ISAKanyakumari - Anaesthesia Practice in Kanyakumari District

BRACHIAL PLEXUS BLOCK WITH NERVE STIMULATOR

Supraclavicular Catheterisation Infraclavicular Catheterisation Classical Approach Axillary Approach Posterior Approach

Dr.R.Silamban(Asst. Professor)

Supraclavicular Catheterisation Part I

Supraclavicular Catheterisation Part II

Supraclavicular Catheterisation Part III

BRACHIAL PLEXUS BLOCK –SUPRACLAVICULAR APPROACH
Introduction:
Cornerstone of upper extremity of regional anaesthesia. It is used extensively in clinical practice. Various techniques of reaching the brachial plexus from the supraclavicular site are described. In this approach the drug is delivered at the level of the trunks which is the most compact part of the brachial plexus.

In any supraclavicular technique the chance of pneumothorax will always have to be kept in mind. The dome of the pleura is in close relationship to the convacity of the first rib. If the needle is introduced close to the lateral border of the clavicular head of the sternocleidomastoid as usual, the chance of pleural damage is high. In this technique which we are going to describe, the needle is introduced between the two scalene muscle which is a safe 1.5cm away from the dome of the pleura. It is always better to have a safe distance 1cm from the pleura.
Distrbution of consistent anaesthesia
It can be used for any upper extremity procedure from the shoulder to the fingers. Distal digital pressure makes the drug to rise up to the level of the roots and making surgery in the alteral half of the clavicle also possible.

Position:
Patient is supine, hands on the side, head turned to the opposite side.

Landmarks

Clavicle, lateral head of sternocleidomastoid, scalenus anterior and medius muscle, external jugular vein.
Site of needle entry

In the interscalene groove about 1.5 to 2 cm above the clavicle.


The patient is asked to lift his head up to make the lateral head of sternocleidomastoid prominent. After the lateral border of the sternocleidomastoid is identified, the fingers are slowly moved laterally to feel the anterior and medial scalene muscles and the groove between them is appreciated. A point 1.5 to 2cm above the clavicle is marked in the groove and a 5cm long needle with nerve locator attached is entered through the skin. The needle is directed towards the ipsilateral toe. The needle is advanced till a ‘pop off’ is felt signifying entry into the perivascular sheath. Now the nerve locator isswitched on at 1mA current. At this point muscle twitches are invariably seen. A current greater than 1mA may be uncomfortable to the patient. As the brachial plexus is in close proximity to the inferior surface of the scalene muscle, difficulty in nerve location does not occur. The current is slowly reduced -.2mA to get the desired response below 0.6mA. At this point the drug is given.
Motor response to nerve stimulation
The following motor responses are elicited and result in the same success rate.

	Pectoralis muscle twitch
	Deltoid muscle twitch
	Triceps muscle twitch
	Biceps muscle twitch
	Hand and forearm muscle twitch

Rhythmic movements of the shoulder, elbow, hands and fingers are seen. Form ideal results the twitches should be obtained at less than 0.6mA. Twitches of the neck muscles and movement of the scapula are not considered.

'The initial sign of supraclavicular blockade is loss of should abduction which occurs before sensory block’. Advantages

	Drug is delivered at the level of the trunks which is the most compact part of the brachial plexues. So success rates are high.
	Rapid onset
	Dense anaesthesia
	Predictable result
	As the needle is entered about 1.5cm above the calvicle, chance of phenumothraox are very rare.

INFRACLAVICULAR APPROACH
Infraclavicular Catheterisation


There are 2 approaches

	Raj infraclavicular block
	Lateral infraclavicular block

Position: It is the same for both approaches Patient supine, neck turned to opposite side, arm preferably in abduction. In cases where arm abduction is not possible it can be done in any position.
RAJINFRACLAVICULAR BLOCK
Landmarks:

	Acromioclavicular joint
	Sternoclavicular joint
	Midpoint of clavicle
	Sternoclavicular joint Brachial artery pulsations in the axilla

Distribution of consistent anaesthesia
The onset of predictable anaesthesia is at the hand, wrist, forearm, elbow and distal arm.


