New method for evaluating maximal respiratory pressures: Concurrent validity, test-retest, and inter-rater reliability.

Background: Maximal respiratory pressures (MRP) obtained at functional residual capacity (FRC) may reflect the real respiratory muscle pressure.

Objectives: To evaluate concurrent validity, test-retest, and inter-rater reliability of MRP performed with a new instrument in healthy individuals, and to compare values obtained at different volumes in healthy individuals and individuals with COPD.

Methods: MRP of 100 healthy individuals were obtained using the TrueForce and the MicroRPM® at residual volume (RV) and total lung capacity (TLC) to evaluate concurrent validity.