Predictive equations for respiratory muscle strength in children and adolescents: an integrative review

Background: Several childhood illnesses are at risk of developing significant respiratory problems associated with insufficient respiratory muscle strength. Predictive equations for respiratory muscle strength have been proposed in healthy children and adolescents. There are no studies summarizing prediction equations for respiratory muscle strength (RMS) in pediatric population. Objectice: To provide and discuss the contemporary literature regarding predictive equations for respiratory maximal mouth presssures in children and adolescents. Methods: Online databases were used in this integrative review to identify papers published up to 2023, from which we selected those used equations to predict RMS by maximum inspiratory and expiratory pressures in subjects under 18 years of age. Results: The publications reported nine studies from 2,534 healthy individuals ranging from 4 to 18 years old and 38 equations. The variables used for constructing the predictive model diverge, but the most used were lung function (spirometry) and independent variables (age, gender, weight, height and adequate geographic population). Conclusion: This review gathered different predictive equations that determine the normal value of maximum respiratory pressures in the pediatric population. Although most equations were generated from unstandardized procedure, it should compose the functional assessment of the respiratory muscles, as it is a quick, non-invasive and effective measure to detect respiratory muscle weakness. The proposed equations must be judiciously used by the health professional, taking into account demographic and individual characteristics.