5-174
- Locate the posterior tibial artery. The tibial nerve lies posterior and lateral to the tibial artery.
- Insert the needle toward the artery, anterior to the Achilles tendon and posterior to the medial
malleolus, injecting 5 mls of local anesthetic solution in a fan-like manner while withdrawing the
needle.
VI. Axillary Blockade
Achieve regional anesthesia for surgery below the elbow by brachial plexus blockade using the axillary
approach. The nervous and vascular structures of the upper arm are encased within a perivascular sheath,
a tubular structure surrounding the nerves and vessels. Introducing local anesthetic solution into this sheath
at the axillary level affords excellent blockade below the elbow, and many times, satisfactory anesthesia of
the elbow itself.
When: For any surgical procedure of the forearm or hand; upon surgeon request or in high-risk patients
where a general anesthetic would be deleterious.
What You Need:
Equipment: 22 gauge needle, 60cc syringe, tourniquet, sterile gloves, anesthetic agent(s), epinephrine,
bicarb, razor, prep solution and resuscitation equipment (including oxygen).
Local Anesthetic (Table 5-15)
- Total of 50-60 ml needed: 40 ml to fill the plexus sheath and an additional 10 - 20 ml are needed for
ring block and musculocutaneous nerve. - Add 1:200,000 epinephrine as a marker to assist in detecting accidental intravascular injection (add
0.25cc of 1:1000 epinephrine to each 50 ml of local for a 1:200,000 solution). - Combinations: Combining a fast onset local anesthetic with another of long duration is done at times
to take advantage of both of these desirable characteristics. Remember to not exceed maximum dosage
levels. - Add NaHCO3, 1 mEq per 10 ml of local anesthetic solution for all agent (except bupivacaine, where 0.1
mEq is added) to accelerate the onset of block.
Choice of local anesthetic solution and the appropriate concentration depends on nerves to be blocked,
desired onset time and desired duration of action.
Table 5-15
Drug Concentration Onset (min) Duration (w/epi) Max Dose-w/epi
Chloroprocaine 2-3% 10-20 min 60-120 min 1000mg-14mg/kg
Lidocaine 0.5-1.5% 15-30 min 150-180 min 500mg -7mg/kg
Mepivacaine 1-1.5% 15-30 min 180-240 min 500mg-7mg/kg
Bupivacaine 0.25-0.5% 20-30 min 180-360 min 225mg-3mg/kg
Tetracaine 0.2-0.25% 10-20 min 240-360 min 200mg
NOTE: Add epinephrine 1:200,000 to all mixtures (see above)
What To Do:
- Basic set up for general anesthesia (see Total Intravenous Anesthesia section).
- Prepare patient with appropriate premedications and monitors (see Total Intravenous Anesthesia section).
- Patient position: Supine, with head turned away from side to be blocked and the arm abducted ~90°. The
forearm is flexed to 90° and externally rotated so the dorsum of the hand lies on the table and the forearm
is parallel to the long axis of the patient’s body. Do not place the hand of the arm to be blocked under the
head. This hyperabduction obliterates the brachial artery pulse. - Paresthesia technique (Optional: Transarterial and Peripheral Nerve Stimulator Techniques found on
CD-ROM).
a. Use the index finger of the non-dominant hand to palpate the axillary artery as high up into the
axilla as possible.
b. Prep the area with razor if needed and with povidone-iodine swabs. Place a skin wheal over the
artery proximal to the index finger.