Upper Ext Blocks Flashcards
Advantages of peripheral nerve block
Potent analgesia
Reduction in stress response
Reduction in systemic analgesia requirement
Reduction in opioid-related side effects
Reduction in general anesthesia requirement
Decrease the incidence/occurrence of chronic pain
Regional anesthesia is often favored in pts with
multiple comorbidities for whom a general anesthetic carries a greater risk.
T/F - Periph nerve blocks last longer than spinals
True
Pt. cooperation and participation are key to the success and safety of every regional anesthetic/procedure. What pt populations would be at increased risk for complications?
Pts. who are unable to remain still may be exposed to increased risk - younger pts., developmentally delayed individuals, dementia, movement disorders.
No regional block if platelets < _____ and pt/aptt >_____
100,000
2X normal
Never inject through infected tissue, what will happen to your block of you do?
you can tract infection
there will be more unionized medication and it won’t work as well
Pts with pre-existing nerve injuries may pose a risk or contraindication - what should you do before you place a block?
Make sure you document prior existing nerve injury BEFORE you place block incase you cause damage or so the patient cant say caused it
T:F - Peripheral neuropathy or previous nerve injury may have a higher incidence of complications
True, could have prolonged sensory block
What should you do if you get LAST
Call for help - code blue
CPR
Lipid emulsion administration to sequester the LA - intralipid 20% 1.5ml/kg/min bolus, max 8ml/kg
Preparation for cardiopulmonary bypass
What happens when you mix epi with LA?
prolongs duration
How long can bupivocaine and ropivicaine have effects for?
up to 12-18 hrs
Lidocaine
2% = ___ mg/ml
0.5% = ____ mg/ml
0.25% = ____mg/ml
2% = 20mg/ml
- 5% = 5mg/ ml
- 25% = 2.5mg/ml
How do you determine the concentration of epi if you are given:
EPI 1:200,000
divide 1 million by second number
1,000,000/200,000 = 5mcg/ml
If I have 3cc Lido 1.5 % with 1:200,000 Epi, what are my concentrations?
Lido
1.5% = 15mg/ml X 3cc = 45 mg
Epi
1 mil/200,000 = 5 X3 cc = 15 mcg
What standard hemodynamic monitors should be on for a block?
BP and pulse Ox
have O2 nearby
Placing blocks is a ____ _____ technique
strick sterile
What is a field block technique
A local anesthetic injection that targets terminal cutaneous nerves
Commonly used by surgeons to minimize incisional pain
Dentist
Why can a field block be undesirable?
Undesirable when block may obscure the operative anatomy or where local tissue acidosis (ie. Infection) prevents effective local anesthetic function
What is the paresthesia technique?
Practitioner uses known anatomic relationships and surface landmarks as a guide
Block needle is inserted in proximity of the target nerve or nerve plexus
When needle makes direct contact with a sensory nerve, a paresthesia is elicited and the LA is injected
What is the nerve stimulation technique?
When the insulated needle is placed in proximity to a motor nerve, muscle contractions are induced.
For nerve stimulation technique, It is common to redirect the block needle until muscle contractions occur at a current less than
0.5 mA
For nerve stimulation technique, what does 0.5mA mean?
Lets me know I am close to the nerve
Usually start around 2
If I lose signal, going away from nerve
Some thought that a muscle contraction elicited at less than 0.2 mA implies
intraneural needle placement
What is the ultrasound technique?
Ultrasound for peripheral nerve location and subsequent block
high-frequency sound waves emitted from piezoelectric crystals that travel at different rates through tissues of different densities, returning a signal to the transducer.
1-20 MHz
What is Echogenicity
the degree of efficiency with which sound passes through a substance
Hypoechoic
Hyperechoic
Anechoic
What is Hypoechoic
structures and substances through which sound easily passes. Appear DARK or BLACK on the ultrasound screen.
solid organs, deep structures
What is Hyperechoic
structures reflecting more sound waves appear BRIGHTER, “WHITE” on the ultrasound screen.
diaphragm, gallstones, bone, pericardium
What is Anechoic
no reflection
fluid and blood filled structures
What does muscle look like on an ultrasound?
striations
T/F: nerve bundles can bee hyper or hypoechoic?
