Ovid: Peripheral Nerve Blocks: A Color Atlas

Continuous Brachial Plexus Blocks

Maria Matuszczak

Didier Sciard

A. Interscalene Approach

Patient Position: Supine, with the head slightly turned away from the side where the block is performed, and the arm extended along the side of the body.

Indications: Anesthesia and postoperative analgesia for shoulder surgery.

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

Skin–Nerve Distance: 0.6 cm (5 mm) at the age of 1 year, 2.5 cm (5 mm) at the age of 18 years (Fig. 57-1).

Volume and Infusion Rate: (Table 57-1).

Anatomic Landmarks: The lateral border of the sternocleidomastoid muscle is identified and marked. Posteriorly, the groove between the anterior and the middle scalene muscle is identified. Next, a line is drawn at the level of the cricoid cartilage. At the intersection of these two lines, the brachial plexus will be found in the interscalene groove.

Approach and Technique: The insertion point should be high in the interscalene groove. In an appropriately anesthetized/sedated child, the insulated introducer Tuohy needle, connected to a nerve stimulator (1.5 mA, 2 Hz, 0.1 ms), is positioned parallel to the neck, close to the external jugular vein and directed anteriorly to the interscalene groove. After appropriate positioning of the needle to maintain the muscle response with a current of 0.5 mA, the local anesthetic solution is slowly injected after negative aspiration for blood. Maintaining the insulated introducer needle in the same position, the catheter is threaded 2 cm beyond the needle tip. The Tuohy needle is removed, and the catheter is

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secured in place with Steri-Strip (3M, St. Paul, MN) and covered with a transparent dressing (Fig. 57-2).

Figure 57-1. Skin–nerve distance.

Tips

The site of introduction of the needle is often lateral and posterior to the jugular vein.
A stimulation of the musculocutaneous nerve or the median nerve is preferred to a stimulation of the axillary nerve (deltoid contraction).
The roots C8 and T1 (ulnar and median nerves) are partially blocked or not blocked with this approach.
If a trapezius contraction is elicited, indicating a stimulation of the dorsal scapular root, the needle is too posterior and should be redirected more anteriorly.
If a diaphragm contraction is elicited, indicating a stimulation of the phrenic nerve, the needle is too anterior and should be redirected more posteriorly.
A needle position parallel to the plexus sheath allows a better introduction of the catheter.
This approach should be used carefully in children with reduced pulmonary function since a phrenic nerve block is observed in 100% of the cases.
Horner syndrome is a side effect related to cervical plexus diffusion encountered when using larger volumes.
Tunneling the catheter reduces catheter displacement in patients with good neck mobility.

Table 57-1. Bolus Volume Depending on Weight. Ropivacaine 0.2% for Continuous Infusion 0.4–0.5 mg/kg/h

Initial Bolus
kg	2–10 kg	15 kg	20 kg	25 kg	30 kg	40 kg	50 kg	60 kg	70 kg
mL	1 mL/kg	12.5 mL	15 mL	17.5 mL	20 mL	22.5 mL	25 mL	27.5 mL	30 mL

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Figure 57-2. The Tuohy needle is removed and the catheter is secured in place and covered with a transparent dressing.

Suggested Readings

Dalens B. Regional anesthesia in infants, children, and adolescents. Baltimore: Williams & Wilkins, 1995:285–298.

Ivani G. Pediatric regional anaesthesia. A practical approach. Firenze, Italy: S.E.E. Firenze, 2001:103–112.

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B. Infraclavicular Approach

Two different approaches are possible for the infraclavicular approach to continuous brachial plexus block: vertical and coracoid.

Patient Position: Supine, with the head straight, and the arm extended along the body. The forearm may be lying on the chest.

Indications: Anesthesia and postoperative analgesia for arm, elbow, forearm, or hand surgery. This is a very good approach for a fractured humerus or elbow because the block can be performed without moving the fractured arm.

Needle Size and Catheter: 18-gauge, 38-mm (or 50-mm, depending on the age) insulated introducer Tuohy needle and a 20- or 21-gauge catheter.

Skin–Nerve Distance: The depth of the brachial plexus at this level has not yet been investigated in children. For an adult, the skin–plexus distance is about 4 cm. In children, the plexus is found at a depth of 1 to 4 cm.

Volume and Infusion Rate: (Table 57-2).

Vertical Infraclavicular Approach

Anatomic Landmarks: The ventral border of the acromial process of the scapula (lateral landmark) is identified as well as the fossa jugularis (medial landmark). A line is drawn between these two landmarks, and the midpoint of this line, just below the clavicle, is the point of insertion.

Approach and Technique: The Tuohy needle is introduced strictly vertical to the supine position in an appropriately anesthetized/sedated child. It is essential to obtain a movement of the hand (radial, median, or ulnar). Contraction of the muscles of the arm is not sufficient. With an appropriate muscle response still present at a current of 0.5 mA, the local anesthetic solution is slowly injected after negative aspiration for blood. Maintaining the insulated introducer needle in the same position, the catheter is threaded 2 cm beyond the needle tip and directed to the axilla (Fig. 57-3). The Tuohy needle is removed, and the catheter is secured in place with Steri-Strip and covered with a transparent dressing.

Table 57-2. Bolus Volume Depending on Weight. Ropivacaine 0.2% for Continuous Infusion 0.4–0.5 mg/kg/h

Initial Bolus
kg	2–10 kg	15 kg	20 kg	25 kg	30 kg	40 kg	50 kg	60 kg	70 kg
mL	1 mL/kg	12.5 mL	15 mL	17.5 mL	20 mL	22.5 mL	25 mL	27.5 mL	30 mL

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Figure 57-3. The catheter is threaded.

Figure 57-4. Coracoid infraclavicular approach.

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Coracoid Infraclavicular Approach

Anatomic Landmarks: Coracoid process.

Approach and Technique: The Tuohy needle is introduced strictly vertical to the supine position of the patient, at 1 to 2 cm medial and caudal (depending on the age) to the coracoid process in an appropriately anesthetized/sedated child. The plexus is found at a depth of 1 to 4 cm. It is essential to obtain a movement of the hand (radial, median, or ulnar). Contraction of the muscles of the arm is not sufficient. With an appropriate muscle response still present at a current of 0.5 mA, the local anesthetic solution is slowly injected after negative aspiration for blood (Fig. 57-4). The catheter is introduced, directed to the axilla, and advanced no more than 2 cm beyond the tip of the needle. The catheter is secured in place with Steri-Strip and covered with a transparent dressing.

Tips

A pneumothorax can occur if the needle is directed too medially.
If the plexus is not found at an appropriate depth, the needle should be redirected more laterally.
The ulnar distribution is sometimes missed by the infraclavicular approach.
Because of the reduced mobility of this area, catheter displacement is very unlikely.