A 22-year-old man with IV drug use presents with an erythematous fluctuance on the left forearm. In preparing for irrigation and debridement, which technique is most appropriate?

• A. Withdraw the syringe prior to injecting lidocaine to assure that you are not in a blood vessel
• B. Inject lidocaine without aspiration
• C. Use a larger gauge needle
• D. Use topical antibiotics only

Answer: (A)

Before giving local anesthesia for incision and drainage, you want to confirm you’re not in a blood vessel. Aspirate by pulling back the plunger after placing the needle or syringe near the targeted tissues. If blood appears, reposition and aspirate again until no blood is drawn, then inject slowly. This prevents accidentally injecting lidocaine into a vessel, which can cause systemic toxicity or cardiovascular problems—dangerous in any patient, but especially in someone with a history of IV drug use who may have abnormal venous anatomy.

Using a larger gauge needle isn’t necessary for this purpose and can cause more tissue trauma. Injecting without aspiration risks intravascular injection, and topical antibiotics alone won’t provide anesthesia or allow proper debridement and irrigation.