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Peripheral nerve blocks
1.
2. Peripheral nerve blocks are gaining widespread popularity for perioperative pain
management because:
Pain relief with PNB avoids side effects such as nausea and vomiting,
hemodynamic instability avoiding complications of general and central neuraxial
anesthesia.
Patients with unstable cardiovascular disease can undergo surgery under PNB
without significant hemodynamic changes.
Patients who have abnormalities in hemostasis or infection which
contraindicate use of central neuraxial block can be candidates for surgery
under PNB.
A substantial savings in operating room turnover time can occur if PNB is done
outside the operating room. Patients with a PNB can frequently position
themselves.
When used as part of a combined general regional technique, PNB facilitates
lighter planes of anesthesia, avoiding the use of opioids and allowing a quick
emergence and recovery.
3. Fully prepare the equipment and patient, including consent. Ensure
intravenous access, monitoring and full resuscitation facilities.
A linear ultrasound probe (Frequency 10-15 MHz) is used with the depth
setting of 2-4 cm. A 50mm length insulated nerve stimulator needle is used
to perform the block. Peripheral nerve stimulation
(PNS) is desirable as an additional way of confirming nerve location but
not essential. If PNS used,
Initial settings should be 0.5 mA for current , frequency of 2Hz and pulse
width of 0.1 msec. Higher currents may result in muscle contractions which
cause the arm to move and make it difficult to maintain a stable ultrasound
image.
If a PNS is used, the usual precautions of a threshold potential > 0.3mA,
immediate twitch ablation on injection and painless easy injection should be
observed. It is not a requirement to seek out specific nerve stimulator
twitches if the relevant anatomy is clearly identified.
4.
5. The brachial plexus is formed by the ventral rami of the lower
cervical and upper thoracic nerve roots (C5-T1).
The trunks pass laterally and lies around the subclavian artery
while passing over the first rib to enter the axilla, between the
clavicle and the scapula.
Behind the clavicle, each trunk splits into anterior and posterior
divisions. These recombine to form the posterior , lateral and
medial cords around the axillary artery.
The upper roots (C5–7) tend to stay lateral, the lower roots
(C8,T1) tend to stay medial and all roots contribute to the
posterior cord, and therefore also to the radial nerve.
9. Indications
operations on the elbow, forearm, and hand. Blockade
occurs at the distal trunk–proximal division level.
Location-
The three trunks are clustered vertically over the first
rib cephaloposterior to the subclavian artery. The
neurovascular bundle lies inferior to the clavicle at
about its midpoint.
10. In the classic technique, the
midpoint of the clavicle is
identified . The posterior border
of the sternocleidomastoid is
felt. The palpating fingers can
then roll over the belly of the
anterior scalene muscle into the
interscalene groove, where a
mark should be made
approximately 1.5 to 2.0 cm
posterior to the midpoint of the
clavicle. Palpation of the
subclavian artery at this site
confirms the landmark
11. A 22-gauge, 4-cm needle is directed in a caudad, slightly
medial, and posterior direction until a paresthesia is elicited
or the first rib is encountered.
If a syringe is attached, this orientation causes the needle
shaft and syringe to lie almost parallel to a line joining the
skin entry site and the patient's ear.
If the first rib is encountered without elicitation of a
paresthesia, the needle can be systematically walked
anteriorly and posteriorly along the rib until the plexus or
the subclavian artery is located .
The needle can be withdrawn and reinserted in a more
posterolateral direction, which generally results in a
paresthesia or motor response. 20 to 30 mL of solution is
injected in incremental pattern.
13. Landmarks
There is no proper landmark, besides the
clavicle, which in most patients is easily felt.
The subclavian pulse might be palpated above
the clavicle, but that is not indispensable.
The ultrasound probe is positioned in the
supraclavicular fossa, pointing caudad, and
moved laterally and medially, as well as in a
rocking fashion, in order to locate the subclavian
artery
14. Position of probe and
needle:-
-Probe is positioned just above
the clavicle.
It can be moved laterally or
medially, and rocked back and
forth until a good quality picture
is obtained.
-The needle is inserted from the
lateral side of the probe, as the
plexus lies lateral to the
subclavian artery.
It has to be exactly in the long
axis of the probe.
