Patients undergoing coronary artery bypass grafting are at risk for perioperative myocardial ischemia. Episodes of tachycardia and hypertension, which are associated with an increase in myocardial oxygen consumption, are predictive events of these ischemia.

During cardiac surgery by sternotomy, some maneuvers, e.g. intubation, skin incision, sternotomy and cannulation, may be associated with tachycardia and/or increases in blood pressure despite an adequate level of anesthesia. Usually these episodes are controlled by the administration of a high-dose of anesthetic agents.

The parasternal block, by bolus or continuous infusion through a single catheter, showed its effectiveness on postoperative pain after sternotomy. It allows a blocking of anterior branches of intercostal nerves at the lateral edge of the sternum; branches in charge of innervation of the sternum and the overlying skin surface.

The preoperative parasternal block, once general anesthesia performed, could provide an effective level of locoregional anesthesia of the chest wall, thus limiting the occurrence of episodes of tachycardia and / or hypertension without having to resort to massive doses of anesthetic agents during sternotomy in patients undergoing coronary bypass surgery.

This randomized double blinded placebo-controlled clinical trial will include patients undergoing coronary artery bypass grafting.

Locoregional anesthesia of the chest wall will be performed under ultrasound, once general anesthesia performed. A total volume of 60 ml of sodium chloride 0.9% (placebo group) or ropivacaine 0.25% (experimental group) divided into 4 injections of 15 ml (2 per side, between ribs 2 and 3 and between ribs 4 and 5) will be injected.

Inclusion Criteria:

• Patients undergoing coronary artery bypass graft requiring sternotomy other than re-interventions and combined surgeries
• Consent for participation
• Affiliation to the french social security system

Exclusion Criteria:

• Pregnant or breastfeeding women
• Patients under protection of the adults (guardianship, curator or safeguard of justice)
• Communication difficulties or neuropsychiatric disorder
• Neuropathic disease
• Constitutional coagulation disorders
• Kidney insufficiency
• Sensitivity to nonsteroidal anti-inflammatory drugs
• Hypersensitivity to local anaesthetics
• Chronic use of opioid analgesics
• Corticosteroid treatment or immunosuppressive therapy
• Autoimmune disease
• Chronic pain syndrome or fibromyalgia
• Emergency cardiac surgery
• Hypovolemia