Site of Needle Entry

A point 2 to 2.5cm below the midpoint of the clavicle
Technique:
Mark acromioclavicular and stemoclavicular junction. The line joining the two points determines the length of the clavicle. Market the mid point of the line. Mark another point 2 to 2.5cm below the first point. This is the site of needle entry. A7.5cm insulated needle connected to a nerve locator is preferred. After skin infiltration with 2% xylocaine, the insulated needle is inserted at 45 degree angle into the skin and directed towards the axillary artery pulsations in the axilla. This maneuver directs the needle laterally posteriorly and slightly caudally. A initial current of 1.5 to 2mA is preferred. As the needle passes through the pectoralis muscle twitches can be seen due to direct stimulation of the muscle. Once the muscle is crossed the twitches cease. Now the current is reduced to 1mA and needle is advanced to get the nerve response. A lower current causes less patient discomfort and is preferred. The needle is directed in a cephalocaudal are to search for motor response. In thin individuals the response may be obtained at a depth of 3cm. In obese the response may be obtained at about 5-7.5cm.

Motor response: Flexion of the wrist and the fingers due to nerve stimulation is preferred. Stimulation of the radial and ulnar nerves leading to any movement in the region of forearm, wrist and fingers can be taken as the end point. Contraction of the deltoid and biceps are not acceptable as the axillary and musculocutaneous nerve leave the plexus at a higher level. For a successful blockade, response at a current less than 0.4mA is required. Response to higher current leads to unsuccessful and incomplete blockade.
LATERAL INFRACLAVICULAR BLOCK
This block was developed to present a more constant landmark, the coracoid process.

Landmark - Coracoid process

Position - Similar to Raj technique

Site of needle entry - 1cm medial and caudal to corocoid process

Technique:

The coracoid process of scapula is identified. Marked shrugging helps identify the coracoid process better. A point 1cm medial and 1cmcaudal to the medial aspect of coracoid process is marked. This is the point of needle entry. After skin infiltration with local anaesthetic the stimulation needle is inserted directly perpendicular to the skin. The usual depth of desired response is about 3cm in thin individuals but may vary upto 7.5cm in obese individuals. The needle size, motor response and eliciting parasthesia are similar to the Raj approach

Interpreting responses to nerve stimulation

There are some common responses that occur due to nerve stimulation. Then corrective measures will have to be taken to obtain the desired response.

Stimulation	Motor responses	Explanation	Corrective action
Pectrolis muscle direct stimulation	Arm abduction	Shallow needle placement	Continue to advance the needle
Axillary nerve	Deltoid muscle contraction	Needle placed inferiorly	Withdraw needle to the skin and reinsert with a superior angulation
Musculocutaneous nerve	Biceps twitch	Needle placed superiorily	Withdrfaw the needle to skin and reinsert with caudal angulation

Advantages

	Decreased incidence of lung injury and pneumothorax
	Decreased incidence of arterial injury
	Can be performed, with the hand in any position
	Ideal site for continuous catheter insertion
	More patient comfort after catheterization The chances of unilateral phrenic nerve blockade are nil. In the classical approach it is almost 100% and about 30-50% in the supraclavicular approach.
	The chances of unilateral phrenic nerve blockade are nil. In the classical approach it is almost 100% and about 30-50% in the supraclavicular approach.

Disadvantages:Test

	The plexus is deeply placed at this site. The pectoralis major and minor muscles will have to be pierced to reach the plexus. So, more painful to the patient
	As the plexus is deeply placed, blind approach is not possible. Eliciting paraesthesia is more difficult. So a nerve locator or ultrasound guidance becomes mandatory for performance of the block.
	Because of the above problem a more deep sedation may be required during performance of the block
	Surgeries on the shoulder and upper humerus cannot be done.

Potential Problems:

Complications are less when compared to classical and supraclavicular approaches. Pneumothorax and arterial puncture are possible and mostly related to a wrongly directed needle.

Despite adequate initial needle position, if the catheter is threaded too much it may be away from the plexus resulting the ineffective blockade.

Usage of a large volume of local of local anaesthetic may lead to systemic toxicity.

Torniquet application can be a problem as musculocutaneous nerve is not blocked.

AXILLARY RPPROACH

It is a very basic nerve block technique and very commonly employed. Here the durg is delivered within the perivascular sheath close to the axillary artery.

Distribution of consistent anaesthesia

This block provides anaesthesia of the lower part of arm, elbow, forearm, wrist and hand. As the musculocutaneous nerve leaves the plexus much before the site of needle entry, tourniquet pain is not abolished.

Position:

Patient is in supine position with head turned away from the side to be blocked. The arm is abducted and to form a 90 degree angle in the elbow. Excessive abduction makes palpation of axillary artery pulse difficult and also stretches and fixes the brachial plexus making it vulnerable to injury during needle placement.

