Peripheral Nerve Blocks: A Color Atlas, 3rd Edition

26. Continuous Brachial Plexus Nerve Block

A. Continuous Interscalene Block

Stephen M. Klein

Charles Pham Dang

Terese T. Horlocker

Andre P. Boezaart

1. Classic Approach

Patient Position: Supine, with head and neck slightly rotated to the opposite side. The arm and shoulder are placed caudad (toward the feet) to widen the space between the neck and shoulder.

Indications: Anesthesia and postoperative analgesia of the shoulder, biceps, and humerus surgery.

Needle Size and Catheter: 18-gauge, 38-mm insulated Tuohy needle and 20- or 21-gauge catheter.

Volume and Infusion rate: 30 to 40 mL initially 0.5% ropivacaine, followed by either a continuous infusion of 8 to 10 mL/hour or a patient-controlled infusion of 0.2% ropivacaine (5 mL/hour basal, 3 to 4 mL bolus, with a lockout period of 20 minutes).

Anatomic Landmarks: The sternocleidomastoid (SCM) muscle, the clavicle, and the anterior and middle scalene muscles as well as the cricothyroid membrane (C6).

Approach and Technique: With the head and neck rotated to the opposite side, the patient is asked to lift the head slightly off the bed (contracting and accentuating the SCM muscle). The lateral border of the SCM muscle is identified and marked. Next, two fingers are placed on the posterior edge of the muscle, and the patient is asked to relax the neck.

The fingers are gently slid posteriorly and the first bandlike muscle is the anterior scalene muscle. The next muscle is the middle scalene muscle. The interscalene groove is marked. The site of needle introduction is the intersection between the horizontal line drawn at the level of the cricothyroid membrane and the interscalene groove. The insulated Tuohy needle connected to a nerve stimulator (1.5 mA, 2 Hz, 0.1 ms) with the bevel oriented to the axilla is introduced through the skin and directed medially, slightly caudad, and posterior (Fig. 26-1A) at approximately 30° to the skin. As the needle punctures the fascia, there is a subtle “click” and sudden motor movement, which helps confirm proper placement. The position of the needle is adjusted to produce a motor response distal to the shoulder, which is maintained with a current less than 0.5 mA. After negative aspiration for blood, the local anesthetic is slowly injected with repeated aspiration for blood. Maintaining the introducer-insulated needle in the same position, the catheter is threaded 3 to 5 cm beyond the needle tip. The introducer needle is removed, and the catheter is secured in place with Steri-Strip (3M, St. Paul, MN) and covered with a transparent dressing (Fig. 26-1B).

Figure 26-1. Interscalene block—classic approach.

Tips

1.   To increase operator steadiness, the bed may be raised to chest height with the operator's forearms resting on the bed.

2.   The introducer needle should be manipulated cautiously.

3.   The interscalene groove is subtle and narrow. It should not be confused with the groove between the SCM muscle and the anterior scalene muscle.

4.   A pre-hole with a sharp 18-gauge needle helps reduce pressure on the neck while introducing the dull insulated Tuohy needle.

5.   Avoid aggressive searching with the 18-gauge needle. If necessary, find the plexus first with a 22-gauge insulated needle.

6.   Seek a stimulus distal to the shoulder with the lowest achievable current (<0.5 mA).

7.   If a deltoid stimulus is obtained, this may be acceptable, but make sure it is not pectoralis or suprascapular stimulation, since these nerves usually have already separated from the main plexus.

8.   Phrenic stimulation (diaphragm contraction) indicates that the needle is >1 cm too far anterior.

9.   A pectoralis muscle stimulation indicates that the needle is slightly (<0.5 cm) anterior.

10.       A suprascapular muscle (posterior shoulder) stimulation suggests that the needle is slightly (<0.5 cm) posterior.

11.       If subtle redirection produces constant anterior/posterior stimulus but not arm movement, consider moving the entry point caudad.

12.       There is slight resistance as the catheter passes the needle tip, but afterward it should pass easily. After 3 to 4 cm in the sheath, resistance is typically encountered. Gradually withdraw the needle and advance the catheter another 3 to 4 cm in the subcutaneous tissue. This tunnels the catheter and helps secure it.

