ESPB Versus PVPB Regarding Their Effect on Peri-operative Opioid Consumption in Patients Undergoing Minimally Invasive Mitral Valve Replacement

After induction of general Anaesthesia,a high frequency ultrasound probe will be placed in a longitudinal orientation 3 cm from the midline. Once the erector spinal muscle and the transverse processes are identified, spinal needle will be inserted after standard skin disinfection in a caudal to cephalad direction using a sterile probe cover until the tip lay in the interfacial plane deep to the erector spinal muscle. After hydrolocalization with ml normal saline, this plane will be opened and 20 ml of 0.25 %bupivacaine will be administered for block performance

After induction of general Anaesthesia ,with the probe in the longitudinal paramedian position, it is then moved from medial to lateral direction to appreciate the saw tooth appearance of the facet joints close to the midline which changes to long finger-like shadow of the transverse process as the probe is moved slightly laterally. Repositioning the probe over the transverse process ensuring the space of interest is in the middle of the probe once again one should appreciate the intercostal muscles and the dense bright white line of the pleura in between the shadows of the transverse processes. The needle is then introduced at the caudal end of the probe in plane in a caudal to cranial direction aiming for the angle between the bottom of the transverse process and the pleura. Once position is confirmed, 20 ml of 0.25% bupivacaine will be administered for the block performance.