Pulmonary Function, Muscle Strength, and Functional Capacity in Minimally Invasive Cardiac Surgery

Coronary artery bypass grafting (CABG) is one of the most commonly performed surgical procedures for patients with complex coronary artery disease. While the standard approach is through median sternotomy, minimally invasive cardiac surgery performed via mini-thoracotomy has gained popularity due to potential benefits such as smaller incisions, reduced surgical trauma, lower risk of sternal complications, shorter hospital stays, and faster mobilization. However, its effects on pulmonary function, respiratory muscle strength, peripheral muscle strength, and functional capacity have not been sufficiently clarified.

Postoperative pulmonary complications are a significant concern in cardiac surgery. Procedures involving cardiopulmonary bypass may result in atelectasis, pneumonia, pleural effusion, phrenic nerve injury, and diaphragm dysfunction. These complications can impair respiratory mechanics, delay rehabilitation, and increase morbidity and mortality. Therefore, identifying surgical approaches that better preserve pulmonary and muscular function is of great clinical importance.

This observational study will prospectively evaluate adult patients undergoing CABG at Gülhane Training and Research Hospital, comparing two groups: those receiving minimally invasive cardiac surgery via mini-thoracotomy and those undergoing conventional sternotomy. The primary outcomes are changes in pulmonary function parameters measured by spirometry (FVC, FEV1, PEF) from baseline to postoperative day 4. Secondary outcomes include respiratory muscle strength (MIP, MEP), peripheral muscle strength (handgrip, shoulder flexion/abduction, hip flexion, knee extension), functional capacity (30-second sit-to-stand test, 6-minute walk test), pain intensity (McGill Pain Questionnaire), and fear of movement (Tampa Scale of Kinesiophobia).

All assessments will be performed twice: before surgery (preoperative baseline) and on postoperative day 4. This time frame was chosen to capture early postoperative functional changes, which may influence short-term recovery and rehabilitation strategies. By comparing the two surgical techniques, this study aims to determine whether minimally invasive cardiac surgery provides better preservation of pulmonary and muscular function, ultimately supporting improved patient-centered outcomes and guiding clinical decision-making in surgical practice.

Inclusion criteria

• Adults aged 18-80 years
• Scheduled for elective cardiac surgery via either minimally invasive approach (mini-thoracotomy) or conventional sternotomy at Gülhane Training and Research Hospital
• Able to provide written informed consent

Exclusion criteria

• Previous history of cardiac surgery
• Presence of orthopedic or neurological disorders affecting mobility or muscle strength
• Postoperative cerebrovascular event
• Requirement for mechanical ventilation > 24 hours postoperatively
• Intensive care unit stay > 48 hours