This prospective observational study aims to compare three routinely used postoperative analgesia techniques in patients undergoing open heart surgery: intravenous analgesia, thoracic epidural analgesia (TEA), and bilateral erector spinae plane block (ESPB). The primary objective is to evaluate the impact of these analgesia modalities on the development of chronic postoperative pain at 3 months. Secondary objectives include assessing postoperative acute pain scores, additional analgesic requirements, extubation time, mobilization time, intensive care unit stay, hospital stay, respiratory complications, and the relationship between acute and chronic pain. No intervention is assigned by protocol, and all analgesia methods are applied as part of routine clinical practice.

This prospective observational study is designed to evaluate and compare three commonly used postoperative analgesia modalities in adult patients undergoing open heart surgery through median sternotomy: intravenous analgesia, thoracic epidural analgesia (TEA), and bilateral erector spinae plane block (ESPB). All analgesia techniques included in this study represent routine clinical practices performed by the anesthesia team, and no intervention is assigned according to a research protocol. Patients receive whichever analgesia method is chosen by the clinical anesthesia team based on individual clinical conditions. Thus, the study reflects real-world practice in a single tertiary cardiac surgery center.

The primary objective is to determine the effect of these analgesia methods on the development of chronic postoperative pain at 3 months following surgery. Chronic pain will be assessed using the Numeric Rating Scale (NRS) and the S-LANSS questionnaire, administered either via telephone or in-person follow-up. Secondary objectives include the evaluation of postoperative acute pain scores, additional analgesic consumption, extubation time, mobilization time, intensive care unit (ICU) length of stay, hospital length of stay, respiratory parameters, complications such as reintubation or need for non-invasive mechanical ventilation, bronchodilator use, sedation requirements, urine output, and perioperative hemodynamic stability. The study also aims to analyze the correlation between acute postoperative pain and subsequent chronic pain development.

Eligible patients are those aged 18-85 years, classified as ASA I-III, with a body mass index (BMI) below 35 kg/m², and scheduled for open heart surgery at Karadeniz Technical University Farabi Hospital. Exclusion criteria include coagulation disorders, infection at the intervention site, psychiatric disorders, chronic pain treatment, allergy to anesthetic agents, inability to cooperate or communicate, prior open heart surgery, chronic analgesic or antidepressant use, and significant comorbid conditions affecting participation.

Patients included in the study will have their perioperative data extracted from anesthesia records, ICU follow-up forms, and hospital medical charts. Routine postoperative pain measurements will be performed using the NRS. No additional procedures, medications, or interventions beyond routine care will be conducted.

The study aims to enroll 90 patients (30 per group). Data will be analyzed using Statistical Package for the Social Sciences (SPSS). Normality will be assessed using the Kolmogorov-Smirnov test. Parametric and nonparametric tests, including Student's t-test, Mann-Whitney U, chi-square test, repeated-measures ANOVA, and Friedman test, will be used as appropriate. A significance level of p < 0.05 will be accepted.

This study is expected to contribute to the understanding of analgesic strategies in cardiac surgery and their role in preventing chronic postoperative pain, improving recovery, and reducing complications.

Inclusion Criteria:

• Adults aged 18 to 85 years
• Classified as ASA physical status I-III
• Scheduled to undergo open heart surgery with median sternotomy
• BMI < 35 kg/m²
• Able to understand and provide written informed consent
• Eligible to receive any of the routine analgesia methods (intravenous analgesia, thoracic epidural analgesia, or erector spinae plane block)

Exclusion Criteria:

• Age < 18 or > 85 years
• BMI ≥ 35 kg/m²
• Coagulation disorders
• Infection at the intervention site
• Known allergy to local anesthetics or induction agents
• Psychiatric disorders limiting cooperation
• Use of chronic pain medications, antidepressants, corticosteroids, antiepileptics, or routine analgesics
• Inability to cooperate, communicate, or follow commands
• Physical or verbal performance impairment
• Previous open heart surgery

Adult patients aged 18 to 85 years who are scheduled to undergo open heart surgery with median sternotomy at Karadeniz Technical University Farabi Hospital. All participants will receive one of the routinely used postoperative analgesia methods (intravenous analgesia, thoracic epidural analgesia, or erector spinae plane block) as determined by the clinical anesthesia team. Only patients classified as ASA physical status I-III and able to provide informed consent are included. Individuals with major comorbidities that interfere with participation, prior cardiac surgery, chronic pain treatment, or contraindications to routine analgesia methods are excluded.

Individual participant data (IPD) will not be shared. The study is based on clinical follow-up data collected for a single-center observational thesis project, and no data sharing plan has been established.