Regional III- Part 2-Peripheral nerve blocks

Regional III: Peripheral Nerve Blocks-Part II:

Regional III: Peripheral Nerve Blocks-Part II ANE: 623 Principles of Anesthesia II University of New England School of Nurse Anesthesia

Brachial Plexus Blockade:

Brachial Plexus Blockade Brachial plexus blockade anesthetizes various areas of the upper extremity. Injection into the fascial sheath surrounding the plexus allows LA to spread and block the C5-T1 nerve roots, but the degree of neural blockade will depend somewhat on the level of the injection.

Approaches to Brachial Plexus Blockade:

Approaches to Brachial Plexus Blockade Brachial Plexus Blocks: Interscalene Supraclavicular Infraclavicular Axillary The preferred approach to the plexus depends on the surgical site, the risk of complications and the experience of the individual anesthetist.

Interscalene Approach:

Interscalene Approach Blocks at the level of the roots/trunks and can impact the cervical plexus in addition to the brachial plexus, thereby anesthetizing the skin over the shoulder. Useful for shoulder and proximal humerus surgery. The ulnar nerve (inferior trunk) is frequently spared, so it is less useful for forearm and hand operations, unless accompanied by an ulnar nerve block.

Interscalene Approach:

Interscalene Approach The plexus runs between the anterior and middle scalene muscles at the level of transverse process of C6 (Chassaignac’s tubercle). External jugular vein often overrides this area.

Interscalene Approach:

Interscalene Approach Stimulation of the plexus will result in a paresthesia or muscle twitch in either the deltoid, biceps or pectoris major muscle. Activity of the phrenic nerve suggests needle is too anterior ; stimulation of trapezius muscle may indicate needle is too posterior .

Interscalene Approach:

Interscalene Approach A volume of 30-40 mL of LA solution is injected after needle positioned. Pressure distal to the injection site will promote proximal spread and the addition of a cervical plexus block. Proximal pressure to the injection site will encourage distal spread of the LA down the fascial sheath of the plexus

Interscalene: Side Effects amd Complications:

Interscalene: Side Effects amd Complications Ipsilateral phrenic nerve block often occurs and will result in diaphragmatic paresis, a 25% reduction in pulmonary function and subjective complaints of dyspnea. Caused by spread of solution over anterior scalene muscle. May cause respiratory compromise in patients with severe respiratory disease.

Interscalene: Side Effects amd Complications:

Interscalene: Side Effects amd Complications Risk of pneumothorax is remote when the needle is correctly placed at the C5 or C6 level because of the distance from the dome of the pleura. Should be considered if cough or chest pain occurs while exploring for the location of the brachial plexus.

Interscalene: Side Effects amd Complications:

Interscalene: Side Effects amd Complications High rate of incident blockade of stellate ganglion and recurrent laryngeal nerve with interscalene approach. Stellate ganglia blockade causes Horner’s syndrome (30-50%) with miosis, ptosis, and anhydrosis. RLN blockade (30-50%) causes hoarseness and vocal cord dysfunction.

Interscalene: Side Effects amd Complications:

Interscalene: Side Effects amd Complications Spinal or epidural injection of LA possible if needle passes too medially. Vertebral artery injection due to its close proximity of the injection site can rapidly produce central nervous system toxicity and convulsions. Venous injection can cause slower onset of CNS symptoms.

Supraclavicular Approach:

Supraclavicular Approach Anesthetizes the entire plexus due to its compact nature at the point of injection (three trunks compactly arranged) and the fact that none of the nerves have yet left the plexus. Provides rapid onset of excellent anesthesia for elbow, forearm and hand surgery.

Supraclavicular Approach:

Supraclavicular Approach Accomplished with patient in supine position with head turned to contralateral side. Techniques include parascalene, classic, and plumb-bob approaches.

Supraclavicular Approach:

Supraclavicular Approach The needle is advanced until a paresthesia is elicited or muscle contraction of the forearm is noted. 30-40 mL of LA is injected (1.5% mepivacaine for 2-3 hours of anesthesia or 0.5-0.75% ropivacaine for 4-7 hours).

Supraclavicular: Side Effects/ Complications:

Supraclavicular: Side Effects/ Complications A relatively high incidence of pneumothorax (1-6%) manifested as cough, dyspnea or pleuritic chest pain. Block of the phrenic nerve occurs frequently (50%) but general causes no clinically significant symptoms. Horner’s syndrome can occur also.

Infraclavicular Approach:

Infraclavicular Approach Provides good anesthesia to the brachial plexus and can be used for procedures involving the hand, forearm and elbow. Blockade of the cords of the brachial plexus occurs in the axilla, just distal to the clavicle.

