Effects and relationships of early physiotherapy on respiratory functions and functional capacity at discharge in patients undergoing open heart surgery

Open heart surgery (OHS) often leads to declines in respiratory functions and functional capacity. Postoperative challenges, including changes in pulmonary function and respiratory muscle strength, can negatively impact patients’ recovery and quality of life. Early physiotherapy interventions aim to support the restoration of respiratory and physical functions during the critical discharge phase. The aim of this study was to investigate the changes in pulmonary function, respiratory muscle strength, and functional capacity, as well as the relationships among these markers, in patients discharged after undergoing open heart surgery. The pre-operative and post-operative discharge stage assessment results of 34 patients were examined. The evaluations included in the medical records consisted of demographic data, respiratory functions (spirometric measurements reported as % predicted and intraoral pressure measurements), and functional capacity measurement results. It was found that patients’ Forced Vital Capacity (FVC) (% predicted) and 6-Minute Walk Test (6MWT) distance at discharge were significantly reduced compared to pre-operative values. Forced Expiratory Volume in One Second (FEV1) (% predicted), however, showed no statistically significant change. After applying Benjamini-Hochberg False Discovery Rate (FDR) correction, significant positive correlations were observed between FVC (% predicted) and Forced Expiratory Flow at 25–75% of Vital Capacity (FEF25-75) (% predicted); FVC (% predicted) and Peak Expiratory Flow (PEF) (% predicted); PEF (% predicted) and FEF25-75 (% predicted); PEF (% predicted) and Maximal Expiratory Pressure (MEP); FEV1 (% predicted) and 6MWT; Maximal Inspiratory Pressure (MIP) and MEP; and MIP and 6MWT. In patients undergoing OHS who received early physiotherapy, FVC and 6MWT distance significantly declined at discharge compared to preoperative levels, while PEF, FEV1, FEF25-75, MIP, and MEP did not show significant changes. The decreased FVC and FEV1 at discharge were specifically related to functional capacity. Therefore, routine assessment of respiratory muscle strength is essential in OHS patients, with results needing evaluation within homogeneous surgical groups to guide effective rehabilitation. This study was registered at ClinicalTrials.gov (Identifier NCT05932368) on June 20, 2023.