13.       Careful attention should be paid to securing the catheter. Subcutaneous tunneling is helpful.

Suggested Readings

Borgeat A, Tewes E, Biasca N, et al. Patient-controlled interscalene analgesia with ropivacaine after major shoulder surgery: PCIA vs PCA. Br J Anaesth 1998;81:603–605.

Lierz P, Schroegendorfer K, Choi S, et al. Continuous blockade of both brachial plexus with ropivacaine in phantom pain. Pain 1998;78:135–137.

Singelyn F, Seguy S, Gouverneur J. Interscalene brachial plexus analgesia after open shoulder surgery: continuous versus patient-controlled infusion. Anesth Analg 1999;89:1216–1220.

Tuominen M, Haasio J, Hekali R, et al. Continuous interscalene brachial plexus block: clinical efficacy, technical problems and bupivacaine plasma concentrations. Acta Anaesthesiol Scand 1989;33:84–88.

Winnie AP. Plexus anesthesia: perivascular techniques of brachial plexus block. Philadelphia: WB Saunders Co, 1993.

2. Intersternocleidomastoid Approach

Patient Position: Supine, with the head slightly turned away, and with the hand placed on the abdomen.

Operator Position: Stand next to the patient's head, opposite the side to be blocked.

Indications: Anesthesia, postoperative analgesia for shoulder surgery, and active physical therapy.

Needle Size and Catheter: 18-gauge, 50- to 100-mm (depending on the size of the neck) insulated introducer catheter needle and 20- or 21-gauge catheter.

Volume and Infusion Rate: 30 to 40 mL initially 0.5% ropivacaine, followed by either a continuous infusion of 8 to 10 mL/hour or a patient-controlled infusion of 0.2% ropivacaine (5 mL/hour basal, 3 to 4 mL bolus, with a lockout period of 20 minutes).

Anatomic Landmarks: The sternal and clavicular heads of the SCM, the midclavicle, and the superior border of the chest wall.

Approach and Technique: The sternal and clavicular heads of the SCM as well as the midclavicle are located and marked. The puncture site is situated one fingerbreadth above the clavicle, between the heads of the SCM, medial to the clavicular head. Next, the puncture site is pre-incised with an 18-gauge needle to facilitate the penetration of the introducer needle or catheter (Fig. 26-2A). The introducer needle connected to a nerve stimulator (2 mA, 2 Hz, 0.1 ms) is introduced, initially at a 45° angle from the table plane and 15° from (almost parallel to) the posterior border of the clavicular head of the SCM and advanced laterally, posteriorly, and caudally aiming at a point 1 cm posterior to the midclavicle. This initial orientation leads to stimulation of the lateral border of the superior trunk (Fig. 26-2B) which is lateral to the rest of the brachial plexus and produces glenohumeral coaptation and contraction of the supraspinatus muscle. From this initial position lateral to the brachial plexus, the needle can be slightly walked medially and inferiorly to seek for stimulation of the middle trunk. The following motor responses help identify which part of the brachial plexus is being stimulated:

Figure 26-2. Intersternocleidomastoid approach.

· The superior trunk frontally—contraction of the biceps brachii muscle with elbow flexion.

· The superior trunk medially—contraction of the deltoid with abduction of the arm.

· The middle trunk—contraction of the triceps and elbow extension.

· The inferior trunk frontally—contraction of the pectoralis major muscle, ulnar inclination of the wrist, and flexion of the fourth and fifth fingers.

After appropriate positioning of the needle allowing the same motor response to be maintained with a current less than 0.5 to 0.6 mA, and after negative aspiration for blood, the local anesthetic solution is injected slowly, 5 mL at a time, with aspiration in between.

The catheter is introduced 2 to 3 cm beyond the tip of the introducer needle. The introducing cannula is removed, and the catheter is secured in place with Steri-Strip and covered with a transparent dressing.

Tips

1.   In the intersternocleidomastoid block, the brachial plexus can be reached at the level of the superior, middle, or inferior trunk when the needle is directed into the supraclavicular area. The brachial plexus will be contacted at a depth varying from 3 to 8 cm, depending on needle direction and the size of the patient.

