USG ESPB
DrugAfter obtaining the appropriate sonographic window, under strict aseptic precautions, the block needle is inserted in the plane of the US beam in a caudad to cranial direction until the tip is in contact with the transverse process (TP) at its lateral aspect. A test bolus of 0.9% saline (1-2 ml) is injected and sonographic evidence of erector spinae muscle displacement (posterior) from the underlying TP is sought to ensure that the tip of the block needle is indeed at the erector spinae muscle plane. The study drug from the 25 ml syringe with the label 'study drug for ESPB' (containing either 25 ml of 0.5% ropivacaine with 1:200,000 adrenaline or 0.9% saline depending on the group allocation) is injected in small aliquots over a minute. The anaesthesiologist performing the block and the patient is blinded to the group allocation.
Successful injection reveals a clearly delineated posterior displacement of the erector spinae muscle.