SPIP vs ESP Block in Cardiac Surgery

Comparative Analgesic Efficacy of Superficial Parasternal Intercostal Plane Block Versus Erector Spinae Plane Block After Cardiac Surgery: a Multicenter Randomized Non-inferiority Trial

This multicentre, randomized, assessor-blinded, non-inferiority trial will compare the analgesic efficacy of bilateral superficial parasternal intercostal plane (SPIP) block with bilateral erector spinae plane (ESP) block in adults undergoing first-time on-pump cardiac surgery through median sternotomy. Participants will be randomly assigned in a 1:1 ratio to receive either SPIP or ESP block before induction of general anesthesia, in addition to standardized perioperative multimodal analgesia. The primary outcome is cumulative intravenous morphine milligram equivalent (IV-MME) consumption from extubation to 24 hours after extubation. The study will evaluate whether SPIP block is non-inferior to ESP block using a prespecified non-inferiority margin of 3 mg IV-MME.

Inclusion Criteria:

• written informed consent
• age 18 to 80 years
• American Society of Anesthesiologists (ASA) physical status II-IV
• Scheduled for first-time on-pump cardiac surgery through a median sternotomy, including coronary artery bypass grafting, valve repair or replacement, or another open cardiac procedure requiring sternotomy
• Ability to understand postoperative pain and recovery assessments and to use an intravenous patient-controlled analgesia device.

Exclusion Criteria:

• Emergency surgery.
• Previous median sternotomy.
• Minimally invasive cardiac surgery without median sternotomy.
• Known allergy or hypersensitivity to bupivacaine, morphine, paracetamol, ondansetron or another protocol medication.
• Chronic opioid use, defined as continuous opioid treatment for at least 30 days at a daily oral morphine equivalent dose of 15 mg or more.
• Alcohol or substance use disorder that, in the investigator's judgment, may affect adherence or outcome assessment.
• Clinically significant hepatic dysfunction, defined as alanine aminotransferase or aspartate aminotransferase greater than twice the upper limit of normal.
• Clinically significant renal dysfunction, defined as serum creatinine greater than twice the upper limit of normal.
• Coagulation disorder or antithrombotic treatment that precludes safe block performance according to current institutional guidance.
• Infection at a planned needle insertion site.
• Severe psychiatric illness, cognitive impairment or communication difficulty preventing valid postoperative assessment.
• Pregnancy or breastfeeding.
• Body mass index greater than 40 kg/m².
• Prolonged postoperative mechanical ventilation, defined as failure to achieve extubation within 8 hours after surgery.
• Refusal to participate.