Comparison of Respiratory Calibration Methods for the Estimation of Lung Volume in Children With and Without Neuromotor Disorders

Purpose: The primary purpose of this study was to validate common respiratory calibration methods for estimating lung volume in children. Method: Respiratory kinematic data were collected via inductive plethysmography from 81 typically developing children and nine children with neuromotor disorders. Correction factors for the rib cage and abdomen were calculated using three different methods: (a) least squares method with both rib cage and abdomen corrections (LsqRC/AB), (b) least squares method with rib cage correction only (LsqRC), and (c) a standard 2:1 rib-cage-to-abdomen ratio (Banzett). Correction factors for the LsqRC/AB and LsqRC methods were calculated with and without the use of the speech-like breathing calibration task. Lung volume estimation errors were calculated by comparing the estimated lung volumes based on the correction factors and the actual lung volumes acquired from a spirometer, normalized to each participant’s vital capacity. Results: For typically developing children, the LsqRC/AB method resulted in significantly smaller lung volume estimation errors compared with other methods. Lung volume estimation errors decreased as age increased for each method. For the children with neuromotor disorders, the LsqRC/AB and LsqRC methods resulted in significantly smaller lung volume estimation errors than the Banzett method but were not significantly different from one another. There were no significant differences in lung volume estimation errors for the LsqRC/AB and LsqRC methods when the correction factors were calculated with and without the speech-like breathing calibration task. Conclusion: The LsqRC/AB method exclusively utilizing the rest breathing calibration task is the most accurate and efficient respiratory calibration method for use with children with and without neuromotor disorders at this time.