Introduction: The thoracoabdominal rebalancing (TAR) method aims to promote diaphragmatic juxtaposition, in addition to seeking to increase respiratory muscle strength and adjust muscle tone. However, scientific publications on this method in heart patients undergoing coronary artery bypass grafting (CABG) are still scarce, justifying the need to carry out this study for information, evaluation, diagnosis and treatment purposes in the health area with an emphasis on cardiology.

Objective: To evaluate whether diaphragmatic ultrasound findings differ between the TAR method and conventional physiotherapy in post-CABG patients.

Methods: This is a randomized, single-blind clinical trial. Adults (>35 years), hemodynamically stable, who underwent CABG (<24 hours) and had a prescription for physiotherapy will be included. Patients will be randomized into two groups: 1) intervention group [IG] - TAR; 2) control group [CG] - standard physiotherapy approach. Interventions will be performed at a single time and the following variables will be collected pre- and post-intervention: heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2), mean arterial pressure (MAP), diaphragmatic ultrasound (US) to identify possible acute findings in both groups, respiratory distress scale and pulmonary complications scale will be applied at the end of the interventions.

Keywords: Physiotherapy; Cardiology; Ultrasonography

To compare the effect of conventional physiotherapy techniques with the management of thoracoabdominal rebalancing in postoperative patients after myocardial revascularization surgery, carefully evaluating these effects through diaphragm ultrasound and pulmonary spirometry, in addition to variables such as vital signs and respiratory distress scales and pulmonary complications after cardiac surgery. This is a randomized trial in which patients undergoing myocardial revascularization surgery at the Cardiology Institute of Rio Grande do Sul will participate.

Individuals over 35 years of age who underwent myocardial revascularization surgery with prescribed physiotherapy treatment will be included in the study. Patients who were intubated and/or remained on mechanical ventilation for more than twelve hours or who required non-invasive mechanical ventilation before or during the collection period will be excluded.

The study was submitted to the Research Ethics Committee of the Cardiology Institute of Porto Alegre (CEP-ICFUC). All study participants will receive clear explanations about the research, and those who voluntarily agree to participate in the study will sign the informed consent form in two copies, one of which will be made available to the participant and the other to the researchers. Participants will not be paid, nor will they receive any assistance during or after the end of the research (466/12).

The benefits of this research will be in improved conduct that prevents or reduces complications and/or respiratory discomfort, as well as speeding up the patient's recovery, aiming for faster hospital discharge. Patients selected for the control group (conventional physiotherapy) will be exposed to respiratory physiotherapy techniques such as vibrocompression, passive manual expiratory therapy, acceleration of expiratory flow, fractional inspiration in times, diaphragmatic breathing and aspiration when necessary, and patients selected for group intervention will undergo thoracoabdominal rebalancing management such as abdominal supports and/or in the ileocostal space, inspiratory assistance, release of the shoulder girdle, thoracic swing, release of the pectoralis major and deltoid muscles together with aspiration if necessary.

The research presents minimal risks for the participants, which are related to the measurement of hemodynamic variables through the monitor, in addition to the pulmonary spirometry test and diaphragmatic analysis through ultrasound, and/or application of conventional physiotherapy techniques such as vibrocompression, acceleration of expiratory flow, passive manual expiratory therapy that may suggest some discomfort or pain when touching the chest in a sensation of pressure and vibration. Patients undergoing thoracoabdominal rebalancing treatment are expected to have lower scores on the pulmonary complications scale, Downes and Raphaelly respiratory distress scale and, consequently, better diaphragmatic excursion, as well as improvements in other variables.

Inclusion Criteria:

• Individuals over 35 years of age who undergo coronary artery bypass graft surgery with prescribed physiotherapy treatment will be included in the study.

Exclusion Criteria:

• Patients who are intubated and/or have remained on mechanical ventilation for more than twelve hours, or who require non-invasive mechanical ventilation (NIV) before or during the collection period will be excluded.