Intradermal anaesthesia: comparison of several compounds.

OBJECTIVE

To compare the efficacy of different local anaesthetics to produce intradermal anaesthesia for venous cannulation and the discomfort associated with skin infiltration.

DESIGN

Randomized, double blind study.

SETTING

Induction room of a university hospital.

PATIENTS: Convenience sample of 600 patients (18-65 years; ASA I-II) scheduled for elective surgery.

INTERVENTIONS: Patients received one of six preparations: 0.9% saline, 1% prilocaine (Xylonest), 1% lidocaine (Xylocain), 1% mepivacaine-1 (Meaverin), 1% mepivacaine-2 (Scandicain), 1% procaine (Novocain). A skin wheal was raised on the dorsum of the hand by injecting 0.1 ml intradermally and 0.1 ml subcutaneously via a 27-g hypodermic needle. 60 seconds later an 18-g intravenous cannula was passed through that skin wheal into a vein.

MEASUREMENTS: A visual analog scale (VAS) for pain (0 = no pain/10 = most pain imaginable) was used to assess pain elicited by raising the skin wheal and inserting the cannula.

MAIN

RESULTS

With regard to analgesic potency all five local anaesthetics were comparable (mean VAS-score 1.7-2.09) and effective when compared to 0.9% saline (mean VAS-score 4.2; P < 0.001). Infiltration pain was least with mepivacaine-1 (mean VAS-score 1.0; P < 0.001) and highest with procaine (mean VAS score 2.7; P < 0.001).

CONCLUSIONS

Of the local anaesthetics tested, Mepivacaine-1 is the drug of choice for skin infiltration as its injection elicits least discomfort.