brachial block

UPPER LIMB BLOCKS

BRACHIAL PLEXUS BLOCK

• HISTORY – HALSTED 1884– HIRSCHEL AND KULENKAMPFF 1911

INDICATIONS

• General, Vascular, Neurological, Orthopedic surgeries on upper extremity

• Patient with reflex sympathetic dystrophy, causalgia, raynaud’s phenomenon offers benefit with sympathetic blockade

• diagnostic to help to determine whether pain is central or peripheral

• releive pain- post-operative, traumatic painful neuropathy

ADVANTAGES

• Anesthesia is limited to restricted portion of the body

• Patients with full stomach present less danger of aspiration

• Provides post-operative analgesia

• well suited for out-patient procedures

• vasodilation secondary to sympathetic blockade can benefit

• Complications of GA like post-operative nausea, vomiting reduced

• Early ambulation possible

• allows patients who dread losing consciousness to be awake

ANATOMY

• Brachial plexus supplies all of motor, and almost all sensory function of upper limb except

• skin over the shoulder - descending braches of cervical plexus

• posteromedial aspect of arm - intercostobrachial

Brachial Plexus

Netter 2nd ed

upper limb -

cutaneousinnervation

Netter 2nd ed

upper limb –

dermatomepattern

Netter 2nd ed

SUPRACLAVICULAR BLOCK

LAND MARKS

• Mid-point of clavicle

• first rib to prevent needle from passing medially and entering pleural dome

PROCEDURE• Pt placed in supine position , head turned to

opposite side, shoulder depressed downward and posteriorly (asking patient to touch knee)

• mark the clavicular head of SCM

• Interscalene groove marked by rolling finger back over the belly of anterior scalene

• subclavian artery pulse - confirms landmark

TECHNIQUE

• Under aseptic precautions, skin wheal raised at determined point

• A 22 gauge, 4 cm needle inserted through skin wheal in downward, inwards and posterior direction until paresthesia or motor response is elicited or first rib encountered (shaft of needle and syringe are parallel to patient’s head)

• Paresthesia is elicited, needle fixed and drug injected

• if paresthesia could not be elicited and first rib encountered, needle is walked anteriorly and posteriorly along the rib until plexus or subclavian artery is located

MODIFIED PLUMB-BOB APPROACH

• Similar patient positioning, needle inserted at point where lateral border of SCM inserts into clavicle

• 22 gauge 4cm needle inserted while mimicking plumb-bob suspended over the needle entry site.

• Paresthesia or motor response is elicited before contacting the rib or artery

• if not reinsert at cephalad or caudad angle

COMPLICATIONS

• Pneumothorax

• Phrenic nerve block

• Horner’s syndrome

• Nerve damage or neuritis

• Local anesthetic toxicity

CONTRAINDICATIONS

• Bilateral block required

• Patients with respiratory compromise

INTERSCALENE BLOCK

• Suitable when proximal block required

• Pneumothorax risk is reduced

• Landmarks clear even in stout patients

• But large volume required, lower trunk may be missed

TECHNIQUE

• Under sterile precautions, after raising skin wheal, 22 gauge needle inserted perpendicular to skin with 45deg caudad and slightly posterior angle

• paresthesia elicited or click detected as needle passes through prevertebral fascia

• if bone is encountered within 2cm- transverse process, needle walked across to locate nerve

COMPLICATIONS

• Inadvertant spinal or epidural blockade

• Ipsilateral phrenic nerve block- 100%

• Vertebral artery close proximity

• Vagus, recurrent laryngeal, cervical sympathetic nerve may be blocked

• Severe hypotension and bradycardia have been reported

AXILLARY BLOCK

• Block at level of terminal nerves

• excellent operating conditions for forearm and hand surgeries

• useful for children, safe

• but insufficient for shoulder or upper arm surgery

• musculocutaneous nerve missed

TECHNIQUE

• Position

• point of entry- needle inserted just superior to finger on axillary artery directing towards apex of axilla

• evidence of entering sheath sought by- feel of fascial click, paresthesia, trans-arterial technique, using nerve stimulator

• drug injected

Success rate depends on -

• digital pressure distal to needle during and after injection

• arm adducted and placed at patient’s side immediately after injecting

• Winnie recommends using immobile needle technique

COMPLICATIONS

• Haematoma

• local anesthetic toxicity

• intravascular injection - prevented by repeated aspirations, for early detection add epinephrine 5mcg/ml

INFRACLAVICULAR BLOCK

TECHNIQUE

• Pt in supine position, head turned to opposite side, arm abducted to 90 deg

• line drawn along entire length of clavicle (midpoint of clavicle marked)

• brachial artery marked high in axilla

• a line drawn from C-6 in neck across mid-point of clavicle & to trace brachial artery.

• after raising skin wheal at 2.5cm below the clavicle on chest wall, needle inserted directing laterally towards the line marked at 45 deg to skin

• Using nerve stimulator, nerve located and drug injected

• digital pressure in axilla encourages central flow of local anesthetic

USE OF NERVE STIMULATORS (NS)

• More accurate needle placement possible

• NS deliver pulses of current 0.1 - 1 mA

• connecting NS - anode attatched to ECG pad placed on opposite shoulder - cathode attatched to needle with alligator clip to hub

• needle advanced to skin, NS should not be turned on until target approached

• Once target approached NS delivers current. response noted and needle advanced to find point of maximum contractions with minimum current

• after needle properly positioned , test dose given, muscle contraction or paresthesia should be abolished and total dose administered