TRUE
Linear probe - a high frequency transducer that offers a high resolution picture with
less tissue penetration.
What is a linear probe good for?
Good for superficial nerves
Provide undistorted image
First choice among practitioners
Curvilinear probe - a low frequency transducer that offers better tissue penetration with
lower resolution, or poorer image quality.
What is a curvilinear probe good for?
Good for deeper structures
The optimal transducer varies depending on the ____ of the target nerve and ___ _____ of the needle relative to the transducer.
depth
approach angle
Nerves are best imaged in
cross section (short axis)
What is the characteristic appearance of nerves?
honeycomb
bundle of grapes
In-plane needle alignment (longitudinal, long-axis): In-plane needle alignment refers to aligning the needle with the long-axis of the transducer (along the ultrasound beam) so that the ______________________. One of the disadvantages of the in-plane needle view is that, it is easy to lose the image with a slight movement of the transducer as the ultrasound beam is thin. This technique requires excellent hand-eye coordination.
entire shaft and tip of the needle are visible
Out-of-plane alignment (transverse or short axis): This refers to when the transducer and the needle are perpendicular to each other. It is important to slide the transducer along the shaft of the needle to identify the needle tip. Both the needle tip and shaft in cross section appear as a ________ ______ ______ on the screen. Since only the needle tip is observed as a bright dot, it is sometimes difficult to accurately observe the needle during advancement.
hyperechoic white dot
Which plane alignment is easier for a peripheral nerve block
Out-of-plane
nerve(s) are identified and local anesthetic is infiltrated via a one time injection, to achieve desired effect
Single injection nerve block
involves placement of a percutaneous catheter adjacent to a peripheral nerve, followed by local anesthetic administration to prolong the effect
Continuous Peripheral Nerve Block
Advantages of peripheral nerve block
- Reduction in resting and dynamic pain
- Reduction in supplemental analgesia requirements
- Reduction in opioid related side effects
- Reduction in sleep disturbance
- Improved patient satisfaction
- Improved patient ambulation
- Accelerated resumption of passive joint range-of-motion
- Reduced time to discharge
Complications of continuous peripheral nerve block
Systemic local anesthetic toxicity Catheter retention Nerve injury Infection Retroperitoneal hematoma Increased risk of falling (femoral nerve catheter)
T/F: Local anesthetics are the primary medication infused, as adjuvants do not add benefits to perineural infusions (unlike single-injection peripheral nerve blocks).
TRUE
Pain pumps - Long acting LA (eg. Ropivacaine) are more commonly used as they provide a favorable sensory to motor block ratio, optimizing analgesia while
minimizing motor block
Pain pumps: Recent studies suggest that it is the _______ and not the concentration that determines the majority of block effects.
total dose
What are the 4 brachial plexus blocks?
Interscalene block
Supraclavicular block
Infraclavicular block
Axillary block
Interscalene blocks are indicated for surgical procedures involving the
shoulder and upper arm
What roots are commonly used for an interscalene block?
C5-C7
In an interscalene block, the _______ originating from C8-T1 may be spared
ulnar nerve
What is an interscalene block NOT appropriate for?
surgery at or distal to the elbow
For complete surgical anesthesia of the shoulder, the _____ cutaneous branches may need to be supplemented with a superficial cervical plexus block or local infiltration
C3-C4
Does an interscalene block cover the neck?
Not necessarily
A good interscalene block has 100% block of the
phrenic nerve
Never ever do a ____ interscalene block
BL
Contraindications to interscalene block (4)
Local infection
Severe coagulopathy
Local anesthetic allergy
Patient refusal
A properly performed interscalene block will invariably block the ipsilateral phrenic nerve. Careful consideration should be given to patients with
severe pulmonary disease or preexisting contralateral phrenic nerve palsy
The hemidiaphragmatic paresis may result in
dyspnea, hypercapnia, and hypoxemia
With an interscalene block, Horner’s syndrome may result from proximal tracking of local anesthetic and blockade of sympathetic fibers to the
cervicothoracic ganglion
What is Horner’s Syndrome
myosis(pupil constricts), ptosis (droopy eyelid), anhidrosis (no sweat, no tear), can also turn red on that side
Superior cervical ganglia is blocked
In a patient that has pre-existing contralateral vocal cord paralysis, respiratory distress may ensue if there is _____ involvement
RLN
If there is RLN involvement,
1 VC =
2VC =
1 VC = hoarseness
2VC = stridor
How do know if you have an accidental vertebral artery injection?