2.   Catheter insertion seems to be easier following stimulation of the middle trunk than following stimulation of the superior trunk.

3.   This approach minimizes the risk for inadvertent spinal injection of anesthetics and pleural puncture.

4.   This approach does not require tunneling the catheter because it approaches the brachial plexus from a distance.

5.   The rotation of the neck should be moderate to avoid distortion of the anatomic landmarks, particularly in patients with long necks.

6.   The presence of fat may obscure the SCM triangle. Asking the patient to elevate the head and breathe deeply allows easier palpation of the muscles.

7.   Compressing the SCM triangle above the clavicle with the forefinger helps to determine the puncture site, raise the clavicular head of the SCM, and facilitate the passage of the needle behind the clavicular head.

8.   To prevent misdirection of the needle, which may result in pleural puncture, it is recommended to mark the superior border of the chest wall, and keep the needle lateral and away from the dome of the pleura.

9.   To avoid a puncture of the internal jugular vein, especially during the local infiltration, the needle should be directed in the same direction as described in the intersternocleidomastoid technique. Such an infiltration provides more comfort during insertion of the introducer needle.

10.       The introducer needle may transmit an arterial pulsation, indicating proximity to the subclavian artery. In this case, the needle is withdrawn and directed slightly more posterior to prevent puncture of the subclavian artery.

11.       To minimize the risk for associated diaphragmatic palsy, the tip of the catheter should be placed in an infraclavicular position.

12.       Movements of the abdomen (contraction of the diaphragm) can be seen in response to stimulation of the phrenic nerve. Since the phrenic nerve is anterior to the scalene muscle and medial to the brachial plexus, these stimulations require withdrawal and redirection of the needle.

13.       The position of the catheter can be controlled radiologically before starting the infusion. The use of a stimulating catheter may also increase the likelihood of an appropriate placement.

14.       Complications of these techniques include the risk for internal jugular puncture (during local anesthesia of the region) and subclavian artery puncture (in the case of misdirection of the needle), pleural puncture (misdirection of the needle), associated diaphragmatic palsy, Horner syndrome (uncomfortable for the patient), and recurrent laryngeal nerve palsy due to catheter misplacement.

Suggested Readings

Carter C, Mayfield JB. Evaluation of a new supraclavicular brachial plexus catheter technique for shoulder surgery anesthesia and analgesia. Anesthesiology 2000;93:A849.

Enneking K. How do I do … brachial plexus intersternocleidomastoid approach. ASRA Newsletter 2001(Nov):2–3.

Petitfaux F, Pham Dang C, Dupas B, et al. Diaphragmatic excursion after intersternocleidomastoid block depending on the site injection. Ann Fr Anesth Reanim 2000;19:517–522.

Pham Dang C, Gunst JP, Gouin F, et al. A novel supraclavicular approach to brachial plexus block. Analg Anesth 1997;85:111–116.

Pham Dang C, Kick O, Bérard L, et al. Motor response characteristics to neurostimulation of supraclavicular brachial plexus. Anesthesiology 2001;95:A943.

3. Parascalene Approach

Patient Position: Supine, with head slightly turned to opposite side.

Indications: Shoulder surgery, including arthroscopic procedures. Continuous interscalene infusions are typically used to allow aggressive postoperative physical therapy and to maintain joint range of motion.

Needle Size and Catheter: 18-gauge, 44.5-mm catheter over 20-gauge short-bevel introducer needle, and a 20- or 21-gauge catheter.

Volume and Infusion Rate: 20 mL 0.5% ropivacaine followed by continuous infusion at the rate of 8 to 14 mL/hour 0.2% ropivacaine starting within 1 hour of loading. A patient-controlled analgesic technique for continuous interscalene block has also been described.

Anatomic Landmarks: SCM muscle and interscalene groove. The patient is positioned supine with the head turned to the contralateral side. The interscalene groove is located by rolling the index finger laterally across the belly of the anterior scalene muscle to determine the groove between the anterior and middle scalene muscles. The needle insertion site is high in the interscalene groove, at the level of C6.

