Early Rehabilitation in Patients Following Major Cardiac Surgery: Changes in Functional Capacity and Energy Efficiency in Walking and ADLs.

Cardiac rehabilitation (CR) is an established component of the multidisciplinary management of patients following major cardiac surgery. In Italy, patients undergoing coronary artery bypass grafting, valve surgery, or combined cardiac procedures are frequently referred to inpatient or outpatient CR programs shortly after surgery. Although CR is routinely provided in this setting, detailed data describing functional recovery, energy efficiency, and changes in physical performance during the early post-operative rehabilitation period remain limited.

The present study aims to characterize changes in functional capacity and physiological responses to exercise and activities of daily living following a structured CR program in patients who have recently undergone major cardiac surgery. Patients will undergo a standardized assessment at the beginning and at the completion of their rehabilitation program, while the rehabilitation intervention itself will remain unchanged and will follow the routine clinical pathway used at the participating ICS Maugeri centres.

The assessment battery includes the Six-Minute Walk Test (6MWT), a constant-load treadmill test, an oxygen kinetics test performed on a cycle ergometer, the Glittre ADL-Test, the Short Physical Performance Battery (SPPB), the Five-Times Sit-to-Stand Test (5STS), and the EuroQol questionnaire. The 6MWT is performed first and is also used to guide the subsequent exercise testing procedures according to the patient's functional capacity. The remaining tests are administered according to a predefined randomized sequence to reduce potential effects related to test order and cumulative fatigue.

Selected functional and exercise assessments are performed using the COSMED K5 portable metabolic analyzer. The device is a CE-marked portable system consisting of a face mask and a lightweight unit containing the metabolic analyzer. It enables breath-by-breath measurement of oxygen consumption (VO2), carbon dioxide production (VCO2), ventilation, and related physiological variables during walking, exercise, and activities of daily living. In this study, the K5 is used during the constant-load treadmill test, the oxygen kinetics test, and the Glittre ADL-Test to quantify physiological responses and energy efficiency.

For patients undergoing inpatient rehabilitation, the first assessment is performed within the first 96 hours after admission and the second assessment no earlier than 96 hours before discharge. For patients undergoing outpatient rehabilitation, assessments are performed during the initial and final rehabilitation sessions. Between the two assessments, patients participate in the standard CR program prescribed according to the clinical pathway for patients following major cardiac surgery.

The study is designed as a low-intervention investigation. The additional assessments are performed within the clinical rehabilitation setting and do not modify the prescribed rehabilitation program. Clinical condition is monitored throughout the testing procedures, and testing is discontinued if clinically relevant symptoms or signs of instability occur.

The study will provide information on changes in functional capacity, physical performance, quality of life, and energy efficiency during rehabilitation following major cardiac surgery. These data may help to better characterize the early functional recovery of this population and provide a basis for future studies aimed at optimizing individualized rehabilitation strategies.