Infraclavicular Approach:

Infraclavicular Approach Landmarks include the clavicle, the coracoid process and the chest wall. The needle path is remote from the lung and neuraxis.

Infraclavicular Approach:

Infraclavicular Approach Functionally, really a form of axillary block in which the needle enters the axilla through its anterior wall (pectoralis muscles) instead of through its base. Can be painful as it is a deep block that requires the needle to go through muscle.

Infraclavicular Approach:

Infraclavicular Approach An evoked motor response below the elbow is most consistent with a favorable spread of LA. Stimulation of the posterior cord gives a good indication of adequate placement with finger, hand and arm extension. Accepting activity of the musculocutaneous nerve (ie, biceps or brachialis twitch) may result in an unsatisfactory block.

Infraclavicular: Side Effects / Complications:

Infraclavicular: Side Effects / Complications Patient discomfort from pain of placing needle through pectoralis major and minor muscles requires adequate levels of sedation and LA infiltration along needle path. Risk of vascular puncture and/or injection due to proximity to structures.

Infraclavicular: Side Effects / Complications:

Infraclavicular: Side Effects / Complications Pneumothorax, hemothorax and chylothorax are possible. Infection, nerve injury, hematoma or failed block have been documented.

Axillary Approach:

Axillary Approach Best suited for surgery below the elbow. The needle approaches the plexus at the level of the terminal branches that lie in close proximity to the axillary artery. Musculocutaneous nerve has already exited the sheath and must be blocked separately.

Axillary Approach:

Axillary Approach May be accomplished by the use of a nerve stimulator, loss of resistance technique or with a transarterial approach.

Axillary Approach:

Axillary Approach End points of needle placement include: Hand twitch at 0.3-0.4 mA stimulation; Paresthesia of hand “Pop” when entering sheath with LOR Aspiration of arterial blood with transarterial approach.

Axillary Approach:

Axillary Approach Terminal nerves are more separated than in proximal locations and are enclosed in a fibrous, multicompartment sheath that can be an obstacle to the free flow of LA.

Axillary Approach:

Axillary Approach Larger volumes may be used (up to 50-60 mL) or multi-injections (2-3) to promote adequate spread.

Axillary: Side Effects / Complications:

Axillary: Side Effects / Complications Risk of intravascular injection, particularly if transarterial approach is used. Hematoma and infection are rare complications.

Assessment of Brachial Plexus Block:

Assessment of Brachial Plexus Block Terminal nerves of the brachial plexus can be assessed with the Four Ps mnemonic: Push, Pull, Pinch, Pinch. Four Ps Patient Action Nerve Checked Push Extend arms w/ triceps Radial Pull Flex arms with biceps Musculocutaneous Pinch Fifth digit Ulnar Pinch Index finger Median

Lower Extremity Blocks:

Lower Extremity Blocks Lower extremity nerve blocks can provide effective anesthesia and analgesia for procedures of the lower extremities. Anesthetizing the entire lower extremity requires blocking components of both the lumbar and sacral plexuses.

Lower Extremity Blocks:

Lower Extremity Blocks Considered technically more difficult because the nerves of the lower extremities are not anatomically clustered as in the brachial plexus and often require multiple injections. For many operations, it is easier to perform an epidural or spinal anesthetic than attempt the same extent of anesthetic with multiple peripheral nerve blocks.

Lower Extremity Blocks:

Lower Extremity Blocks May be useful when limited anesthesia is required, or when a regional technique is preferable, but a central neuraxial block is contraindicated.

Lumbar Plexus:

Lumbar Plexus Formed within the psoas muscle from the anterior rami of the L1-L4 spinal nerves, with a contribution from T12.

Lumbar Plexus:

Lumbar Plexus Cephalad nerves of the plexus are iliohypogastric, ilioinguinal and genitofemoral nerves. Caudal nerves of the plexus are lateral femoral cutaneous, femoral and obturator nerves.

Sacral Plexus:

Sacral Plexus The sacral plexus is formed from the anterior rami of the L4-L5 spinal nerves and S1-S3 nerves. The two major nerves of the sacral plexus are the sciatic nerve and the posterior cutaneous nerve of the thigh.

Lumbar Plexus vs. Sciatic Nerve:

Lumbar Plexus vs. Sciatic Nerve

Indications for Lumbar and Sacral Plexus Blocks:

Indications for Lumbar and Sacral Plexus Blocks Hip operations : require anesthesia of the entire lumbar plexus except ilioinguinal and iliohypogastric nerves. Major thigh operations (ie, placement of a femoral rod): Require anesthesia of lateral femoral cutaneous, femoral, obturator and sciatic nerves.

