Peripheral Nerve Blocks Flashcards
What class of drug includes bupivacaine, lidocaine, mepivacaine, prilocaine, and ropivacaine?
Amides
What is the maximum dose and duration for bupivacaine?
Max dose = 3 mg/kg
duration = 1.5 to 8 hours
What is the maximum dose and duration for lidocaine?
Max dose = 4.5 mg/kg (7 w epi)
duration = 0.75 to 2 hours
What is the maximum dose and duration for mepivacaine?
Max dose = 4.5 mg/kg ( 7 w epi)
duration = 1 to 2 hours
What is the maximum dose and duration for ropivacaine?
Max dose = 3 mg/kg
duration = 1.5 to 8 hours
What drug can be added to lidocaine in mepivacaine to prolong their action?
Epinephrine
Benzocaine, chloroprocaine, cocaine, procaine, and tetracaine all fall into what category of drugs?
Esters
It is more common to have an allergic reaction to amides or esters? why?
Esters
PABA
A toxic dose of benzocaine can cause what?
Met hemoglobinemia
How is met hemoglobinemia treated?
Methyline blue
Why is epinephrine added to local anesthetics?
Intravascular marker
improves quality of block
decreases absorption (prolong action)
vasoconstriction on surgical field
What are the three major risks of nerve blocks?
Systemic toxicity
infection
peripheral nerve damage
What is LAST?
Local anesthetic systemic toxicity
Which CNS symptoms come first C&S excitation or CNS depression?
CNS excitation
What are the cardiovascular effects of LAST?
Depression of myocardial conduction and contractility
production of arterial vasodilatation
How can LAST be prevented?
Incremental injection Frequent aspiration Adding a marker Limiting local anesthetic dose and concentration Communication with the patient
How is LAST treated?
Seizures: Versed, propofol, thiopental Cardio/pulmonary symptoms: airway management ACLS/BLS Intralipid infusion CP Bypass
How is Intralipid administered?
1.5 mL/kg as an initial bolus followed by .25 mL/kg/min for 30 to 60 minutes
Name three techniques for placement of blocks
Ultrasound technique
Peripheral nerve stimulator
Paresthesia technique
The brachial plexus stems from what roots?
C5-8, T1
Name the five main branches of the brachial plexus?
Musculocutaneous axillary Radial median Ulnar
Name the three main nerves or groups of nerves that are in Close proximity to the brachial plexus
Superficial cervical plexus
Phrenic nerve
Intercostal brachial nerve
What are the main approaches to the brachial plexus?
Interscalene
Supraclavicular
Infraclavicular
Axillary
What type of block is most commonly done for shoulder, humorous and clavicle procedures?
Interscalene block
What area is commonly missed by an interscalene block?
C8-T1 ulnar nerve
In what patients would you be most concerned with the possibility of phrenic nerve palsy?
Ascites Pregnant COPD Respiratory depression Oxygen dependent Obese
What type of block would you perform for surgeries for the entire arm below the level of the shoulder?
Supraclavicular block
Supraclavicular blocks are performed at what level of the brachial plexus?
At the level of the divisions
What type of block is performed at the level of the cords and is indicated for elbow forearm and hand surgery?
Infraclavicular
What type of block is performed at the level of the terminal branches for elbow forearm and hand surgery?
Axillary
How is a bier block performed?
By inserting IV catheter distally, inflating a double pneumatic tourniquet, wrapping the arm in eschmark elastic bandages and injecting 50mL of 0.5% lidocaine
What type of block would be performed for surgery on the hip anterior thigh and knee?
Lumbar plexus block
What nerves does the lumbar plexus block cover?
Femoral nerve
Lateral femoral cutaneous nerve
Obturator nerve
The femoral nerve is medial or lateral to the artery?
Lateral
Femoral nerve blocks are performed for what types of surgeries?
Knee surgeries
Femoral ORIF
Surgery involving the medial aspect of the leg
What is the largest sensory branch of the femoral nerve?
Saphenous nerve
What is the largest nerve of the leg?
Sciatic nerve
The sciatic nerve is composed of what 2 nerves?
Tibial nerve and common peroneal nerve
What are the two common approaches to a sciatic nerve block?
Popliteal fossa and subgluteal
What type of block is performed for foot and toe surgeries?
Ankle block
Which nerves are blocked in the ankle block?
Deep peroneal Superficial peroneal Posterior tibial Sural Saphenous
