Nerve Blocks

Share Button

In a disaster that knocks us off the grid, increased exertion from activities of daily survival, combined with poor health and sanitation, can lead to injuries that pose a challenge to the family medic.  For example, an injured patient that requires a suture repair will suffer discomfort due to the unavailability of local anesthesia.

I am often asked about the use of Lidocaine (brand name Xylocaine), and other injectable local anesthetics for the purpose of preparing an injured area for suturing. Although difficult to find without a prescription, the medic should be acquainted with the use of these useful medications. Relatively small and superficial lacerations are best anesthetized with place a small amount of drug at the wound site itself (“local infiltration”).  In other circumstances, nerve blocks are more appropriate.  Each nerve block is intended to numb a portion of the course of a nerve as it travels through the body to the wound site. 

As each area of the body and wound is different, the corresponding nerve block method is different as well; let’s take the example of a hand injury.  A nerve block may be required for:

·         Multiple lacerations to the hand or fingers.

·         Injuries with multiple embedded foreign objects and debris.

·         Large lacerations.

·         Burns where extensive removal of dead tissue (debridement) is required.

·         Poisonous bites that involve the removal of significant foreign material, such as a stingray spine

·         Areas that are particularly sensitive (e.g., the palm of the hand).

There are various injectable local anesthetics on the market, such as Procaine (Novocain), Bupivacaine (Marcaine), and Mepivacaine (Carbocaine).  Lidocaine (Xylocaine) is, however, the most widely used these days, due to the rapidity and effectiveness of its anesthetic action.  Lidocaine also comes in the form of an ointment, jelly, patch, and aerosol spray. Injecting the drug gives, of course, a much stronger effect. You can obtain one or two percent Lidocaine; the more concentrated dosage is useful for longer procedures.

Lidocaine and Its Use

You can expect full effect about ten minutes after administration, and the effect should last one to two hours.  Epinephrine 1.200,000-1,000,000 has been used in conjunction with lidocaine to help decrease bleeding and prolong the effect further. This combo should not be used in areas with limited circulation, such as the fingers or earlobes.  The epinephrine could constrict the blood vessels excessively and cause lack of blood flow to the tissues (also called “ischemia”).

Before you consider the use of local anesthetic, you should be aware of your patient’s medical history. Some, such as those with liver disease, cardiac disease, or the elderly, should receive less quantities of the drug.

Of course, you’ll need some equipment:  Sterile towels and gauze to create a sterile field in which to work, an antiseptic such as povidone-iodine or chlorhexidine, at least one 6 cc or 10 cc syringe, and a thin gauge needle (25 or 27 gauge will do fine).  You can decrease the “sting” of the injection by warming the local anesthetic slightly and/or adding 1 cc of sodium bicarbonate solution to each 10 cc of medication.

Supplies for local anesthesia

Performing a local infiltration with injectable Lidocaine is relatively simple.  Position your needle at one end of each side of the laceration and insert superficially at a 45-degree angle to the skin.  Pull back on the syringe to make sure you haven’t entered a blood vessel by mistake (Intravenous or intra-arterial injection of Lidocaine can cause seizures or cardiac arrhythmias). Then, inject the drug slowly as you withdraw the syringe.  A swelling should form (called a “wheal”). 

Forming a “wheal” (or “weal”)

Repeat until each side appears slightly swollen.  You can decrease the discomfort of multiple injections by entering in an area already anesthetized by a previous injection.  To see this procedure in real time, check out my YouTube video “How to Suture with Dr. Bones”.

To describe every type of nerve block would take an entire medical textbook, so let’s pick a specific one and go through the procedure.  We’ll use the example of a laceration on the back of hand.

The nerve we want to block is the radial nerve, as it supplies sensation to that area.  If you’re the designated medic, It’s helpful to have a book on anatomy in your medical library so you can see where the nerve travels in that area.  For now, see the image below:

Radial nerve distribution

You’ll start with the patient’s hand in the palm-up position. Clean the entire wrist and back of the hand with your antiseptic. Feel the radial artery pulse; this is the one that the doctor takes your pulse with when you have a physical exam.  Then feel the radial styloid, this is the part of the wrist that protrudes slightly below the thumb area (see image below).

Insert your needle between the radial artery and the styloid near the crease of the palm, and inject two to three cc of the anesthetic. Don’t forget to pull back on the syringe to rule out an accidental entrance into a blood vessel.

radial nerve block injection #1

Next, you will turn the hand over and, using the same insertion site, inject another five cc or so of Lidocaine along the back of the wrist to about the midpoint area.  Use a longer needle than the one in the images if you can; this will decrease the numbers of injections you’ll have to do.

radial nerve block injection #2

Finally, wait 10 minutes and then test the area for anesthetic effect by lightly touching the area to be sutured with a needle.

Lidocaine is a prescription drug, and for good reason. Complications of injecting local anesthesia include:

·         Nerve injury – a sign of this is severe pain during the injection.

·         Vascular injury – usually with Lidocaine in combination with epinephrine.

·         Hematoma – blood accumulating under the skin due to puncture of a blood vessel.

·         Lidocaine toxicity – accidental injection of anesthetic into a blood vessel.

Lidocaine toxicity presents with lightheadedness, visual changes, numbness (often in the tongue), metallic taste, and ringing in the ears. Severe cases can progress to irregular heart rhythms, unconsciousness, and convulsions.  In rare instances, a patient could develop heart arrhythmias, respiratory arrest, and even go into a coma.

Finally, it’s important to remember that, while we have the luxury of modern medical care, injuries and wounds should be treated by medical professionals.  There are doctors with a lot of experience performing nerve blocks; take advantage of their expertise while they’re still there for you.

Joe Alton MD

Dr. Alton

Hey, if you believe in our mission to put a medically prepared person in every family, please check out our entire line of quality medical kits (some one-of-a-kind), individual supplies, and personal protection gear at

Hey, don’t forget to check out our entire line of quality medical kits and individual supplies at Also, our Book Excellence Award-winning 700-page SURVIVAL MEDICINE HANDBOOK: THE ESSENTIAL GUIDE FOR WHEN HELP IS NOT ON THE WAY is now available in black and white on Amazon and in color and color spiral-bound versions at

Share Button
Print Friendly, PDF & Email
Nail Bed Issues Off The Grid
Eye Trauma Off The Grid