This is especially important for
this block, in which the needle
can easily cause a pneumothorax
if not fully visible at all times.
15. Technique
Once the subclavian artery is visualized, the
area lateral and superficial to it is explored
until the plexus is seen, with a characteristic
“honeycomb” appearance.
Multiple nerves can be seen, or as few as
two, depending on the level and the patient
(Figure 1).
A caudad-cephalad rocking motion is then
used to find the plane where the nerves are
best seen.
16. Figure 1: Left subclavian
artery and nerves of the
brachial plexus.
The subclavian artery is seen
beating at the center of the
field.
Underlying it is the first rib,
with a bright cortical bone
and a posterior shadow.
The pleura are seen on each
side of the rib, somewhat
deeper, and moving with the
patient’s respiration.
The nerves of the brachial
plexus can be seen lateral
and a little superficial to the
artery.
The distribution is variable,
with as little as two or as
many as 10 nerves seen.
17. Indications- Hand, wrist, elbow and distal arm surgery
Blockade occurs at the level of the cords of the
musculocutaneous and axillary nerves.
Anatomical landmarks: The boundaries of the infraclavicular
fossa are
pectoralis minor and major muscles anteriorly,
ribs medially ,
clavicle and the coracoid process superiorly,
and humerus laterally.
18. Technique-
Classic approach
The needle is inserted 2 cm below the midpoint of the
inferior clavicular border, advanced laterally and
directed toward the axillary artery
A coracoid technique consisting of insertion of the
needle 2 cm medial and 2 cm caudal to the coracoid
process has also been described
19.
20.
21. Described by winnie in 1970.
Indications-
Surgery in shoulder ,upper arm and forearm.
Post operative analgesia for total shoulder arthroplasty
Blockade occurs at the level of the upper and middle
trunks.
22.
23.
24. TECHNIQUE-
Under sterile precautions and development of a skin wheal, a 22-
to 25-gauge, 4-cm needle is inserted perpendicular to the skin at
a 45-degree caudad and slightly posterior angle. The needle is
advanced until paresthesia is elicited.
If bone is encountered within 2 cm of the skin, it is likely to be a
transverse process, and the needle may be “walked” across this
structure to locate the nerve.
After negative aspiration, 10 to 40 mL of solution is injected
incrementally, depending on the desired extent of blockade.
contraction of the diaphragm indicates phrenic nerve stimulation
and anterior needle placement; the needle should be redirected
posteriorly to locate the brachial plexus.
25. Complications
Ipsilateral diaphragmatic paresis
Severe hypotension and bradycardia (i.e., the Bezold-
Jarisch reflex)
Inadvertent epidural or spinal block
Nerve damage or neuritis
intravascular injection with Seizure activity
Horner’s syndrome with dyspnea and hoarseness of
voice.
Puncture of the pleura may cause Pneumothorax.
Hemothorax.
Hematoma and Infection.
26. Indications –
include surgery on the forearm and hand. Elbow
procedures are also successfully performed with the
axillary approach.
Blockade occurs at the level of the terminal nerves.
blockade of the musculocutaneous nerve is not always
produced with this approach.
27. •The axillary artery is the most important
landmark
• The median nerve is found superior to the
artery, the ulnar nerve is inferior, and the radial
nerve is posterior and somewhat lateral
• At this level, the musculocutaneous nerve has
already left the sheath and lies in the substance
of the coracobrachialis muscle.
28. A transarterial
technique can be used
whereby the needle
pierces the artery and 40
to 50 mL of solution is
injected posterior to the
artery; alternatively, half
of the solution can be
injected posterior and half
injected anterior to the
artery.
29. Complications-
Nerve injury and systemic toxicity
intravascular injection
Hematoma and infection are rare complications.
36. Anesthesia for knee arthroscopy in
combination with intraarticular local
anesthesia and analgesia for femoral shaft
fractures
anterior cruciate ligament reconstruction
total knee arthroplasty as a part of
multimodal regimens.
37.
38.
39.
40.
41.
42. This block is chiefly used for foot and ankle
surgery.
Popliteal fossa block is preferable to ankle
block for surgical procedures requiring the
use of a calf tourniquet.
