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