Adequate postoperative pain relief in patients in cardiac surgery is very essential. multimodal techniques for perioperative pain management post cardiac surgery include intravenous patient controlled analgesia, thoracic epidural and paravertebral blockade. Analgesia through thoracic epidural is the gold standard technique for post-sternotomy pain control but it has serious complications. ESP block is an easy technique compared to paravertebral block and less hazardous than thoracic epidural. Hence, this study will compare continuous bilateral erector spinae block guided by ultrasound with intravenous analgesia which is the standard method for pain management in cardiac surgery.

Analgesia through thoracic epidural is the gold standard technique for post-sternotomy pain control. in spite of its serious complications such as epidural hematoma with or without paraplegia that enhanced by heparin administered during cardiac bypass surgery..

Paravertebral blockade is comparable to Thoracic epidural analgesia in cardiac surgery but it may cause complications such as vascular injuries and pneumothorax.

Erector spinae block is recently implemented technique for treatment and analgesia of thoracic neuropathic pain and post mastectomy syndrome. ESP block is an easy technique compared to paravertebral block and less hazardous than thoracic epidural.

This study will compare continuous bilateral erector spinae block guided by ultrasound versus intravenous analgesia for pain management in cardiac surgery Patients will be enrolled in the study will be divided into two groups In Group A: 20 patients will receive fentanyl after induction and intubation in the dose of ( 3-52mcg/kg ) according to the patients haemodynamic parameters and the decision of the anaesthesia team at skin incision, before starting Cardiopulmonary bypass and again after bypass and before sternal closure. Once the surgical procedure is finished, patients will be transferred to ICU. After ICU transfer acetaminophen 1 gm/6hrs will be given regularly and NSAID if there is no contraindication after extubation. morphine 0.5mg/kg as rescue analgesia will be started upon arrival till extubation.

In Group B: 20 patients will have bilateral ESP block will be done under general anaesthesia 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 8 ml/h starting in ICU for 48 h after extubation. patients will receive intraoperative boluses of fentanyl according to the patients' haemodynamic and the decision of the anaesthesia team at skin incision, before starting Cardiopulmonary bypass and again after bypass and before sternal closure. Once the surgical procedure is finished, patients will be transferred to ICU morphine 0.5mg/kg as rescue analgesia will be started upon arrival till extubation. Infusion rate will be titrated according to haemodynamics, pain assessment, and complications. After extubation acetaminophen 1gm/6hrs will be given regularly.

Inclusion Criteria:

• elective cardiac surgery.
• age 18-65 years.
• patients with median sternotomy.
• body mass index <30kg.m2.
• left ventricular ejection fraction >50%.

Exclusion Criteria:

• significant aortic stenosis.
• left main coronary artery disease.
• patient on anti-coagulants0
• pre-existing respiratory, neurological, or renal disease.
• CSF or blood tap during the procedure.
• failure to thread the catheter.
• anomalies of vertebral column.