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Ultrasound guided
Interscalene Brachial plexus block
The patient is in semi-sitting supine
position with the head facing away from the
side to be anesthetized.
The premedication of an adult, average
size patient typically consists of
2-4 mg of midazolam;
250mcg -500mcg of alfentanyl
administered just before insertion of the
needle
TIP: Visualization of the brachial plexus in
the interscalene grove can be challenging
in patients who are tense, moving or
exhibit guarding. Proper sedation can go a
long way toward obtaining quality images.
The ultrasound probe (10-12MHz) is
applied in the axial oblique plane
closer to the midline and angled to first
visualize the carotid artery
Note the position of the internal jugular vein (IJ) as the pressure on the
ultrasound probe is lightened. The internal jugular vein is positioned slightly
superficially and lateral to the carotid artery. Changing the pressure on the
probe causes the IJ to open and close.
The ultrasound probe is then moved slightly laterally to visualize the
brachial plexus in the interscalene grove between anterior and middle
scalene muscles.
The roots/trunks (N) of the brachial plexus are seen stacked between the
scalene muscles usually as round, hypoechoic structures
Sliding or angling the ultrasound probe slightly more inferior allows
visualization in the low-interscalene position in which the brachial plexus
is positioned in proximity to the subclavian artery
After the brachial plexus is identified
on the image, a 50 mm (max)
stimulating needle is inserted
perpendicular to the long axis of the
ultrasound probe. The needle is
inserted at the point on the probe that
corresponds to the location of the
brachial plexus on the screen
The needle insertion results in
shadowing of the ultrasound image
which indicates the path of the needle
TIP: Make sure to estimate the exact
depth of the brachial plexus (typically
0.5-1.5 cm) before inserting the
needle. The needle should never be
inserted deeper than the depth
indicated on the ultrasound image.
Injection of local anesthetic is made with monitoring of the dispersion of
the injectate. If the injectate does not appear to fill the lower
compartment of the interscalene space, the needle is slightly
advanced (0.5-1cm) and additional injection is made at a slightly
greater depth (0.5-1cm deeper).
Local anesthetic is injected slowly and with frequent aspirations, while
avoiding excessive injection pressures (<20 psi).
Thirty to forty ml of local anesthetic is more than adequate for
reliable blockade of the brachial plexus.
Typical indications for this block are surgery on the shoulder, lateral
clavicle, acromioclavicular joint, proximal humerus and elbow (with low
interscalene block).
Supraclavicular
Brachial Plexus Block
The trunks divide
behind
the clavicle into
anterior
and posterior
divisions,
which separate the
innervation of the
ventral and dorsal
halves of the upper
limb.
Classic Kulenkampff technique
In 1988 Brown described the plumb-bob technique
Ultrasound guided
Supraclavicular Brachial Plexus Block
POSITIONING
• The patient is placed supine
• The patient’s head is turned toward the
contralateral side
• The operator is positioned on the
ipsilateral side
• The ultrasound machine should be
placed on the contralateral side
SONOANATOMY.
The
subclavian
artery
appears hypoechoic and pulsatile
and the individual nerves
as
hypoechoic small circles.
It is very important to identify
the pleura while performing this
block so as to avoid pneumothorax.
The first rib acts as a backstop to
prevent pleural puncture, which
means that the needle tip is in the
same plane
the "chimney" effect as local anesthetic is forced to spread up between the
anterior and middle scalene muscles, unable to go down because the first rib is in the
way.
Pre injection
Post injection
•The major advantage of the supraclavicular approach is that the nerves
are very tightly packed, so that the onset is fast and the blockade deep,
leading to this technique being nicknamed “the spinal of the arm”.
•Ultrasound guidance, the pleura can be visualized, and as long as proper
technique is used, i.e. if the needle, and especially the needle tip, is
visualized at all times, pneumothorax should not occur.
•Typical Indication : For surgeries below the mid-humerus level.
It will not diffuse to the lower roots of the cervical
plexus, and thus will not block the upper aspect of
the shoulder.
•Twenty to Forty mls local anaesthetic is adequate for reliable block
Possible Complications
•Peripheral Nerve Injury
Most nerve injury presents as residual paresthesia, hand or forearm hypoesthesia,
and rarely as permanent Paresis
The overall incidence of long-term nerve injury ranges between 0.02% and 0.4%
•Vascular Injury
The risk of hematoma immediately after brachial plexus techniques is small (0.001 to
0.02%)
•Muscle Injury
Myonecrosis from local anesthetics at concentrations typically achieved at the site of
injection is well proven and characteristic of all local anesthetics, with bupivacaine
producing the most intense effect. Because damage is dose related, continuous
local anesthetic administration may worsen injury.
•Hemidiaphramatic Paresis
The proximity of the phrenic nerve to the interscalene groove frequently leads to
unintended local anesthetic block and resultant diaphragmatic dysfunction.