57. Anesthesia or analgesia to patients
undergoing intrathoracic,abdominal, or pelvic
procedures or surgery to the breast
Diagnosis and treatment of certain chronic
pain disorders, including postthoracotomy
and postmastectomy pain.
58. Epidural or subarachnoid injection of local
anesthetic
Intravascular injection through the lumbar
vessels, vena cava or aorta
Pleural puncture and pneumothorax
Editor's Notes
Roots
The ventral rami of spinal nerves C5 to T1 are referred to as the roots of the plexus.
Trunks
Shortly after emerging from the intervertebral foramina , these 5 roots unite to form three trunks.–The ventral rami of C5 & C6 unite to form the Upper Trunk.–The ventral ramus of C 7 continues as the Middle Trunk.–The ventral rami of C 8 & T 1 unite to form the Lower Trunk.
•DivisionsEach trunk splits into an anterior division and a posterior division.–The anterior divisions usually supply flexor muscles–The posterior divisions usually supply extensor muscles.
Cords
–The anterior divisions of the upper and middle trunks unite to form the lateral cord.
–The anterior division of the lower trunk forms the medial cord.
–All 3 posterior divisions from each of the 3 cords unite to form the posterior cord.
–The cords are named according to their position relative to the axillary artery
In plane & out plane approach
in supine position with the head turned away from the side to be blocked.
The arm to be anesthetized is adducted, and the hand should be extended along the side toward the ipsilateral knee as far as possible.
After appropriate preparation and development of a skin wheal, the anesthesiologist stands at the side of the patient facing the patient's head.
Positioning- supine position with the head turned away from the side to be blocked.
The posterior border of the sternocleidomastoid muscle is palpated by having the patient briefly lift the head.
The interscalene groove can be palpated by rolling the fingers posterolaterally from this border over the belly of the anterior scalene muscle into the groove.
A line extended laterally from the cricoid cartilage and intersecting the interscalene groove indicates the level of the transverse process of C6.
The external jugular vein often overlies this point of intersection.
Nerve stimulation,paresthesia and usg guided
Lumbar plexus lies between the psoas major and quadratus lumborum muscles in the so called psoas compartment. The lower components of thenplexus, L2, L3, and L4, primarily innervate the anterior and medial thigh.
The anterior divisions of L2, L3, and
L4 form the obturator nerve; the posterior divisions of the same components form the femoral nerve; and the lateral femoral cutaneous nerve is formed from posterior divisions of L2 and L3.
The sacral plexus gives off two nerves that are important
for lower extremity surgery: the posterior cutaneous
nerve of the thigh and the sciatic nerve. The
posterior cutaneous nerve of the thigh and the sciatic
nerve are derived from the first, second, and third sacral
nerves plus branches from the anterior rami of L4 and
L5, respectively.
These nerves pass through the pelvis
together, and the greater sciatic foramen and are blocked
b the same technique. The sciatic nerve is a combination
of two major nerve trunks, the tibial (i.e., ventral
branches of the anterior rami of L4, L5, S1, S2, and S3)
and the common peroneal (i.e., dorsal branches of the
anterior rami of L4, L5, S1, S2, and S3), which form the
sciatic nerve. The trunks separate at or above the popliteal
fossa, with the tibial nerve passing medially and the
common peroneal laterally.
The posterior muscles of the thigh are the biceps femoris,
the semimembranosus, semitendinosus, and the posterior
portion of the adductor magnus. As these muscles are
traced distally from their origin on the ischial tuberosity,
they separate into medial (semimembranosus, semitendinosus)
and lateral (biceps) musculature, and they form the
upper border of the popliteal fossa. The lower border of the
popliteal fossa is defined by the two heads of the gastrocnemius.
In the upper part of the popliteal fossa, the sciatic
nerve lies posterolateral to the popliteal vessels. The popliteal
vein is medial to the nerve, and the popliteal artery is
most anterior, lying on the popliteal surface of the femur.
The posterior tibial artery is palpated, and a
25-gauge, 3-cm needle is inserted posterolateral to the
artery at the level of the medial malleolus
Typically,
the thoracic spinous processes are identified, and the
needle is inserted 2.5 to 3 cm lateral to the most cephalad
aspect of the spinous process and advanced perpendicular
to the skin in all planes to contact the transverse process of
the vertebra below, typically at a depth of 2 to 4 cm