - molecules selectively bind to sodium
channels in the inactivated state, thus preventing membrane depolarization
For sensory blockade Right Ans - use lower % of local anesthetic
For motor blockade Right Ans - use higher % of local anesthetic
Potency Right Ans - is directly related to lipid solubility
- Only the lipid soluble form diffuses across the epineurium (neural sheath)
and the nerve membrane
Duration of action Right Ans - is correlated to plasma protein binding,
specifically a1-acid glycoprotein
Role of NaHCO3 Right Ans - - Adding NaHCO3 alkalinizes the local
anesthetic
o Hastens onset
o Improves quality of the block
o Improves neural blockade by increasing the amount of available free base
Dose of NaHCO3 Right Ans - - Use 1 mEq per 10 ml of solution
o Not clinically relevant with Bupivicaine or Ropivicaine
Role of Epinephrine Right Ans - - Adding Epinephrine causes
vasoconstriction
o Decreases absorption
o Prolongs duration of action
o Limits toxic side effects
o Enhances neural uptake
Clonidine Right Ans - alpha-2 adrenergic receptor agonist often used in
conjunction with local anesthetics
- Mechanism of action unknown as it relates to peripheral nerve blocks
- Postulated that there is decreased plasma absorption of local anesthetic at
the site of injection
,- Prolongs block for up to 24 hours
- Not effective if used alone
o For some reason it seems to work synergistically with the local anesthetic
Clonidine Dose Right Ans - - Dose = 0.1-0.5 mcg/kg
Local anesthetic dosing for regional blocks Right Ans - 30-40 ml
Alpha Fibers Right Ans - Proprioception/motor
Beta Fibers Right Ans - Touch Pressure
Gama Fibers Right Ans - Muscle Tone
Delta Fibers Right Ans - Pain, Cold,Temp, Touch
Type B Right Ans - Preganglionic Autonomic Vasomotor
Type C Right Ans - Postganglionic Vasomotor
Pain, Warm, Cold, Temp, Touch
Regional Blocks Indications Right Ans - - Perioperative pain control
- Decreased opioid use
Regional Blocks Contraindications Absolute Right Ans - o Patient refusal
o If neural blockade would hinder surgical procedure (i.e. intraoperative
nerve testing)
Uncorrected coagulation deficiencies
Systemic anticoagulation
Long term ASA or NSAIDs
Infection at the site of the block
Intraoperative/immediate post-op nerve testing
Severe or potential bleeding
Severe Hypovolemia
Severe Aortic or Mitral Valve Stenosis
Increased ICP
Regional Blocks Contraindications Relative Right Ans - Uncooperative
patient
, Septicemia/bacteremia
Preexisting neurologic disease
Chronic head or back ache
Stenotic valvular disease
Severe spinal deformity
Block Complications Immediate Right Ans - Related to Intravascular
Injection
CV
Local anesthetic toxicity reaction (LAST)
Block Complications Delayed Right Ans - Nerve injury
Pneumothorax
CV
Local Anesthetic Toxicity Right Ans - Tinnitus
Metallic Taste
Tongue & Circumoral Numbness
Lightheaded
Tremors
Obtundation
Seizures
Coma-Respiratory Depression-Cardiac Arrest
Local Anesthetic Toxicity Management Right Ans - DC injection
ABCs administer 100% O2
Intubate if needed
Give anti-seizure medications
Be prepared to began ACLS
Treat bradyarrhythmias with atropine
Intralipid 20% 1.5ml/kg bolus followed by a 0.25ml/kg/min infusion over 60
min
Intralipid dose Right Ans - Intralipid 20% 1.5ml/kg bolus followed by a
0.25ml/kg/min infusion over 60 min
Universal Block Setup Right Ans - Patient consent
IV access
O2