Approach and Technique: The modified perivascular technique allows easy catheter advancement because the needle approach is parallel to the brachial plexus sheath. However, the clinician must be able to visualize the nerves of the brachial plexus as they travel from the cervical foramen, through the interscalene groove, and posteriorly to the midpoint of the clavicle, where they form terminal nerves at the level of the axilla. The needle is inserted high in the interscalene groove and advanced parallel to the long axis of the body. A paresthesia or nerve stimulator response usually occurs at a depth of approximately 2.5 cm (Fig. 26-3). The catheter is advanced 5 cm into the sheath. The introducer needle is removed, and the catheter is secured in place with Steri-Strip and covered with a transparent dressing.

If the brachial plexus is not identified, the needle should be redirected laterally in small steps.

Tips

1.   A marked rotation of the patient's head results in distortion of the anatomic landmarks and relationships.

2.   Continuous interscalene block is best suited for shoulder surgery. High volumes of local anesthetic are required to reliably block the elbow, forearm, or hand.

3.   Accurate identification of the interscalene groove is essential to both single-injection and continuous interscalene techniques. Do not be confused by the groove between the SCM and anterior scalene muscles. If the correct groove has been identified, the pulsation of the subclavian artery may be palpated.

Figure 26-3. Parascalene approach.

4.   Continuous catheter techniques often use large-gauge, blunt needles. Generous subcutaneous infiltration of local anesthetic increases patient comfort.

5.   A shallow angle of needle insertion, with an approach parallel to the brachial plexus sheath, facilitates catheter placement.

6.   An alternate classic approach to the perivascular technique uses a needle insertion angle and site identical to those with the single-dose interscalene block. (The needle is directed perpendicular to the skin, with a slightly caudal and posterior angulation.) However, catheter advancement may be difficult because the needle approaches the brachial plexus at a right angle, forcing the catheter to turn 90°. Proximal advancement may result in cannulation of the epidural or intrathecal spaces.

7.   The brachial plexus is near significant vascular and neural structures at the interscalene level. Meticulous regional technique must be used to avoid subarachnoid, epidural, and intravascular injection and cannulation.

8.   Although there is a possibility of pneumothorax with the perivascular approach, this complication may be avoided by limiting the depth of needle insertion.

9.   Phrenic nerve paralysis should be expected in all patients with a continuous interscalene infusion. Concentrations as low as 0.125% bupivacaine still result in a significant decrease in diaphragmatic motion and ventilatory function, which persists for the duration of the block.

10.       This technique should not be used in patients who are unable to tolerate a 25% reduction in pulmonary function.

11.       The high mobility of the cervical spine makes catheter dislodgment a common complaint. The perivascular approach allows catheter advancement of 5 to 10 cm, whereas only 2 to 3 cm may be possible with the classic approach. The improved catheter placement with the perivascular technique makes it the superior approach.

12.       The stiff tip of the indwelling catheter combined with cervical and upper extremity movement may result in plexus irritation. Patients should be observed for new (nonsurgical) pain or neurologic complaints.

Suggested Readings

Borgeat A, Schappi B, Biasca N, et al. Patient-controlled analgesia after major shoulder surgery. Anesthesiology 1997;87:1343–1347.

DeKrey JA, Schroeder CF, Buechel DR. Continuous brachial plexus block. Anesthesiology 1969;30:332.

Pere P. The effect of continuous interscalene brachial plexus block with 0.125% bupivacaine plus fentanyl on diaphragmatic motility and ventilatory function. Reg Anesth 1993;18:93–97.

Ribeiro FC, Georgousis H, Bertram R, et al. Plexus irritation caused by interscalene brachial plexus catheter for shoulder surgery. Anesth Analg 1996;82:870–872.

Tuominen M, Haasio J, Hekali R, et al. Continuous interscalene brachial plexus block: clinical efficacy, technical problems and bupivacaine plasma concentrations. Acta Anaesthesiol Scand 1989;33:84–88.

Winnie AP, Collins VJ. The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology 1964;25:353–363.

4. Paravertebral Approach (Posterior Approach)

Patient Position: Sitting, with the head slightly flexed forward.

Indications: Anesthesia and postoperative analgesia following shoulder surgery.

