Introduction

Cardiac surgery improves survival, enhances physical exercise capacity, and increases overall quality of life (Borges et al. 2022; Windecker et al. 2014). Advances in surgical techniques and perioperative care have contributed to reduced mortality rates in recent decades (Vervoort 2019). However, the COVID‐19 pandemic significantly reduced the number of elective cardiac surgeries, resulting in longer waiting lists and clinical deterioration among patients. Studies have reported increased postoperative complications and mortality rates of up to 46.7% in unvaccinated individuals undergoing surgery who tested positive for COVID‐19 (Pau et al. 2022; Salenger et al. 2020; Wang et al. 2021).

Postoperative pulmonary complications (PPCs) remain a major cause of morbidity and mortality following cardiac surgery and are associated with prolonged hospital stays and reduced quality of life (Chang et al. 2023; de Moura et al. 2024; Katsura et al. 2015; Kendall et al. 2018). The incidence of PPCs in cardiac surgery ranges from 10% to 25%, with common conditions including atelectasis, pneumonia, pleural effusion, pulmonary edema, respiratory failure, and acute respiratory distress syndrome (de Moura et al. 2024; Katsura et al. 2015; Kendall et al. 2018). These complications contribute substantially to increased healthcare costs and adverse clinical outcomes (Chang et al. 2023; de Moura et al. 2024; Katsura et al. 2015).

Cardiac rehabilitation (CR), which includes respiratory exercises, functional training, and patient education, is an essential component of postoperative management aimed at reducing complications and promoting recovery (Gremeaux and Casillas 2017). Incentive spirometry (IS) is a low‐cost and widely used intervention to prevent PPCs, particularly atelectasis, after major surgery (Chang et al. 2023; Freitas et al. 2012). Although some studies have reported reductions in atelectasis (Sweity et al. 2021), hospital length of stay (Sweity et al. 2021; Eltorai et al. 2019), and duration of mechanical ventilation with IS use (Sweity et al. 2021), other investigations and meta‐analyses have found limited or no additional benefit compared with standard respiratory care (Alaparthi et al. 2021; Manapunsopee et al. 2020; Silva et al. 2024; Sullivan et al. 2021). The overall quality of evidence remains low, highlighting the need for well‐designed clinical studies to clarify the role of IS in perioperative rehabilitation (Sullivan et al. 2021).

Despite the widespread use of IS in clinical practice, evidence regarding its effectiveness when combined with postoperative CR in patients undergoing cardiac surgery remains limited. Therefore, this study aimed to evaluate the effects of IS combined with CR (IS + CR) compared with CR alone on PPCs, hospital length of stay, and clinical‐functional recovery in individuals undergoing cardiac surgery.