The Effect of Superficial Parasternal Intercostal Plane Block on Pulmonary Function Tests After Cardiac Surgery

Inclusion criteria: * Patients who are scheduled to undergo elective cardiac surgery via sternotomy (i.e., coronary artery bypass graft, valvular surgery, and combined surgery). * Body Mass Index (BMI) above 20 and below 40 kg m-2 * Age above 18 years. * Eligible to sign informed consent. Exclusion criteria: * Emergency surgery. * Redo surgery. * Off-pump surgeries. * Pregnancy. * Preoperative mechanical circulatory support (i.e., intra-aortic balloon pump, extracorporeal membrane oxygenation, ventricular assist devices). * Preoperative chronic pain (i.e., fibromyalgia, chronic neuropathic pain). * Contraindication for regional analgesia (i.e., known allergy to LA, skin lesions in the injection site). * Known allergy to one or more of the components of multimodal analgesia (i.e., opioids, paracetamol, tramadol, dipyrone). * Preexisting severe pulmonary disease (i.e., an obstructive lung disease with FEV1 below 49%, restrictive lung disease with FVC below 49%, pulmonary hypertension). Criteria For Discontinuing (Postoperative Exclusion Criteria): * Prolonged cardiopulmonary bypass (CPB) of more than three hours. * Transfusion of more than three units of blood products. * Severe coagulation disturbance requiring prothrombin complex concentrate or recombinant factor VII. * Left ventricular failure with vasoactive-inotropic score (VIS) at the end of the surgery of ≥ 20. * Right ventricular failure requires inhaled nitric oxide. * Need for mechanical circulatory support (i.e.…