Chapter 33 Continuous Peripheral Nerve Blocks Flashcards Preview

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Flashcards in Chapter 33 Continuous Peripheral Nerve Blocks Deck (31):

continuous peripheral nerve block (CPNB)— also called “perineural local anesthetic infusion”

involves the percutaneous insertion of a catheter directly adjacent to the peripheral nerve(s) supplying the surgical site


Patients who should receive CPNB

CPNB is usually provided to patients expected to have at
least moderate postoperative pain of a duration greater
than 24 hr that is not easily managed with oral opioids.


In general, axillary, cervical
paravertebral (CPVB), infraclavicular, or supraclavicular
infusions are used for surgical procedures involving

the hand, wrist, forearm, and elbow; interscalene, CPVB


intersternocleidomastoid catheters are used for surgical
procedures involving

the shoulder or proximal humerus;


thoracic paravertebral catheters are used for breast or
thorax procedures; psoas compartment catheters are used

hip surgery


fascia iliaca, femoral, and psoas compartment catheters are used for

knee or thigh procedures;
and popliteal


subgluteal catheters are used for surgical procedures of the

leg, ankle, and foot


an interscalene catheter for

shoulder or proximal
humerus procedures;


infraclavicular catheter for more
distal procedures of the

upper extremity;


a transabdominal
plane catheter for inguinal or lower abdominal procedures;
a femoral catheter for

knee surgery


a popliteal-sciatic catheter for

foot/leg procedures.


For ultrasound-guided procedures, the term “long axis

used when the length of a nerve is within the ultrasound


For ultrasound-guided procedures “short axis”

when viewed in cross section.


in plane,”

A needle inserted with its length within a two dimensional
ultrasound beam


out of plane

a needle inserted across a two-dimensional ultrasound


multiple benefits of the needle in-plane, nerve
in short-axis approach

practitioners may learn
only one technique because it may be used for both single injection and catheter insertion procedures. it may be used for nearly all anatomic catheter locations, even for deeper target nerves.
If a 17- or 18-gauge needle
is used, the needle tip may be more-easily identified and
remains within the ultrasound plane due to its rigidity
compared with smaller gauge needles.


The potential benefits of
using a larger needle gauge

(fewer needle passes given the
relative ease of keeping a rigid, larger-gauge needle in plane; less risk of undesired tissue contact due to misinterpretation of the needle shaft for the needle tip) must be
weighed against the potential risks (increased patient
discomfort; increased tissue trauma; increased injury if a
vessel is punctured)


disadvantages of the needle in-plane, nerve in short-axis approach

new needle entry sites relative to the nerve compared
with more traditional nerve stimulation modalities
that typically use a parallel needle-to-nerve insertion; challenges keeping the needle shaft in-plane; difficult needle tip visualization for relatively deep nerves; and, as noted above, the catheter tip may bypass the target nerve given the perpendicular orientation of the needle and nerve.


Needle Out-of-Plane, Nerve in Short-Axis Approach: potential benefits

generally familiar parallel needle-to-nerve trajectory used
with traditional nerve stimulation techniques (and also vascular access); and because the needle is parallel to the target nerve, the catheter theoretically may remain in closer proximity to the nerve, even when threaded more than a centimeter past the needle tip


Needle Out-of-Plane, Nerve in Short-Axis Approach: disadvantage

the relative inability to
visualize the advancing needle tip, which some speculate increases the likelihood of unwanted contact with nerves, vessels, peritoneum, pleura, or even meninges


The majority of perineural infusion publications have involved

bupivacaine (0.1–0.25%) or ropivacaine (0.1–0.4%)


The main determinant of CPNB effects

local anesthetic concentration and volume or simply total drug dose. although there is evidence that for continuous posterior lumbar plexus blocks, local anesthetic concentration and volume do not influence nerve block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.


For procedures resulting in at least moderate postoperative

a basal infusion optimizes benefits such as analgesia
and sleep quality.


Providing patients with the ability to self-administer local anesthetic doses increases perioperative benefits such as

improving analgesia, minimizing supplemental opioids, and allowing a decreased basal infusion
rate which minimizes the risk of limb weakness and
maximizes the infusion duration for ambulatory patients with a finite local anesthetic infusion pump reservoir volume.


successful analgesia with CPNB using the following with

long-acting local
anesthetics: basal rate of 4 to 8 ml/hr, bolus volume of 2 to
5 ml, and lockout duration of 20 to 60 min


CPNB-related complications

Nerve injury is a recognized complication following
placement of both single-injection and CPNB, presumably related to needle trauma and/or subsequent local
anesthetic/adjuvant neurotoxicity


use of ultrasound decrease CPNB-related complications

the use of ultrasound will improve catheter insertion success rates Ultrasound also decreases other risks as well, such as vascular puncture (reported between 0% and 11% with nerve stimulation), perineuraxis catheter placement, as well as intravascular and intraneural
catheter insertion. Prolonged Horner’s syndrome due to neck hematoma is a rare complication


The most common complication during perineural infusion

simply inadvertent catheter dislodgement


Effort to optimally secure the catheter

Measures have included the use of sterile liquid adhesive
(e.g., benzoin), sterile tape (e.g., Steri-Strips), securing
of the catheter–hub connection with either tape or specifically designed devices (e.g., Statlock), subcutaneous
tunneling of the catheter and the use of 2-octyl
cyanoacrylate glue


occurring during infusion

phrenic nerve
block and ipsilateral diaphragm dysfunction during interscalene
CPNB, local anesthetic toxicity (incredibly rare),
and infection.


potential CPNB complications,

catheter knotting
(do not pass the catheter >5 cm past the needle tip), retention (with the Arrow Stimucath), and shearing (do not withdraw the catheter back into the needle unless the design
is approved for this maneuver).

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