Indications for Lumbar and Sacral Plexus Blocks:

Indications for Lumbar and Sacral Plexus Blocks Tourniquet pain: Requires LFC and femoral nerve block. Open operations of the knee: LFC, femoral, obturator and sciatic nerves. Operations distal to the knee: Require sciatic nerve block and the saphenous component of the femoral nerve.

Femoral Nerve Catheters:

Femoral Nerve Catheters Used for intraoperative and postoperative analgesia in unilateral knee surgery.

Femoral Nerve Anatomy:

Femoral Nerve Anatomy Arises from lumbar segments L2-L4. Reaches the thigh by passing underneath the inguinal ligament just lateral to the femoral artery and vein.

Femoral Nerve :

Femoral Nerve Nerve is located with stimulator by twitches of the quadriceps muscle (patella movement). Important to enter both fascia lata and iliaca fascia (two “pops”) before injecting LA because current can cross layers but the solution may be deposited too superficially.

Femoral Nerve Catheter:

Femoral Nerve Catheter Catheter is advanced through needle 3- 5 cm beyond the needle tip. Syringe is aspirated before injection of an initial dose. Continuous infusion may be instituted with or without a patient-controlled dosing regimen.

Assessment of FNC:

Assessment of FNC May not cover posterior discomfort due to femoral nerve innervation. Supplementation with narcotics may be required. Quadriceps motor function should be assessed and dose reduced if motor weakness occurs. May remain in place from 24-72 hours.

FNC: Complications:

FNC: Complications Vascular puncture and intravascular injection. Hematoma Nerve injury

Ankle Blocks:

Ankle Blocks Five nerve branches to be blocked: Posterior tibial : sole/heel Saphenous : anterior/medial aspect of foot Deep peroneal : major nerve of dorsum of the foot and between great and 2nd toe Superficial peroneal : dorsum of foot Sural : lateral aspect of foot.

Ankle Block Anatomy:

Ankle Block Anatomy

Ankle Blocks:

Ankle Blocks Complete or partial block of the foot for procedures not requiring a tourniquet around the ankle. Provides good sensory and vasomotor blockage. No motor blockade.

Ankle Blocks:

Ankle Blocks Generally, infiltration is technique of choice without need for nerve stimulation or paresthesia. Requires 3-5 separate injections up to 20 mL of local anesthetic. Low complication rate. Neuropathy possible.

IV Regional Block:

IV Regional Block Also referred to as Bier block. Used for producing anesthesia of an extremity (arm or leg). Involves the injection of large volumes of dilute LA into an extremity after occlusion of circulation with a tourniquet.

IV Regional Block:

IV Regional Block Can be used for open soft tissue surgical procedures or closed reductions of bony fractures lasting less than 90 minutes. Duration of postoperative analgesia is limited, so not usually performed when postoperative pain is a significant issue.

Contraindications:

Contraindications Conditions which contraindicate use of a tourniquet: Sickle cell disease, infection, ischemic vascular disease. Pain limits the effectiveness of exsanguination of extremities with fractures. Traumatic lacerations may allow escape of LA from extremity.

IV Regional Block:

IV Regional Block Small IV catheter is placed in the distal portion of the extremity.

IV Regional Block:

IV Regional Block Extremity is exsanguinated with an Esmarch bandage and the tourniquet applied and inflated to 250 to 275 mmHg or 100 mmHg above patient’s SBP.

IV Regional Blocks:

IV Regional Blocks After exsanguination and application of the tourniquet, the extremity should appear extremely pale. A blotchy appearance after injection may indicate inadequate exsanguination with an inadequate block and surgical field.

Tourniquet Inflation:

Tourniquet Inflation A double tourniquet is often used to help reduce tourniquet pain. The proximal cuff is inflated first; when pain is subsequently experienced (usually within 45 minutes), the more distal cuff is inflated over the anesthetized skin and the proximal cuff then deflated.

IV Regional Block:

IV Regional Block Local anesthetic solution without epinephrine is injected into the distal IV (40-50 mL) and the IV removed. Lidocaine 0.5%, Ropivacaine have been used successfully. Onset of anesthesia takes place within 5 minutes.

Complications:

Complications A toxic reaction to LA is the major complication associated with IV regional anesthesia. May occur during injection if the tourniquet fails or after tourniquet deflation particularly if tourniquet time is less than 25 minutes.

Complications:

Complications If 40 minutes has elapsed, tourniquet can be deflated in a single maneuver. Between 20 and 40 minutes, can deflated and reinflated immediately and finally deflated after 1 minute. This reduces the peak plasma level of LA.

The end……..:

The end……..