EFFECTS OF FLOW RESPIRATORY ENCOURAGEMENT ON LUNG FUNCTION OF HOSPITALIZED PATIENTS WITH RESTRICTIVE RESPIRATORY DYSFUNCTION

Abstract

Introduction: Restrictive respiratory disorders are characterized by reduced lung volumes and can compromise the respiratory function of hospitalized patients. Flow-based incentive spirometers are used in respiratory physical therapy; however, their effects on lung function in this population have not yet been clearly established. Therefore, investigating their application with and without resistance could contribute to a better understanding of their effects on lung function. Objective: To evaluate the effects of flow-oriented incentive spirometry, with and without inspiratory loading, on pulmonary function in hospitalized patients presenting a restrictive ventilatory pattern. Methods: This prospective, randomized, analytical clinical trial included 41 hospitalized patients allocated into two intervention groups. Group A performed training using the Respiron® flow-oriented incentive spirometer with an inspiratory load adjusted to 50% of maximal inspiratory pressure (MIP), whereas Group B followed an adapted protocol using the same device without additional loading. Physiological and functional variables were assessed, including heart rate, respiratory rate, peripheral oxygen saturation (SpO₂), pulmonary function parameters (FVC and FEV₁), peak expiratory flow (PEF), and respiratory muscle strength (MIP and MEP). Categorical variables were analyzed using Pearson’s chi-square test. Physiological and functional variables were compared both within and between groups. Paired Student’s t-test was used for intragroup analyses, while the Mann–Whitney U test was applied for between-group comparisons based on the variation (delta) of the evaluated parameters. Statistical significance was set at p < 0.05. Results: Both groups demonstrated statistically significant improvements in most of the respiratory parameters assessed. However, only Group A achieved significant gains in inspiratory muscle strength (p < 0.001) and expiratory muscle strength (p = 0.030), indicating greater effectiveness of the protocol incorporating inspiratory loading. Conclusion: Flow-oriented incentive spirometry proved to be an effective strategy for the rehabilitation of hospitalized patients with restrictive ventilatory disorders. These findings support a paradigm shift in its clinical prescription, advocating its use primarily as a respiratory muscle training device, while improvements in pulmonary volumes and ventilatory parameters should be considered secondary outcomes of this active therapeutic intervention.