Continuous Erector Spinea Block Versus Intravenous Analgesia in Coronary Bypass Surgery

Ultrasound guided erector spinea block will be performed while the patient is in left lateral position ) the US probe will be placed in longitudinal parasagittal plane lateral to the T5 spinous process. An 18-gauge epidural needle will be inserted in-plane in a cranial-to-caudal direction until the tip is deep to erector spinae muscle. A 5 cm of epidural catheter will be threaded in cephalad direction. The same steps will be performed on the other side, after the negative aspiration for blood, bolus dose 15 ml of 0.25% bupivacaine will be injected in each of the catheters followed by a continuous infusion of 0.125% plain bupivacaine at the rate of 0.1 ml/kg/h.

intervention: injection of boluses of intra venous Narcotic drugs (fentanyl) in the dose of (1-2mcg/kg) during the surgery after induction of anesthesia then fentanyl infusion through the postoperative first 24 hours postoperative till extubation then intravenous pethidine till 48 hours after surgery.