Landmarks:

Axillary artery pulsation
Coracobrachalis muscles
Pectrolis major muscle

	The axildlary artery pulsation are best felt high in the axilla between the coracobrachalis and pectrolis major muscle.
	When location of the pulse is not immediately apparent, adduction of the arm decreases the resistance and makes the groove between the coracobrachalis and pectrolis major muscle prominent. This maneuver helps to identify the pulse better.

Technique:

One finger is kept on the axillary pulse and a 5cm needle is advanced justg below the pulse. In most patients motor response obtained at 2cm depth at about 1mA current. The needle tip is adjusted to get a motor response below 0.4mA and drug is injected.

Motor response

Twitches in the region of the wrist and fingers are indicators of successful blockade. Biceps and triceps twitch should not be considered.

Interpreting responses to nerve stimulation

Local twitche of arm muscle	Direct stimulation of biceps and triceps	Needle has been inserted for superior or inferiorly	Withdrawl the needle and direct
Needle contacts bone at 3cm	Needle stopped by humerus	Brachial plexus missed	Withdraw the needle to skin and reinsert at an angle of 15-30 degree superiorly or inferiorly

POSTERIOR APPROACH

A very rarely used approach. It is not performed in many centres. It does not some indication especially in a pain clinic setup.

Landmarks:C6 spine C7 spine

Position:

Can performed in sitting or lateral decubitus position

Distribution of consistent anaesthesia

Mainly around the shoulder upto the middle of the clavicle and upper arm. So this is useful in surgeries involving the clavicle, shoulder and upper arm.

Site of needle entry

A point 3cm lateral to the midpoint of C6 and C7 spine

Technique

In the sitting position C6 and C7 spine are identified. A point 3cm lateral to the midpoint of the spine is the site of needle entry. The needle entered perpendicular to the floor and directed slightly laterally. The depth at which stimulus is obtained is between 4-6cm. A nerve locator starting with a current strength of 3.5mA is connected to the needle. Response to nerve stimulation is mainly movement of the shoulder muscles. If response is obtained at a current of 0.4mA, drug can be given.

Indication

Mainly surgeries on the clavicle shoulder and upper arm For relief of severe pain due to apical lung cancer inadvertently infiltrating the brachial plexus.

Disadvantage

	As it is deeply placed it is a painful procedure
	Surgeries on the forearm, wrist and fingers cannot be done
	Chances of neuraxial catheter placement and blockade are high

CONTINUOUS CATHETRIZATION

Catheterization of the brachial plexus for postoperative pain relief is becoming increasing popular nowadays. It is one of the best modality of pain relief. Routinely catheters can be kept for upto 5 days in the postoperative period. Daily cleaning and dressing of the catheter entry site is a must.

These cathetes are similar to the epidural catheters with markings. They are about 30cm in length. The catheters are placed about 3cms past needle tip. If placed more the chances of moving away from the plexus may arise.

The catheter can be usedfor intermittent or continuous drug administration. PCA pumps can also be attached.

PHARMACOLOGY

The drugs used for anaesthesia are

	Lignocaine 2% with adrenaline
	Bupivacaine 0.5%
	The addition of opioids to the local anaesthetic ensures a more intense pain relief

Opioids commonly used are

	Fentanyl
	Sufentanyl
	Marphine

For anaesthesia a minimum volume of 30ml is required for a successful blockade. The above drugs can be mixed judiciously taking care not to exceed the toxic dose.

POSTOPERATIVE PAIN RELIEF

Bupivacaine is the peferred drug. As Lignocaine causes tachyphylaxis it is not preferred. It is also better to combine local anaesthetic along with opoids.

The advantages of combining local anesthetics with opioids are

	Superior postoperative analgesia
	Decreased dose and concentration of local anaesthetic
	Prolongs the duration of action of local anaesthetic

Intermittent administration:

25ml of 0.125% bupivacaine along with 50mcg of Fentanyl is given 8th hourly.

Continuous administration

10ml/hr of a solution containing 0.125% bupivacaine along with 10-20mcg/hr of Fentanyl is given

Doses of various opioids that can be used.

Opioids	Intermittent	Infusion
Fentanyl	50-100 mcg	10-25 mcg/hr
Sufentanyl	10-50mcg	10-20mcg/hr
Morphine	1-5 mg	0.1 – 1 mg/hr
Buprinorphine	2-3 mcg/kg	0.1 – 1 mg/hr

Break through pain

This is managed by giving a bolus of 5ml of local anaesthetic every 2 hours. Then the infusion can be reduced to 7.5ml/hr. Increasing the infusion rate or concentration of the local anaesthetic has not effect on breakthrough pain.

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