Needle Size and Catheter: A 17-gauge Tuohy needle, a 19-gauge catheter with a steel spring conducting electrical impulses to its distal uncovered end (a “stimulating catheter”), and a loss-of-resistance syringe.

Volume and Infusion Rate: 30 to 40 mL 0.5% ropivacaine, followed by either a continuous infusion of 8 to 10 mL/hour or a patient-controlled infusion of 0.2% ropivacaine (5 mL/hour basal, 3 to 4 mL bolus, with a lockout period of 20 minutes).

Anatomic Landmarks: The brachial plexus (BP), the anterior (AS) and middle (MS) scalene muscles, the vertebral artery (VA) guarded by the bony structures of the vertebrae, the trapezius muscle (TM) and levator scapulae muscles (SM), the phrenic nerve (PN), the internal jugular vein (IJV), the carotid artery (CA), and the trachea (T) (Fig. 26-4).

Approach and Technique: The lateral border of the trapezius muscle and the medial border of the levator scapula muscles are located and marked. The site of Tuohy needle introduction is located immediately superior to the apex of the “V” formed by the intersection between the lateral border of the trapezius muscle and the medial border of the levator scapula muscle (Fig. 26-5). The insulated introducer Tuohy needle, with the bevel oriented laterally and connected to a nerve stimulator (1.5 mA, 2 Hz, 0.2 ms) and to a loss-of-resistance syringe, is introduced through the skin in an anterior, slightly caudal, and medial direction toward the suprasternal notch until contact is made with the transverse process of C6. Next, the needle stylet is removed and replaced with a syringe (loss-of-resistance device) containing 2 to 3 mL air. The needle is then walked laterally off the transverse process and slowly advanced anteroinferiorly (Fig. 26-6A). When the needle enters the cervical paravertebral space, there will be a sudden loss of resistance to air followed immediately by a stimulation of the brachial plexus resulting in related muscle responses. Next, the nerve stimulator is disconnected from the introducing Tuohy insulated needle and connected to the stimulating catheter. The stimulating catheter is introduced into the Tuohy needle, which results in a motor response similar to the one initially obtained with the introducer needle (Fig. 26-6B). The catheter is then gradually advanced beyond the needle tip by 3 to 5 cm. After negative blood aspiration, the local anesthetic solution is injected slowly with repeat negative blood aspiration every 5 mL (Fig. 26-7A).

Figure 26-4. Anatomic landmarks for paravertebral approach.

Figure 26-5. The site of the Tuohy needle introduction is located immediately superior to the apex of the “V” formed by the intersection between the lateral border of the trapezius muscle and the medial border of the levator scapula muscle.

Figure 26-6. A: The needle is then walked laterally off the transverse process and slowly advanced anteroinferiorly. B: The stimulating catheter is introduced into the Tuohy needle, which results in a motor response similar to the one initially obtained with the introducer needle.

After the injection, the catheter is tunneled posteriorly (Fig. 26-7B). The catheter is secured in place with Steri-Strip and covered with a transparent dressing.

Tips

1.   This block can also be performed with the patient in the lateral decubitus position.

2.   The catheter should always be withdrawn entirely into the needle before the needle is repositioned. Catheter withdrawal should be done carefully to prevent damage to the catheter.

3.   The presence of significant paresthesia during catheter advancement should be carefully evaluated before advancing the catheter.

Figure 26-7. A: The local anesthetic solution is injected slowly with repeat negative blood aspiration every 5 mL. B: The catheter is tunneled posteriorly.

4.   Conditions such as existing brachial plexitis or pre- or subclinical complex regional pain syndromes should be specifically documented before any brachial plexus block is administered. Patients with bona fide shoulder joint pathology present with shoulder pain but very infrequently with pain distal to the elbow. Pain distal to the elbow is usually an indication of a neurologic condition.

5.   Be suspicious of intraperineural needle or catheter placement if brisk muscle twitches are present with nerve stimulator settings less than 0.2 mA (except in children).

6.   This block is almost always associated with a Horner syndrome. Reassurance of patients is all that is required if this syndrome occurs.

