Ketamine as Adjunctive Analgesic With Bupivacaine in Paravertebral Analgesia for Breast Cancer Surgery

Thoracic paravertebral blocks will be performed as described by Moore and Katz. Intradermal lidocaine will be used at the site of the needle insertion. The superior aspect of the spinous processes of T1- T6 will be marked. The skin entry points will 3 cm laterals to the marks. A 22- gauge quincke spinal needle attach to extension tubing to a syringe containing study drugs will be used. The needle will be inserted perpendicular to the skin for a distance of 2 to 4 cm until the transverse process will contact. The needle will be withdrawn and walk cephalad off the transverse process and advance for a further 1.5 to 2 cm.