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 L2/s2. 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 L2/s2. Pump corrections for these six waveforms resulted in a mean decrease in MSE of 58.4%.
Reynolds
Jeffrey S
JS
Engineering and Controls Technology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA. JReynolds@cdc.gov
Stemple
Kimberly J
KJ
Petsko
Raymond A
RA
Ebeling
Thomas R
TR
Frazer
David G
DG
D002138:Calibration / Q000592:standards; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods* / Q000592:standards; D008954:Models, Biological; D017711:Nonlinear Dynamics; D010366:Peak Expiratory Flow Rate; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000295:instrumentation* / Q000379:methods / Q000592:standards*; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D013147:Spirometry / Q000295:instrumentation / Q000592:standards; D013594:Syringes / Q000592:standards; D014481:United States