Comparing Intravenous Magnesium Sulfate With Dexamethasone as Adjuvants to Ultrasound Guided TAPblock

Using an 18 G Tuohy needle (80 mm Smiths medical Portex®) and the layers of the abdominal wall will be identified guided by superficial high-frequency 45 mm linear array ultrasound probe (13 MHz) as described by McDonnell and colleagues.(1) Twenty millilitre of 0.25% bupivacaine will be injected slowly after careful aspiration to ensure no vascular injury has occurred. Successful injection will produce an echo-lucent space between the muscle layers (internal oblique and transversus abdominis). All TAP blocks will be performed by the same anesthetist.