Nonlinear model for offline correction of pulmonary waveform generators

Pulmonary waveform generators consisting of motor-driven piston pumps are frequently used to test respiratory-function equipment such as spirometers and peak expiratory flow (PEF) meters. Gas compression within these generators can produce significant distortion of the output flow-time profile. A nonlinear model of the generator was developed along with a method to compensate for gas compression when testing pulmonary function equipment. The model and correction procedure were tested on an Assess Full Range PEF meter and a Micro DiaryCard PEF meter. The tests were performed using the 26 American Thoracic Society standard flow-time waveforms as the target flow profiles. Without correction, the pump loaded with the higher resistance Assess meter resulted in ten waveforms having a mean square error (MSE) higher than 0.001 L/sup 2//s/sup 2/. Correction of the pump for these ten waveforms resulted in a mean decrease in MSE of 87.0%. When loaded with the Micro DiaryCard meter, the uncorrected pump outputs included six waveforms with MSE higher than 0.001 L/sup 2//s/sup 2/. Pump corrections for these six waveforms resulted in a mean decrease in MSE of 58.4%.

[1]  A. Jackson.  Accuracy, reproducibility, and variability of portable peak flowmeters. , 1995, Chest.

[2]  M. Miller,et al.  Peak expiratory flow profiles delivered by pump systems. Limitations due to wave action. , 2000, American journal of respiratory and critical care medicine.

[3]  J. Hankinson,et al.  Method to produce American Thoracic Society flow-time waveforms using a mechanical pump. , 1997, The European respiratory journal.

[4]  R M Gardner,et al.  Performance evaluation of contemporary spirometers. , 1990, Chest.

[5]  J. Hankinson,et al.  Standard flow-time waveforms for testing of PEF meters. , 1995, American journal of respiratory and critical care medicine.

[6]  John King Vennard,et al.  Elementary Fluid Mechanics , 1940 .

[7]  John L. Hankinson,et al.  Standardization of Spirometry, 1994 Update. American Thoracic Society. , 1995, American journal of respiratory and critical care medicine.

[8]  R M Gardner,et al.  Standard waveforms for spirometer testing. , 2015, The American review of respiratory disease.

[9]  D. Navajas,et al.  Gas compression artefacts when testing peak expiratory flow meters with mechanically-driven syringes. , 1997, The European respiratory journal.

[10]  Thomas F. Coleman,et al.  Optimization Toolbox User's Guide , 1998 .

[11]  D J Hitchings,et al.  The accuracy of portable peak flow meters. , 1992, Thorax.

[12]  R M Gardner,et al.  Evaluation of accuracy and reproducibility of peak flowmeters at 1,400 m. , 1992, Chest.