Special Operations Forces Medical Handbook

5-159

Anesthesia: Local Anesthetics / Regional Anesthesia

LTC Howard Burtnett, AN, USA & LTC Eugene Acosta, AN, USA

Introduction: Regional techniques utilizing local anesthetics may be used for surgical, diagnostic or therapeu-
tic procedures or for providing relief of acute or chronic pain. Techniques range from subcutaneous infiltration
of a small, specified area to major regional plexus blockade.

I. Local Inltration of an Area
When: Whenever good operative conditions can be obtained with a moderate volume of local anesthetic or to
perform a minor surgical procedure such as suturing a wound or excising a small tumor.

What You Need: Sterile barrier (towels or drapes), an antiseptic prepping solution (Betadine or alcohol),
appropriate sized syringe, 25 or 27 gauge needle, local anesthetic (Table 5-13). Note: A 50:50 ratio of
lidocaine and bupivacaine offers the luxury of a fast onset and long duration.

What to Do:

1. Assemble equipment.


2. Prep area and establish a sterile field with the chosen barrier.


3. Use the smallest possible gauge needle to minimize pain. With the bevel of the needle facing down
   and parallel to the skin, quickly insert the needle up to the hub. Begin infiltrating the desired area
   while withdrawing the needle. Slowly inject the medication. Perform subsequent needle insertions from
   this anesthetized area.


4. Injections should be systematic and delivered in a triangular geometric pattern to ensure an adequate
   block. Should deeper tissue levels need anesthetizing, utilize a systematic approach again, anesthetizing
   progressively deeper layers.


5. Adding the vasoconstrictor epinephrine delays the systemic absorption of the anesthetic, which prolongs
   the duration of the block and allows for the safe administration of a larger dose of local anesthetic.
   (Table 5-13).

What Not To Do:
Contraindications: There are no specific contraindications to this technique.

1. Avoid local anesthetics in patients reporting allergies to them.


2. Avoid using vasoconstrictors with these blocks in the fingers or toes.
   Complications: tissue ischemia and necrosis-- large volumes of local anesthetics and high concentrations
   of epinephrine can lead to ischemia and necrosis of wound edges. Should epinephrine be utilized, a
   concentration of 1:200,000 affords the maximum vasoconstrictive property sought for these procedures.

Table 5-13: Inltration Anesthetics
Plain Solutions Epinephrine Containing Solutions
Drug Concentration Maximum Dose Duration Maximum Dose Duration
(%) (milligrams) (minutes) (milligrams) (minutes)
Lidocaine 0.5 - 1.0 300 30 - 60 500 120 - 360
Prilocaine 0.5 - 1.0 500 30 - 90 600 60 - 120
Bupivacaine 0.25 - 0.5 175 120 - 240 225 180 - 240

II. Digital Block of the Finger or Toe (Figures 5-27 through 5-32)

When: Whenever good operative conditions can be obtained with a moderate volume of local anesthetic. To
perform a surgical procedure on the area.

What You Need: An antiseptic prepping solution (Betadine or alcohol), appropriate sized syringe, 25 or 27