brachial plexus block
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Brachial plexus blockDr.Indubala Maurya MD,DNBAssistant Professor Dept of Aanesthesia & Critical Care, MGMCRI
Indication of peripheral nerve blocks
Surgical procedurePostoperative pain relief Chronic pain management
Advantages /Disadvanges for Nerve blocksAdvantages :Can be formed in all age groupAvoid poly pharmacyEarly recovery /ambulationExcellent analgesia
Disadvantages:Difficult in obese Need expertise Specific complication associated with particular blockNerve injury( needle ?)Local anesthetic toxicity
ContraindicationsUncooperative patientBleeding diathesis( on anticoagulant, DIC,hemophilia)A hematoma --->risk of ischemic nerve damage (limb or digit ischemia)Infectionplacement of a catheter a nidus for infection. Peripheral neuropathy
Techniques for Localizing Neural Structures AIM : Correct positioning of the needle tip in the perineural sheath, prior to injection of local anesthetic
Fascial popsElicitation of paresthesias, Perivascular or Transarterial injection, Electrical stimulationDirect imaging Ultra Sonography Computed tomography
What is Electrical Nerve Stimulation? Low-intensity (up to 5 mA) , short-duration (0.05-1 ms) electrical stimulus (at 1-2 Hz repetition rate) to obtain a defined response (muscle twitch or sensation) to locate a peripheral nerve or nerve plexus with an (insulated) needle.The goal is to inject a certain amount of local anesthetic in close proximity to the nerve
Electrical nerve stimulation in regional anesthesia is a method of using a low-intensity (up to 5 mA) and short-duration (0.05-1 ms) electrical stimulus (at 1-2 Hz repetition rate) to obtain a defined response (muscle twitch or sensation) to locate a peripheral nerve or nerve plexus with an (insulated) needle. The goal is to inject a certain amount of local anesthetic in close proximity to the nerve to block nerve conduction and provide a sensory and motor block for surgery and/or, eventually, analgesia for pain management. The use of nerve stimulation can also help to avoid an intraneural intrafascicular injection and, consequently, nerve injury.
Electrical nerve stimulation can be used for a single-injection technique, as well as for guidance during the insertion of continuous nerve block catheters. More recently, ultrasound (US) guidance and, in particular, the so-called dual guidance technique in which both techniques (peripheral nerve stimulation [PNS] and US) are combined, has become a common practice in many institutions.
Patients PreparationPre Operative Assessment ( Document any neurological deficit, consent)Pre op fastingAspiration prophylaxisAnxiolysis & sedation Emergency drugs & Resuscitation equipments
CHOICE OF ANESTHETIC Local anesthetic drugs :Toxicity of the agent Cardiac toxicity CNS toxicityCharacteristics of individual local anesthetics such Time to onset Duration of actionDegree of sensory versus motor block
Additives: Morphine, Fentanyl, Clonidine, Epinephrine,Dexa
*CHOICE OF ANESTHETICLocal anesthetics are discussed elsewhere (see Chapter 14), but when performing a block, the anesthesiologist must weigh the toxicity of the agent to be used and the characteristics of individual local anesthetics such as time to onset and duration of action, degree of sensory versus motor block, and the cardiac toxicity of large volumes of local anesthetics delivered into the perineural sheath
Brachial plexus Blocks
*Successful regional anesthesia of the upper extremity requires knowledge of brachial plexus anatomy from its origin, where the nerves emerge from the intervertebral foramina, to its termination in the peripheral nerves. Detailed anatomic knowledge enables the anesthesiologist to choose the appropriate technique for the intended surgical procedure and to salvage inadequate blocks by supplementation with local anesthetic. Without mastery of the anatomy, luck rather than skill becomes the primary determinant of successful neural blockade. Also important is an understanding of the side effects and complications of upper extremity regional techniques, as well as the clinical application of available local anesthetics for these blocks. The role of appropriate sedation during placement of the block and during the surgical procedure should not be underestimated. Many a perfect regional anesthetic technique has been undone by inadequate management of sedation.
