Erector Spinae Plane Block in Post-operative Recovery in Cardiac Surgery With Median Sternotomy.

On arrival to the operating room, an I.V 20 G cannula will be inserted. . and 500 ml of ringer acetate solution will be infused within 30 minutes. .A five-lead electrocardiogram, a pulse oximeter and an noninvasive blood pressure monitor will be applied. Basal readings ( HR,blood pressur) will be recorded . Then arterial cannula will be inserted in the radial artery of the non dominant hand. Sedation with Midazolam 0.02 mg/kg will be administered at the pre- anethesia room. . Induction will be done using titrated doses of propofol (1-2 mg /kg). ,atracurium 0.5 mg /kg and 200 mcg of fentanyl

• patients will be randomly assigned into two groups :
• Group A (n=110): will receive Ultrasound guided bilateral ESBP.
• Group B (n=110): will receive fentanyl IV infusion 2mic/kg/hr. Patients in group A will be positioned in the lateral position , ESPB will be done under complete aseptic conditions , using , linear ultrasound probe(Philips HD11XE Ultrasound System) , to locate the ESP at the level of the fifth dorsal vertebrae , 22 G spinal needle will be used to inject 20 ml of 0.25% of bupivacaine in the ESP bilaterally, block will done by an expert anesthesiologist , who will not be included in the data collection.

Patients in group B will be on fentanyl infusion 2 mcg /kg/hr. Blood pressure and heart rate will be recorded every 15 min until we go on CPB. An incremental dose of fentanyl bolus 50 mcg will be given when there is increase in the heart rate or the blood pressure by 20% from the baseline. If more than tow boluses needed, then the block will be considered as failed block .Then patients will go on CPB after heparinization and cannulation of the aorta and the venous system ( single venous or double venous ), after valve replacement or CABG done , weaning from the CPB , and inotropic support will start if needed . Then patient will be transferred to ICU mechanically ventilated on assisted control mode, FiO2 :0.6 , TV: 6ml /kg , RR: 12-16/min , PEEP:5. After fulfilling the criteria for extubation ( such as P/F ratio more than 200 , spontaneous tidal volume greater than 5 mL/kg, vital capacity greater than 15 mL/kg, maximum inspiratory pressure (MIP) greater than 25 cm H2O,, fully conscious patient , stable hemodynamics and accepted valves for the arterial blood gases and chest tube drains, patient will be extubated.

All patients will be observed in the postoperative period at 4, 6, 8, 12,24 hours interval and all hemodynamics will be recorded including heart rate ,blood pressure ,the need for incremental doses of narcotics, pain assessment using the Numerical rating scales (NRS), (use numbers to rate pain), and time of extubation ( the time from the arrival to the ICU until successful extubation).