General Procedure Techniques

Needle Insertion and Local Anesthesia

Steps should be taken to make all procedures as pain-free as possible. The liberal use of local anesthetics in adequate concentrations will promote this goal while minimizing repeat needle sticks. Small diameter needles, 28 to 30 gauge, are initially used to anesthetize the skin and subcutaneous tissue. Distracting the skin with one’s fingers while slowly advancing the needle helps to reduce pain. The tip of the needle can be placed in the subcutaneous fat and, upon injection, less pain is noted than with intradermal injections because of the distensibility of fat. Rapid infusion of medication, especially with large volumes, causes tissue distention and results in pain. Lidocaine^23–26 and bupivacaine,²⁷ buffered with 8.4% sodium bicarbonate causes less pain than plain anesthetics and is equally efficacious. A 1:10 to 1:20 ratio of sodium bicarbonate to anesthetics can be used. Morris and colleagues found that, when injected, subcutaneous procaine and lidocaine were the least painful anesthetics.^28,29 Only etidocaine was found to be more painful than bupivacaine. Varelmann and coworkers found that patients who were told “We are going to give you a local anesthetic that will numb the area and you will be comfortable during the procedure” perceived less pain than patients who were told “You are going to feel a big bee sting; this is the worst part of the procedure.”³⁰

Other preparations used to reduce pain with initial needle injections include topical anesthetics (eutectic mixtures of local anesthetics, or EMLA), vapocoolant sprays, and preheated local anesthetics.³¹ If the patient is intolerant of or allergic to anesthetic agents, 0.9% intradermal saline or dilute antihistamines such as diphenhydramine (Benadryl) in 10 to 25 mg/mL injections can be used as alternatives;³² however, they are often considered painful, especially when injected intradermally.

Before administering injection anesthetics, one should aspirate to prevent inadvertent injection into a vascular structure. Small-gauge needles are unreliable when aspirating for blood. Needles of 25 gauge or larger rotated in two planes are necessary for this purpose. Continual movement of the needle tip makes injection into a vessel less likely. Slow, fractionated dosing is recommended while monitoring the patient for early signs of anesthetic toxicity.

Precautions

Good technique not only reduces the risk of wound infection, but also lowers the rate of viral transmission between patient and physician. Physicians who perform exposure-prone procedures should know their own human immunodeficiency virus (HIV) and hepatitis B virus (HBV) antibody status. The risk to the patient of contracting the HIV virus ranges from 1 in 42,000 to 1 in 420,000; the risk of contracting fatal HBV infection from an HBeAg positive surgeon during a procedure ranges from 1 in 76,000 to 1 in 1.4 million.³³ Universal precautions should be understood and include the use of gloves, protective eyewear, masks, (optional), and gowns (optional). Recapping used needles should be avoided and is seldom necessary.