Brachial plexus Anatomy
Except for cutaneous supply to upper medial aspect of the arm and uppermost aspect of shoulder entire supply to the arm is by brachial plexus
The brachial plexus is derived from the anterior primary rami of the fifth, sixth, seventh, and eighth cervical nerves and the first thoracic nerve, with variable contributions from the fourth cervical and second thoracic nerves.
Between the scalene muscles, these nerve roots unite to form three trunks that emerge from the interscalene space to lie cephaloposterior to the subclavian artery as it courses along the upper surface of the first rib. The superior (C5 and C6), middle (C7), and inferior (C8 and T1) trunks are arranged accordingly and are not in a strict horizontal formation, as is often depicted.
At the lateral edge of the first rib, each trunk forms anterior and posterior divisions that pass posterior to the midportion of the clavicle to enter the axilla.
Within the axilla, these divisions form the lateral, posterior, and medial cords, named for their relationship with the second part of the axillary artery. The superior divisions from the superior and middle trunks form the lateral cord, the inferior divisions from all three trunks form the posterior cord, and the anterior division of the inferior trunk continues as the medial cord.
At the lateral border of the pectoralis minor, the three cords divide into the peripheral nerves of the upper extremity. The lateral cord gives rise to the lateral head of the median nerve and the musculocutaneous nerve; the medial cord gives rise to the medial head of the median nerve, as well as the ulnar, the medial antebrachial, and the medial brachial cutaneous nerves; and the posterior cord divides into the axillary and radial nerves Aside from branches from the cords that form the peripheral nerves as described, several branches arising from roots of the brachial plexus provide motor innervation to the rhomboid muscles (C5), the subclavian muscles (C5 and C6), and the serratus anterior muscle (C5, C6, and C7). The suprascapular nerve arises from C5 and C6; it supplies the muscles of the dorsal aspect of the scapula and makes a significant contribution to the sensory supply of the shoulder joint.*
RELATION WITH SCALENE MUSCLES
After leaving their intervertebral foramina, these nerves course anterolaterally and inferiorly to lie between the anterior and middle scalene muscles, which arise from the anterior and posterior tubercles of the cervical vertebra, respectively. The anterior scalene muscle passes caudad and laterally and inserts into the scalene tubercle of the first rib; the middle scalene muscle inserts on the first rib posterior to the subclavian artery, which passes between these two scalene muscles along the subclavian groove. The prevertebral fascia invests the anterior and middle scalene muscles and fuses laterally to enclose the brachial plexus in a fascial sheath.*
Relation with bone
Relation with Blood vessels
Relationships: vertebral A. travels cephalaud and enters bony canal ar C6.Ext. Jugular vein overlies the interscalene groove at C6. Over the first rib the divisions of B.P lie post., cephalaud and lat. To subclavain A. Axillary A. lies ant. To radial N., Postero medial to median nerve, Posterolateral to ulnar N.Cervical roots are just post. To vertebral A.
Various ApproachInterscaleneSupraclavicular Infraclavicular Axillary
Interscalene BP Block
Blockade occurs at the level of the upper and middle trunks. Although this approach can also be used for forearm and hand surgery, blockade of the inferior trunk (C8 through T1) is often incomplete and requires supplementation at the ulnar nerve for adequate surgical anesthesia in that distribution
In its course between the anterior and middle scalene muscles, the plexus is superior and posterior to the second and third parts of the subclavian artery. The dome of the pleura lies anteromedial to the inferior trunk
Surgery on or manipulation of the shoulderProximal Arm
Blockade occurs at the level of the upper and middle trunks. Although this approach can also be used for forearm and hand surgery, blockade of the inferior trunk (C8 through T1) is often incomplete and requires supplementation at the ulnar nerve for adequate surgical anesthesia in that distribution.[
Supraclavicular nerve c3-4------ upper most part of shoulderInntercostal T2 --- upper medial aspect of arm *
Interscalene Paresthesia/ NS Technique
This technique can be performed with the patient's arm in any position and is technically simple because of easy identification of the necessary landmarks. The patient should be in the supine position with the head turned away from the side to be blocked. The posterior border of the sternocleidomastoid muscle is readily palpated by having the patient briefly lift the head. The interscalene groove may 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. Although the external jugular vein often overlies this point