The main objective of this study is to evaluate postoperative pain intensity comparatively between erector spinae plane block and transversus thoracic muscle plane block in patients undergoing open coronary artery surgery. The primary question it aims to address is which of these two regional techniques causes less postoperative pain.

Primary aim in this study is to evaluate the postoperative pain severity of erector spina plane block in comparison with transversus thorasis muscle plane block in patients undergoing open coronary artery surgery. Secondary aim is to retrospectively evaluate the analgesic requirements, complications, extubation times, mortality and morbidity of these patients.

The study will be designed as a prospective randomized controlled trial. After ethics committee approval is obtained, the regional anesthesia method to be applied to 60 patients who are planned to undergo coronary artery surgery in the TR Ministry of Health Ankara City Hospital Cardiovascular Surgery Operating Room and who do not have exclusion criteria will be determined according to the closed envelope method, erector spina plan and transversus thorasis muscle plan (two groups) and will be reported to the anesthesiologist.

Patients who will undergo bilateral erector spinae plane block will be taken to the operating room non-premedicated. In the operating room, after ASA monitoring, intra-arterial, BIS, NIRS monitoring, anesthesia induction with propofol 1-3 mg/kg, fentanyl 2 µg/kg and rocuronium 0.6 mg/kg, endotracheal intubation will be performed, central vein catheterization, urinary catheter and nasopharyngeal temperature probe will be placed. . After the patient is placed in the prone position by the same experienced researcher, appropriate sterilization conditions for the skin and equipment are provided, the USG probe will be fixed on the transverse process in the area where the block is desired, and a 22 gauge 80 mm block needle will be placed parallel to the longitudinal axis. The bone structure will be reached by viewing the needle with an in plane technique at an angle of approximately 45 degrees and advancing it to the posterior of the transverse process. When the needle tip is in the appropriate position under the erector spinae muscle, intermittent aspiration will be performed to confirm that there is no vascular puncture. Following negative aspiration, saline is administered and local anesthetic injection is applied after the erector spinae muscle is seen to be separated from the transverse process. For TTP, the same experienced practitioner places the USG probe, which should be placed approximately 2-3 cm lateral to the sternal border, under the same sterile conditions. The T4-T5 intercostal space will then be identified under ultrasound guidance in a parasagittal view, and the nerve block needle is inserted in-plane into the catheter. The needle is then directed into the transversus thoracic muscle plane between this muscle and the internal intercostal muscle. Here, the local anesthetic solution will be given, taking care to aspirate before each injection to avoid intravascular and intrapleural administration.

Anesthesia will be maintained with propofol/oxygen/air mixture and remifentanil 1 mcg/kg/hour. If systolic arterial blood pressure or heart rate increases more than 20% above baseline in response to surgical stimuli, additional fentanyl 2 µg/kg increments will be administered.

IV tramadol PCA bolus 10mg will be prepared for each patient with a lock-in time of 20 minutes and its use will be explained to the patients in the preoperative period. The total dose of madol used will be monitored.

At the end of the surgery, patients will be taken to intensive care and monitored on a mechanical ventilator. According to standard ICU policy, extubation will be performed at the earliest clinically appropriate time. Patients will be monitored in intensive care for 24 hours after extubation. In the ICU, VAS and BPS will be used to evaluate pain. When VAS is greater than 4 and BPS is greater than 3, additional analgesia will be given.

Induction and maintenance anesthetic drugs and dosages, analgesic drugs and dosages (15mg/kg every 8 hours after routine paracetamol, analgesic need with PCA device, total doses, before and after anesthesia induction, after skin incision, after sternotomy, after 30 hours after leaving CPB Minutes later and after closing the sternum, heart rate (beats/min) and systolic arterial pressure (mmHg) will be measured. 0, 4, 8, 12, 24 hours after postoperative extubation, respiratory rate (respiratory rate/min) and from ICU arrival to endotracheal extubation. Extubation time (minutes) defined as the time from extubation to first rescue analgesia (hours), pain problems: time from extubation to first rescue analgesia (hours), VAS and BPS scores at 0, 4, 8, 12, 24 hours after extubation, postoperative pain at rest and sternal Complications associated with the non-pain block will be recorded.

Sample size calculation was performed using MedCalc 15.8 (MedCalc Software bvba, Ostend, Belgium). It was determined that a minimum 60 patient (30+30) was sufficient for 90% (1-β) power.

Inclusion Criteria:

• Patients aged 18-80 who will undergo elective coronary artery surgery in TR Ankara City Hospital cardiovascular surgery operating room will be included in the study.

Exclusion Criteria:

• Exclusion criteria for patients aged 18-80 who will undergo isolated coronary artery bypass surgery
• Non-coronary artery surgery cases
• Re-operations
• Low EF (<40%)
• psychiatric illness
• Those who have contraindications for block (infection at the block site, etc.)
• Patients who do not or cannot give consent to participate in the study

Group 1 patients will undergo bilateral erector spinae plane block. Heart rate (beats/min) and systolic arterial pressure (mmHg) will be measured before and after induction, after skin incision, after sternotomy, 30 minutes after weaning from CPB, and after sternum closure. VAS and BPS will be used to evaluate pain at 0, 4, 8, 12, 24 hours postoperatively.

Group 2 patients will undergo transversus thoracic plane block and the same parameters as group 1 will be saved.