Continuous Terminal Nerve Blocks

By admin Last updated Jul 27, 2023

Ovid: Peripheral Nerve Blocks: A Color Atlas

Editors: Chelly, Jacques E.

Title: Peripheral Nerve Blocks: A Color Atlas, 3rd Edition

> Table of Contents > Section
VI – Continuous Nerve Blocks in Infants and Children > 58 –
Continuous Terminal Nerve Blocks

Continuous Terminal Nerve Blocks

Maria Matuszczak

A. Continuous Axillary Blocks

Patient Position: Supine, with the arm to be blocked abducted at 90°.

Indications: Anesthesia and postoperative analgesia for elbow, forearm, and hand surgery.

Needle Size and Catheter: 18-gauge, 25-, 38-, or 50-mm insulated introducer needle and 20- or 21-gauge catheter.

Skin–Nerve Distance: 1.5 cm at one year, increasing to 2.5 cm or more in adolescents (Fig. 58-1). Distance from skin to axillary nerve sheath also depends on patient’s weight.

Volume and Infusion Rate: (Table 58-1); maximum initial bolus volume of ropivacaine 0.2%. Dosage of ropivacaine 0.2% for continuous infusion: 0.4 to 0.5 mg/kg/h.

Anatomic Landmarks:
The axillary artery in the axilla crease is identified. The insertion
point is directly next to the artery at the lateral border of the
axillary crease.

Approach and Technique:
In an appropriately anesthetized/sedated child the needle is inserted
directly next to the artery, pointing almost parallel to the artery in
a proximal direction with a 30° to 45° angle to the skin. As
appropriate muscle twitches in the hand are still present at a current
of 0.5 mA, the local anesthetic solution is slowly injected after
negative aspiration for blood. Maintaining the introducer needle in the
same position, the catheter is threaded 2 cm beyond the needle tip (Fig. 58-2). The introducer needle is removed and the catheter is secured in place with benzoin and a transparent adhesive dressing.

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Figure 58-1. Skin–nerve distance, axillary approach.

Tips

At this level, there are no vital structures and it is a perfect approach for beginners in pediatric peripheral nerve blocks.
By introducing the needle more distally
from the axilla crease, the catheter can be placed close to a specific
nerve that needs to be anesthetized.
Because of shoulder mobility the axillary catheter is easily dislocated.
To prevent easy dislocation, the catheter
can be tunneled by inserting a longer needle subcutaneously at the
midhumeral level toward the axillary crease. Only when the needle is
close to the axillary crease, look for nerve stimulation.
In obese children, ultrasound guidance facilitates this approach.
This approach can be used to rescue an
incomplete continuous infraclavicular block. Ulnar distribution is
sometimes missed by the infraclavicular approach.
Ultrasound can be used to localize the
axillary nerves, to position the needle, and to verify that the local
anesthetic is injected via the catheter around the nerves.
A stimulating catheter can be used in older children.

Figure 58-2. Axillary catheter placement.

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Table 58-1. Maximal Initial Volume Bolus of Ropivacaine 0.2%

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	25 mL	30 mL