if immediate seizure activity is observed
In an interscalene, how will you know if you have accidental spinal or epidural injection
Massive hypotenon, bradycardia, pneumothorax
Why is a pneumothorax possible with an interscalne block
possible due to close proximity of pleura
In a good interscalene block, does the lung aerate?
no, because we blocked it
The interscalene triangle is formed by
Clavicaulr head, sternal head, mastoid head
Where does the nerve bundle come out in regards to the interscalene triangle..
inbetween the middle and anterior scalene muscles (scalene triangle)
____ & ____ are right next to the interscalene triangle
subclavian artery and IJ
A supraclavicular block is used for which surgical procedures
at or distal to the elbow.
Does NOT reliably anesthetize the axillary
Historically, the supraclavicular block fell out of favor due to the high incidence of complications that occurred with paresthesia and nerve stimulator techniques. ______ guidance has improved its safety and increased its current use.
Ultrasound
Which brachial plexus block has the highest risk of pneumothorax
Supraclavicular block
For a supraclavicular block, we are down to the
divisions
Complications of supraclavicular block
Ipsilateral phrenic nerve palsy in ~50% of patients
(Still caution in patients with COPD)
Horner’s syndrome
Recurrent laryngeal nerve palsy
Pneumothorax
Subclavian artery puncture
Where do you place a supraclavicular block?
just above clavicle
What surgical procedures is an Infraclavicular block used for?
at or distal to the elbow
Where do you place an infraclavicular block?
just below clavicle
The Infraclavicular block is a brachial plexus block now at the level of
cords
In an Infraclavicular block, the _______ nerve is spared (T2 dermatome)
intercostobrachial
with an Infraclavicular block, the chorioid process…
2 cm medial, 2 cm inferior -Put needle in
What is a pretty high contraindication for this block?
anticoagulants
The axially block is good for what surgical procedures?
entire arm distal to the elbow
Axillary block - Multiple injections of ___ each may be required to reliably produce anesthesia of the entire arm distal to the elbow.
10ml
At the lateral border of the ____ ____ _____, the cords of the brachial plexus form large terminal branches.
pectoralis minor muscle
The axillary block provided good block of what 3 nerves
ulnar, median, radial
Axillary block: What nerves branch proximal to local injection site and are usually spared?
axillary, musculocutaneous, and medial brachial cutaneous
T/F: Axilla is highly vascularized - there is a risk of LA uptake through small veins traumatized by needle placement.
TRUE
Contraindications for axillary block
Local infection
NEUROPATHY
Bleeding risk
A single _____ ____ is often anesthetizes for minor surgical procedures with a limited field or as a supplement to an incomplete brachial plexus block.
terminal nerve
Terminal nerves may be anesthetized anywhere along their course, but the ____ & _____ are the favored sites for injection.
elbow and the wrist
What is a bier block used for?
Surgical anesthesia for short duration procedures
45-60 minutes
Carpal tunnel release
BIER BLOCK
IV Catheter is inserted on the ____ of the surgical hand/foot
A _____ pneumatic tourniquet is placed on the arm/thigh
The extremity is elevated and exsanguinated by tightly wrapping an ____ elastic bandage from distal to proximal direction
The _____ TQ is inflated, the Esmarch bandage removed, and 0.5% lidocaine is injected over ____ minutes through the IV catheter which is subsequently removed
Anesthesia is usually established after ____ minutes.
TQ pain usually develops after ____ minutes at which time the distal TQ is inflated and the proximal TQ is subsequently deflated.
Pts. Usually tolerate the distal TQ for an additional 15-20 minutes because it is inflated over an ______
dorsum
double
Esmarch
proximal
2-3 min
5-10
20-30
anesthetized area.
Why can you not let the TQ down for 20 minutes after lidocaine is injected?
huge blast of LA – systemic toxicity
What else can you do to provided a additional margin of safety when letting a TQ down?
Slow, incremental deflation of tourniquet
