The goal of this clinical trial is to compare the efficacy of Transversus Thoracic Muscle Plane Block (TTMPB) integrated in a modern multimodal analgesia protocol, following the ERAS® recommendations, in adult patients undergoing planned open heart surgery.

The main study question is:

Does the addition of TTMPB to a standard analgesic protocol significantly improve analgesia following elective open heart surgery?

The investigators will primarily compare postoperative opioid consumption and pain scores in patients who will be randomly allocated to one of two groups:

The control group will receive standard analgesia per institutional Intensive Care Unit protocol.

The intervention group will receive the same standard of care plus a TTMP block (40ml of bupivacaine 0.375%, total dose of 150 mg).

The investigators will also study the impact of group allocation on secondary outcomes, such as the rate of early mobilization.

Inclusion Criteria:

• Direct informed consent as documented by signature
• Major adult (≥ 18 years old) with body weight ≥ 50 kg. For the record, fifty kilograms is the minimal weight to ensure that participants remain safely away from maximal doses of LA (3 mg/kg)
• Planned and primary cardiac surgery via a sternotomy approach
• Planned for ultra-fast-track procedure (i.e. postoperative extubation time of maximum two hours)

Exclusion Criteria:

• Participation in another study with investigational drug within the 30 days preceding and during the present study
• Refusal and/or inability to understand or sign the informed consent
• Emergent cardiac surgery
• Previous cardiac surgery
• Known hypersensitivity or true allergy to bupivacaine and other amide-class LA
• Chronic pain history
• Substance abuse history
• Inability to follow the procedures of the study (e.g. due to language problems, psychological / psychiatric disorders, dementia)
• Clinically significant concomitant diseases: severe cardiac dysfunction (i.e. LVEF ≤ 35%); severe chronic obstructive pulmonary disease (i.e. FEV < 50%); severe hepatic disease.
• Severe obesity (BMI > 35kg/m2)