Suggested Readings

Boezaart AP, Berry AR, Nell ML, et al. A comparison of propofol and remifentanil for sedation and limitation of movement during peri-retrobulbar block. J Clin Anesth 2001;13:422–426.

Boezaart AP, de Beer JF, du Toit C, et al. A new technique of continuous interscalene nerve block. Can J Anesth 1999;46:275–281.

Pippa P, Cominelli E, Marinelli C, et al. Brachial plexus block using the posterior approach. Eur J Anaesthesiol 1990;7:411–420.

B. Continuous Infraclavicular Block

Alain Borgeat

Indications: Continuous infraclavicular blocks are indicated for surgery of the forearm, wrist, hand, and distal part of the humerus because it covers all sensory territories of the distal part of the upper limb with only one puncture.

Patient Position: The patient lays supine with the head turned to the side opposite to that on which the block is to be performed. The relevant shoulder is depressed and the arm abducted approximately 45° from the chest wall.

1. The Coracoid Approach of Whiffler

Anatomic Landmarks: The main anatomic landmark is the coracoid process of the scapula. From the center of the coracoid process mark a point that is exactly 2 cm caudal and 1 cm medial as per Whiffler or 2 cm medial as per Wilson. This point represents the site of introduction of the needle.

Approach and Technique: The direction of the puncture is oriented toward the patient's axilla and the long axis of the needle perpendicular to the gurney in all planes. Directing the needle tip out of the paramedian sagittal plane must be avoided because it increases the risk of pneumothorax.

2. The Modified Approach of the Raj Technique

Anatomic Landmarks: A point bisecting a line joining the ventral acromial process of the scapula (lateral landmark) and the incisura jugularis sternii (medial landmark) is marked. To identify these landmarks, the patient lies supine with the arm in a neutral position along the body. The point of emergence of the axillary artery at the fossa axillary is next identified.

Patient Position: To perform the block, the patient's head is slightly turned away from the arm to be anesthetized, the arm being abducted to 90° and elevated by approximately 30°.

Approach and Technique: The whole length of the clavicle is marked after palpation. A skin wheal is raised 1 cm caudal below the inferior border of the clavicle at its central point. The needle is directed laterally between 45° and 60° to the skin toward the emergence of the axillary artery in the fossa axillary as close as possible to the lateral border of the pectoralis major muscle.

Stimulation-Modus

All infraclavicular blocks are performed with a standardized procedure by using a nerve stimulator, connected to a cannula over the needle. Start with a modus of stimulation from 1.4 mA current and an impulse duration of 0.1 ms. The placement of the needle is successful when a muscle distal to the deltoid is stimulated with a threshold intensity of the current ≤0.3 mA and an impulse duration of 0.1 ms. The aim is to elicit a distal response of the hand to predict a successful infraclavicular block (flexion or extension of the fingers or the wrist, for example flexor carpi radialis or ulnaris). The best response is finger or wrist extension (posterior cord stimulation).

Catheter Placement

In the case of the Whiffler approach the needle is introduced perpendicular to the cord, while with the modified approach of the Raj the direction of the needle is tangential to the cords, leading to an easier catheter placement. For the catheter placement, the cannula over needle technique is used with a plastic cannula and a catheter with a stylet. The catheter is threaded no more than 2 to 3 cm distal to the end of the cannula. After subcutaneous tunneling, the catheter is fixed with adhesive tape.

1.   After identification of the landmarks—the central point between the ventral acromial process of the scapula and the incisura jugularis sternii—the skin is extensively disinfected and the puncture point is surrounded by an aseptic “cover” (Figs. 26-8, 26-9).

2.   Insert the needle at an angle between 60° and 70° to the skin toward the emergence of the axillary artery in the fossa axillary with an initial nerve stimulation intensity of 1.4 mA, an impulse duration of 0.1ms, and frequency of stimulation of 2 Hz. The first motion elicited often results from direct stimulation of the major and minor pectoral muscles. The needle must be advanced further in order to elicit a good distal answer of the hand (Fig. 26-9).

