Onset and Duration of Anesthesia of Varying Lidocaine and Epinephrine Concentrations used in WALANT: A Randomized Double Blind Comparative Study

ABSTRACT

BACKGROUND

Wide awake local anesthesia no tourniquet (WALANT) is an increasingly popular anesthetic technique used in hand surgery which utilizes a combination of local anesthetic   and epinephrine to achieve adequate anesthesia   and eliminates the need of a tourniquet. Lidocaine is the most common local   anesthetic used, and this study aims to compare the onset and duration of the three most used concentrations of lidocaine and epinephrine for WALANT.

METHODOLOGY

This is a randomized double blind comparative study of   78 middle fingers subjected to either 1% lidocaine with 1:100,000 epinephrine, 0.5% lidocaine with 1:200,000 epinephrine or 0.25% lidocaine with 1:400,000   epinephrine. Onset time and anesthetic duration for the local effect   and as a digital nerve block were measured   via pin prick test.

RESULTS

The contents of each arm were as follows: Arm A: 0.25% lidocaine with 1:400,000   epinephrine, Arm B: 1% lidocaine with 1:100,000 epinephrine and Arm C: 0.5%   lidocaine with 1:200,000 epinephrine. Statistically significant results were seen for onset times in both local and digital block effect, Arm   B had the shortest onset time followed by Arm C and Arm A, respectively.   Longer duration of anesthetic effect was achieved in both local and digital block for Arm B followed by Arm C   then Arm A, which were statistically significant.

CONCLUSION

In conclusion, higher   concentration of lidocaine and epinephrine provides faster   onset and longer duration of anesthesia both as a local agent and in digital nerve block however lower   doses can prove sufficient for   simple hand procedures that does not entail   lengthy operative time. Achieving the required   effect and utilizing lower concentrations of lidocaine and epinephrine is more favorable in terms of its safety profile.