Anesthetic management for surgery of aortic coarctation needs special care due to severe pain during lateral thoracotomy incision, the intraoperative hemodynamic instability related to skin incision at lateral thoracotomy, clamping and declamping of the aorta, needs of large doses of analgesia perioperative, needs of vasodilators. Also, postoperative care of the patients after repair is very important issue. The investigators will compare the effect of para-vertebral block with bupivacaine alone or with dexamethasone on Intra and postoperative analgesia.

The patients will be divided randomly by sealed envelope into 2 equal groups. Group I (n=30) will receive paravertebral block with 0.5mg/kg bupivacaine 0.25% diluted with isotonic saline (total volume 15ml) and group II (n=30) will receive paravertebral block with 0.5mg/kg 0.25% bupivacaine and 0.1mg/kg dexamethasone.intraoperative fentanyl needs, Intra and postoperative hemodynamics and OPS pain scores will be recorded. Possible risks as hypertension will be treated by nitroglycerin infusion 0.5ug/kg/min or tachycardia (HR more than 20% than baseline) will be managed by additional doses of fentanyl 1-2ug/kg, bradycardia (20% decrease from the baseline) will be managed by atropine 0.02mg/kg. Also, the complications of paravertebral block as peridural and intravascular injection can be avoided by careful aspiration before injection and injection while visualization of the needle by U/S.

Inclusion Criteria:

• 4m-6 years males and females scheduled for surgery for coarctation of the aorta

Exclusion Criteria:

• patients with associated other cardiac anomalies (e.g. VSD), patients with airway abnormality, patients with heart failure, patients with endocrine disorders, patients with history of convulsions, neurological disorder, hepatic, renal and neuromuscular diseases, coagulopathy, history of hyperthermia, infection at site of the block and family history of hypersensitivity