3.   Decrease the stimulation intensity from 1.4 mA to 0.6 mA, always maintaining a good muscle response, or “twitch.”

4.   When 0.6 mA is achieved, insert the cannula over the needle. When the cannula is inserted until the marked point of the needle is reached, it means that the tip of the cannula coincides with the tip of the needle. Continue to reduce the stimulation intensity to 0.3 to 0.2 mA, looking for the minimal current able to elicit a twitch.

5.   Withdraw the needle, hold the cannula and insert the catheter (resistance may be sometimes felt at the beginning of catheter insertion) (Fig. 26-10).

6.   After catheter placement, withdraw carefully the cannula over the catheter. The aim is to position the tip of the catheter 2 to 3 cm distal to the end of the cannula (e.g., if the depth of the nerve is 5 cm, catheter discharge from the skin is 7 cm).

Figure 26-8. Anatomic landmarks.

7. 

8.  

Figure 26-9. The needle must be advanced further to elicit a good distal answer of the hand.

Figure 26-10. Withdraw the needle, hold the cannula, and insert the catheter.

9.   

10.      

Figure 26-11. Subcutaneous tunneling to secure the catheter against dislocation with an I.V. 18-gauge catheter.

11.       Subcutaneous tunneling to secure the catheter against dislocation with an I.V. 18-gauge catheter (Fig. 26-11).

12.       Drug application: LA application should follow the basic safety rules: slow administration with repeated aspiration—every 5 ml. The administration of the first 2 to 3 mL are crucial. They must be given very slowly. At the same time, the patient should be asked about pain level and special attention should be paid to any resistance when administrating the local anesthetic.

13.       At the end of the procedure disinfect the point of puncture and the exit of the tunnel with antiseptic and fix the catheter with moisture-responsive cannula dressing (Fig. 26-12).

Local anesthetics/dosage

If general anesthesia is not part of the anesthetic procedure a complete block of the brachial plexus with good muscular relaxation is necessary. To achieve this aim, an initial bolus of 40 mL ropivacaine 0.5% over the catheter is recommended. The onset time with ropivacaine 0.5% is on average 15 to 30 minutes.

Postoperative analgesia:

· First 24 hours: 0.3% ropivacaine with patient-controlled analgesia (PCA). (Standard dosage is 8 mL ground infusion, 5 mL bolus, lockout time 20 minutes.)

· Afterwards: 0.2% ropivacaine with the same standard-dosage PCA.

If general anesthesia is part of the anesthetic procedure (combined regional and general anesthesia), an initial bolus of 20 to 30 mL ropivacaine 0.5% is sufficient.

 

Figure 26-12. Disinfect the point of the puncture and the exit of the tunnel with antiseptic and fix the catheter with moisture-responsive cannula dressing.

The surgeon may wish to check the neurological status of the arm after some surgeries. In this context the infraclavicular catheter is placed before surgery but activated only after neurological control has been performed by the surgeon.

Tips

1.   At the infraclavicular level the cords can be separated by large amounts of connective tissue.

2.   The best response is a distal response of the posterior cord (for example, distal response of the radial nerve; muscle of extensor carpi radialis or extensors of the fingers).

3.   Correction for musculocutaneous response: redirect the needle slightly more caudal and posterior in order to elicit a distal radial response.

4.   Correction for deltoid response: redirect the needle more anterior and caudal in order to elicit a distal radial response.

5.   Two types of situations may be encountered:

· First: the cords are surrounded by more or less well-organized connective tissue → short onset time will occur.

· Second: the cords are surrounded by large amounts of disorganized connective tissue → longer onset time will occur.

6.   Light/short sedation is recommended during performance of the infraclavicular catheter (e.g., remifentanil/propofol), as going through the pectoralis muscle may be painful.

7.   It is preferable to first place the catheter and then perform the block.

Contraindications

1.   Deformity of the thorax

2.   A healed dislocated fracture of the clavicle

3.   A foreign body in the field of puncture (Pacemaker, Port-à-cat)

4.   Any coagulation dysfunction

Suggested Readings

Borgeat A, Ekatodramis G, Dumont C. An evaluation of the infraclavicular block via modified approach of the Raj technique. Anesth Analg 2001;93:436–441.

Whiffler K. Coracoid block: a safe and easy technique. Br J Anaesth 1981;53:845–848.