The incidence of hemidiaphragmatic paresis (HDP) is 50-100% after interscalene
brachial plexus block
•Pneumothorax
The reported incidence of pneumothorax after supraclavicular block is 0.5% to
6.1%
•Intravascular Injection
local anesthetic injected directly into the vertebral or carotid artery, or retrograde
flow of local anesthetic via the subclavian artery, may proceed directly to the
brain.
•Subarachnoid or Epidural Injection.
Interscalene brachial plexus block has been linked to unintended subarachnoid
block and to cervical or thoracic epidural block.
•Cervical Sympathetic Chain.
•Excessive local anesthetic spread can also affect the cervical sympathetic chain,
causing the patient to manifest Horner’s syndrome.
with20% to 90% incidence
•Recurrent Laryngeal Nerve.
•Hoarseness may transpire after interscalene block or after 1.3% of supraclavicular
blocks
Advantages of Ultrasound Guidance
Ultrasound guidance with real-time needle visualization in relation to anatomic
structures and target nerves makes regional anesthesia safer and more
successful.
With ultrasound guidance in experienced hands, brachial plexus blockade can
lead to
•Decreased block performance and onset time,
•Increased success rate and
•Decreased rate of complications.
These advantages result in increased operating room efficiency, as well as
increased patient satisfaction.
Thank You
The infraclavicular block is a
blockade of the brachial plexus
below the level of the clavicle and in
the proximity of the coracoid
process.
This block is uniquely well-suited for
hand, wrist, elbow, and distal arm
surgery. It also provides excellent
analgesia for an arm tourniquet.
As opposed to a supraclavicular
block, an infraclavicular block is
not a good choice for shoulder
surgery.
Anatomic structures of
importance. Pectoralis muscle
(shown cut to expose brachial
plexus)
clavicle (removed)
coracoid process
humerus
brachial plexus
subclavian/axillary artery and
vein
The boundaries of the infraclavicular fossa are the pectoralis minor and major
muscles anteriorly, ribs medially, clavicle and the coracoid process superiorly,
and humerus laterally. At this location, the brachial plexus is composed of
cords. The sheath surrounding the plexus is delicate. It contains the
subclavian/axillary artery and vein. Axillary and musculocutanous nerves
leave the sheath at or before the coracoid process in 50% of patients.
Consequently, the deltoid and biceps twitches should not be accepted as
reliable signs of brachial plexus identification.
The patient is in the supine position
with the head facing away from the
side to be blocked.
The anesthesiologist also stands
opposite to the side to be blocked to
assume an ergonomic position during
the block performance.
It is best to keep the arm abducted and
flexed in the elbow to keep the
relationship of the landmarks to the
brachial plexus constant.
Attention should be paid when the arm
is supported at the wrist to allow clear
unobstructed detection of the twitches
of the hand
Surface Landmarks
The following surface anatomy
landmarks are useful in
identifying the estimated site for
an infraclavicular block:
1.Sternoclavicular joint
2.Medial end of the clavicle
3.Coracoid process
4.Acromioclavicular joint
5.Head of the humerus
Anatomic Landmarks
Landmarks for the infraclavicular block
include:
1.Coracoid Process
2.Medial clavicular head
3.Midpoint of line connecting 1 and 2 and
3cm caudal
The needle insertion site is marked
approximately 3cm caudal to the
midpoint of the line connecting points 1
and 2.
TIP: Palpation of the bony prominence just medial to the shoulder,
while the arm is elevated and lowered, identifies the coracoid
process. As the arm is lowered, the coracoid process meets the
fingers of the palpating hand. This maneuver should be used to
identify the coracoid process in each patient planned for an
infraclavicular block
Needle insertion
A 10-cm long, 22-gauge
insulated needle, attached to a
nerve stimulator, is
Inserted at a 45-degree angle
to the skin and
Advanced parallel to the line
connecting
the
medial
clavicular head with the
coracoid process.
The nerve stimulator is initially set to deliver 1.5 mA. A local twitch of the
pectoralis muscle is typically elicited as the needle is advanced
beyond the subcutanous tissue. Once the pectoralis twitches disappear,
the needle advancement should be slow and methodical while looking
for the twitch of the brachial plexus
TIPS:
When the pectoralis twitch is absent despite appropriately deep needle
insertion, the landmarks should be checked as the needle is most likely
inserted too cranially (underneath the clavicle).
The bevel of the needle should be facing down to facilitate nerve stimulation
and reduce the risk of vascular puncture (subclavian or axillary artery and
vein).
Brachial plexus stimulation is typically obtained at a depth of 5 to 8 cm.
Twitches from the biceps or deltoid muscles should not be accepted,
since the musculocutaneous and axillary nerve, respectively, may depart
the brachial sheath before the caracoid process
Ultrasound guided
Infraclavicular Brachial Plexus Block