Applied Evidence

How to minimize the pain of local anesthetic administration

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References

EMLA is a mixture of 25 mg/mL of lidocaine and 25 mg/mL of prilocaine. It is indicated for topical anesthesia on intact, nonmucosal, uninjured skin (maximal dose 20 g/200 cm2 of surface area). It is applied in a thick layer and covered with an occlusive dressing (eg, Tegaderm) to enhance dermal penetration. The depth of penetration increases with application time and may reach a maximum depth of 3 mm and 5 mm following 60-minute and 120-minute application times, respectively.28 Duration of effect is 60 to 120 minutes.

LET, which is a mixture of 4% lidocaine, 0.1% epinephrine, and 0.5% tetracaine, may be used on nonintact, nonmucosal surfaces. Typically, 1 mL to 5 mL of gel is applied directly to the target area and is followed by application of direct pressure for 15 to 30 minutes. LET is not effective on intact skin and is contraindicated in children < 2 years of age.28

Cooling sprays or ice. Topical skin refrigerants, or vapocoolants (eg, ethyl chloride spray), offer an option for short-term local anesthesia that is noninvasive and quick acting. Ethyl chloride is a gaseous substance that extracts heat as it evaporates from the skin, resulting in a transient local conduction block. Skin refrigerants are an option to consider for short procedures such as intra-articular injections, venipuncture, or skin tag excision, or as an adjunct prior to local anesthetic delivery.29-32 Research has shown that topical ethyl chloride spray also possesses antiseptic properties.29,33

Environment: Make a few simple changes

Direct observation of needle penetration is associated with increased pain; advising patients to avert their gaze will mitigate the perception of pain.34 Additionally, research has shown that creating a low-anxiety environment improves patient-reported outcomes in both children and adults.35 Music or audiovisual or multimedia aids, for example, decrease pain and anxiety, particularly among children, and can be readily accessed with smart devices.36-39

Warming and buffering solution provide a synergistic effect on pain reduction.

We also recommend avoiding terms such as “pinch,” “bee sting,” or “stick” in order to reduce patient anxiety. Instead, we use language such as, “This is the medicine that will numb the area so you will be comfortable during the procedure.”40

Continue to: Injection technique

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