Skin perfusion and pain evaluation with different local anaesthetics in a double blind randomized study following digital nerve block anaesthesia

Abstract

Supplementing a local anaesthetic with epinephrine has advantages in hand surgery: faster onset of anaesthesia, extended effect of anaesthetics with prolonged pain reduction, decreased bleeding into the operative field, and abandoned need for tourniquet. We hypothesized that the use of ropivacaine with epinephrine additive in digits allows good skin perfusion rates with prolonged pain reduction. In this prospective, double-blinded, randomized study with 20 volunteers (80 fingers, without operation) the chronological course of changes in digit blood flow, post injection pain status and complication rates after two-injection dorsal technique anaesthetic block with ropivacaine (group 1: ropivacaine 0.75%, group 2: ropivacaine 0.75% and epinephrine 1 : 1.000.000, group 3: local tumescent anaesthesia 0.15% TLA: ropivacaine, lidocaine, saline solution plus epinephrine 1 : 1.000.000) were examined. As a control group, injection of 2% lidocaine in the way with 20 minutes tourniquet (group 4) was used. Group 1 showed increased skin perfusion with a maximum of 160.2%, group 2 showed no significant changes with a following significant increase of skin perfusion (+66.6%). In group 3, a significant reduction (-54.1%) was followed by an increase of skin perfusion (+45.7%). In the control group (group 4) the skin perfusion was decreased (-66.2%) and increased significantly after opening the tourniquet (+248.1%). The longest pain reduction was shown for ropivacaine 0.75% and epinephrine with 18.0 hours (group 2); the other groups were between 4.6 to 8.1 hours. Using ropivacaine with epinephrine additive in digits could improve the intra-, and postoperative terms.