Effect of lidocaine with and without epinephrine on lymphatic contractile activity in mice in vivo.

Abstract

A local anesthetic, lidocaine, is known to affect cutaneous blood flow when injected into the skin. However, it is unknown if dermal lymphatic function can also be affected. Therefore, we characterized lymphatic function in response to administration of lidocaine with and without epinephrine. Non-invasive near-infrared fluorescence imaging (NIRFI) with intradermal injection of indocyanine green (ICG) was used to characterize the lymphatic "pumping" function in mice after subcutaneous injection of 2% lidocaine with and without 1:100,000 epinephrine or saline. NIRFI was performed for 10-20min immediately after and 1, 3, and 5h after these interventions. Lymphatic contraction frequencies significantly decreased 10min after subcutaneous injection of lidocaine and remained plateaued for another 5min, before returning to baseline. However, addition of 1:100,000 epinephrine to 2% lidocaine rapidly increased lymphatic contraction frequencies at 5min post-injection, which returned to baseline levels 15min later. Injection of saline also increased lymphatic contraction frequency 5min after injection, which returned to baseline 10min post-injection. Although lidocaine administration showed a decrease in lymphatic function, the combination of epinephrine with lidocaine resulted in a predominant net effect of increased contractile activity.