Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
77 Cards in this Set
- Front
- Back
Before performing a peripheral nerve block what should you check for in your patient assessment?
|
1) presence of existing neuropathy
2) confirm normal coagulation 3) recognize presence of a skin infection in area to be used |
|
What must be available to perform a block?
|
appropriate monitors
equipment drugs available (should adverse reactions to LA occur) IV catheter in place |
|
Lidocaine and Mepivacaine 1% to 1.5% produce surgical anesthesia
a) onset in how many minutes b) duration in hours |
a) 10-20 minutes onset
b) duration of 2-3 hours |
|
Ropivacaine 0.5% and Bupivacaine 0.375%-0.5%
Onset: Duration: |
Onset: slower onset than Lidocaine and Mepivacaine
Duration: 6-8 hours Less motor blockade |
|
What are paresthesias?
|
Paresthesias are radiating electric shock-like sensations that can occur during regional anesthetic procedures.
|
|
Why do you not inject LA in the presence of persistent paresthesia?
|
Don't want intraneural injection
intense pain and high likelihood of permanent injury. |
|
Is cathodal stimulation more or less efficient than anodal stimulation when using nerve stimulation to evoke a motor response?
|
Cathodeal stimulation is more efficient
|
|
During nerve stimulation, a motor response is evoked with currents of approximately _________mA.
|
0.5mA
sufficient proximity of the block needle to the nerve |
|
Ultrasound imaging
Give 2 advantages for using it. |
1) improves block success
2) minimizes local anesthetic volume |
|
Name one major advantage for using ultrasound imaging.
|
variability in surface landmarks, body habitus, and patient positioning can be appreciated
|
|
Why are peripheral nerve catheters more prone to dislodgement than epidural catheters?
|
Movement of skin near the catheter entry point is usually greater.
|
|
What nerves make up the cervical plexus?
|
C1-C4
|
|
What block is most often used in patients undergoing carotid endarterectomy?
|
Cervical plexus block
Superficial block alone is sufficient although most do both superficial and deep. |
|
What nerves make up the brachial plexus?
|
C5-C8 and T1
|
|
Skin over the shoulders is supplied by what plexus?
|
Cervical plexus
|
|
Medial aspect of the arm is innervated by _________?
|
intercostobrachial branch of the 2nd intercostal nerve
|
|
Interscalene block is placed at what level of the brachial plexus?
|
Roots/trunks
|
|
Supraclavicular block is placed at what level of brachial plexus?
|
Trunks/divisions
|
|
Infraclavicular block is placed at what level of the brachial plexus?
|
Cords
|
|
Axillary block is placed at what level of the brachial plexus?
|
Branches
|
|
During an interscalene block which nerve may be spared?
|
C8-T1 Ulnar nerve
fibers that innervate the ulnar side of the forearm and hand |
|
Complications of an interscalene block include?
|
ipsilateral phrenic nerve block
hemiparesis of the diaphragm |
|
Because the phrenic nerve lies on the anterior scalene muscle what is the incidence of diaphragmatic paralysis after an interscalene block?
|
100%
|
|
What patients will poorly tolerate an interscalene block?
|
Those with respiratory insufficiency
contralateral phrenic nerve palsy |
|
What is the most serious complication of a supraclavicular block?
|
Pneumothorax
about a 1% incidence |
|
EXAM QUESTION
Which block provides excellent anesthesia for procedures on the hand,forearm, and elbow? |
Infraclavicular block
or even the Axillary block |
|
Which block spares the musculocutaneous nerve?
|
Axillary block
|
|
Which nerve provides most of the sensory innervation to the palm of the hand?
|
Median nerve
|
|
Which nerve provides sensation to the dorsal and palmar sides of hand?
|
Ulnar nerve
|
|
What is the benefit of intercostal nerve blocks?
|
provide sensory and motor anesthesia of the chest wall in a dermatomal distribution without associated sympathetic nervous system blockade.
|
|
What are the 2 major risks of intercostal nerve blocks?
|
1) pneumothorax
2) inadvertent intravascular injection of local anesthetic solution |
|
Where is absorption of LA the highest?
|
Intercostal nerve blocks
|
|
The saphenous nerve is the only branch of which nerve to contribute to innervation below the knee?
|
Femoral nerve
|
|
Which nerve is frequently missed in 3-in-1 blocks?
|
obturator nerve
|
|
What nerves give rise to the sacral plexus?
|
L4-5, S1-3
|
|
What nerves give rise to the lumbar plexus?
