This prospective randomized controlled clinical trial evaluated the effects of bilateral erector spinae plane block (ESPB) on postoperative systemic functions in adult patients undergoing elective open-heart surgery via median sternotomy. Sixty-six participants were randomized to receive either bilateral ultrasound-guided ESPB before anesthesia induction or standard intravenous opioid analgesia. Postoperative outcomes-including pain scores, rescue analgesic requirements, hemodynamic parameters, respiratory variables, and laboratory values-were monitored for forty-eight hours. The study was conducted to determine whether ESPB provides improved postoperative pain control and supports systemic recovery compared with intravenous opioid-based analgesia.

Open-heart surgery performed through median sternotomy is associated with significant postoperative pain, sympathetic activation, respiratory impairment, and delayed recovery. Conventional postoperative analgesia, primarily based on intravenous opioids, may provide adequate pain relief but is frequently limited by adverse effects such as sedation, nausea, respiratory depression, and hemodynamic fluctuations. Therefore, safer and more effective multimodal analgesia strategies are required for cardiac surgical patients.

The erector spinae plane block (ESPB) is a paraspinal interfascial block that allows the spread of local anesthetic to the dorsal and ventral rami, intercostal nerves, and paravertebral region, providing both somatic and visceral analgesia. ESPB has been increasingly used as an alternative to thoracic epidural analgesia, especially in patients undergoing cardiac surgery where neuraxial techniques may pose risks related to anticoagulation and sympathetic blockade.

This prospective randomized controlled clinical trial was designed to evaluate whether bilateral ultrasound-guided ESPB can improve postoperative systemic functions in patients undergoing elective open-heart surgery via sternotomy. A total of sixty-six adults classified as ASA II-III were randomized into two groups. The intervention group received bilateral ESPB at the T5 level using twenty milliliters of 0.25% bupivacaine per side prior to induction of general anesthesia, whereas the control group received standard intravenous opioid-based analgesia.

Postoperative outcomes were monitored for forty-eight hours and included pain scores measured by the Numeric Rating Scale (NRS), time to rescue analgesia, total analgesic consumption, hemodynamic parameters, respiratory measurements, and laboratory markers such as hemoglobin, creatinine, AST, and ALT. The primary objective was to determine whether ESPB provides superior postoperative pain control compared with intravenous opioid analgesia. Secondary objectives included assessing the effects of ESPB on hemodynamic stability, respiratory recovery, and systemic laboratory parameters.

The study was conducted after ethics committee approval, and written informed consent was obtained from all participants prior to enrollment.

Inclusion Criteria:

• Adults aged 18 to 75 years
• Scheduled for elective open-heart surgery via median sternotomy (CABG or valve surgery)
• ASA physical status II-III
• Provided written informed consent
• BMI < 35 kg/m²

Exclusion Criteria:

• Age <18 or >75 years
• Known coagulopathy or anticoagulation contraindicating regional block
• Infection or dermatological lesion at the injection site
• Allergy to local anesthetics
• Chronic use of opioids, anticonvulsants, antidepressants, or corticosteroids
• Significant psychiatric or cognitive disorder preventing cooperation
• Severe arrhythmia or hemodynamic instability prior to surgery
• Local anesthetic toxicity risk factors or anatomic deformity preventing block placement
• Non-elective or emergency cardiac surgery

This study was conducted as an open-label randomized controlled trial. Neither participants nor care providers nor investigators were blinded to group allocation because the erector spinae plane block procedure is a hands-on regional anesthesia technique that cannot be feasibly masked. Outcome assessors were also not blinded due to the nature of the intervention and perioperative workflow.