Plasma ropivacaine concentrations after ultrasound-guided transversus abdominis plane block, with and without adrenaline, for gynaecologic surgery

This study will investigate the effect of including a small amount of adrenaline in the local anaesthetic (ropivacaine) solution used for the abdominal wall nerve blocks commonly performed now to provide pain relief after abdominal surgery. Ropivacaine is commonly used for these nerve blocks because it is a longer-acting local anaesthetic. Adrenaline is a naturally occurring substance in the human body. It is commonly added to local anaesthetics to increase the duration of their effect, and to reduce the rate local anaesthetic is taken up into the blood stream (to limit the risk of side effects to the local anaesthetic). The specific purpose of this study is to determine how much, if at all, the inclusion of adrenaline reduces uptake of the local anaesthetic ropivacaine, with these particular blocks, and thus whether or not it increases the safety. Currently, adrenaline is routinely added to local anaesthesics for certain types of nerve blocks but its potential safety benefit in abdominal wall blocks using ropivacaine is unclear.