Agreement between clinical and non-clinical digital manometer for assessing maximal respiratory pressures in healthy subjects

Measurement of respiratory muscles strength such as maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) are used to detect, diagnose and treat respiratory weakness. However, devices used for these measurements are not widely available and are costly. Currently, the use of a digital manometer is recommended. In industry, several inexpensive devices are available, but these have not been validated for clinical use. Our objective was to determine the agreement between maximal respiratory pressures obtained with a clinical digital manometer and that with a non-clinical digital manometer in healthy volunteers. We assessed the height, weight, lung function, MIP, and MEP of healthy volunteers. To compare pressures obtained by each type of digital manometer, a parallel approach configuration was used. The agreement was measured with the Intraclass Coefficient Correlation (ICC) and the Bland-Altman plot. Twenty-seven participants (14 men) were recruited with a median age of 22 (range: 21-23) years. Each participant underwent three measurements to give a total of 81 measurements. The mean MIPs were 90.8 ± 26.4 (SEM 2.9) and 91.1 ± 26.4 (SEM 2.9) cmH2O for the clinical and non-clinical digital manometers, respectively. The mean MEPs were 113.8 ± 40.4 (SEM 4.5) and 114.5 ± 40.5 (SEM 4.5) cmH2O for the clinical and non-clinical digital manometers, respectively. We obtained an ICC of 0.998 (IC 0.997-0.999) for MIP and 0.999 (IC 0.998-0.999) for MEP. There is a high agreement in the values obtained for MIP and MEP between clinical and non-clinical digital manometers in healthy volunteers. Further validation at lower pressures and safety profiling among human subjects is needed.