|
L1-4
|
|
How many nerves supply the foot?
|
5
|
|
What are the nerves that supply the foot?
|
1) tibial nerve
2)sural nerve- lateral side of foot 3) saphenous nerve- medial aspect of foot 4)Deep peroneal nerve- innervates webing b/w 1st-2nd toes 5) superficial peroneal nerve-dorsum of foot |
|
The saphenous nerve is a branch off what main nerve?
|
Femoral
|
|
Bier block can be used for procedures lasting less than how long?
|
2 hours
|
|
Commonly used anesthetic for bier blocks include...
|
0.5% Lidocaine
0.5% Prilocaine |
|
During a bier block what is the minimal time the tourniquet must be left inflated?
|
20 minutes
|
|
After how long can the tourniquet on a bier block be deflated and left deflated?
|
40 minutes
|
|
What do you do between 20-40 minutes on a bier block if the surgical procedure has ended?
|
Tourniquet can be deflated, reinflated immediately, and then deflated after 1 minute.
This reduces the peak plasma level of local anesthetic. |
|
What segment of the spinal cord is most concave?
|
L4
|
|
What level of the spinal cord is most convex?
|
T5
|
|
Motor block is how many dermatomes lower than the sensory block?
|
2 levels lower
|
|
Sympathetic block is how many dermatomes higher than the sensory block?
|
2-6 levels higher
|
|
Total CSF volume
|
120-150 ml total volume
|
|
Rate of formation of CSF
|
150 ml/day
|
|
Interscalene block is at what level of the brachial plexus?
|
Trunks
|
|
What is the largest upper extremity nerve?
|
Radial
|
|
What is the largest lower extremity nerve?
|
Sciatic
|
|
The lateral femoral cutaneous nerve has...
a) sensory only b) motor only c) sensory and motor |
a) sensory only
LFC is L2-3 |
|
Femoral nerve is made of what lumbar nerves?
|
L2-3-4
|
|
Femoral nerve brances out into which distal nerve?
|
Saphenous
|
|
Obturator nerve is made of which nerves?
|
L2-3-4
|
|
Sciatic nerve is made from which nerves?
|
L4-5, S1-2-3
|
|
Sciatic nerve brances into which 2 nerves?
|
Common Peroneal and the Tibial
|
|
The common peroneal and the tibial nerve meet to form which nerve?
|
Sural
|
|
The common peroneal branches off to form which 3 nerves?
|
Superficial peroneal
Deep peroneal Sural |
|
What position must the patient be in to do a correct sciatic nerve block?
|
Prone position
|
|
What is the consequence of peroneal nerve damage
ie...patient legs in stirrups |
foot drop
|
|
Widest level in the epidural space is...
|
L2
|
|
Narrowest level in the epidural space is...
|
C5
|
|
Blood flow is related to toxicity=the higher the tissue blood flow the higher the rate of tissue absorption and possibly toxicity.
ranking of blood flow is... |
highest=tracheal
intercostal caudal paracervical epidural brachial plexus subarachnoid,sciatic,femoral lowest= subcutaneous |
|
What is the usual dosing of cc's per desired segment in epidural anesthesia?
|
Notes: 1-2cc's per desired segment
Book: 1cc per desired segment |
|
Epidural lidocaine dosing, onset, dose plain and dose with epi
|
1.5-2% concentration
onset 5-15 min Dose plain 5mg/kg Dose w/ epi 7 mg/kg Duration 75-120 min Reinject after 60-75 min |
|
Bupivacaine/ Ropivacaine
Concentration Onset Dose plain Dose w/ epi Duration Reinject: |
Conc. 0.25-0.75%
Onset 10-20 min Dose plain 2-3mg/kg Dose w/ epi 3mg/kgB 3-4mg/kg R Duration 120-240B 90-120R Reinject: B:90min R:75-90min |
|
What is the most important factor affecting spinal block level?
|
Baricity of solution
|
|
Horners syndrome
Stellate ganglion blockade what are s/s? |
ptosis
miosis (dilated) enophthalmus Anhidrosis |
|
Axillary block is for surgery below what structure?
|
Below the elbow
|
|
What block do you use for procedures above the elbow?
|
Interscalene
|
|
What block is used for shoulder surgery?
|
Interscalene
|
|
pKa effects the _________ characteristics of a Local anesthetic
|
ONSET
|
|
Lipid solubility is a primary determinant of ____________.
|
Potency
|
|
Protein binding is a primary determinant of __________
|
Duration
|