Already emphasized is the importance of administering anesthesia even before prepping or cleansing the wound for closure. Injection will not spread infection.

Lidocaine (xylocaine) is the most frequently selected local anesthetic. It is considered more intense than Procaine (novocaine), but it is not as long-lasting as the newer Marcaine. Xylocaine's effects last from 1-3 hours.

The toxic limit of xylocaine is 7 mg/kg given within any one hour interval. You might not remember that number, but you'll likely recall this guideline: one 50 cc bottle of 1% solution for an average 70kg adult. Choose 0.5% and you can use twice as much. If you select 2% you must use only half the volume. For small people, adjust the dosage accordingly.

The pain associated with giving local anesthetic is mostly related to needle size, speed of administration, and sometimes the drug itself. Use a 27- or 30-gauge needle. Larger needles are unnecessarily painful. Also remember to inject the anesthetic inside the wound, not into the surrounding intact skin where nerve endings are more concentrated. Inject the anesthetic very slowly! Xylocaine is acidic, a fact which contributes to its pain at injection. It may be buffered with 1cc sodium bicarbonate to 9cc Xylocaine. Buffering significantly reduces pain on administration.

Always wait long enough for the anesthesia to take effect before proceeding. The epinephrine in the local anesthetic usually takes 5-6 minutes to cause vasoconstriction. Ideally, you should infiltrate, then do some other task before proceeding with the repair. The patient will rarely mind, especially if you explain that you are waiting for the anesthetic to take full effect.

Use xylocaine with epinephrine most of the time, especially on the face. Epinephrine reduces the bleeding from the subderinal plexus. However, never use epinephrine for anesthesia of the hand.

Signs of toxicity from a local anesthetic include restlessness, followed by agitation and convulsive seizures. Treatment should include oxygen and diazpam (Valium^TM). In addition, call for skilled help, especially if you are not located near a fully-equipped hospital. Avoid the problem in the first place by paying close attention to the volume of drug you are using and the speed with which you are giving it.

Administration of a local anesthetic is both a technical skill and an art. Remember the dentists you have known who have injected xylocaine with great skill. Try always to emulate them.